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Table 10.6 Summary of the main emergy-based indexes for the conventional poultry production analysed Energetic resources, such as fuels, electricity and liquid petroleum gas, human labour and buildings materials make up the rest of the inputs since the other natural renewable inputs, such as sun, rain and wind, represent less than 1% of the total. Table 10.6 shows how the characteristics of renewability and the location of the inputs are reflected in the emergy indicators. The investment ratio is quite high, indicating that the emergy acquired from outside the system is 3.69 times higher than the local emergy. The environmental loading ratio (ELR) indicates that the non- renewable resources are more than four times higher than the renewable ones, demonstrating a high concentration of non-renewable inputs in the area, confirmed by the empower density (ED), that can highly impact the environmental character- istics of the area. The impact suggested by this ratio can be located anywhere, since the exploitation of non-renewable resources has an impact per se, while their use implies another impact, the empower density, which is around two orders of mag- nitude higher that in the case of agricultural or extensive breeding systems; it sug- gests that the main impact is local. This explains the need of further inputs for the cleaning up and the additional energy, material (and economic!) expenses for the environmental and health safety of the system.

Table 10 6 Summary of the main emergy-based indexes for the conventional poultry production analysed Energetic resources, such as fuels, electricity and liquid petroleum gas, human labour and buildings materials make up the rest of the inputs since the other natural renewable inputs, such as sun, rain and wind, represent less than 1% of the total. Table 10.6 shows how the characteristics of renewability and the location of the inputs are reflected in the emergy indicators. The investment ratio is quite high, indicating that the emergy acquired from outside the system is 3.69 times higher than the local emergy. The environmental loading ratio (ELR) indicates that the non- renewable resources are more than four times higher than the renewable ones, demonstrating a high concentration of non-renewable inputs in the area, confirmed by the empower density (ED), that can highly impact the environmental character- istics of the area. The impact suggested by this ratio can be located anywhere, since the exploitation of non-renewable resources has an impact per se, while their use implies another impact, the empower density, which is around two orders of mag- nitude higher that in the case of agricultural or extensive breeding systems; it sug- gests that the main impact is local. This explains the need of further inputs for the cleaning up and the additional energy, material (and economic!) expenses for the environmental and health safety of the system.

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PALL S© OL HIS@Cts UiddDIe 1.1). Due to their insecticidal properties, avidin, and the functionally related strepto- myces protein, streptavidin, have been expressed in a variety of agriculturally important plant species, for example, tobacco, apple, maize and rice. Table 1.1 summarises the insecticidal effects of exogenous and transgenically expressed avidin on various insect larvae. A single instance of an insect, which is not susceptible to the presence of avidin in its diet, is the larger grain borer (Kramer et al. 2000), which tolerates high quantities of dietary avidin. Kramer suggests that this might be due to unusually high proteinase activity in the insects’ gut digesting the avidin and precluding biotin sequestration. Alternatively, Kramer suggests that the larger grain borer may have a supply of biotin from gut symbionts. LC) Ee ee ee See) NE ie fae ee ee ae: ee a Se Cee hi io See mer eee ll
PALL S© OL HIS@Cts UiddDIe 1.1). Due to their insecticidal properties, avidin, and the functionally related strepto- myces protein, streptavidin, have been expressed in a variety of agriculturally important plant species, for example, tobacco, apple, maize and rice. Table 1.1 summarises the insecticidal effects of exogenous and transgenically expressed avidin on various insect larvae. A single instance of an insect, which is not susceptible to the presence of avidin in its diet, is the larger grain borer (Kramer et al. 2000), which tolerates high quantities of dietary avidin. Kramer suggests that this might be due to unusually high proteinase activity in the insects’ gut digesting the avidin and precluding biotin sequestration. Alternatively, Kramer suggests that the larger grain borer may have a supply of biotin from gut symbionts. LC) Ee ee ee See) NE ie fae ee ee ae: ee a Se Cee hi io See mer eee ll
Table 1.1 (continued) Unlike insecticidal chemical sprays, avidin has a minimal effect as an environmental pollutant. The inclusion of avidin in crops raises the possibility of the induction of an allergic response to the protein. However, avidin is known not to be highly allergenic and is absent from the World Health Organization’s official list of food allergens, whereas many highly allergenic proteins from common fruit, nuts, corn, and egg-white are present. The official website for the WHO/IUIS Sub-Committee on Allergen Nomenclature is www.allergen.org. This site lists all allergens and isoforms that are recognised by the committee and is updated on a regular basis.
Table 1.1 (continued) Unlike insecticidal chemical sprays, avidin has a minimal effect as an environmental pollutant. The inclusion of avidin in crops raises the possibility of the induction of an allergic response to the protein. However, avidin is known not to be highly allergenic and is absent from the World Health Organization’s official list of food allergens, whereas many highly allergenic proteins from common fruit, nuts, corn, and egg-white are present. The official website for the WHO/IUIS Sub-Committee on Allergen Nomenclature is www.allergen.org. This site lists all allergens and isoforms that are recognised by the committee and is updated on a regular basis.
Fig. 1.2. Methods for transformation and detection of the avidin gene. (a) Transforming the DNA sequence of chicken avidin into a sequence which will be efficiently expressed in the maize plant. (b) The avidin gene is inserted into plants so that the protein avidin is only expressed in plant vacuoles where it does not interfere with the plants’ own biotin resources
Fig. 1.2. Methods for transformation and detection of the avidin gene. (a) Transforming the DNA sequence of chicken avidin into a sequence which will be efficiently expressed in the maize plant. (b) The avidin gene is inserted into plants so that the protein avidin is only expressed in plant vacuoles where it does not interfere with the plants’ own biotin resources
Fig. 1.3 Insecticidal mechanism of avidin. Normal and transgenic-avidin plants develop nor- mally. Transgenic avidin is restricted to vacuoles within the leaf cells and, therefore, cannot interfere with normal leaf biotin function. Avidin is released from the vacuoles and binds the leaf avidin when the caterpillar chews the leaf tissue the functionally similar protein streptavidin have been transgenically expressed in tobacco and apple (Markwick et al. 2003; Murray et al. 2002). In these studies, the Cauliflower Mosaic Virus promoter was employed which lead to a non-tissue-specific expression of avidin. Male infertility did not occur. However, to prevent toxicity due to sequestration of essential plant biotin, the avidin was targeted to intracellular vacu- oles by the use of N-terminal vacuole targeting sequences from potato proteinase inhibitors (Fig. 1.2b). If targeting sequences were not used then avidin expression was lethal (Hood et al. 1997; Murray et al. 2002) since biotin is synthesised in the plant cytoplasm and used in the mitochondrial and chloroplastic compartments (Baldet et al. 1992, 1993). The leaf concentrations of avidin achieved by Murray and Marckwick were approximately 10 uM. This is approximately a 7.5-fold molar excess of avidin over the normal biotin levels in the plant leaf (Murray et al. 2002) and is sufficient to ensure that insect pests feeding on the leaves are killed or never reach reproductive maturity (Fig. 1.3). From a human toxicity aspect, the insecticidal level of avidin in transgenic apple and tobacco leaves is somewhat lower than that of chicken egg-white.
