Respostas do feijoeiro lâminas de água e adubação nitrogenada

Abstract

Withthe objective ofevaluating the responses of beanplants to dif&rent water leveis, nitrogen fertilization and cultivars, a study was conducted at the UFLA Experimental Field located in Lavras, Minas Gerais, under randomized block design in the scheme of subdivided parcels with three replications. The internai water status of the beanplant alongthe plant cycle and ofa day, growth, leafárea, drymatter accumulation, accumulation ofnutrients, evapotranspiration, stand, yield, components andthe water use efificiency were evaluated. The results obtained allowed to verify that during the cycle, under high evaporative demand, onlynitrogen stimulated the increase in the leafwaterpotential without afifecting the stomatic conductance. The water layer stimulated only the increase in the stomatic conductance. The bean cultivars affected both the plant water potential and the conductance. Under the condition oflow demand, the nitrogen and water layers did not affect the leaf water potential or conductance and the cultivars affected only the stomatic conductance. m the evolution during a day, the nitrogen, water layers andcultivars affected theleafwaterpotential and stomatic conductance. These parameters showed high correlation with the lack of vapor pressure and air and leaftemperatures. Thetotal soil-leafhydrauüc conductance was affected by the nitrogen levei, water layers and cultivars of the bean plant. Nitrogen stimulated the increase in teh growth rate, final stand, yield and components and the water use efficiency. The water layers affectec the growth rate, leaf área, accumulation of nutrients and dry matter and stimulated the increase in evapotranspiration, final stand, yield, number ofgrains per pod and number of pods per plant, weight reduction of 100 grains and the water use efficiency. The Ouro Negro cultivar was more productive, with more weight per grain and higher production per plant. The Roxo 90 cultivar was less efficient with respect to the wateruse efficiency.