Soil Physical Properties, Dynamics of N P K and Crop Yield as Influenced by Soil Compaction Under No-Till

The no-till system of cultivation occupies 95 million ha of cropped land in the world. In Brazil, 25 million ha of cropped land are under such a system of cultivation. The utilization of no-till has been increasing due mainly to a more adequate soil conversation in these areas. Although, soil compaction has been noted as one of the main problems in areas under no-till cultivation for years. Not plowing the soil, plus the traffic of machines in these areas, lead to soil structure alterations, resulting in poor soil physical quality and changes in the dynamics of N P and K, which can reduce crop yields. In terms of N, soil compaction can reduce the transport of the nutrient to plant roots and also result in higher N denitrification. Plant bioavailability of P and K can also be reduced in compacted soils due to less plant root system development. In Brazil, there is not enough information on how to manage these problems. This project intends to integrate chemical and physical evaluations of soils under no-till foreseeing future practical information to farmers on how to manage the soil compaction as to obtain higher yields.