Fig. 1.3 Insecticidal mechanism of avidin. Normal and transgenic-avidin plants develop nor- mally. Transgenic avidin is restricted to vacuoles within the leaf cells and, therefore, cannot interfere with normal leaf biotin function. Avidin is released from the vacuoles and binds the leaf avidin when the caterpillar chews the leaf tissue the functionally similar protein streptavidin have been transgenically expressed in tobacco and apple (Markwick et al. 2003; Murray et al. 2002). In these studies, the Cauliflower Mosaic Virus promoter was employed which lead to a non-tissue-specific expression of avidin. Male infertility did not occur. However, to prevent toxicity due to sequestration of essential plant biotin, the avidin was targeted to intracellular vacu- oles by the use of N-terminal vacuole targeting sequences from potato proteinase inhibitors (Fig. 1.2b). If targeting sequences were not used then avidin expression was lethal (Hood et al. 1997; Murray et al. 2002) since biotin is synthesised in the plant cytoplasm and used in the mitochondrial and chloroplastic compartments (Baldet et al. 1992, 1993). The leaf concentrations of avidin achieved by Murray and Marckwick were approximately 10 uM. This is approximately a 7.5-fold molar excess of avidin over the normal biotin levels in the plant leaf (Murray et al. 2002) and is sufficient to ensure that insect pests feeding on the leaves are killed or never reach reproductive maturity (Fig. 1.3). From a human toxicity aspect, the insecticidal level of avidin in transgenic apple and tobacco leaves is somewhat lower than that of chicken egg-white.
Methods for detection of avidin protein
Methods for detection of avidin protein
Fig. 2.1 Schematic overview of cover crops and corresponding primary and secondary effects on different agroecological services. SOM: soil organic matter
Fig. 2.1 Schematic overview of cover crops and corresponding primary and secondary effects on different agroecological services. SOM: soil organic matter
for both beneficial insects and birds, and by reducing light levels and soil temperature fluctuations at the soil surface, they also reduce weed germination (Bottenberg et al. 1997; Bugg and Waddington 1994). Moreover, cover-crop residues conserve soil moisture and favor beneficial fungi producing glomalin that, in turn, enhances the formation of stable soil aggregates, water percolation, and retention (Sustainable Agricultural Network 2007; Altieri 2002).
for both beneficial insects and birds, and by reducing light levels and soil temperature fluctuations at the soil surface, they also reduce weed germination (Bottenberg et al. 1997; Bugg and Waddington 1994). Moreover, cover-crop residues conserve soil moisture and favor beneficial fungi producing glomalin that, in turn, enhances the formation of stable soil aggregates, water percolation, and retention (Sustainable Agricultural Network 2007; Altieri 2002).
Fig. 2.3 Prostrate growth and flat-leaf angle of crimson clover complements more erect growth characteristics of winter rye (eff) and black oats (right) while these cereal crops also have higher initial growth and are thus more effective in retaining residual soil nutrients on sandy soils in Florida
Fig. 2.3 Prostrate growth and flat-leaf angle of crimson clover complements more erect growth characteristics of winter rye (eff) and black oats (right) while these cereal crops also have higher initial growth and are thus more effective in retaining residual soil nutrients on sandy soils in Florida
Fig. 2.4 Use of mowed cowpea residue as a mulch in a subsequent no-tillage broccoli crop (left) and forage radish as a live mulch in an organic citrus orchard (right) in Florida
Fig. 2.4 Use of mowed cowpea residue as a mulch in a subsequent no-tillage broccoli crop (left) and forage radish as a live mulch in an organic citrus orchard (right) in Florida
Fig. 3.2 Key aspects (diagnosis vs. design), system development steps (observing, reflecting, planning, and acting), and system develop actions (measuring, analysis/discussion, and deciding/ selecting) during experiential learning cycle (Rossing et al. 2007) by farmers (e.g., participatory modeling). Examples of how models may be used in this fashion for the exploration, and design of more sustainable cover-crops-based vegetable production systems in Uruguay will be discussed in more detail later. The use of the NDICEA model for exploration of more sustainable production practices for vegetable cropping systems in southern Uruguay demonstrated that cover crops could be effective in maintaining and/or enhancing SOM content while reducing external N-fertilizer requirements. However, these benefits differed between soil types (Selaya Garvizu 2000). This work was extended and model- based explorative land use studies were implemented to evaluate a much larger number of potential production systems, thereby providing a strategic support base for re-orientation of local vegetable production systems (Dogliotti et al. 2004). First, the ROTAT system (Dogliotti et al. 2003), a tool that was previously devel- oped for generating crop rotation based on user-selected agronomic criteria, was used to assess all possible crop rotations. One proposed technical intervention was the introduction of cover crops and integrate pastures into vegetable cropping systems to reduce soil erosion and increase SOM. Key input and output parameters, including soil erosion, SOM and nutrient balances, environmental impacts, labor use, and economic performance were assessed by different quantitative standard methods using a target-oriented approach. This work generated a large number of
Fig. 3.2 Key aspects (diagnosis vs. design), system development steps (observing, reflecting, planning, and acting), and system develop actions (measuring, analysis/discussion, and deciding/ selecting) during experiential learning cycle (Rossing et al. 2007) by farmers (e.g., participatory modeling). Examples of how models may be used in this fashion for the exploration, and design of more sustainable cover-crops-based vegetable production systems in Uruguay will be discussed in more detail later. The use of the NDICEA model for exploration of more sustainable production practices for vegetable cropping systems in southern Uruguay demonstrated that cover crops could be effective in maintaining and/or enhancing SOM content while reducing external N-fertilizer requirements. However, these benefits differed between soil types (Selaya Garvizu 2000). This work was extended and model- based explorative land use studies were implemented to evaluate a much larger number of potential production systems, thereby providing a strategic support base for re-orientation of local vegetable production systems (Dogliotti et al. 2004). First, the ROTAT system (Dogliotti et al. 2003), a tool that was previously devel- oped for generating crop rotation based on user-selected agronomic criteria, was used to assess all possible crop rotations. One proposed technical intervention was the introduction of cover crops and integrate pastures into vegetable cropping systems to reduce soil erosion and increase SOM. Key input and output parameters, including soil erosion, SOM and nutrient balances, environmental impacts, labor use, and economic performance were assessed by different quantitative standard methods using a target-oriented approach. This work generated a large number of
Fig. 3.3, Example of use of simulation models to explore potential benefits of including cover crops during the fallow period on reducing annual soil erosion (a) and improving soil organic matter content (b) for 7447 different crop rotation schemes in southern Uruguay. Overall soil erosion values were 13.2 versus 6.9 Mg ha‘! year for conventional versus cover-crop-based systems, whereas corresponding values for soil organic matter (SOM) changes where —223 versus 100 kg SOM ha"! year"! (Modified from Dogliotti et al. 2006)
Fig. 3.3, Example of use of simulation models to explore potential benefits of including cover crops during the fallow period on reducing annual soil erosion (a) and improving soil organic matter content (b) for 7447 different crop rotation schemes in southern Uruguay. Overall soil erosion values were 13.2 versus 6.9 Mg ha‘! year for conventional versus cover-crop-based systems, whereas corresponding values for soil organic matter (SOM) changes where —223 versus 100 kg SOM ha"! year"! (Modified from Dogliotti et al. 2006)
Fig. 3.4 Problem tree, which serves as an initial system diagnosis tool, as identified by a com- mercial vegetable producer in Uruguay. This diagram exemplifies potential benefits of cover crops to enhance crop diversity, suppress weeds, improve soil cover, and inherent soil fertility of ero- sion-prone intensive vegetable production systems
Fig. 3.4 Problem tree, which serves as an initial system diagnosis tool, as identified by a com- mercial vegetable producer in Uruguay. This diagram exemplifies potential benefits of cover crops to enhance crop diversity, suppress weeds, improve soil cover, and inherent soil fertility of ero- sion-prone intensive vegetable production systems
