Temporal Erosion‐Induced Soil Degradation and Yield Loss

Sustainability, 2023

Agricultural soils provide ecosystem services, but the removal of natural vegetation reduces water infiltration capacity, increasing surface runoff. Thus, monitoring erosion is critical for sustainable agricultural management. Sediment losses and surface runoff were evaluated using a simulated rainfall of 75 mm/h in areas with crops and pastures in both the Caiabi River and Renato River sub-basins of the Teles Pires River watershed in Mato Grosso State, Brazil. In both the Caiabi and Renato sub-basins, data were collected from 156 observations in the upper, middle, and lower regions where (1) soybeans, (2) maize, and (3) pasture were grown alone, with another crop, or with soil that was scarified. Erosion occurred independent of soil texture and was closely related to the management and use of systems involving fewer crops and more soil scarification, regardless of sub-basin location. In uncovered, scarified soil, the soil losses from erosion were greater compared to covered soil, regardless of sub-basin and sub-basin region. In the Renato River sub- basin, soil losses in cultivated areas not planted with crops but with scarification were 66.01, 90.79, and 60.02 g/square meter in the upper, middle, and lower regions, respectively. Agricultural producers need to increase the planting of crops throughout the year and minimize soil disturbance, which will reduce soil erosion and improve sustainability.

Agroforestry Systems, 2010

Inadequate soil management practices adopted in the Brazilian semi-arid region contribute to erosive processes. Agroforestry systems (AFs) have been considered an alternative to reduce water erosion. This study aimed to evaluate the impact of two alternatives AFs, a traditional and an intensive cropping system on the losses of sediments, water, organic carbon and nutrients caused by water erosion in comparison to the natural vegetation (caatinga) in a semi-arid region of northeastern Brazil. The agroecosystems studied were: agrosilvopasture (AGP) which consisted of an alley cropping system, cultivated with Leucaena leucocephala and maize, within an area composed by 22% of native trees (200 native trees per hectare) which was grazed during the dry season; silvopasture (SILV) that was composed by 38% of native trees (260 trees per hectare) with a stocking rate of 20 ewes during whole year; traditional agrosilvopasture (TRAG) being managed as following: total deforestation, burning of the residues, cropped with maize for 2 years (1998 and 1999) and fallow during 8–10 years; and intensive cropping (IC) system which was deforested and burned in 1997 followed by cultivation of maize from 1998 to 2002, and thereafter by a fallow period of 8–10 years similar to TRAG. Two areas of native forest (NF1, NF2) known as ‘caatinga’, used as grassland during the dry season and as a source of wood, were selected and used as reference of steady state in the comparative study in relation to the cultivated sites. Sediment and water losses as a result of erosion were collected during two rainy seasons, i.e. 2003 and 2004, and nutrients and organic carbon contents were determined. Soil samples were collected and organic carbon, pH in water, pH in KCl, water dispersible clay (WDC) and hydraulic conductivity (K0) were measured. In 2003, sediment and water losses did not differ significantly among all treatments. However, in 2004, TRAG (0.70 Mg ha−1) and NF1 (1.37 Mg ha−1) showed the highest sediment losses, whereas TRAG and IC presented the highest water losses. On average, nutrients losses in cropped areas were lower than in natural vegetation (NF1, NF2). The alternative AFs (AGP, SILV) were efficient to reduce water erosion effects when compared to the most common agricultural practices adopted in the region, being highly recommended as sustainable technical alternatives for food production in the region.

Revista Brasileira de Ciência do Solo, 2015

The assessment of spatial uncertainty in the prediction of nutrient losses by erosion associated with landscape models is an important tool for soil conservation planning. The purpose of this study was to evaluate the spatial and local uncertainty in predicting depletion rates of soil nutrients (P, K, Ca, and Mg) by soil erosion from green and burnt sugarcane harvesting scenarios, using sequential Gaussian simulation (SGS). A regular grid with equidistant intervals of 50 m (626 points) was established in the 200-ha study area, in Tabapuã, São Paulo, Brazil. The rate of soil depletion (SD) was calculated from the relation between the nutrient concentration in the sediments and the chemical properties in the original soil for all grid points. The data were subjected to descriptive statistical and geostatistical analysis. The mean SD rate for all nutrients was higher in the slash-and-burn than the green cane harvest scenario (Student’s t-test, p<0.05). In both scenarios, nutrient lo...

