Effect of Different N, P, K and Organic Fertilization Rates on Growth and Yield of Actinidia chinensis‘Hongyang’

The effects of different nitrogen (N), phosphorus (P), potassium (K) and organic fertilizing treatments on growth, leaf photosynthesis characteristics, yield and quality in field experiments were studied using kiwifruit orchards (Actinidia chinensis ‘Hongyang’) in Dujiangyan of Sichuan Province. Results showed that deficiency of N, P, and K in soil constrained plant growth and decreased yield in kiwifruit trees. The combination of N, P and K fertilization could significantly increase the net photosynthetic rate (P_n) of leaves, promote the growth of new shoots and trunk, and increase yield. However, high ratios of N or K in N:P:K combination decreased stomatal conductance (G_s), intercellular CO₂ concentration (C_i), and P_n of leaves by stomatal limitation, and reduced yield. Organic fertilizer application had no significant effect on yield but increased average fruit weight, whereas excess application of organic fertilizer reduced fruit yield. In general, an appropriate combination of N,P,K and organic fertilization (N 560 g/plant, P₂O₅ 250 g/plant, K₂O 250 g/plant, organic fertilizer 6 kg/plant) greatly promoted plant growth, yield and quality of kiwifruit (Actinidia chinensis ‘Hongyang’) in our field experiments.