Agronomic efficiency of nitrogen fertilizers in tillage systems that retain the chaff on the soil

• Grant number: 10/06962-0
• Support Opportunities: Regular Research Grants
• Start date: July 01, 2010
• End date: June 30, 2012
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Godofredo Cesar Vitti
• Grantee: Godofredo Cesar Vitti
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

Nitrogen (N) source more used is urea but it has serious problems with high nitrogen losses by ammonia volatilization. It is intensified in no-tillage system and in cane harvested green. Brazil is one of the producing greaters of maize. The cultivation of these crops occurs predominantly in tillage systems that retain the chaff on the soil because of many benefits to practical conservation and soil fertility in tropical region. These systems promote deposition of a straw layer in soil surface. Straw modifies the traditional management with direct relation in topdressing fertilization. Objectives will be evaluate the efficiency of the coat urea with copper sulfate and boron acid, zeolite added in urea, mixtures of ammonium sulphate with urea and coat urea in maize topdressing fertilization in no-tillage system, and coat urea with copper sulfate and boron acid and, coat urea with sulfur in sugar cane culture compared with N traditional sources. Ammonia volatilization and proportion of ammonium:nitrate and pH of the soil. The nutrition state, productivity and quality parameters will be evaluate in plants. Experimental design will be in blocks completely randomized with eight treatments in maize: 1) control, 2) control + gypsum, 3) urea + gypsum, 4) urea + zeolite + gypsum, 5) ammonium nitrate + gypsum, 6) ammonium sulphate + urea, 7) ammonium sulphate + coat urea with copper sulfate and boron acid, 8) coat urea with copper sulfate and boron acid + gypsum, with four repetitions. The sugar cane experimental will be six treatments: 1) control, 2) urea, 3) ammonium nitrate, 4) coat urea with copper sulfate and boron acid, 5) ammonium sulphate and 6) coat urea with sulfur. The determinations of losses by ammonia volatilization and soil proportion of ammonium: nitrate and pH will be evaluated in the 2, 4, 6, 8, 12, 16, 20, 24 and 28 days after application of the products. (AU)