1986

Revista Agrogeoambiental, 2020

Water erosion modeling is a fast and accurate way to estimate erosion potential in watersheds. Among the models, we have the Revised Universal Soil Loss Equation (RUSLE) which has a simple structure, low implementation cost and can be used with readily available information, contributing to the planning of soil conservation practices. In this context, the objective of the work was to apply RUSLE to estimate water erosion in the Córrego da Laje watershed affluent directly from the reservoir of the Furnas Hydroelectric Plant, located in the south of Minas Gerais, a region of southeastern Brazil. In this region, water erosion is a serious problem that has caused the silting up of the hydroelectric reservoir and the depreciation of water quality. Soil losses were calculated in Geographic Information System based on topographic, edaphoclimatic characteristics, soil cover, and management practices. The average soil loss of the watershed was 26.80 Mg ha-1 year-1 with the predominance of highintensity erosive rates (> 15 Mg ha-¹ year-¹). Considering the basin use classes, sediment generation was higher in pasture areas (35.87 Mg ha-¹ year-¹), and in areas under maize cultivation (32.05 Mg ha-¹ year-¹). As areas with severe erosion are distributed throughout the watershed, a comprehensive water erosion mitigation plan should be adopted to reduce the environmental damage of the process.

IRRIGA, 2016

FACTORS OF SOIL EROSION IN THE CÓRREGO RICO WATERSHED, SÃO PAULO, BRAZIL BEATRIZ DE OLIVEIRA COSTA1;GILDRIANO SOARES DE OLIVEIRA2; TERESA CRISTINA TARLÉ PISSARRA2; SERGIO CAMPOS1; ARMIN WERNER3; JORGE PEREIRA SANTOS4 E LUIZ SERGIO VANZELA5 1Pós-Doutoranda; Professor Doutor, Departamento de Engenharia Agrícola, Faculdade de Ciências Agronômicas FCA UNESP, Botucatu, São Paulo, Brasil, beatriz.oliveira.costa@hotmail.com; seca@fca.unesp.br2Mestre em Agronomia; Professora Doutora, Departamento de Engenharia Agrícola, Faculdade de Ciências Agrárias e Veterinárias FCAV UENSP, Jaboticabal, São Paulo, Brasil, gilsoaresoliveira@yahoo.com.br, teresap@fcav.unesp.br3Pesquisador Doutor, Lincoln Agritech, New Zealand, Armin.werner@lvl.co.nz4Geógrafo, AMS Kepler, Rio de Janeiro, Brasil, procdigital@gmail.com5Professor Doutor, Universidade Camilo Castelo Branco – UNICASTELO, Fernandópolis, São Paulo, Brasil, lsvanzela@yahoo.com.br 1 ABSTRACT This study aimed to estimate soil losses in 1984 and 201...

Hydrological Sciences Journal, 2023

Land use is a driver for hydrological and soil erosion responses at the watershed scale. This study aimed to assess the hydrological and soil erosion processes in small watersheds under three different land uses, at three time scales. We investigated four small watersheds in southern Brazil: Agricultural North watershed (ANW), Agricultural South watershed (ASW), Eucalyptus watershed (EW), and Grassland watershed (GW). The SWAT (Soil and Water Assessment Tool) model was used to simulate streamflow (SF) and sediment yield (SY) at monthly, daily and hourly time scales. EW had the lowest SF and SY, whereas ANW showed the highest SY with an increase of 90% and ASW had the highest SF with an increase of 70%. The SWAT model had a satisfactory performance in all time scales and watersheds for SF and SY (NSE and R 2 ≥ 0.3 and P bias ≤ ± 39%). Overall, land use has a major impact on hydrological and soil erosion responses, and the magnitude of these processes depends on the time scale.

2013

Termos de indexação: plantas de cobertura, escoamento superficial de água, erosão do solo.

