| In this research,Xinluzhong No.66 was used as the experimental material,and four recommended fertilization strategies were set:Yang Tao model?Y?,Pan Weiwei model?P?,conventional fertilization?C?,and no fertilization?B?.Comprehensive analysis and comparison of different fertilization strategies The effects of nitrogen recovery(Y 305.7kg·hm-2,P 352.95 kg·hm-2,C 315 kg·hm-2,0 kg·hm-2)on cotton growth and development,nitrogen absorption and utilization,and yield effects Through verification and comparison,the optimal fertilization strategy model is screened to provide a scientific theoretical basis for the timely and appropriate amount of top dressing and yield increase in the southern Xinjiang cotton area.The results of research and verification at this stage are as follows:1.Under different fertilization strategies,cotton plant height,true leaf number of main stem,stem thickness and other agronomic traits will be different.From seedling stage to bud stage,the impact of different fertilization strategies is not significant,as the cotton growth process Advancement,cotton enters the reproductive growth stage,the plant height,stem thickness,and true leaf number under the P fertilization strategy are higher than other fertilization strategies,but there is no obvious difference from the Y fertilization strategy,the plant height,stem thickness,true The leaf number was significantly lower than the fertilization strategies of Y,P and C.2.Under the four fertilization strategies in this experiment,there was no significant difference in the dry matter accumulation characteristics of cotton at the seedling stage of each fertilization strategy.With the application of different fertilization strategies at a specific growth period,the aerial part of cotton under each fertilization strategy The amount of dry matter accumulation is increasing,but the Y-fertilization strategy has the highest dry matter accumulation per plant?88.56 g?,and the absorption and utilization efficiency of nutrients is high;in the entire dry matter accumulation and distribution,P fertilization with the largest total nitrogen application The strategy in transporting dry matter to reproductive organs is lower than the Y and C fertilization strategies,respectively.Therefore,Y fertilization strategy can maintain a better leaf area index.3.Among the four fertilization strategies in this experiment,with the growth and development of cotton,the leaf SPAD value and chlorophyll content showed a trend of increasing first and then decreasing.The SPAD value of the Y and P fertilization strategies and the chlorophyll content in the leaves were significantly higher than that of C and B fertilization.Strategy,and Y fertilization strategy>P fertilization strategy,Y fertilization strategy 305.7 kg·hm-22 cotton leaf area index is more suitable in the heyday period,the main functional leaves of cotton can still maintain a high Physiologically active state.4.There are significant differences in the nitrogen utilization efficiency of cotton under the 4 fertilization strategies.Under the Y fertilization strategy,the cotton has the most nitrogen accumulation(368.8 kg·hm-2)and the nitrogen utilization efficiency is 36.1%.This fertilization strategy The cotton has better nitrogen absorption effect,and comprehensively compares the soil nitrate nitrogen content,the soil nitrate nitrogen under the Y fertilization strategy is mostly distributed between 30-40 cm soil layers,and the soil nitrate nitrogen under the P and C fertilization strategies The peak content appears between 50-60 cm soil layers,and there is a certain risk of nitrogen leakage loss.5.Under the four fertilization strategies in this experiment,the number of bolls per plant in Y and C fertilization strategies is significantly higher than that of P and B fertilization strategies,and the single bell of Y fertilization strategy is significantly higher than that of the other three fertilization strategies.There was no significant difference in the percentage of clothing between the fertilization strategies.There was no difference between the Y and C fertilization strategies for seed cotton yield and lint yield,but both were significantly higher than the P and B fertilization strategies.Based on the above conclusions,under the same planting management model in the field,under the B fertilization strategy,the cotton plant type is small,nutrient absorption and conversion,dry matter accumulation is small,the leaf SPAD value and chlorophyll content are overall low,and the yield is the least.The total amount of nitrogen applied under the P fertilization strategy was the most(352.95 kg·hm-2),and the average cotton yield was not optimal.Compared with the C fertilization strategy(315 kg·hm-2),the nitrogen application rate(305.7 kg·hm-2)of the Y fertilization strategy was reduced by 2.95%,but the yield was increased by 4.99%,and the nitrogen utilization efficiency reached the highest.The C fertilization strategy is a routine and common method of fertilization in cotton fields,and the Y fertilization strategy reduces a certain amount of nitrogen application on this basis,but it does not affect the nitrogen absorption,conversion and yield components of cotton.It can be seen that the amount of nitrogen applied according to local conditions is the prerequisite for the high yield and increase of cotton.With the Y fertilization strategy in the experimental area,according to the growth and development of cotton,nitrogen is applied scientifically and reasonably to meet the nutrient requirements of cotton,and the optimal yield structure and the highest economy can be obtained.Benefits,meet the needs of cotton farmers,and reduce production costs and pollution of cotton fields under limited resource conditions. |
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