Knowledge assessment and sharing on sustainable agriculture. Main results, gaps in knowledge and challenges in the Latin American platform.

1 CD-ROM. Projeto DG-Research - Contract nº GOCE-CT-2004-505582

Soil physical properties affected by soil management and crop rotation in a long term experiment in Southern Brazil

The main objective of this work is to evaluate soil physical properties affected by cover crop rotations and soil management after 19 years of applying NoTill and Conventional Tillage systems with different winter species on a clayey Oxisol in South Brazil

Knowledge assessment and sharing on sustainable agriculture. Main lessons.

1 CD-ROM. Projeto DG-Research - Contract nº GOCE-CT-2004-505582

Long-term effect of different soil management systems and winter crops on soil acidity and vertical distribution of nutrients in a Brazilian Oxisol

“Strategies” to sustain crop productivity by reducing the fertilizer and lime demands must be developed. The use of plant species that use more efficiently the soil nutrients and tillage systems that provide nutrients accumulation in more labile forms are prerequisites for sustainable agroecosystems. This study aimed to evaluate the long period effect of cultivating different winter species under different soil management systems on vertical distribution of soil nutrients and the soil acidity distribution in soil profile. The experiment was established in 1986 with six winter treatments (blue lupine, hairy vetch, oat, radish, wheat and fallow) under conventional tillage (CT) and no-tillage (NT) in a very clayey Rhodic Hapludox in Southern Brazil. As a result of 19 years of no soil disturbance, soil chemical attributes related to soil acidity and the availability of P and K were more favorable to crops growth up to 10 cm in the soil under no-tillage than in the conventional tillage. On other hand, lime applications in low doses on the soil surface were not efficient in neutralizing the aluminum toxicity below 10 cm depth. It shows that repeated use of lime on the soil surface under NT system can be a viable alternative strategy only when soil acidity and aluminum toxicity in subsurface has been previously eliminated using the adequate amount of lime and incorporating it into the arable layer. Moreover, in the conventional tillage system P and K availability were higher below 10 cm depth compared to the no-tillage system. Even after 19 years of no soil disturbance in the NT system the available P content below 10 cm soil layer was lower than the optimal content of available P recommended to cash crops. The reduced surface K application over time was sufficient to gain adequate crop yields and to maintain the optimal content of soil available K in both soil management systems. The effects of soil management systems were predominant on the soil acidity attributes, and no effects of winter cover crops were observed on soil acidity attributes. Black oat and blue lupine were more efficient in P cycling, increasing the soil available P content especially in the surface soil under NT. The lower amount of biomass produced over time when no cover crops were used in the winter period resulted in lower P and K availability in the soil, showing the important role of growing winter species to maintain soil fertility

Comment limiter la teneur en nitrate des laitues? Contribution à la modélisation des effets d'un stress azoté dans le cadre du projet européen NICOLET

National audienc

Mise au point d'un modele d'optimisation de la date d'un traitement insecticide contre le puceron des epis, Sitobion avenae, dans une perspective de lutte integree

National audienc

Effect of soil management and crop rotation on physical properties in a long term experiment in Southern Brazil

No-tillage system associated with crop rotation increases the amount of crop residues left as mulch on the topsoil, and can be an important and sustainable alternative for soil management in tropical and subtropical conditions. The objective of this work was to evaluate the soil physical properties affected by cover crop, rotation and soil management in a long-term experiment in South Brazil. The experimental site was cultivated for 10 years in a conventional system. Subsequently, the field experiment was established in 1986, and treatments combined six winter cover crop species, and two tillage systems (conventional tillage - CT and no-tillage - NT). The treatments were laid out using a split-plot design in three blocks. The soil samples were collected in October 2005 from trenches at six depths. The bulk density, aggregate size fractions and porosity were determined. The NT system contributed to increase the formation of coarse aggregates and improved the soil aggregation parameters. In the first upper layers, the soil disturbance due to ploughing every season, enhanced the macroporosity and diminished the microporosity on conventional system comparatively to NT. Independently of the type of soil management all winter species increased the higher aggregate size class

An optimization of the effect of deltamethrin against the grain aphid Sitobion avenae

International audienc