BA = barley; CA = canola; LU = lupin; M = mucuna; MA = maize; OA=oats; PM = pearl millet; SO = soybean; VE= vetch; WH = wheat Table 3.1 Examples of crop rotation systems recommended to Parana (Embrapa 2006)
BA = barley; CA = canola; LU = lupin; M = mucuna; MA = maize; OA=oats; PM = pearl millet; SO = soybean; VE= vetch; WH = wheat Table 3.1 Examples of crop rotation systems recommended to Parana (Embrapa 2006)
Table 4.1 A comparison of the total phosphorus (percent P) contents of various phosphate roc] sources (source of data include Schnug et al. 2006 and FAO 2004). The proportion (%) of total | that is citric acid soluble is also shown
Table 4.1 A comparison of the total phosphorus (percent P) contents of various phosphate roc] sources (source of data include Schnug et al. 2006 and FAO 2004). The proportion (%) of total | that is citric acid soluble is also shown
Fig. 4.1 Schematic plan of the factors significantly influencing the dissolution, reactivity, and uptake of P derived from phosphate rock (PR). A major distinction is made between those factors which are likely to apply to either pre- or post-application situations
Fig. 4.1 Schematic plan of the factors significantly influencing the dissolution, reactivity, and uptake of P derived from phosphate rock (PR). A major distinction is made between those factors which are likely to apply to either pre- or post-application situations
Fig. 4.2 Phosphorus (water extractable) released from sugarcane residue (bagasse) mixed with and without farmyard manure (FYM) that had been enriched with phosphate rock and composted for 105 days (data from Zayed and Abdel-Motaal 2005). After 30 days samples were collected and analyzed after 15-day intervals. Standard deviations are shown and the treatments are: Without any treatment (black filling), Treated with FYM (light gray), Treated with A. niger and T: viride (open), Treated with A. niger, T: viride, and FYM (dark gray)
Fig. 4.2 Phosphorus (water extractable) released from sugarcane residue (bagasse) mixed with and without farmyard manure (FYM) that had been enriched with phosphate rock and composted for 105 days (data from Zayed and Abdel-Motaal 2005). After 30 days samples were collected and analyzed after 15-day intervals. Standard deviations are shown and the treatments are: Without any treatment (black filling), Treated with FYM (light gray), Treated with A. niger and T: viride (open), Treated with A. niger, T: viride, and FYM (dark gray)
Fig. 5.1 Mixed-cropping systems
Fig. 5.1 Mixed-cropping systems
Fig. 5.2. Strip mix crop (Photo courtesy of Tim McCabe 1999, USDA-NRCS)
Fig. 5.2. Strip mix crop (Photo courtesy of Tim McCabe 1999, USDA-NRCS)
“Both physical barrier and unfavorable microclimate are mentioned for disease suppression, in totals therefore only taken up once (as physical barrier) Table 5.3. Disease-reducing mechanisms in mixed-cropping systems for soilborne and splash- dispersed pathogens described in the literature
“Both physical barrier and unfavorable microclimate are mentioned for disease suppression, in totals therefore only taken up once (as physical barrier) Table 5.3. Disease-reducing mechanisms in mixed-cropping systems for soilborne and splash- dispersed pathogens described in the literature
Fig. 6.1 Example of N losses by leaching and yield as dry matter versus amount of applied N fertilised to grass (Modified from Lord et al. 1999) linked to climate change and acidification (Neeteson and Carton 2001). Therefore, a holistic approach that broadens concerns over nitrate leaching to include the man- agement of nitrogen in the soil—plant system (accounting for N in crop residues and biomass) must also take into consideration the extent of the impact of gaseous losses related to agricultural practices. If practices lead to increased gaseous N emis- sions by buffering against nitrate losses from fields to water bodies, the environ- mental pollution risk has only been shifted from one point of impact or ‘receptor’ (water) to another (air). Recent studies on fertiliser management have highlighted the danger of this so-called pollution-swapping between nitrate leaching and ammonia loss in fruit production as a function of the type of nitrogen fertilisers and the application schedule (Cantarella et al. 2003, Stevens and Quinton 2009). So in order to achieve more sustainable nitrogen management, the research
Fig. 6.1 Example of N losses by leaching and yield as dry matter versus amount of applied N fertilised to grass (Modified from Lord et al. 1999) linked to climate change and acidification (Neeteson and Carton 2001). Therefore, a holistic approach that broadens concerns over nitrate leaching to include the man- agement of nitrogen in the soil—plant system (accounting for N in crop residues and biomass) must also take into consideration the extent of the impact of gaseous losses related to agricultural practices. If practices lead to increased gaseous N emis- sions by buffering against nitrate losses from fields to water bodies, the environ- mental pollution risk has only been shifted from one point of impact or ‘receptor’ (water) to another (air). Recent studies on fertiliser management have highlighted the danger of this so-called pollution-swapping between nitrate leaching and ammonia loss in fruit production as a function of the type of nitrogen fertilisers and the application schedule (Cantarella et al. 2003, Stevens and Quinton 2009). So in order to achieve more sustainable nitrogen management, the research
Table 6.1 Typical apparent recoveries from yield expressed as Dry Matter (DM) at optimum N-fertiliser rates for a range of field vegetable crops (D.J. Greenwood, personal communication in Burns 2006) The relationship (6.4) is species-specific (Greenwood et al. 1989; Jones and Schwab 1993; Karitonas 2003; Tei et al. 1999, 2000, 2002, Burns 2006) because it depends on the efficiency with which plants extract N from the soil due to differ- ences in root functioning and architecture (Thorup-Kristensen and S¢rensen 1999; Thorup-Kristensen and Van der Boogard 1999), but it is also affected by soil condi- tions, weather conditions, agronomic practices and fertiliser application methods. Although it was a rough estimation of the N-recovery efficiency of a crop, the knowledge of REC value for a species (Table 6.1) is useful for the determination of the optimum N-fertiliser requirements and gives clear information on the proportion of N fertiliser not taken up by the crop and so at risk of leaching (Burns 2006). The recovery factor for soil N (fj in equations 6.1 and 6.2) is usually estimated from the uptake of N when no fertiliser is applied (U, in equation 6.3), although it is 9 rouch estimation hecanuse there 1s an interaction hetween N-fertiliser rate. available
Table 6.1 Typical apparent recoveries from yield expressed as Dry Matter (DM) at optimum N-fertiliser rates for a range of field vegetable crops (D.J. Greenwood, personal communication in Burns 2006) The relationship (6.4) is species-specific (Greenwood et al. 1989; Jones and Schwab 1993; Karitonas 2003; Tei et al. 1999, 2000, 2002, Burns 2006) because it depends on the efficiency with which plants extract N from the soil due to differ- ences in root functioning and architecture (Thorup-Kristensen and S¢rensen 1999; Thorup-Kristensen and Van der Boogard 1999), but it is also affected by soil condi- tions, weather conditions, agronomic practices and fertiliser application methods. Although it was a rough estimation of the N-recovery efficiency of a crop, the knowledge of REC value for a species (Table 6.1) is useful for the determination of the optimum N-fertiliser requirements and gives clear information on the proportion of N fertiliser not taken up by the crop and so at risk of leaching (Burns 2006). The recovery factor for soil N (fj in equations 6.1 and 6.2) is usually estimated from the uptake of N when no fertiliser is applied (U, in equation 6.3), although it is 9 rouch estimation hecanuse there 1s an interaction hetween N-fertiliser rate. available
Table 6.2 Mineral nitrogen safety margin required up until harvest (Tremblay et al. 2003) exploit the pool of mineralised nitrogen already present in the soul, and consider nitrate leaching losses as ‘lost fertiliser’ (= money) in the context of farm profitability. Given the limited efficiency of fertiliser use by crops, and the associated residual N available for leaching after harvest, a further consideration is that some authors of N cycle studies comment that they cannot realistically envisage annual reduc- tions of more than 20 kg N ha"! in open field farming. This implies that regions with low drainage will risk breaking the Nitrates Directive limit on nitrate concentration in surface and groundwaters (e.g. Silgram et al. 2003), and in some areas the only practical solution may be the change from intensively managed and fertilised hor- ticultural systems to a lower input and more extensive land used based on pasture land (Goulding 2000).
