Crop residues in rotations systems as determinants of soil aggregate fractionation and c and n mineralization

• Grant number: 15/23389-6
• Support type: Scholarships abroad - Research Internship - Doctorate
• Effective date (Start): March 15, 2016
• Effective date (End): December 14, 2016
• Field of knowledge: Agronomical Sciences - Agronomy
• Principal Investigator: Juliano Carlos Calonego
• Grantee: João Paulo Gonsiorkiewicz Rigon
• Supervisor abroad: Alan Joseph Franzluebbers
• Home Institution: Faculdade de Ciências Agronômicas (FCA). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Local de pesquisa : North Carolina State University (NC State), United States
• Associated to the scholarship: 13/23359-4 - Management systems and crop sequences as determinants in the amount and quality of the soil organic matter, BP.DR

Abstract

Soil aggregate distribution and associated C and N fractions and soil C and N mineralization are important for understanding soil quality dynamics. The influence of management practices on soil C and N concentrations and aggregate distribution depends on the quantity and quality of crop residues at the soil surface under no-till. This project is a continuation of two experiments initiated in 2003 on a Typic Rhodudalf (TR) and in 2006 on a Rhodic Hapludox (RH) at the Lageado Experimental Farm, College of Agricultural Sciences - UNESP, Botucatu, SP, Brazil. Treatments were (1) different dry-season crops - triticale or sunflower in TR and ruzigrass, grain sorghum, and ruzigrass + grain sorghum in RH and (2) different spring cover crops - pearl millet, sunn hemp, and sorghum-sudangrass in both experiments. In the Typic Rhodudalf, there was also a treatment with a bare fallow. Soybean was grown every year in the summer. Soil samples were collected at 0.0-0.1 and 0.1-0.2 m depths to determine Wet-aggregate distribution and aggregate-associated C and N concentrations and soil C and N mineralization in both experiments.