Nutrients Release Characters Of Bag-Controlled Fertilizer And Its Effects On Peach Production

Nutrient release characteristic of bag-controlled fertilizer was studied both in field and laboratory. Effects of bag-controlled fertilizer on soil available nutrients concentration, nitrogen utilization rate and peach production were studied. The results showed as follows:1. Nutrients release characteristic of bag-controlled fertilizer was evaluated by water extraction method. Nitrogen, phosphorous, potassium release rate were determined by the row of microhole of bag, when the bag has same volume. The more rows of microhole the bag have the quicker nutrient release. Small package of bag-controlled release fertilizer released quicker than the big one, as both have same rows of microhole. As temperature of extracted water increased, nutrient release rate improved. Nitrogen released quicker than potassium, and potassium released quicker than phosphorous. Nutrient release of bag-controlled fertilizer was quicker than coated fertilizer, and controlled release period decreased significantly.2. Like in water extraction condition, nutrient release rate was also determined by rows of microhole of bag and volume of bag, in field condition. The nutrient release curve could be simulated by second-order equation, r2>0.95, and it was same to the coated controlled release fertilizer which have same controlled release period. Nutrient release was different when bag-controlled fertilizer applied to different soil types. It released significantly quicker in stick soil than in sand soil. There were little differences between different rows of microholes'bag on controlled release period, but the release course was differen.3. AS bag-controlled fertilizer released nutrients steadily and incessancily, the soil Nmin, available phosphorous and available potassium concentrations were higher than those of fertilizer spread application treatment signifficantly. It kept soil nutrients concentration at a higher level during peach growth period. Nmin, available phosphorous and available potassium concentrations near fertilzer application site were at 100~150mg/kg, 150mg/kg, 700mg/kg respectively. Bag controlled-release fertilizer increased the N utilization rate significantly; N utilization rate was 2 and 2.5 times as high as fertilizer being spread application in one and two time treatments respectively.4. Compared with spread application, bag-controlled fertilizer treatment increased chlorophyll content of leaf significantly, and the density of fine root in fertilized region. The shoot stopped growth at proper time and it was benefit for nutrition cumulation and organ differentiation, so it increased yield and quality of peach significantly.