Table 6.2 Mineral nitrogen safety margin required up until harvest (Tremblay et al. 2003) exploit the pool of mineralised nitrogen already present in the soul, and consider nitrate leaching losses as ‘lost fertiliser’ (= money) in the context of farm profitability. Given the limited efficiency of fertiliser use by crops, and the associated residual N available for leaching after harvest, a further consideration is that some authors of N cycle studies comment that they cannot realistically envisage annual reduc- tions of more than 20 kg N ha"! in open field farming. This implies that regions with low drainage will risk breaking the Nitrates Directive limit on nitrate concentration in surface and groundwaters (e.g. Silgram et al. 2003), and in some areas the only practical solution may be the change from intensively managed and fertilised hor- ticultural systems to a lower input and more extensive land used based on pasture land (Goulding 2000).
Kulturebegleitende Nmin Sollwerte) are two methods for developing fertilizer rec ymmendations based on measurements of soil mineral nitrogen. In the Nmin method (Wehrmann and Scharpf 1986), the N-fertiliser requiremen f the crop (N__,,) is estimated as N= IY cg IN eet Meg is a specific target leve f nitrogen that must be available for maximum growth and yield to occur (Felle nd Fink 2002); the target value is determined experimentally and takes int iccount both nitrogen already in the soil and nitrogen supplied by the applicatior f fertilisers. Nis determined from soil samples collected early in the field sea on, just before seeding or transplanting, taken to a depth of 0.3, 0.6 or 0.9 n lepending on the root depth of the crop (Table 6.3). The method makes no adjust nent for N mineralised during growth. [MS hor Re ae a a a - ee oe: a i a ” re. ee cae
Kulturebegleitende Nmin Sollwerte) are two methods for developing fertilizer rec ymmendations based on measurements of soil mineral nitrogen. In the Nmin method (Wehrmann and Scharpf 1986), the N-fertiliser requiremen f the crop (N__,,) is estimated as N= IY cg IN eet Meg is a specific target leve f nitrogen that must be available for maximum growth and yield to occur (Felle nd Fink 2002); the target value is determined experimentally and takes int iccount both nitrogen already in the soil and nitrogen supplied by the applicatior f fertilisers. Nis determined from soil samples collected early in the field sea on, just before seeding or transplanting, taken to a depth of 0.3, 0.6 or 0.9 n lepending on the root depth of the crop (Table 6.3). The method makes no adjust nent for N mineralised during growth. [MS hor Re ae a a a - ee oe: a i a ” re. ee cae
Table 6.4 Determination method for available nitrogen (Adapted from Dachler 2001)
Table 6.4 Determination method for available nitrogen (Adapted from Dachler 2001)
However, the implementation of DSSs over large areas cannot be effective without a well-connected network including farmers, technical advisory services, and local authorities. Meynard et al. (2002) described this interaction between farmers and advisory services using a DSS to generate guidelines in crop management (Fig. 6.2). However, care is required to prevent the quality of the information supplied losing detail and integrity during the communication process from farmer or farm adviser to modeller, which could result in misleading recommendations being produced. The use of such DSS tools is necessarily limited to the range of typical situations (crop, soil, climate, hydrology) for which they were originally developed. Realisation of the
However, the implementation of DSSs over large areas cannot be effective without a well-connected network including farmers, technical advisory services, and local authorities. Meynard et al. (2002) described this interaction between farmers and advisory services using a DSS to generate guidelines in crop management (Fig. 6.2). However, care is required to prevent the quality of the information supplied losing detail and integrity during the communication process from farmer or farm adviser to modeller, which could result in misleading recommendations being produced. The use of such DSS tools is necessarily limited to the range of typical situations (crop, soil, climate, hydrology) for which they were originally developed. Realisation of the
Table 6.5 Suggested N inputs based on standard yields for different vegetable crops in Italy (http://www. politicheagricole.it/norme/mezzitec/19990419__DM.htm)
Table 6.5 Suggested N inputs based on standard yields for different vegetable crops in Italy (http://www. politicheagricole.it/norme/mezzitec/19990419__DM.htm)
Fig. 7.1 The results of an assessment of confined animal farms by species and size within the years 1982-1997. The findings clearly illustrate the decline in very small and small livestock farms and the emergence of medium-to-large livestock operations (Gollehon et al. 2001)
Fig. 7.1 The results of an assessment of confined animal farms by species and size within the years 1982-1997. The findings clearly illustrate the decline in very small and small livestock farms and the emergence of medium-to-large livestock operations (Gollehon et al. 2001)
Table 7.1 Chemical analysis of various animal wastes, suggesting that total phosphorus (TP) is most prominent in swine effluent (Hutchins et al. 2007). TN: total nitrogen
Table 7.1 Chemical analysis of various animal wastes, suggesting that total phosphorus (TP) is most prominent in swine effluent (Hutchins et al. 2007). TN: total nitrogen
Sources: 1992 National Resources Inventory and World Resources Institute
Sources: 1992 National Resources Inventory and World Resources Institute
Fig. 7.3. The causes of major manure spill in Iowa, leading swine producing state, between the years 1992 and 2002 (Osterburg and Wallinga 2004)
Fig. 7.3. The causes of major manure spill in Iowa, leading swine producing state, between the years 1992 and 2002 (Osterburg and Wallinga 2004)
Fig. 7.4 Average concentration of total N, P, and ammonia from upstream, entry point, and down- stream sampling location of 97 manure spills (Hoorman et al. 2005)
Fig. 7.4 Average concentration of total N, P, and ammonia from upstream, entry point, and down- stream sampling location of 97 manure spills (Hoorman et al. 2005)
Table 7.2. The ability of sediments to act as a phosphorus source for up to 61 days after a manure spill has occurred due to sediment phosphorus desorption (Burkholder et al. 1997) phosphorus concentration of the overlying water column within a fluvial system. Therefore, these elevated phosphorus concentrations observed days and weeks after the contamination plume had passed clearly indicate that the sediments became sig- nificant sources of phosphorus thereby releasing phosphorus into the water column. In other words, the sediments that contained elevated concentrations of phosphorus, release phosphorus to the subsequent flow with low phosphorus concentrations to maintain equilibrium with the water column. Rurkholder et al. (1997) aleo fonnd that the dencitv af fecal coliform hacteria at
Table 7.2. The ability of sediments to act as a phosphorus source for up to 61 days after a manure spill has occurred due to sediment phosphorus desorption (Burkholder et al. 1997) phosphorus concentration of the overlying water column within a fluvial system. Therefore, these elevated phosphorus concentrations observed days and weeks after the contamination plume had passed clearly indicate that the sediments became sig- nificant sources of phosphorus thereby releasing phosphorus into the water column. In other words, the sediments that contained elevated concentrations of phosphorus, release phosphorus to the subsequent flow with low phosphorus concentrations to maintain equilibrium with the water column. Rurkholder et al. (1997) aleo fonnd that the dencitv af fecal coliform hacteria at
