Yields and Nitrogen Dynamics in a Rice–Wheat System Using Green Manure and Inorganic Fertilizer

Integrating fertilizer N (FN) with legume green manures (GM) can foster sustainable and environmentally sound agricultural systems in subtropical, semiarid soils low in organic matter. A 4-yr replicated field experiment with irrigated rice (Oryza sativa L.) and wheat (Triticum aestivum L.) rotations was conducted on a sandy loam soil in the Punjab of India to evaluate the effects of incorporating cowpea (Vigna unguiculata L.) or sesbania (Sesbania aculeata L.) GM on crop productivity, N-use efficiency, and NO3 leaching. Rice grain yields with pretransplant incorporation of 20 and 40 Mg GM ha-1 (GM20 and GM40) ranged from 5.18 to 5.81 Mg ha-1, which were equivalent to the 5.40 Mg ha-1 obtained with 120 kg FN ha-1 (FN120). Rice yield with 60 kg FN ha-1 (FN60) and GM20 was double the control yield and 6% greater than the FN120 treatment. Nitrogen utilization by rice was greater for GM20 than FN, as indicated by greater fertilizer N equivalents and an apparent N recovery by rice of 79 vs. 63%. While FN had no residual effects, residual GM produced greater wheat yields, indicating that FN applied to wheat could be reduced by 25%. Soil NO3–N leaching to 60 cm in the rice crop was apparently used by the subsequent wheat crop, which has a deeper and more extensive rooting system. After 4 yr, use of FN120 for both crops resulted in 35 kg of residual NO3–N ha-1 in the 150-cm soil profile (74% below 90 cm), whereas only 19 kg NO3–N ha-1 remained with GM20 plus FN60. Use of GM20 with FN60 for a rice–wheat rotation demonstrated greater yields of rice and wheat, 25 to 50% reduction in fertilizer N use, and decreased potential for groundwater NO3 contamination

Status of the World’s Soil Resources Main report

The SWSR will constitute the reference document on the status of global soil resources with a strong regional assessment on soil change. The information is based on peer-reviewed scientific literature, complemented with expert knowledge and reliable project outputs (mainly FAO ones). It provides a description and a ranking of ten major soil threats that endanger ecosystem functions, goods and services globally and in each region separately. Additionally, it describes direct and indirect pressure son soils and ways and means to combat soil degradation at all levels. The report contains a Synthesis report for policy makers that summarizes its findings, conclusions and recommendations.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro de Investigaciones Agronómicas (CIA)UCR::Vicerrectoría de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Agronomí

Etat des Ressources en Sols dans le Monde (Résumé technique)

Etat des Ressources en Sols dans le Monde (Résumé technique

World’s soils are under threat

The Intergovernmental Technical Panel on Soils has completed the first State of the World's Soil Resources Report. Globally soil erosion was identified as the gravest threat, leading to deteriorating water quality in developed regions and to lowering of crop yields in many developing regions. We need to increase nitrogen and phosphorus fertilizer use in infertile tropical and semi-tropical soils – the regions where the most food insecurity among us are found – while reducing global use of these products overall. Stores of soil organic carbon are critical in the global carbon balance, and national governments must set specific targets to stabilize or ideally increase soil organic carbon stores. Finally the quality of soil information available for policy formulation must be improved – the regional assessments in the State of the World's Soil Resources Report frequently base their evaluations on studies from the 1990s based on observations made in the 1980s or earlier.European Commission/[]//BélgicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Agroalimentarias::Centro de Investigaciones Agronómicas (CIA