Assessment of current conditions of household fertilizationof apples in Weibei Plateau

To evaluate the level of apple plantation management and fertilization status, 300 apple-farmer households were investigated for selected attributed including apple yield, fertilization and other management techniques in the Weibei Plateau of Shaanxi Province. The results showed that the yield and fertilization rate of apple were very different among regions. The average amount of used nitrogen fertilizer was 671.71 kg·hm^-2, that of phosphate fertilizer was 338.21 kg·hm^-2 and then that of potassium was 240.70 kg·hm ^-2. While chemical N application in 78.3% of the investigated orchards was higher than the recommended, chemical P2O5 application in only 22.2% of the investigated orchards was rational. Also chemical K₂O application in 51.2% of the investigated orchards was lower than the recommended. The proportion of organic fertilizer in total nutrient declined significantly, from 51% in 1994 to 5.54% at present. While nitrogen fertilizer was excessive in some orchards, some orchards received no fertilizer application; especially potassium fertilizer and organic manure. Based on the results of the experiment and expert experience, the suitable fertilization amounts were suggested. If 25 000~45 000 kg·hm^-2 apple yield was to be realized, about 240~360 kg·hm ^-2 N, 220~340 kg·hm^-2 P₂O₅, 160~240 kg·hm ^-2 K₂O and 40 000~60 000 kg·hm 2 organic manure were recommended. Furthermore, the method and time of fertilization were found unsuitable and the traditional way of fertilization was not changed. Over 70% of the fertilization was done as base fertilizer. It was probably a good way to reduce N fertilizer use and to improve fertilizer utilization ratio. Application of more potassium fertilizer and organic manure and combination of spring fertilization with suitable irrigation were critical for apple production. This achieved integrated management of nutrients and improved nutrient use efficiency.