Forage and nitrogen rates on P-ORGANIC stock in maize cropped soil

• Grant number: 18/05725-7
• Support Opportunities: Scholarships in Brazil - Master
• Start date: September 01, 2018
• End date: August 31, 2019
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: Juliano Carlos Calonego
• Grantee: Bárbara Fernanda da Silva
• Host Institution: Faculdade de Ciências Agronômicas (FCA). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Associated research grant: 15/50305-8 - A virtual joint centre to deliver enhanced nitrogen use efficiency via an integrated soil-plant systems approach for the UK & Brazil, AP.TEM

Abstract

Phosphorus (P) is one of the most limiting nutrients on plant nutrition in tropical soils. In soil it is found as inorganic (Pi) and organic (Po) forms, with different lability. The less labile forms of Pi and Po may also contribute to plant nutrition, but for this it needs to be, respectively, solubilized and mineralized.Cover crops contribute to the solubilization of less labile compounds and increasing soil avaliablie P content, but does not always imply in its recycling and absorption by plants.Thus, two main hypotheses were raised: a) the cover crop roots may release organic acids capable of complexing P through a metal bridge, reducing P movement in the soil; b) covercrops absorbs soil P and, after decomposition, returns it, for the most part, in the form of phytic acid, which the plant does not absorb. Nitrogem fertilization may influence the mineralization of soil organic compounds and potentiate Po as phosphorus source for cash crops.Therefore, two experiments will be carred out: the first one aiming to evaluate the effect of cover crops (U. ruziziensis, U. brizantha and P. maximum) and nitrogen rates (70, 140 and 210 kg ha-1) on Po soil stock and its relation with the yield and P accumulation by maize two seasons; and the second experiment aiming to evaluate the P mobility in previously corvercrops grown soil. The analyzed variables will be: fractions of Pi and Po in the soil; phytic acid content in soil and covercrops; and P in maize plants. In greenhouse and laboratory, the mobility of the phosphorus will be evaluated to time in contrasting texture soils previously growing with the three cover plants, as well as in these soils without previous cultivation of these cover plants.

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

SILVA, Bárbara Fernanda da. Forage and nitrogen influencing the P dynamics in soil under maize crop. 2019. Master's Dissertation - Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agronômicas. Botucatu Botucatu.