Establishment And Application Of Variable Rate Fertilizer Application Model For Rice Based On Soil Fertility

The “3414” fertilizer experiment was investigated, super hybrid rice Q-you No.6as the sample of this experiment, from 2014-2015 in Jiuzhou town Gui Zhou province.In the experiment, the Variable fertilization model is studied utilizing fertilizer effect function method and nutrient balance method. The influence of N, P and K fertilizer on rice dry matter, Nutrient uptake and yield under a same soil fertility are also investigated. The results are shown as follows:The maximum amount of fertilizer and soil available nutrient value are established using fertilizer response functions method. Based on the maximum amount of fertilizer and Soil available nutrient content, the fertilization model are built: Y1 =- 171.57 ln(X1)+ 1026;Y2 =- 10.355 ln(X2)+ 102.92;Y3 =- 107.32ln(X3)+ 590.97.Y1, Y2 and Y3 in the formula indicated that nitrogen, phosphorus and potassium fertilizers were best(kg/ha), and X1, X2 and X3 were available for soil available N, P and K(kg/ha).In the nutrient balance method: the amount of available nitrogen and potassium is proportional to the fertility yield; the fertility yield increases at first and then decreases with the increase of the amount of available phosphorus; the fertility yield is proportional to the target yield; Correction coefficient of soil available nutrient has a negative correlation with soil available nutrient; Fertilizer utilization ratio has anegative correlation with soil available nutrient.Variable fertilization model is obtained by the nutrient balance method is as follows: Y1 =(25.1146 X1 + 12299.165- X1 × 112.99 X1-1.1581 × 2.25) ÷(-35.785 ln(X1) + 200.06); Y2 =(- 33.7096 X22 + 388.775 x2 + 2224.337- X2 × 4.9957X2-0.48515 × 2.25) ÷ 34.146X2-1.4468; Y3 =(58.9574 X3 + 11645.9658- X3 ×163.69 X3-1.2267 × 2.25) ÷ 8703.7 X3-1.524. The meanings of Y1?Y2?Y3?X1?X2?X3 are as above.When variable fertilization model is applied in areas with different soil fertility,the fertilizer utilization ratio highly increases and the yield of rice is greater than that with normal amount of fertilizer. The purpose of increasing yield and reduce cost is achieved with the decrease of the fertilizer utilization amount at the same time.The influence of different nitrogen, phosphorus and potassium levels on rice stem material quality, yield and nutrient uptake was investigated. Results showed that with the amount of nitrogen application increased, the yield, effective panicle number and spikelets per panicle number gradually increased, while seed setting rate decreased; in different growing periods, leaf area index(LAI) and dry matter accumulation were at the highest level under maximum value of nitrogen application.With the amount of phosphorus application increased, yield, effective panicle number and grain weight slightly increased; LAI increased at first and then decreased in different growing periods; at jointing stage, the dry matter accumulation gradually increased. When the amount of potassium fertilizer application was increased, the yield and LAI increased gradually, and the dry matter accumulation increased first and then decreased. With the amount of Nitrogen, phosphorus and potassium fertilizer application increased, the total nutrient uptake of rice and the demand of grain nutrients per 100 kg increased, while nutrient harvest index, absorption utilization rate and agronomic utilization rate showed a downward trend.