Abstract:
Objectives Banana production requires large amount of water and nutrient supply, especially K nutrition. We studied the response of banana yield, quality, efficiency and soil potassium balance to different potash input levels, to serve the integrated nutrient and water management in Fujian banana production.
Methods A three-year fixed-site experiment was carried out from 2016 to 2018. With the same N and P input, five treatments were set up, K0 (no K input) and K1 (K input rate of 1400 kg/hm2) treatment were under conventional irrigation, and K0.4, K0.6 and K0.8 (applying 40%, 60% and 80% of K rate in K1 treatment) were under drip irrigation. At maturing stage, the banana yield, quality, K uptake and soil K balance were investigated.
Results The 3-year average yield of K0.4, K0.6, K0.8 treatments were –11.5%, 2.4% and 13.5% higher than that of K1, respectively. Compared with K1, the growth, single banana size and weight under K0.4 were significantly lower; The growth of K0.6 and K0.8 were similar to those of K1, the fruit number and single fruit size and weight under K0.6 were similar, while the fruit number and single fruit size and weight under K0.8 were significantly higher. The average three-year net income was in descent order of K0.8 (54179.4 yuan/hm2) > K0.6 (46663.7 yuan/hm2) > K1 (42538.1 yuan/hm2) > K0.4 (36808.1 yuan/hm2), and the net income differences among them were all significant. After three years of continuous plantation of banana, the soil K was apparently deficit in K0 (–406.5 kg/hm2) and K0.4 (–93.3 kg/hm2), basically balanced in K0.6 (8.9 kg/hm2), and surplus in K0.8 (220.4 kg/hm2) and heavily surplus under K1 (501.9 kg/hm2).
Conclusions Integrated considering yield, quality, economic benefits and soil potassium balance, the proper decreasing rate of potash is 20% under drip irrigation in banana orchards in Fujian Province.