Fig. 7.5 The effect of alum application on the soluble phosphorus concentration of sediments collected from three watersheds within the St. Joseph River Watershed in North East Indiana (Smith et al. 2005) increases the formation of minerals such as varisite (AIPO,-2H,O) and wavellite [Al,(PO,),(OH),-5H,O)] may form and persist under acidic conditions. Sims and Luka-McCafferty (2002) conducted a large-scale on-farm poultry litter study where alum was amended to poultry litter in 97 poultry houses for a 16-month period. They found that alum amendment at a rate 1.0 kg alum m”® flock" (approxi- mately 0.09 kg alum per bird) decreased the dissolved phosphorus content in manure by 67%. Similar studies have also demonstrated that the addition of alum to poultry litter resulted in a reduction of phosphorus loss via runoff by as much as 52-87% using the following application rates 1:5 ratio of alum to poultry litter (Shreve et al. 1995); applications of 5%, 10%, 15% alum to poultry litter on a weight basis (Delaune et al. 2004); and 10% alum application by weight to poultry litter (Smith et al. 2004). Smith et al. (2005) investigated the effect of alum application on the phosphorus con- centration and adsorption properties of sediments from tile-fed drainage ditches in an agricultural watershed in northeast Indiana. They determined that applying alum reduced the extractable phosphorus in sediments by 50-90% and the portioning index by 50% (Fig. 7.5). Haggard et al. (2004) evaluated the use of alum as a chemical amendment to sediments from streams that received a daily influx of phosphorus from a municipal waste water treatment plant’s effluent discharge. Results from their study demonstrated that applying alum with CaCO, to phosphorus-enriched sediments resulted in a significant reduction in sediment labile phosphorus, equilibrium phos- phorus concentrations, and a significantly increased in the phosphorus-buffering capacity of the sediments. The sediment equilibrium concentration is the concentra- tion at which the net phosphorus adsorption and desorption of fluvial sediment is zero
Fig. 7.5 The effect of alum application on the soluble phosphorus concentration of sediments collected from three watersheds within the St. Joseph River Watershed in North East Indiana (Smith et al. 2005) increases the formation of minerals such as varisite (AIPO,-2H,O) and wavellite [Al,(PO,),(OH),-5H,O)] may form and persist under acidic conditions. Sims and Luka-McCafferty (2002) conducted a large-scale on-farm poultry litter study where alum was amended to poultry litter in 97 poultry houses for a 16-month period. They found that alum amendment at a rate 1.0 kg alum m”® flock" (approxi- mately 0.09 kg alum per bird) decreased the dissolved phosphorus content in manure by 67%. Similar studies have also demonstrated that the addition of alum to poultry litter resulted in a reduction of phosphorus loss via runoff by as much as 52-87% using the following application rates 1:5 ratio of alum to poultry litter (Shreve et al. 1995); applications of 5%, 10%, 15% alum to poultry litter on a weight basis (Delaune et al. 2004); and 10% alum application by weight to poultry litter (Smith et al. 2004). Smith et al. (2005) investigated the effect of alum application on the phosphorus con- centration and adsorption properties of sediments from tile-fed drainage ditches in an agricultural watershed in northeast Indiana. They determined that applying alum reduced the extractable phosphorus in sediments by 50-90% and the portioning index by 50% (Fig. 7.5). Haggard et al. (2004) evaluated the use of alum as a chemical amendment to sediments from streams that received a daily influx of phosphorus from a municipal waste water treatment plant’s effluent discharge. Results from their study demonstrated that applying alum with CaCO, to phosphorus-enriched sediments resulted in a significant reduction in sediment labile phosphorus, equilibrium phos- phorus concentrations, and a significantly increased in the phosphorus-buffering capacity of the sediments. The sediment equilibrium concentration is the concentra- tion at which the net phosphorus adsorption and desorption of fluvial sediment is zero
Fig. 8.1 A drawing to show the difference between a population, all one species within a soil system, and a community, a grouping of populations within a soil system. A population is present within a community. Species richness is a measure of how many different species are present within a soil system. Species evenness is a measure of how even the numbers of the various species are within a soil system. Diversity is a measure that incorporates both species richness and evenness
Fig. 8.1 A drawing to show the difference between a population, all one species within a soil system, and a community, a grouping of populations within a soil system. A population is present within a community. Species richness is a measure of how many different species are present within a soil system. Species evenness is a measure of how even the numbers of the various species are within a soil system. Diversity is a measure that incorporates both species richness and evenness
Fig. 8.2. An example of an arbuscular mycorrhizal fungi association with a plant root showing some of the typical structures present. Arbuscules form within the apoplastic space of root cortical cells and are believed to be the site of nutrient exchange between the fungi and plant. Vesicles can form in some species/strains of mycorrhizae, their function is not fully known, but is believed to have a role in storage. Extramatrical hyphae (hyphae extending beyond the root) take up nutrients from the soil. Hyphae can access areas beyond the root depletion zone for some nutrients (hyphae can go about 10mm beyond the root — the P depletion zone is about Imm around the root). Spores are structures of asexual reproduction. Auxillary cells can also be found on the extramatrical hyphae; their positioning on the hyphae and their shape are species/strain-dependent
Fig. 8.2. An example of an arbuscular mycorrhizal fungi association with a plant root showing some of the typical structures present. Arbuscules form within the apoplastic space of root cortical cells and are believed to be the site of nutrient exchange between the fungi and plant. Vesicles can form in some species/strains of mycorrhizae, their function is not fully known, but is believed to have a role in storage. Extramatrical hyphae (hyphae extending beyond the root) take up nutrients from the soil. Hyphae can access areas beyond the root depletion zone for some nutrients (hyphae can go about 10mm beyond the root — the P depletion zone is about Imm around the root). Spores are structures of asexual reproduction. Auxillary cells can also be found on the extramatrical hyphae; their positioning on the hyphae and their shape are species/strain-dependent
Mycorrhizal colonization can also increase or decrease the growth of weeds in the field, depending on the soil and species (Vatovec et al. 2005). The presence of mycorrhiza can change the composition of weed communities, selecting for host species. Conversely, the weed community can alter mycorrhiza communities, with diverse weed hosts encouraging increased mycorrhizal diversity (Jordan et al. 2000). Soil taken from fields under organic, transitioning to organic and conventional management had similar mycorrhizal colonization levels of various weed species (Vatovec et al. 2005). The presence of weeds within a crop lowers crop productivity. However, it appears that organic fields may derive some benefits from weed pressure that is ubiquitous within these systems.
