Leaf area index and SPAD of soybean after offseason crops and nitrogen fertilization, and their relation to grain yield.
leaf area index and SPAD of soybean, as well as the relationship between these variables and grain yield of soybean. 2016/17 and 2017/18 cropping seasons. The winter crops were allocated to the plots: palisadegrass (Urochloa ruziziensis) crotalaria (Crotalaria spectabilis) maize (Zea mays) with 0 and 80 kg N ha 1 topdressing, wheat (Triticum aestivum) and fallow. Two levels of N for soybean were applied at sowing time (0 and 30 kg N ha 1 the SPAD index were negatively correlated with grain yield, but in the second cropping season these correlations were not present.