Sugar beet herbicides and soil nitrification

Environmental Practice, 2007

Substantial progress has been made towards land management practices that fulfill the basic requirements of a burgeoning human population. One of them is extensive use of nitrogen-containing chemical fertilizers to boost crop production. Though their use is beneficial, overuse of these fertilizers is causing serious environmental problems associated with emission of NH 3 , N 2 , and N 2 O (the last being an important greenhouse gas implicated both in the greenhouse effect and ozone layer depletion in the stratosphere) to the atmosphere and contamination of ground and surface water resources via nitrate leaching or runoff. Because these losses have both economic and environmental implications, it is high time to utilize a technique that contains nitrogen losses and enhances nitrogen-use efficiency of agricultural crops. To manage nitrogen losses from agricultural fields, different nitrification inhibitors are currently available, and if used along with NH 4-containing fertilizers, they can effectively increase nitrogen-use efficacy and attenuate the emission of greenhouse gases by decelerating the soil nitrification processes resulting from ammonia metabolism.

Advances in Agronomy, 1995

Frontiers in Microbiology, 2020

Nitrification inhibitors (NIs) applied to soil reduce nitrogen fertilizer losses from agro-ecosystems. NIs that are currently registered for use in agriculture appear to selectively inhibit ammonia-oxidizing bacteria (AOB), while their impact on other nitrifiers is limited or unknown. Ethoxyquin (EQ), a fruit preservative shown to inhibit ammonia-oxidizers (AO) in soil, is rapidly transformed to 2,6-dihydro-2,2,4-trimethyl-6-quinone imine (QI), and 2,4-dimethyl-6-ethoxy-quinoline (EQNL). We compared the inhibitory potential of EQ and its derivatives with that of dicyandiamide (DCD), nitrapyrin (NP), and 3,4-dimethylpyrazole-phosphate (DMPP), NIs that have been used in agricultural settings. The effect of each compound on the growth of AOB (Nitrosomonas europaea, Nitrosospira multiformis), ammonia-oxidizing archaea (AOA; "Candidatus Nitrosocosmicus franklandus," "Candidatus Nitrosotalea sinensis"), and a nitrite-oxidizing bacterium (NOB; Nitrobacter sp. NHB1), all being soil isolates, were determined in liquid culture over a range of concentrations by measuring nitrite production or consumption and qPCR of amoA and nxrB genes, respectively. The degradation of NIs in the liquid cultures was also determined. In all cultures, EQ was transformed to the short-lived QI (major derivative) and the persistent EQNL (minor derivative). They all showed significantly higher inhibition activity of AOA compared to AOB and NOB isolates. QI was the most potent AOA inhibitor (EC 50 = 0.3-0.7 µM) compared to EQ (EC 50 = 1-1.4 µM) and EQNL (EC 50 = 26.6-129.5 µM). The formation and concentration of QI in EQ-amended cultures correlated with the inhibition patterns for all isolates suggesting that it was primarily responsible for inhibition after application of EQ. DCD and DMPP showed greater inhibition of AOB compared to AOA or NOB,

Soil contamination with nitrification inhibitors has received a lot of attention in the last few decades due to their potential toxic effects on the plant and soil, but no action has been taken to control and eliminate contamination with nitrification inhibitors. This work tested the hypothesis that symbiotic interactions between fungi and plant roots can reduce the negative effects of the nitrification inhibitor 1, 2, 4-Triazole (TZ) in plants by reducing its uptake. A greenhouse experiment was conducted, using a complete randomized design, to test the effect of symbiotic fungi (Serendipita indica, Glomus etunicatum and mosseae) on the phytotoxicity of TZ applied at four concentrations (Control, 5, 50 and 100 mg / kg soil). Lactuca sativa, cultivar Siyahoo, was selected for this experiment due to its economic value all over the world. HPLC results the concentration of TZ nitrification inhibitor in lettuce leaves was very important. It was found that plants colonized with symbiotic ...

