肥料袋控缓释对桃氮素利用率及生长和结果的影响

根据果树个体较大的特点，改变一般缓释肥颗粒包膜的设计思路，用控释袋包装肥料，调节控释袋的微孔数目，达到控制养分释放的目的。对微孔数与氮素释放速率的关系进行研究，结果表明:袋控缓释肥料氮素释放可以用二次曲线模拟，相关系数达0.965以上，7排孔设计优于3排孔与5排孔设计，其养分释放较符合桃树对氮素养分需求特性。袋控缓释处理土壤无机氮（铵态氮＋硝态氮，Nmin）稳定，解决了肥料散施造成的短期内土壤有效氮水平过高的问题；袋控缓释处理肥料袋附近细根显著增多，有利于养分吸收利用，明显提高肥料氮素利用率，是一次散施、二次散施利用率的2.5倍、2倍；袋控缓释肥料使桃树新梢适时停止生长，产量显著提高。

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.