Efeitos da compactaÃÃo do solo e da umidade sobre a absorÃÃo de N, P, K, os componentes de produÃÃo e a produtividade de grÃos de arroz. / Effects of soil compaction and moisture upon the uptake of N, P,K , yield components and rice grain yield

AUTOR(ES)
DATA DE PUBLICAÇÃO

2004

RESUMO

The work was intended to study the effects of different compaction levels and water management upon the uptake of nitrogen (N), phosphorus (P) and potassium (K), the development of the root system and shoot of rice plants , the yield components and rice grain yields grown in two sorts of soil. The experiment was conducted in greenhouse of the Agriculture Department of the Universidade Federal de Lavras â UFLA in Lavras, MG, over the period of September, 2002 to January, 2003. The treatments consisted of two soils: fluvic Neosol and Yellow-Red Latosol combined with six levels of soil compaction: 0%, 16%, 32%, 48%, 64% and 80% of the range of the variation of soil density (ds) and three soil water management: M1 âsoil 100% saturated, M2 âirrigation when were consumed from 25% to 30% of the available water for plants (AD) and M3 â irrigation when were consumed from 50% to 60% of the AD. The completely randomized design in a 2 x 6 x 3 factorial scheme was utilized, its being two soil classes, six compaction levels and three water management with three replicates, amounting to 108 plots which, were made up of PVC pipe of 200 mm in diameter x 35 cm high. The contents of N, P and K in the shoot of the plants, blooming, plant height, root and shoot dry matter of plants, number of tillers and panicles per pot, the number of filled grains per panicle, sterility of spikes, the 100-grain weight and grain yield per pot were evaluated. The results showed that soil compaction decreased the uptake of N, P and K, plant height, root and shoot dry matter yield of rice plants, number of tillers and panicles per pot and grain yield per pot. On the other hand, it increased spikesâ sterility and 100-grain weight regardless water and soil management. Out of the three water managements tested, the one with the saturated soil shortened the number of days to blooming, and in general, increased the means of the other characteristics evaluated in bopth soils, regardless compaction level. The results obtained enabled to conclude that compaction âper siâ constitute no barrier to the development of the root system and that its indirect effects upon nutrient availability linked to the decreased soil aeration are more relevant than the physical resistance to root growth.

ASSUNTO(S)

no-tillage arroz; irrigaÃÃo; plantio direto rice fitotecnia irrigation

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