Journal of Environmental Sciences, 2009

The effects of chlorothalonil and carbendazim on nitrification and denitrification in six soils in upland and rice paddy environments were investigated. Laboratory aerobic (60% water holding capacity) and anaerobic (flooded) conditions were studied at 25°C and fungicide addition rates of 5.5 mg/kg A. I. (field rate, FR), 20 times (20FR) and 40 times (40FR) field rate, respectively. The results indicated that chlorothalonil at the field rate had a slight inhibitory effect on one soil only, and that soil did not nitrify much in the first place. But chlorothalonil at higher rates inhibited nitrification significantly in all soils. For soils JXP and JXU with a pH of less than 5.0, chlorothalonil almost completely stopped their nitrification at 20FR and 40FR during the whole 14 d incubation period. For soils HNP and HNU with a pH of greater than 8.0, chlorothalonil also significantly inhibit nitrification at 20FR and 40FR (p < 0.05). However, NH 4 + that was added to the soil was also almost completely nitrified by the end of the incubation period in these two soils. The effects of chlorothalonil at 20FR and 40FR on the nitrification of JSP and JSU soils, with a pH of 5.4 and 7.2, respectively, were intermediate between the other soil types. Chlorothalonil had no effect on denitrification at the field rate and had little effect at the higher rates of application in some soils. Carbendazim had essentially no effect on nitrification and denitrification in soils assessed.

E3S Web of Conferences, 2018

Nitrification has the potential to decrease the efficiency of nitrogen utilization by plants. The use of nitrifying inhibitory chemicals proved to be effective in controlling nitrification, but also affects beneficial soil microbes. Another attempt to inhibit the more environmentally-friendly nitrification is to use plants that have allelochemical nitrification inhibiting compounds such as the grasses ofBrachiaria. The aim of this research is to know the effectivity ofB.mutica, B.decumbens, andB.humidicolaas inhibitors of nitrification rate in soil. The experiment was carried out by pot experimental method based on nondestructive sampling and Complete Randomized Design, consisting of Brachiaria plant types and various doses of N fertilizer, 100 kg/ha, 150 kg/ha, 200 kg/ha. The results of this study show that 1)B.mutica, B.decumbens, and B.humidicola, highly significant to the soil potential nitrification, but the treatment of various doses of N fertilizer is not significant to the s...

Agronomy, 2015

Agriculture is responsible for over half of the input of reactive nitrogen (N) to terrestrial systems; however improving N availability remains the primary management technique to increase crop yields in most regions. In the majority of agricultural soils, ammonium is rapidly converted to nitrate by nitrification, which increases the mobility of N through the soil matrix, strongly influencing N retention in the system. Decreasing nitrification through management is desirable to decrease N losses and increase N fertilizer use efficiency. We review the controlling factors on the rate and extent of nitrification in agricultural soils from temperate regions including substrate supply, environmental conditions, abundance and diversity of nitrifiers and plant and microbial interactions with nitrifiers. Approaches to the management of nitrification include those that control ammonium substrate availability and those that inhibit nitrifiers directly. Strategies for controlling ammonium substrate availability include timing of fertilization to coincide with rapid plant update, formulation of fertilizers for slow release or with inhibitors, keeping plant growing continuously to assimilate N, and intensify internal N cycling (immobilization). Another effective strategy is to inhibit nitrifiers directly with either synthetic or biological nitrification inhibitors. Commercial nitrification inhibitors are effective but their use is complicated by a changing climate and by organic management requirements. The interactions of the nitrifying organisms with plants or microbes producing biological nitrification inhibitors is a promising approach but just beginning to be critically examined. Climate smart agriculture will need to carefully consider optimized seasonal timing for these strategies to remain effective management tools.