Mycorrhizal colonization can also increase or decrease the growth of weeds in the field, depending on the soil and species (Vatovec et al. 2005). The presence of mycorrhiza can change the composition of weed communities, selecting for host species. Conversely, the weed community can alter mycorrhiza communities, with diverse weed hosts encouraging increased mycorrhizal diversity (Jordan et al. 2000). Soil taken from fields under organic, transitioning to organic and conventional management had similar mycorrhizal colonization levels of various weed species (Vatovec et al. 2005). The presence of weeds within a crop lowers crop productivity. However, it appears that organic fields may derive some benefits from weed pressure that is ubiquitous within these systems.
Table 8.2. Summary of the management practices and their relative impact on the soil microbial community and mycorrhizal community *Items in bold indicate that the management practice has a large effect on the community in question. Items not in bold have a small effect on the community
Table 8.2. Summary of the management practices and their relative impact on the soil microbial community and mycorrhizal community *Items in bold indicate that the management practice has a large effect on the community in question. Items not in bold have a small effect on the community
Table 9.1 Main thematic areas for salt-related studies in cyanobacteria
Table 9.1 Main thematic areas for salt-related studies in cyanobacteria
Table 9.2 Mechanisms adopted for salt tolerance by cyanobacteria Cyanobacteria are able to tolerate stresses predominant in salt-affected soils such as nutrient deficiency, salinity, drought and temperature up-shift (Apte et al. 1997). Adaptation to salt stress in cyanobacteria consists of at least three phenomena: (a) accumulation of internal osmoticum in the form of inorganic ions (Miller 1976) or organic solutes (Blumwald et al. 1983; Mackay et al. 1983; Reed et al. 1984); (b) contribution of ion transport processes (Apte et al. 1987; Apte and Thomas 1983, 1986; Reed et al. 1985; Reed and Stewart 1985; Thomas and Apte 1984); and (c) metabolic adjustments (Blumwald and Tel-Or 1984; Thomas and Apte 1984). Several workers have pointed out the various mechanisms adopted by cyanobacteria for salt tolerance (Table 9.2).
Table 9.2 Mechanisms adopted for salt tolerance by cyanobacteria Cyanobacteria are able to tolerate stresses predominant in salt-affected soils such as nutrient deficiency, salinity, drought and temperature up-shift (Apte et al. 1997). Adaptation to salt stress in cyanobacteria consists of at least three phenomena: (a) accumulation of internal osmoticum in the form of inorganic ions (Miller 1976) or organic solutes (Blumwald et al. 1983; Mackay et al. 1983; Reed et al. 1984); (b) contribution of ion transport processes (Apte et al. 1987; Apte and Thomas 1983, 1986; Reed et al. 1985; Reed and Stewart 1985; Thomas and Apte 1984); and (c) metabolic adjustments (Blumwald and Tel-Or 1984; Thomas and Apte 1984). Several workers have pointed out the various mechanisms adopted by cyanobacteria for salt tolerance (Table 9.2).
Table 9.3 Influence on pH, electrical conductivity (EC) and exchangeable sodium (ES) of sodi soils after 3 years of BGA (blue-green algae) application (initial soil pH = 10, exchangeab! Nat = 10.44 meq 100 g™!, CEC = 11.19 meq 100 g"')
Table 9.3 Influence on pH, electrical conductivity (EC) and exchangeable sodium (ES) of sodi soils after 3 years of BGA (blue-green algae) application (initial soil pH = 10, exchangeab! Nat = 10.44 meq 100 g™!, CEC = 11.19 meq 100 g"')
Table 9.4 Yield (q ha) of paddy (var. Pusa 33) and wheat (var. 2393) in salt-affected soils after 2 years of reclamation with different treatments including BGA (blue-green algae) fields, biological nitrogen fixation is mainly a cyanobacterial process and part of the nitrogen demand of the rice crop is met through the indigenous populations or through their application as biofertilizers (Mitra 1951). The yields obtained in blue- green-algae-treated plots were observed at par with gypsum (41-42 q ha’'), although combined application of both was still better. The yield of wheat recorded after 2 years of reclamation with blue-green algae and/or gypsum, was also better in the treatment with combination of blue-green algae and chemical fertilizer than the fertilizer alone (Kaushik 1994; Table 9.4). Se ne, Ty ae, Pe, . ) , ee a.
Table 9.4 Yield (q ha) of paddy (var. Pusa 33) and wheat (var. 2393) in salt-affected soils after 2 years of reclamation with different treatments including BGA (blue-green algae) fields, biological nitrogen fixation is mainly a cyanobacterial process and part of the nitrogen demand of the rice crop is met through the indigenous populations or through their application as biofertilizers (Mitra 1951). The yields obtained in blue- green-algae-treated plots were observed at par with gypsum (41-42 q ha’'), although combined application of both was still better. The yield of wheat recorded after 2 years of reclamation with blue-green algae and/or gypsum, was also better in the treatment with combination of blue-green algae and chemical fertilizer than the fertilizer alone (Kaushik 1994; Table 9.4). Se ne, Ty ae, Pe, . ) , ee a.
