Variabilidade espacial da produtividade de plantas forrageiras em diferentes sistemas de manejo do solo

• Autor(a) principal: Vitória, Edney Leandro da
• Data de Publicação: 2010
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/677
• topic: Preparo do solo; Forragicultura; Geoestatística; Tillage; Forage crops; Geostatistics; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::MECANIZACAO AGRICOLA

Soil management systems aim to create favorable conditions for culture development, but inadequate management conditions may cause structural changes in soil and yield interference. The spatial distribution of culture yield is frequently studied, taking into account its distribution as random and uniform in space. However, such yield may be described and quantified as spatially dependent on the physical properties influenced by soil management. These descriptions have been carried out with the help of geostatistic tools that allow detecting the existence of spatial dependence, to describe it and make estimates for not sampled places. This work investigates spatial dependence of variables related to the physical properties of soil and forage plant yield as well as to the spatial correlation among these variables under three soil management systems: no-till planting, minimum cultivation and conventional preparation. Thus, this work aimed todetermine the influence of soil management on forage plant yield and on the variability of the physical properties of such soil. The samplings were made in 99 points for each system, at the crossing of the coordinates X and Y using a 5 x 5 m net. The nonderformed samples were collected at depth ranges corresponding to 0.0 to0.15 m and 0.15 to 0.30 m. To determine dry matter, the forage plant was cut on an average at 0.10 m from soil at the crossing of the coordinates in an area of 1.0 m²..The material collected was identified, weighed and taken to the oven to determine its total dry matter. Foliar area index was determined indirectly using a canopy analyzing instrument, with 10 measurements above and 10 measurements below the canopy being carried out. The experiment was arranged in a randomized block design, in asplit-split-plot scheme, CHECAR with the plots beingconstituted by the three soil management systems, the split plots, by two forage plants and the split-split plots, by five yield evaluation periods, with four repetitions. The spatial dependence of each attribute was studied by calculating simple semivariograms. However, attributes presenting spatial dependence had their crossed semivariograms calculated. Conventional preparation presented mean results of dry matter production and foliar area index significantly higher than the minimum cultivation and no-till planting systems, as a result of a break in the compacted layer on the surface, providinga better contact of the seed with the soil. A highpercentage in the variation of dry matter yield and foliar area index was observed, explained by the spatial dependence on the three soil management systems. To evaluate the physical properties of the soil, the fit models equally applied in the three soilmanagement systems were the spherical, the exponential and the Gaussian. Aheterogeneous spatial distribution was observed both for dry matter yield andfoliar area index. It was concluded that forage plant yield, in terms of total dry matter and foliar area index, is spatially dependent on the physical properties of the soil in each of the management systems to which this soil is submitted.