Upland rice under no-tillage preceded by crops for soil cover and nitrogen fertilization

Abstract

SUMMARYThe grain yield of upland rice under no-tillage has been unsatisfactory and one reason could be the nitrate/ammonium balance in the soil. Cover crops and nitrogen fertilization can be used to change the nitrate/ammonium relation in the soil and improve conditions for the development of upland rice in the no-tillage (NT) system. The aim was to study the effect of cover crops and nitrogen sources on grain yield of upland rice under no tillage. The study was carried out on the Fazenda Experimental Lageado, in Botucatu, State of São Paulo, Brazil, in an Oxisol area under no-tillage for six years. The experiment was arranged in a randomized block split-plot design with four replications. The plots consisted of six cover crop species (Brachiaria brizantha, B. decumbens, B. humidicola, B. ruziziensis, Pennisetum americanum, and Crotalaria spectabilis) and the split-plots of seven forms of N fertilizer management. Millet is the best cover crop to precede upland rice under NT. The best form of N application, as nitrate, is in split rates or total rate at topdressing or an ammonium source with or without a nitrification inhibitor, in split doses. When the cover crops C. spectabilis, B. brizantha, B. decumbens, B. humidicola, and B. ruziziensis preceded rice, they induced the highest grain yield when rice was fertilized with N as ammonium sulfate source + nitrification inhibitor in split rates or total dose at topdressing.Index terms: Oryza sativa, ammonium, nitrate, millet, Brachiaria, Crotalaria spectabilis, nitrogen.( O arroz de terras altas não está tendo bom desempenho no sistema de plantio direto (SPD) e uma razão pode ser o balanço nitrato e amônio no solo. O uso de plantas de cobertura e a aplicação de N podem ser utilizados para alterar a relação nitrato/amônio no solo e proporcionar melhores condições para o desenvolvimento de arroz de terras altas no SPD. O objetivo deste trabalho foi estudar o efeito de plantas de cobertura e fontes de N na produtividade do arroz de terras altas em SPD. O experimento foi realizado na Fazenda Experimental Lageado, Botucatu, em Latossolo Vermelho distroférrico, em área com seis anos no SPD. O delineamento experimental foi em blocos casualizados, com parcelas subdivididas e quatro repetições. As parcelas foram constituídas por seis espécies de plantas de cobertura do solo (Brachiaria brizantha, B. decumbens, B. humidicola, B. ruziziensis, Pennisetum americanum e Crotalaria spectabilis) e as subparcelas por sete formas de manejo da adubação nitrogenada. Milheto é a melhor planta de cobertura para anteceder o arroz de terras altas no SPD e a melhor forma de aplicar o N como nitrato é parcelado ou dose total na cobertura, ou amônio com ou sem inibidor de nitrificação parcelado. C. spectabilis, B. brizantha, B. decumbens, B. humidicola e B. ruziziensis proporcionam as mais altas produtividades do arroz quando o N é aplicado como sulfato de amônio + inibidor de nitrificação parcelado ou aplicação total na cobertura.Termos para indexação: Oryza sativa, amônio, nitrato, milheto, B...

Upland rice yield enhanced by early nitrogen fertilization on previous palisade grass

“…Upland rice cultivation has lower water consumption requirements and is compatible with current agricultural production practices in subsistence crop systems, with few purchased inputs to high-technology systems needed (Kumar and Ladha 2011; Crusciol et al 2013). Studies have reported grain yields of rainfed upland rice of greater than 3 Mg ha -1 (Moro et al 2013;Nascente and Stone 2018). Upland rice cultivation has been used to convert raw land to agriculture, to quickly renew degraded pasture in one growing season, and in rotation with soybean [Glycine max (L.) Merr.]…”

“…In addition to improving soil fertility and increasing the yield of the subsequent crop (Crusciol et al 2015), these perennial forage grasses reduce potential losses from leaching due to their deep roots (Sullivan et al 2017). Moro et al (2013) obtained maximum grain yields of 4.8-6.8 Mg ha -1 for rainfed upland rice grown in succession to Urochloa grasses.…”

“…N increases shoot dry matter, the grain harvest index, and components that are positively related to grain yield (Fageria 2007;Fageria et al 2010). Recent studies have demonstrated that upland rice grain yield responds to N fertilization rates higher than 100 kg N ha -1 , especially when grown in notillage systems following forage grasses (Guimarães and Stone 2003;Lopes et al 2013). However, forage grasses can also compromise the synchronization between N available in the soil and upland rice N uptake and yields by increasing N immobilization before the cash crop is planted, especially in systems with forage grasses with high C/N ratios (Guimarães and Stone 2003;Cantarella 2007;Rosolem et al 2017).…”

Fertilizers with coated urea in upland rice production and nitrogen apparent recovery

“…Nitrogen is one of the most dynamic nutrients in the soil (MORO et al, 2013;NASCENTE et al, 2014). However, the low efficiency of the agronomical use of this nutrient, observed in most agricultural systems, is the result, in part, of losses associated with nitrification of N, i.e., N losses by leaching and denitrification of N-NO 3…”

“…These modifications include the addition of acidic products (BREMNER;DOUGLAS, 1971) and the production of fertilizers with solubility controlled by means of resins or polymers or even elemental sulfur cover (GOULD et al, 1986;FANSURI et al, 2008;CIVARDI et al, 2011;MORO et al, 2013).…”