Cobertura do solo e acumulação de nutrientes pelo amendoim forrageiro

Abstract

Resumo -O objetivo deste trabalho foi determinar as taxas de cobertura do solo, produção de biomassa e acumulação total de N, P e K da parte aérea da leguminosa herbácea perene amendoim forrageiro (Arachis pintoi Krapov. & W.C. Greg.), em diferentes densidades e espaçamentos de plantio. O delineamento experimental adotado foi de blocos ao acaso, em arranjo fatorial 2x4, com quatro repetições. Os tratamentos constaram de espaçamentos entre sulcos de plantio (25 e 50 cm), e de densidades de plantas (2, 4, 8 e 16 plantas/m linear). A cobertura total do solo ocorreu aos 224 dias após o plantio. Foram constatadas diferenças de densidades de plantio na taxa de cobertura do solo, produção de biomassa e acúmulo de nutrientes na parte aérea do amendoim forrageiro. Todavia, não foram observadas diferenças quando se variou o espaçamento entre sulcos. Entre as alternativas testadas, a densidade de 8 plantas/m linear no espaçamento de 50 cm entre sulcos de plantio foi a combinação mais adequada para a plena formação da cobertura viva com amendoim forrageiro.Termos para indexação: Arachis pintoi, população vegetal, espaçamento, parte aérea, teor em matéria seca. Soil coverage and nutrient accumulation by pinto peanutAbstract -The objective of this work was to determine the rate of soil coverage, biomass yield and total accumulation of N, P and K in the aerial biomass of the legume Arachis pintoi Krapov. & W.C. Greg. The experimental design was a randomized block with four replicates arranged in a 2x4 factorial with two levels of row spacing (25 and 50 cm between rows) and four different planting densities (2, 4, 8 and 16 plants/m). Complete soil coverage was achieved 224 days after planting. Planting density affected the rate of soil coverage and the rate of dry matter and nutrient accumulation by the shoot tissue of the legume, but these parameters were not significantly affected by row spacing. The results suggest that the optimum planting density was 8 plants/m in rows spaced 50 cm apart.Index terms: Arachis pintoi, plant population, spacing, aerial parts, dry matter contents.(1) Aceito para publicação em 25 IntroduçãoPráticas de manejo e conservação, como o emprego de plantas de cobertura, são relevantes para a manutenção ou melhoria das características quími-cas, físicas e biológicas dos solos. A adubação verde utiliza espécies de diferentes famílias botânicas, nativas ou introduzidas, que cobrem o terreno em períodos de tempo ou durante todo ano. As leguminosas se destacam por formarem associações simbióticas com bactérias fixadoras de N 2 , o que resulta no aporte de quantidades expressivas desse nutriente no sistema solo-planta.

Nitrogen fertilization on cotton cropped under straw formed by seed proportions of crotalaria and brachiaria

“…Perin et al (2003) confirmed that C. juncea was able to incorporate 89 kg ha -¹ of N into the soil via BNF, when associated with millet, and under experimental conditions C. juncea had the highest growth competitiveness with millet, due to the higher biomass production, about 31% higher than millet. Heinrichs and Fancelli (1999) found no difference in the levels of nitrogen when the vetch leguminous was associated with oats, regardless of proportion.…”

“…However, for providing low dry matter with composition of low C:N ratio and loads of soluble compounds, it shows rapid decomposition and mineralization (Zotarelli, 2000), and therefore it does not allow adequate coverage and soil protection. However, there is larger N input in the system with the introduction of this leguminous by biological nitrogen fixation (BNF) (Perin et al, 2003) and there are no reports to Cerrado region regarding the reduction of nitrogen fertilization being possible in the cotton in subsequent cultivation.…”

Green manure in coffee systems in the region of Zona da Mata, Minas Gerais: characteristics and kinetics of carbon and nitrogen mineralization

“…The N amount in the dry biomass was much lower than reported by Soares et al (2006). A. pintoi can produce 20 Mg ha -1 of biomass per year and accumulate 520 kg ha -1 N (Perin et al, 2003). S. guianensis and C. mucunoides contained intermediate amounts of nutrients.…”

“…Other factors are the amount and quality of the residue produced, the nutrient amount released through residue decomposition, and the temporary synchrony between the nutrient release by decomposition and crop requirements. Among the many legume species used as green manure, Stizolobium aterrimum, Arachis pintoi, Calopogonium mucunoides and Stylosanthes guianensis stand out owing to the ability to produce high amounts of biomass and to accumulate high nutrient concentrations, even in soils with low natural fertility and high acidity, besides the atmospheric N 2 fixation capacity (Aita et al, 2000;Niang et al, 2002;Muhr et al, 2002;Borkert et al, 2003;Perin et al, 2003).…”

Macronutrients release by green manure species grown in cerrado/pantanal ecotone

“…This characteristic considerably increases the economic return of the main activity considerably, besides reducing the application of the conventional chemical fertilizers. Species from this botanical family also present rapid decomposition compared to other families (PERIN et al, 2003). This happens because these plants present low relation between carbon and nitrogen (C/N ratio) to .…”