Hydrological processes obtained on the plot scale under four simulated rainfall tests during the cycle of different crop systems

The cropping system influences the interception of water by plants, water storage in depressions on the soil surface, water infiltration into the soil and runoff. The aim of this study was to quantify some hydrological processes under no tillage cropping systems at the edge of a slope, in 2009 and 2010, in a Humic Dystrudept soil, with the following treatments: corn, soybeans, and common beans alone; and intercropped corn and common bean. Treatments consisted of four simulated rainfall tests at different times, with a planned intensity of 64 mm h-1 and 90 min duration. The first test was applied 18 days after sowing, and the others at 39, 75 and 120 days after the first test. Different times of the simulated rainfall and stages of the crop cycle affected soil water content prior to the rain, and the time runoff began and its peak flow and, thus, the surface hydrological processes. The depth of the runoff and the depth of the water intercepted by the crop + soil infiltration + soil surface storage were affected by the crop systems and the rainfall applied at different times. The corn crop was the most effective treatment for controlling runoff, with a water loss ratio of 0.38, equivalent to 75 % of the water loss ratio exhibited by common bean (0.51), the least effective treatment in relation to the others. Total water loss by runoff decreased linearly with an increase in the time that runoff began, regardless of the treatment; however, soil water content on the gravimetric basis increased linearly from the beginning to the end of the rainfall. O sistema de cultivo influencia a interceptação de água pelas plantas, a armazenagem de água nas depressões do terreno, a infiltração de água no solo e o escoamento superficial. Este trabalho objetivou quantificar alguns processos hidrológicos em sistemas de cultivo do solo realizados em contorno no declive, em 2009 e 2010, em um Cambissolo Húmico alumínico, cuja área foi mantida sem preparo prévio do solo, nos seguintes tratamentos: solteiros - milho, soja e feijão; e consorciados - milho e feijão. Os tratamentos foram submetidos a quatro testes de chuva simulada, em épocas distintas, com intensidade planejada de 64 mm h-1 e duração de 90 min. O primeiro teste foi aplicado 18 dias após a semeadura e, os demais, aos 39, 75 e 120 dias, após o primeiro. Os diferentes momentos de aplicação das chuvas e os diferentes estádios do ciclo das culturas influenciaram o teor de água no solo antecedente às chuvas, o tempo de iní