“Mean performance considering a female/male ratio = 1
“Mean performance considering a female/male ratio = 1
Total ingredients
Total ingredients
Table 10.3 Principal emissions in the Life Cycle Assessment study (database Ecoinvent; method of impact assessment Ecoindicator 99)
Table 10.3 Principal emissions in the Life Cycle Assessment study (database Ecoinvent; method of impact assessment Ecoindicator 99)
Fig. 10.3. Conventional poultry system life cycle. This figure shows the principal processes involved in the conventional poultry system. For each process the relative quantity (in kg) neces- sary to produce | kg of poultry meat (Functional Unit) and the process contribution to the envi- ronmental impact of the system, in percentage, are presented
Fig. 10.3. Conventional poultry system life cycle. This figure shows the principal processes involved in the conventional poultry system. For each process the relative quantity (in kg) neces- sary to produce | kg of poultry meat (Functional Unit) and the process contribution to the envi- ronmental impact of the system, in percentage, are presented
Fig. 10.4 Conventional poultry system impact assessment. The figure shows the environmental impact of the conventional poultry system relative to the 11 different impact categories by the method Eco-Indicator 99. Results are expressed in normalised Points. The higher the score, the more important is the impact. 4.00E-04 refers to 0.0004
Fig. 10.4 Conventional poultry system impact assessment. The figure shows the environmental impact of the conventional poultry system relative to the 11 different impact categories by the method Eco-Indicator 99. Results are expressed in normalised Points. The higher the score, the more important is the impact. 4.00E-04 refers to 0.0004
fable 10.4 Energy and material data, with relative conversion factor, for conventional poultry a oa see
fable 10.4 Energy and material data, with relative conversion factor, for conventional poultry a oa see
Fig. 10.5 Ecological Footprint for conventional poultry production disaggregated by land categories. The main contribution is due to cropland which is highly needed to cultivate maize and soya meal tion 1s given as the sum of all croplands, energy lands and buult-up areas. Results show that the total amount of bio-productive land, or Ecological Footprint, required for the conventional poultry production is 721.60 gha year that means 12.81 gm? year kg! of chicken. Comparison with other kind of meat produc- tion is not possible due to the lack of specific Footprint literature. However, Gerbens-Leenes and Nonhebel (2005) estimated the land requirement (values are expressed in m* year kg~') for producing three different types of meat: beef (20.9), pork (8.9) and chicken (7.3). FRB eecee® g P akhiccce coco TT “Cheese tee esc ees: seeiale gesceeeeceeee: ape OCWit&ecs ates Bee PS, OE! ee
Fig. 10.5 Ecological Footprint for conventional poultry production disaggregated by land categories. The main contribution is due to cropland which is highly needed to cultivate maize and soya meal tion 1s given as the sum of all croplands, energy lands and buult-up areas. Results show that the total amount of bio-productive land, or Ecological Footprint, required for the conventional poultry production is 721.60 gha year that means 12.81 gm? year kg! of chicken. Comparison with other kind of meat produc- tion is not possible due to the lack of specific Footprint literature. However, Gerbens-Leenes and Nonhebel (2005) estimated the land requirement (values are expressed in m* year kg~') for producing three different types of meat: beef (20.9), pork (8.9) and chicken (7.3). FRB eecee® g P akhiccce coco TT “Cheese tee esc ees: seeiale gesceeeeceeee: ape OCWit&ecs ates Bee PS, OE! ee
Fig. 10.6 Ecological Footprint for conventional poultry production disaggregated by consump- tion categories. Main contributions are related to chickens’ diet
Fig. 10.6 Ecological Footprint for conventional poultry production disaggregated by consump- tion categories. Main contributions are related to chickens’ diet
Table 10.7 Denomination of indicators and measure units used in the analysis (Goedkoop and Spriensma 2001)
Table 10.7 Denomination of indicators and measure units used in the analysis (Goedkoop and Spriensma 2001)
Fig. 10.7 Resources exploitation and resources availability in Ecological Footprint Analysis
Fig. 10.7 Resources exploitation and resources availability in Ecological Footprint Analysis
Fig. 11.1 Soil organic-carbon contents (g kg~') at 0-30 cm depth in spring 2003 (bars) as compared to the initial level in spring 1993 (horizontal line: 20 g/kg). Treatments with the same letters are not significantly different at P < 0.05 (From Hartl and Erhart 2005. With permission from Wiley-VCH) ee eee eI eee eee The DOK-experiment in Therwil, Switzerland, compares, among other treatments, fertilization with composted manure at a rate corresponding to 1.4 livestock units n biodynamic farming with conventional mineral fertilization on a sandy loam Luvisol. The crop rotation includes potatoes + green manure, winter wheat + intercrop, cabbage/beets, winter barley, and 2-3 years grass clover. After 21 years of compost fertilization, soil organic carbon had increased by 1% in the biodynamic treatment using manure compost), while the soils in the organic treatment (with rotted
Fig. 11.1 Soil organic-carbon contents (g kg~') at 0-30 cm depth in spring 2003 (bars) as compared to the initial level in spring 1993 (horizontal line: 20 g/kg). Treatments with the same letters are not significantly different at P < 0.05 (From Hartl and Erhart 2005. With permission from Wiley-VCH) ee eee eI eee eee The DOK-experiment in Therwil, Switzerland, compares, among other treatments, fertilization with composted manure at a rate corresponding to 1.4 livestock units n biodynamic farming with conventional mineral fertilization on a sandy loam Luvisol. The crop rotation includes potatoes + green manure, winter wheat + intercrop, cabbage/beets, winter barley, and 2-3 years grass clover. After 21 years of compost fertilization, soil organic carbon had increased by 1% in the biodynamic treatment using manure compost), while the soils in the organic treatment (with rotted
Fig. 11.2 Effects of compost addition on the available water in the surface layer; means of four replications. The linear term of regression (physical parameters : compost rates was significant at P< 0.01 (Drawn from data from Giusquiani et al. 1995)
Fig. 11.2 Effects of compost addition on the available water in the surface layer; means of four replications. The linear term of regression (physical parameters : compost rates was significant at P< 0.01 (Drawn from data from Giusquiani et al. 1995)
Fig. 11.3. Cd contents (mg kg™' d.m.) in crops fertilized with biowaste compost at 32 t (wet wt.) ha"! year" for 7 years, as compared to mineral fertilization (71 kg N, 19 kg P, and 68 kg K ha"! year!) and to no fertilization. Treatments with the same letters are not significantly different at P < 0.05 (Drawn from data from Bartl et al. 2002)
Fig. 11.3. Cd contents (mg kg™' d.m.) in crops fertilized with biowaste compost at 32 t (wet wt.) ha"! year" for 7 years, as compared to mineral fertilization (71 kg N, 19 kg P, and 68 kg K ha"! year!) and to no fertilization. Treatments with the same letters are not significantly different at P < 0.05 (Drawn from data from Bartl et al. 2002)
Fig. 11.4 Average yields 1995-2002 of five field experiments with a maize—wheat-barley rota- tion with biowaste-compost fertilization at 5 t ha“! year"! (dry wt.) = C1, 10 tha-! year"! = C2, and 20 t ha"! year"! = C3 as compared to no fertilization = CO. Stars indicate statistically significant differences at P < 0.01 (Drawn from data from Timmermann et al. 2003)
Fig. 11.4 Average yields 1995-2002 of five field experiments with a maize—wheat-barley rota- tion with biowaste-compost fertilization at 5 t ha“! year"! (dry wt.) = C1, 10 tha-! year"! = C2, and 20 t ha"! year"! = C3 as compared to no fertilization = CO. Stars indicate statistically significant differences at P < 0.01 (Drawn from data from Timmermann et al. 2003)
Ts not classified as a micronutrient Table 13.1 Foliar application of micronutrients in different crops a A large number of studies were made to measure the rate of mobility of foliar- ipplied nutrients, and radioisotopes were widely employed for the experiments. Basically, the nutrient element supplied to the leaf would move in either direction, .e., toward the tip or base of the leaf. While the root-absorbed nutrients would each the leaf and other aboveground parts through the xylem under the transpiration null, the foliar-applied elements can move out of the leaf or be transported to the pase of the plant. To describe a few, there were three experiments conducted by
Ts not classified as a micronutrient Table 13.1 Foliar application of micronutrients in different crops a A large number of studies were made to measure the rate of mobility of foliar- ipplied nutrients, and radioisotopes were widely employed for the experiments. Basically, the nutrient element supplied to the leaf would move in either direction, .e., toward the tip or base of the leaf. While the root-absorbed nutrients would each the leaf and other aboveground parts through the xylem under the transpiration null, the foliar-applied elements can move out of the leaf or be transported to the pase of the plant. To describe a few, there were three experiments conducted by
