| This study was conducted to evaluate soil nutrient status of field grown mulberry using soil nutrient systematic approach and effects of different N, P, K, B and Zn levels on the mulberry growth, leaf yield, nutrient characteristics and economic benefit. The main results can be summarized as follows:1) Major nutrients limiting mulberry yield are N, K, Zn and B, potential limiting nutrients are P and Fe.2) Suitable application of N, K and P rate significantly improves mulberry growth. Branch lengthand its base diameter, leaf area and weight increase with N, K and P application rate increase.3) Nutrient requirement of field mulberry is N >K2O >P2O5. 12.34 kg N, 4.39 kg P2O5 and 9.28 kg K2O are absorbed to produce 1000 kg mulberry leaves, and nutrient absorption ratio in mulberry, i.e. N: K2O: P2O5, was 1:0.36:0.72, which is suitable for mulberry growth.4) Optimum fertilization rates of field mulberry are 414 kg N /hm2, 300 kg P2O5 /hm2 and 337.5 kg K2O/hm2, and its optimum ratio is 1: 0.72: 0.82. Optimum fertilization rates increased economic yield of mulberry, and N is the major nutrient affecting ecnomic yield, K is the next, P is the smallest.5 ) Balanced fertilization has significant economic benefits. Proper application of N, K and P increases mulberry leaves yield to 36089 kg/hm2, and fertilization treatment increased net income of RMB 4246 yuan. Value/cost ratio (VCR) was 1: 6.43.6 ) After applied N, P and K fertilizers, appropriate rate of B and Zn fertilizers was beneficial to the bulberry growth. B and Zn fertilizers can increase yield, weight and size of mulberry leaf, branch length and single leaf weight. Meanwhile, B and Zn fertilizers can increase N and P absorption.In summary, soil nutrient systematic approach can be used to study soil nutrient systematically, scientifically and precisely and provide scientific basis of rational fertilization in the mulberry production. |
