Nitrogen dynamics in soil management systems. I – flux of inorganic nitrogen (NH4+ and NO3–)
01/Oct/2011
In agricultural systems the N-NH4+ and N-NO3– contents is significantly affected by soil management. This study investigated the dynamics of inorganic nitrogen (N; NH4+ and NO3–) in an experimental evaluation of soil management systems (SMSs) adopted in 1988 at the experimental station of the ABC Foundation in Ponta Grossa, in the Central South region of the State of Paraná. The objective of this study was to evaluate the changes in N-NH4+ and N-NO3– flux in the surface layer of a […]
Soil and water loss and water infiltration in red latosol under different management systems
01/Oct/2011
The soil management systems change the microrelief and the crop residue cover, influencing the soil and water losses. In this study evaluated the soil and water losses and estimated the water final infiltration rate in different soil managements models under simulated rainfall. Crop residues were evaluated in the field after harvest of soybean (Glycine max L. Merrill). Three soil managements systems were studied: no-tillage, disk harrow and chisel plow associated with three levels of dry soybean residue: 0; 2; and […]
Biomass production and nutrient cycling of cover crops in upland rice and soybean
01/Oct/2011
The cover crops in no-till system can contribute to the formation of mulch and nutrient cycling to annual crops in succession. The objective of this study was to evaluate biomass production and nutrient cycling of cover crops sown in the second growing season, in crop rotation after upland rice and soybean, in no-tillage and conventional tillage systems, on a Red Latassol of Rio Verde, state of Goiás, from April 2008 to April 2010. The experiment was evaluated in randomized strips, […]
Content of soil organic carbon in albaqualf soil: influence of irrigated rice management
01/Oct/2011
On paddy soils in the southern region of the State of Rio Grande do Sul, Brazil, irrigated (flooded) rice is grown on 1´000´000 ha, under different soil management systems. The influence of poor drainage and alternating oxidation and reduction cycles on the content of soil organic carbon is still poorly understood. This long-term study (21 years) was conducted in Capão do Leão, RS, Brazil, to evaluate the effect of irrigated rice management systems on soil organic carbon stocks and physical […]
Nitrogen dynamics in soil management systems. II – mineralization and nitrification rates
01/Oct/2011
Nitrogen is the main limiting factor in crop productivity and thereby soil management systems may change the mineralization and nitrification rates. In an experiment on soil management systems implemented in 1988 at the experimental station Fundação ABC, Ponta Grossa, in the central South region of the State of Paraná, inorganic N dynamics were examined to find a soil management strategy with a view to a sustainable environment. The objective of this study was to calculate the net mineralization and nitrification […]
Management systems and the carbon and nitrogen stocks of cerrado oxisol under soybean-maize succession
01/Aug/2011
Carbon and N stocks in soils are determined by the balance between addition and losses, and tillage and cropping systems are decisive in this process. This study aimed to evaluate the effect of soil management systems based on tillage, cover crops and P fertilization on C and N stocks in physical fractions of the soil organic matter and on microbial biomass and respiration in a soil after 11 years under soybean-maize rotation. The experiment was initiated in 1999 in an […]
Carbon stock and its compartments in a subtropical oxisol under long-term tillage and crop rotation systems
01/Jun/2011
Soil organic matter (SOM) plays a crucial role in soil quality and can act as an atmospheric C-CO2 sink under conservationist management systems. This study aimed to evaluate the long-term effects (19 years) of tillage (CT-conventional tillage and NT-no tillage) and crop rotations (R0-monoculture system, R1-winter crop rotation, and R2- intensive crop rotation) on total, particulate and mineral-associated organic carbon (C) stocks of an originally degraded Red Oxisol in Cruz Alta, RS, Southern Brazil. The climate is humid subtropical Cfa […]
Phosphorus distribution in soil as affected by cropping systems and phosphate fertilization management
01/Jun/2011
Cropping systems and management of phosphate fertilization affect P availability in the soil, its accessibility for plants and finally, crop yields. This calls for an evaluation of P distribution in the soil profile, in long-term experiments, to understand the impact of each cropping system and fertilization management on this process. An area of Embrapa Cerrados, in Planaltina – DF, in an Oxisol, with very low P content at the beginning of the experiment, was cultivated for 14 years with soybean […]
Long-term C-CO2 emissions and carbon crop residue mineralization in an oxisol under different tillage and crop rotation systems
01/Jun/2011
Soil C-CO2 emissions are sensitive indicators of management system impacts on soil organic matter (SOM). The main soil C-CO2 sources at the soil-plant interface are the decomposition of crop residues, SOM turnover, and respiration of roots and soil biota. The objectives of this study were to evaluate the impacts of tillage and cropping systems on long-term soil C-CO2 emissions and their relationship with carbon (C) mineralization of crop residues. A long-term experiment was conducted in a Red Oxisol in Cruz […]
Tillage systems and nutrient sources affecting soil cover, temperature and moisture in a clayey oxisol under corn
01/Dec/2010
Tillage affects soil physical properties, e.g., porosity, and leads to different amounts of mulch on the soil surface. Consequently, tillage is related to the soil temperature and moisture regime. Soil cover, temperature and moisture were measured under corn (Zea mays) in the tenth year of five tillage systems (NT = no-tillage; CP = chisel plow and single secondary disking; CT = primary and double secondary disking; CTb = CT with crop residues burned; and CTr = CT with crop residues […]