Study on N and P distribution and nutritional efficiency of mulberry cultivars

Under different N conditions the distribution and nutritional efficiency of N, P and the N recovery of mulberry cultivars were significantly different At higher N rate the concentration of N and accumulated N was increased significantly, the concentration of P was decreased significantly, and the accumulated P was increased in roots and shoots except leaves The concentration of N in different organs decreased in the order: leavesrootsshoots, and the concentration of P∶leavesrootsshoots The accumulated N-P in the whole plant were accumulated N and accumulated P (CK): leavesrootsshoots,but accumulated P (at higher nitrogen rate) in different organs was not significantly different Under higher N conditions the mobilization indexes of N and P decreased significantly, the Nuse efficiency decreased and the Puse efficiency increased significantly The differences of N recovery of supplied N and nutritional efficiency of N and P in mulberry cultivars were considerable All these characteristics may be used as important indices for identifying and selecting high efficient varieties or genotypes