Effects of bag controlled-release fertilizer on nitrogen utilization rate, growth and fruiting of peach

Bag controlled-release fertilizer is a new type of controlled-release fertilizer designed according to the big individual volume characteristic of fruit trees. It used controlled-bag to control the release of nutrients The relationship between micro holes and N release rate was studied. The results showed that nitrogen release curve of bag-controlled fertilizer could be simulated by second-order equation(r2＞0.965). The seven-line micro hole design was better than three- and five-line micro hole design for releasing N to meet peach tree need. Mineral N changed sharply after the use of readily available fertilizer and was easy to induce complication of vegetative growth and reproductive growth, while bag controlled-release fertilizer released nutrients slowly. It was hard to see any fine root near spread application site, but near bag controlled-release fertilizer site there were lots of fine roots, so the nutrients were easy to be absorbed and utilized. Bag controlled-release fertilizer increased N use efficiency significantly, being 2.5 and 2 times of the fertilizer spread in one and two time treatments, respectively. The stage of shoot growth stopped and fruit enlargement of bag controlled-fertilizer treatment was earlier than spread application treatments and CK. Yield of trees were increased significantly.