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Soil organic matter and carbon dynamic in the soil-plant-atmosphere system as a function of crop rotations in notill

Grant number: 14/15589-2
Support type:Regular Research Grants
Duration: November 01, 2014 - October 31, 2016
Field of knowledge:Agronomical Sciences - Agronomy
Principal Investigator:Juliano Carlos Calonego
Grantee:Juliano Carlos Calonego
Home Institution: Faculdade de Ciências Agronômicas (FCA). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
Assoc. researchers:Ciro Antonio Rosolem

Abstract

The importance of soil organic matter (SOM) and their functions are known with and are addressed in the literature, however, the processes that involve the dynamics still need to be better understood, and the factors that affect the accumulation and quality of SOM. The objective of this study is to quantify and qualify the MOS according to crop sequences conducted in No-till (NT) correlating to the supply and quality of waste produced. In addition, the objective is to estimate the need for residue inputs for each crop succession to maintain or increase the C stock. The research will be conducted between 2014/2015 e 2015/2016 harvests, in a Hapludox conducted in notill since 2001, and the last nine years are maintained experimental treatments involving different crop sequences. The experimental area located at the Experimental Farm Lageado (FCA / UNESP, Botucatu). In the autumn-winter are cultivated grain-sorghum (Sorghum bicolor(L.) Moench) and ruzigrass (Urochloa ruziziensis (R. Germ. and C. M. Evrard) Crins), single or intercropped, as plot, while the spring is cultivated Pearl millet (Pennisetum glaucum L.), forage sorghum (Sorghum bicolor (L.) Moench) and sunn hemp (Crotalaria juncea L.), as subplots, and soybeans grown in the summer. The experiment is conducted in split-plot arrangement with four replications. Will be sampled throughout the soil profile for analysis of the levels and total stocks C and N. In soil samples are also analyzed the levels of microbial C and N, as well as studying the degree of lability and humification of organic matter in the soil by chemical and physical fractionation. The plants will be chemically analyzed for the levels of C and N, and structural carbohydrates. The straw on the soil will be sampled to determine the mulch prior to sowing of the succeeding crops. The CO2 emission will be determined and the index calculated carbon conservation. Finally, will be the mathematical modeling of soil organic matter and the results compared with data obtained. The data will be submitted to analysis of variance and t test comparison of means at 5% probability of error. Will be performed Pearson correlation analysis between the variables studied, mainly to check the influence of the quantity and quality of plant residues in the accumulation of SOM and its fractions as well as in C-CO2 emission. (AU)