Difference of nitrogen utilization and distribution of mineral nitrogen in soil profile by competitive abilities of intercropping systems

Difference of nitrogen utilization efficiency and distribution of mineral nitrogen in soil profile by barley/maize, wheat/maize, faba bean/maize intercropping systems and corresponding sole cropping systems with nitrogen application of 0 and N 225 kg/ha were conducted in field microplot experiment. The results indicated that competitive ability of crops for nutrition closely related to the concentration and accumulation of mineral nitrogen in crops root zone. Accumulation of mineral nitrogen under barley and wheat strip intercropped with maize decreased 203-282 and 107-171 kg/ha compared with faba bean intercropped with maize in 0-100 cm soil profile, respectively. Accumulation of mineral nitrogen under maize strip intercropped with barley and wheat reduced 93-120 and 56-87 kg/ha compared with maize intercropped with faba bean, respectively. Crops, interspecific competition and soil condition affected accumulation of mineral nitrogen in soil profile. Interspecific interaction increased nitrogen recovery efficiency for barley and wheat intercropped with maize, however, decreased that for maize intercropped with barley and wheat. Nitrogen utilization efficiency was highest in low soil fertility for competitive intercropping system. Nitrogen harvest index was reduced in barley and wheat with N fertilizer applied, but increased in maize and not changed in faba bean. Crops competition, soil fertility, rate of fertilizer application and cultural measure should be considered carefully in order to achieve intercropping advantage when we choice associated crops. Complement system of legumes/cereals were planted in low soil fertility and competitive system of cereals/cereals in high soil fertility.