Efeitos de diferentes conteúdos de água do solo e doses de nitrogênio sobre o comportamento do trigo (Triticum aestivum L.).

Abstract

The objective of the present work was to study the effects of different soil water contents and nitrogen levels on the wheat behavior. The experiment was carried out on a Vertisoil , at the Mandacaru Experimental Station, located in Ouazeiro, Bahia. The parameters used to estimate the effects of different soil water contents and nitrogen levels on the wheat behavior were the following: grain yield, straw yield, straw / grain relationship, plant height , head lenght, number of grains per head and percentage of grain protein. The experimental design used to study these effects was a randomized split plot with regimes of water as treatments and levels - of fertilization as subtreatments .The treatments were: to irrigate the wheat when the available soil water reached 45, 30, 15 and 0% and the subtreatments were: 0, 40, 80 and 120 Kg/ha of nitrogen. The analyses of the results showed that the grain yield, straw yield, plant height, head lenght and number of grains per head increased with the Increment of soil water content. The highest straw/grain relationship was obtained with the driest treatment (0% of available water) , wich differed significantly of the others. The percen tage of grain protein increased as the soil water content decreased. Grain and straw yields increased with the increment of applied nitrogen, but there wasn't a significantly difference among the fertilized treatments. Nitrogen didn't have a significantly influence in the straw/grain relationship. Plant height, head lenght and number of grains per head of the nitrogen fertilized plants were significantly greater than the unfertilized plants, but there wasn't a significantly difference among the fertilized treatments. The percentage of grain protein increased with the increment of applied nitrogen. With the support of the obtained data it is possible to conclude that, to obtain the greatest grain yields where the study was conducted, the wheat should be irrigated when the available soil water content reach 3056 and fertilized with 80 Kg/ha of nitrogen.