AGRIVITA, Journal of …, 2011

Experiments were conducted under laboratory conditions to elucidate the effect of three nitrification inhibitors viz, 3.4dimethylpyrazolephosphate (DMPP), 4-Chlormethylpyrazole (ClMP) and dicyandiamide (DCD) on mineral nitrogen dynamics of (NH 4 ) 2 SO 4 in soil incubated at 25 o C in soils. The quantitative determination of ammonium, nitrite and nitrate were carried out spectrophotometrically, while potential denitrifycation capacity (PDC) was measured gas chromatographically. DMPP, ClMP and DCD were used on recommended rates of 90kg N ha -1 corresponding to 0.36µg DMPP; 0.25µg ClMP and 10µg DCD g -1 dry soil. In all treatments, the influence of 1, 10, 50, 100, 250 and 500 times of the recommended-concentrations were examined. Results suggested that DMPP, ClMP and DCD applied at rates generally recommended for agricultural use may not be effective to inhibit nitrification. Thus even at the highest tested NIsconcentrations, nitrate and nitrite formation still occurred. Application of high concentrations of these chemicals up to 180µg DMPP, 125µg ClMP and 2500µg DCD were needed for inhibiting nitrification completely. The three NIs began to inhibit PDC at 10 to 50 times recommended concentration and were more effective in sandy than in loamy or clay soils. ClMP influenced PDC at much lower concentration as DMPP or DCD.

An incubation experiment was conducted to evaluate the effect of aqueous extracts of 17 plant materials on nitrification inhibition of urea-N in soil as compared with chemical inhibitor Dicyandiamide (DCD). Plant materials used in study were collected from different areas of Basrah province, south of Iraq. Aqueous extracts were prepared at ratio of 1:10 (plant material:water) and added at conc. of 0.05, 0.10 and 0.20 ml g -1 soil to loamy sand soil. DCD was added to soil at rate of 50 µg g -1 soil . Soil received urea at rate of 1000 µg N g -1 soil. Treated soils were incubated at 30 O C for 40days. Results showed that application of all plant extracts, except those of casuarina, date palm and eucalyptus to soil retarded nitrification in soil. Caper, Sowthistle ,bladygrass and pomegranate extracts showed highest inhibition percentage (51,42,40 and 40% ,respectively) and were found to be more effective than DCD (33%). Highest inhibition was achieved by using those extracts at conc. of 0.1 ml g -1 soil after 10 days of incubation . Data also revealed that treated soil with these plant extracts significantly increased amount of NH 4 + -N and decreased amount of NO 3 --N accumulation in soil compared with DCD and control treatments. Results of the study suggested a possibility of using aqueous extracts of some studied plants as potent nitrification inhibitor in soil.

Abstract Nitrification inhibitors (NIs) delay the oxidation of ammonium by soil microorganisms, maintaining a higher proportion of applied nitrogen (N) in the soil by preventing nitrate-N loss from leaching and gaseous N losses from nitrification and denitrification. Thus, a large number of studies have shown N fertilizers with NIs are more environmentally friendly. In contrast, there are only a limited number of studies about effects of the N fertilizers added with NIs on arable crop yields and the conclusions are also divergent. This study presents a meta-analysis of recent research in Germany investigating the effects of NIs on the yields of different agricultural crops (winter wheat, winter barley, winter rapeseed, potato, grain and silage maize) compared to conventional N fertilization without NIs at a given N rate. Crop yields with and without NIs at a reduced number of N fertilizer applications were also compared. Nitrogen fertilizers with NIs did not significantly influence the yields of all investigated crops. For a given N application rate, the number of fertilizer applications could be reduced by at least one without any significant effect on yield when fertilizers with NIs were used. By contrast, the crude protein content of winter wheat was decreased significantly when the number of applications of NI fertilizers was less than that of non-NI-containing fertilizers. These findings may suggest that the key advantages to using N fertilizers with NIs are helping to protect the environment due to reduced N losses and reducing labor costs due to saving at least one fertilizer application, all while maintaining the yields of the investigated crops.