Effects Of Different Application Ratio Of P And K Fertilizer On Grain Yield And Quality In Medium-gluten Wheat And Weak-gluten Wheat

The experiment with medium-gluten wheat Yangmai 12, Yangmai 16 and weak-gluten wheat Yangmai 15 was carried out on the field of Crop Cultivation and Physiology Key Laboratory of Jiangsu Province, Yangzhou University in 2006-2008. Under the same nitrogen level, the effects of different phosphorus and potassium ratio on grain yield and yield components and grain quality were studied, and the appropriate ratio of P and K in medium-gluten wheat and weak-gluten wheat was suggested. The main results were as follows.1. Different application ratio of phosphorus and potassium had significant effects on grain yield and quality in medium-gluten wheat and weak-gluten wheat. In this experiment, the ratio of N: P₂O₅: K₂O for medium-gluten wheat was 10:6:6, which could result in higher grain yield and better quality. For weak-gluten wheat, the suitable N: P₂O₅: K₂O ratio was 10:4:4 or 10:6:62. The effects of P and K fertilizer on wheat grain yield and the components was not entirely consistent. Under the conditions of non-application of potassium, increasing phosphate fertilizer appropriately had high or low effects on the yield of medium-gluten wheat, but had insignificant effect on yield of weak-gluten wheat. Application of potassium fertilizer could significantly increase grain yield. Under different phosphorus levels, the effects of potassium fertilizer application on wheat yield were different. Applying potassium could significantly increase grain yield when 135kg/hm² phosphate fertilizer was usedfor medium-gluten wheat Yangmai 16 and when 90kg/hm² phosphate fertilizer was used for weak-gluten wheat Yangmai 15 and medium-gluten Yangmai 12. The effects of different application ratio of P and K fertilizer on spike number and 1000-grain weight were significant, but insignificant on grain number per spike. Path analysis showed that different application ratio of P and K increased grain yield mainly through the increasing of spike number in medium-gluten wheat, and through the increasing of spike number and 1000-grain weight in weak-gluten wheat.3. Potassium application could reduce grain protein content, and the largest decrease extent was got when N: P₂O₅: K₂O ratio was 10:4:4 and 10:6:6. With a higher proportion of potassium application, Protein production and the accumulation of starch basically increased and then fell gradually. The application of phosphate and potassium not only increased the total protein yield but also increased starch accumulation, the effect on starch accumulation was greater than that on protein yield , resulting in and the reducing of grain protein content.4. Path analysis showed that starch accumulation amount in medium-gluten wheat and weak-gluten wheat was the key factor affecting grain yield.. Protein accumulation amount was the second factor. In medium-gluten wheat, grain yield was significantly positively correlated with starch accumulation amount, while the relationship between grain yield and protein accumulation amount was positively correlated but not significant. The increase of grain yield by the application of phosphorus and potassium fertilizer in medium-gluten wheat resulted mainly from the increasing of starch accumulation amount in grains. The correlation analysis showed grain yield was significantly positively correlated with starch and protein accumulation amount in weak-gluten wheat. The increase of grain yield by the application of phosphorus and potassium fertilizer in weak-gluten wheat resulted from the increasing of both starch and protein accumulation amount in grains, the role of starch was greater thanthat of protein.5. Increasing the application amount of potassium fertilizer not only raised the uptake of nitrogen, phosphorus, potassium, but also reduced the efflux of potassium. With the increase of potassium fertilizer application amount, the post-anthesis translation amount of N absorbed before anthsis increased, while N accumulation amount after anthesis did not significantly increase of Plant N uptake amount increased after the first lower and the N translation amount after anthesis increased with increasing the proportion of potassium, but The applicationof potassium fertilizer mainly increased the translation amount of N absorbed before anthesis, and promoted the absorption of phosphorus and potassium6. The application of phosphorus and potassium fertilizer could increase LAI, reduce the senescence rate of leaves during grain filling period, and raise SPAD value and net photosynthetic rate of flag leaves, which resulted in the increase of dry matter accumulation amount after anthesis.