Effect Of Fertilazation On Kiwifruit Yield And Quality

Kiwifruit originated from China, with high nutritional and medical valueis the new emerging fruit tree in the world. Kiwifruit is called"vitamin fruit"for containing 100 to 420 Vc per 100g fresh fruit. In recent years, high fertilizer rate may lead to low yield in Shaanxi, China and dampen the willingness of local farmers to plant kiwi. With reasonable and balanced fertilization can enhance stress resistance, improve quality and yield of fruit trees. Balanced fertilization of nitrogen, phosphorus , potassium and other necessary nutrients, not only increase absorption of nutrients, utilization rate of fertilizers and reduce nutrients loss, but prevent the negative effects to environment, improve fruit yield and quality. Our research is to realize the effect of different fertilizer on kiwifruit yield and quality, optimize fertilizer formula and rate; realize the effect of potassium and the optimal rate and the meaning of combined application of chemical and manure fertilizer.1. Shaanxi kiwifruit orchard fertilization status investigation and evaluationWith 2 years investigation of farmers'fertilization status in main kiwifruit producing areas in Shaanxi, the results showed that in Shaanxi province kiwifruit fertilizer amount is N 1415.9 kg/hm2,P2O5 881.7 kg/hm2,K2O 538.5 kg/hm2. Fertilizer rate differs greatly within farmers and chemical fertilizer is the main source of nutrient supply. The phenomenon of excessive fertilization is very common in kiwifruit orchards in Shaanxi, the percentage of farmers who apply reasonable fertilizer rate of nitrogen, phosphorus , potassium is respectively 7.8%, 2.9%, 3.9%. Excessive fertilization of nitrogen and phosphorus is very serious and reducing fertilizer rate is our main future problem during guiding farms on scientific fertilization. Excessive fertilization of potassium is also serious, but still are some farms with whose fertilizer rate is lower than the rational amount.Base fertilizer is the main input of N,P2O5 and K2O in Shaanxi kiwifruit orchards and the other three times of topdressing fertilizer is less and less. The ratio of fertilizer rate in topdressing is low, especially for the potassium fertilizer. Main type of fertilizer is ammonium bicarbonate, urea, compound fertilizer and SSP。Compound fertilizer is main type during topdressing with large fertilized area and high amount. Total annual cost of kiwifruit orchards in Shaanxi is 22973.5yuan/hm2,total income is 97410 yuan/hm2,output is 97410 yuan/hm2 and VCR is 4.74. Fertilizer is the main cost, occupy 77.7% of total cost. The cost of kiwifruit orchards is 41.8% of total cost. With the increasing of total income, the total input, fertilizer input is also increasing.2. Shaanxi kiwifruit orchards soil nutrient status evaluationVia the analysis of 66 kiwifruit orchards soil samples in Xi'an, Baoji, Xianyang, Weinan, Hanzhong of Shaanxi province, the results showed: the average soil organic matter content is 11.69g/kg and Baoji is highest, 15.00g/kg; Hanzhong is lowest, only 6.69g/kg. Available N, available P and available K content is 35.50 mg/kg, 47.97mg/kg, 242.83 mg/kg respectively. Because of the difference on soil and climate in these areas, from north of Weinan to south of Hanzhong, the soil nutrient differed a lot.The soil organic matter in Shaanxi kiwifruit orchards is moderate level, still some orchards lack a lot and only few can reach the optimal level. Content of soil NO3--N is optimal or high and number of orchards which need N supply is less; 73% of orchards is severe shortage of P and ability of soil P supply need to be improved; Soil available K content is sufficient commonly, but still 36% orchards lack it.3. Effect of fertilization on kiwifruit yield and qualityUsing"Actinidia deliciosa cv. Huayou"as material, production, plant nutrition and quality were compared with the treatment of nitrogen + phosphorus + potassium + manure (NPK+M), nitrogen + phosphorus + potassium (NPK), reducing nitrogen (PK+0.5N), reducing phosphorus (NK+0.5P), reducing potassium(NP+0.5K), reducing NPK (0.5NPK), incremental NPK (1.5NPK). The result showed that NPK+M treatment increased the kiwifruit production by 11.7%—31.8% compared to other reducing treatments. The order of contribution of N, P and K on kiwifruit yield is: N>P>K. Excessive fertilization can not increase the yield significantly, but has negative effect on profit. NPK+M treatment can improve the plant nutrition status and quality of fruit and increase Vc 6.9% - 18.7%, soluble total sugar 33.5%– 44.8% compared to other reducing treatments. The effective method of kiwifruit nutrition management should be the balanced chemical fertilizer and manure application.