Revista Brasileira de Ciência do Solo

The identification of erosion-susceptible areas is fundamental for the adoption of soil conservation practices. Thus, the best way to estimate the spatial pattern of soil erosion must be identified, in which the process uncertainties are also taken into consideration. The purpose of this study was to evaluate the spatial and temporal uncertainty of soil loss under two scenarios of sugarcane harvest management: green cane (GC) and burnt cane (BC). The study was carried out on a 200-ha area, in Tabapuã, São Paulo State, Brazil. A regular 626-point sampling grid was established in the area, with equidistant intervals of 50 m and a final plant density of about 3.3 samples per ha. The probability that the soil loss would exceed the tolerable limit of 6.67 t ha-1 yr-1 was estimated for each management scenario and after the five harvests. The temporal uncertainty was determined by integrating the estimated annual probabilities, representing the harvests. Areas with soil loss risks above the threshold were identified based on probability maps, generated from the individual and combined dichotomous variables. Soil losses from the BC were highest, during all five harvests. With the exception of the 5 th harvest and the entire cultivation cycle under GC, all soil loss estimates were spatially dependent. From the 4 th harvest under GC, the probability of the soil loss exceeding the threshold was above 80 % in zero percent of the area, whereas, for BC, the probability exceeded 80 % in 40 % of the area. The production cycle allowed the delimitation of priority areas for the adoption of conservation practices in each management. In the BC, areas with steeper slopes were more likely to exceed the threshold with lower uncertainties.

2004

Cassava, an important staple food and industrial crop of the low to medium-altitude tropics, is associated with soil exhaustion and degradation worldwide. Slow initial soil cover of the crop, in particular when grown without fertilizer, and the erosive nature of tropical rainstorms, combined with the increasing cultivation of marginal and steep lands are the principal factors leading first to the degradation of soils and then of rural livelihoods themselves. They are indeed the loom on which the fabric of poverty is woven. Research focussing on the arrest or reversal of soil degradation has to take a long-term approach since damage to agricultural lands from erosion is not normally detected in a couple of years and the loss in agricultural productivity is more of a gradually progressing than instantaneous nature. Yet, capturing the magnitude of change is necessary to quantify damage and justify investment in research to find viable solutions to the problems outlined above. A special effort has therefore been made to develop a sustained, long-term research programme on factors related to soil erosion and degradation in a mid-altitude location of the tropical Andes representative of vast extensions of agricultural lands in Central-and South America. Over a twelve-year time span (1986-1998), six individual doctoral research programmes, accompanied by numerous MSc programmes were planned and carried out in a sequential, coordinated way so as to explore causes and effects of soil erosion and devise conservation practices in cassava-based cropping systems of an Andean mid-altitude tropical environment. The research reported in this doctoral dissertation , the last of those six , profits greatly from the large stock of scientific data previously generated and is thus able to provide a medium-term perspective on degradation and productivity aspects as well as a solid, critical review of suitable conservation practices. Beyond this 12-year overview and synthesis, the last phase of the project focused on elucidating the role of rainfall erosivity in the context of soil erosion and conservation in this Andean environment from where no scientifically sound results were available until now. The research on rainfall erosivity implied a rigorous scientific approach to evasive and complicated to measure parameters such as raindrop size and a reassessment of the rain drop energy-rainfall intensity relationship. These and other highly demanding tasks were fulfilled with precision and perseverance. Based on the results, future researchers are now able to generate rainfall erosivity maps throughout the region based on rainfall quantity data thus providing an easy to generate and useful planning and decision support tool for agricultural development in the region. What is left behind by this effort which went well beyond the twelve-year project phase is not only a wealth of scientific information on factors driving soil erosion and degradation in mid-altitude tropical Andean hillsides. Beyond science, and by gradually involving more and more stakeholders in the design of this research, planning tools and many practical solutions and approaches to conservation have emerged and have been taken up by local institutions, NGO's and even schools and farmers groups for whom this research was conducted. We are most grateful to Deutsche Forschungsgemeinschaft who provided the seed money to get this programme started, and to the Bundesministerium für wirtschaftliche Zusammenarbeit und Entwicklung (BMZ) who had the vision and the determination to support this research over the necessary length of time to make it relevant and useful to those for whom it was conducted.