Soil Nutrition Management for Sustainable Agriculture in Shaanxi
IPNI-2002-CHN-SN6
04 Feb 2006
2005 Annual Interpretive Summary
Effect of Potash on Yield and Quality of Apple, Grape, and Kiwifruit in Shaanxi, 2005
Apple, grape, and kiwi are important traditional economic crops in Shaanxi. Yields and quality have traditionally been poor because of improper nutrient management. Many farmers apply too much nitrogen (N) and too little potassium (K). Three orchards were selected from Heyang and Fufeng counties to study effect of N, phosphorus (P), and K on these three crops. In kiwi and apple, four treatments included an NPK optimum (OPT) and omission treatments excluding N, P, and K. In grape, six treatments included an NPK OPT, - N, - P, - K, OPT + iron (Fe), and OPT + zinc (Zn).
In apple, K increased 100-leaf weight and leaf area by 14.8 g and 2.6 cm2, respectively. The proportion of apples having a diameter over 7.0 cm increased by 10% due to K. Apple yield increased from 16.5 t/ha to 19.2 t/ha. Pure production value increased by US$263/ha. Potash also increased vitamin C (Vc) content by 1.7mg/100g, and rigidity by 0.68 kg/cm2. With sufficient N and P, K application increased sugar content and decreased available acidity. Results of grape trials found 0.2 kg K2O/tree in combination with 0.2 kg N/tree and 0.1 kg P2O5/tree, increased yield by 2.3 t/ha and production value by US$438/ha. Research on kiwifruit determined that N was most limiting, followed by P and then K. Potassium increased single kiwi fruit weight by 5.9 g and yield by 3.7 t/ha, and pure production value increased by US$113/ha. Potassium also improved fruit quality. When 0.4 kg N/tree and 0.17 kg P2O5/tree was applied, a 23.1 mg/100g of Vc and 1.1% of sugar content increase was attributed to K application if applied at 0.3 kg K2O/tree.
The total apple area is more than 401,000 ha in Shaanxi where its total production reached 5.5 million t in 2004...number one in China. Apple has become one of the most important export industries in Shaanxi. Grape and kiwifruit production are also an important income source for many farmers. The planted area of grape and kiwi has reached 15,000 ha and 11,000 ha, respectively. Demonstration and extension of balanced fertilization will become increasingly important in improving fruit yield and farmer income. Shaanxi-NMS02