Table 13.2 Foliar uptake of nutrients and influence of growth substances GA = gibberellic acid, ABA = abscisic acid scientists. In one experiment, the movement from the site of application to the rest of the leaf was followed. Ringoet et al. (1971) developed a technique to mea- sure the rate of movement of “Ca placed on the middle of an oat leaf by in vivo counting with B-sensitive semiconductor detectors. They found that Ca migrated in the acropetal direction at low concentrations, but moved down to the base of the leaf at concentrations above 0.02 M. They concluded that Ca was fairly mobile and the downward transport was through the phloem while it moved upward in the xylem. There are some nutrient elements for which stable isotopes were not available and a new technique was developed for tracking the movement of boron (Chamel and Eloy 1983). They used ''B/'*B and measured the ratio of the two in plant samples with a highly sensitive spark-source mass spectrometry and microanlytical method using a laser-probe mass spectrograph. They found that the largest fraction of foliar-applied B remained in the applied leaf itself. However, it entered the leaf surface and remained bound as polysaccharide complexes. It was concluded that B is partially mobile, like Fe, Mn, or Zn. Relative mobility of various elements in the leaves was reported in several studies (Kannan 1990). Thus there is enouch evidence that leaf is canable of absorbing inoreanic nutrients
Table 13.2 Foliar uptake of nutrients and influence of growth substances GA = gibberellic acid, ABA = abscisic acid scientists. In one experiment, the movement from the site of application to the rest of the leaf was followed. Ringoet et al. (1971) developed a technique to mea- sure the rate of movement of “Ca placed on the middle of an oat leaf by in vivo counting with B-sensitive semiconductor detectors. They found that Ca migrated in the acropetal direction at low concentrations, but moved down to the base of the leaf at concentrations above 0.02 M. They concluded that Ca was fairly mobile and the downward transport was through the phloem while it moved upward in the xylem. There are some nutrient elements for which stable isotopes were not available and a new technique was developed for tracking the movement of boron (Chamel and Eloy 1983). They used ''B/'*B and measured the ratio of the two in plant samples with a highly sensitive spark-source mass spectrometry and microanlytical method using a laser-probe mass spectrograph. They found that the largest fraction of foliar-applied B remained in the applied leaf itself. However, it entered the leaf surface and remained bound as polysaccharide complexes. It was concluded that B is partially mobile, like Fe, Mn, or Zn. Relative mobility of various elements in the leaves was reported in several studies (Kannan 1990). Thus there is enouch evidence that leaf is canable of absorbing inoreanic nutrients
Fig. 13.1 Adaxial transverse leaf section of Eidothea zoexylocarya showing the pores extending perpendicularly down through the cuticle (Reproduced with the kind permission of the authors (Carpenter et al. 2007) and the editor American Journal of Botany)
Fig. 13.1 Adaxial transverse leaf section of Eidothea zoexylocarya showing the pores extending perpendicularly down through the cuticle (Reproduced with the kind permission of the authors (Carpenter et al. 2007) and the editor American Journal of Botany)
Fig. 13.2 Diagrammatic presentation of the epidermal cells with stomata, guard cells, and the plasmadesmatic connections between them and guard cells. Thus, ions like K absorbed by guard cells move between the guard cells but not into the epidermal cells. Note the lack of symplastic connections between the epidermal cells (Drawn after Erwee et al. 1985)
Fig. 13.2 Diagrammatic presentation of the epidermal cells with stomata, guard cells, and the plasmadesmatic connections between them and guard cells. Thus, ions like K absorbed by guard cells move between the guard cells but not into the epidermal cells. Note the lack of symplastic connections between the epidermal cells (Drawn after Erwee et al. 1985)
Fig. 13.3. Acropetal transport of *°Cl from the supplied leaf to other leaves above and below in Tradescantia viridis. The amount of Cl found after 3 h of application, in the leaves are given as % (Redrawn after Penot and Gallou 1977)
Fig. 13.3. Acropetal transport of *°Cl from the supplied leaf to other leaves above and below in Tradescantia viridis. The amount of Cl found after 3 h of application, in the leaves are given as % (Redrawn after Penot and Gallou 1977)
Fig. 13.4 Wireless Watering: The picture shows in-field sensing stations monitor soil moisture and soil and air temperatures. All in-field data are sent wirelessly to the base station for determin- ing the precise timing for irrigation. The base station communicates back and forth with the mobile irrigation cart and the grower, who controls the station. This picture is included in this review to propose that nutrients could be given through the sprinkler water (Credit: Robert Evans, USDA-ARS Northern Plains Agricultural Research Laboratory, 1500 North Central Ave.,m Sidney, MT 433-5038. Picture from Agricultural Research July 2007 page 6) The development of drip-irrigation technology in 1960s opened the doors for the greatest advancement in fertilizer management especially for vegetables. Early work for example, in Israel (Bar-Yosef 1977) and later in other countries formed some of the basis for the water-management technology that is used today. Drip irrigation led to improvements in water application efficiencies and also reduced the amount of water used for many vegetables by 50-70% (Clark 1992). Furthermore, the reduction in water application has positive implications for nutrient efficiencies, especially N since it is closely related to irrigation efficiency in sandy soil production areas (Hochmuth 2000). Fertilizer materials could be injected into the drip irrigation system, a process referred to as “fertigation.” Soluble nutrients such as N and K are supplied through drip irrigation by injecting small amounts and are also regulated according to the seasonal crop requirement. Schedules for such injections were developed in Florida and other southern states (Cook and Sanders 1991). Water conservation tech- nology has also been developed using many advanced technologies and remote monitoring with computers. One recent advancement is described below. Writing on the ARS role to help conserve the vital resource for agriculture, Evans (2007) has presented a new system called “Wireless Watering.” (Fig. 13.4). He states
Fig. 13.4 Wireless Watering: The picture shows in-field sensing stations monitor soil moisture and soil and air temperatures. All in-field data are sent wirelessly to the base station for determin- ing the precise timing for irrigation. The base station communicates back and forth with the mobile irrigation cart and the grower, who controls the station. This picture is included in this review to propose that nutrients could be given through the sprinkler water (Credit: Robert Evans, USDA-ARS Northern Plains Agricultural Research Laboratory, 1500 North Central Ave.,m Sidney, MT 433-5038. Picture from Agricultural Research July 2007 page 6) The development of drip-irrigation technology in 1960s opened the doors for the greatest advancement in fertilizer management especially for vegetables. Early work for example, in Israel (Bar-Yosef 1977) and later in other countries formed some of the basis for the water-management technology that is used today. Drip irrigation led to improvements in water application efficiencies and also reduced the amount of water used for many vegetables by 50-70% (Clark 1992). Furthermore, the reduction in water application has positive implications for nutrient efficiencies, especially N since it is closely related to irrigation efficiency in sandy soil production areas (Hochmuth 2000). Fertilizer materials could be injected into the drip irrigation system, a process referred to as “fertigation.” Soluble nutrients such as N and K are supplied through drip irrigation by injecting small amounts and are also regulated according to the seasonal crop requirement. Schedules for such injections were developed in Florida and other southern states (Cook and Sanders 1991). Water conservation tech- nology has also been developed using many advanced technologies and remote monitoring with computers. One recent advancement is described below. Writing on the ARS role to help conserve the vital resource for agriculture, Evans (2007) has presented a new system called “Wireless Watering.” (Fig. 13.4). He states
Related topics:
GeneticsCytochrome oxidaseSALT TOLERANCEPlant Growth RegulatorAvailable PhosphorusSalinity stressSaline SoilSalinity ToleranceElectric ConductivityOsmotic Adjustment
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