Effect Of N And K Nutrition On Yield,Nutrients Absorption,Distribution And Quality Of Wheat For Different End Uses

The Experiments been conducted at Badou Township, FeiDong County, and at MaDian Experimental Station of Anhui Academy of Agriculture Sciences in MengCheng County during 2004～2005. The test crop varieties were Yannong 19 for strong gluten wheat and Wanmai 48 for weak gluten wheat. The pot experiments and field trials were adopted to study the effect of different level of K, and combined application of N and K on grain yield, nutrients absorption and distribution and quality of wheat for different end uses. The main results are as follows:1.Effects of different levels of K on grain yield and quality of wheat for different end usesThe potassium fertilizer increased grain yield of strong gluten wheat significantly by 10.2%-24.8%(r=0.962**, n=6).The 1000-grain weight was the most important factor to the yield. K fertilizer also was helpful to increase protein and wet gluten content of wheat, while the sedimentation value is not obviously affected by K fertilizer in the experiments. The treatment K1.0 achieved maximum yield and better quality indexes.The potassium fertilizer could significantly increase grain yield of weak gluten wheat. The maximum yield was 4638 kg/hm2 at the rate of 120kg K2O/hm2 in low-potassium soil while in medium-potassium soil and at 90 kg K2O /hm2, the maximum yield was 5215 kg/hm2. The K content in soil had notable effects on the yield responses of potassium fertilizer. In low-potassium soil, the yield increment of K fertilizer was 8.51%～18.83%, the correlation coefficient of K rate with the yield was 0.765. In medium-potassium soil, the increase was 5.34%～13.74, the correlation coefficient was 0.665. The grains per spike was the primary factor to the yield of weak gluten wheat, the secondary factor was spike number. The K fertilizer also had effects on the quality of weak gluten wheat. In low-potassium soil, the protein content, wet gluten content, sedimentation value and hardness of the wheat had an increasing tendency with moderate addition of K fertilizer. However, K fertilizer was unfavorable to the improvement of the quality when exceeding 120 kg K2O /hm2. In medium-potassium soil, protein content, wet gluten content, sedimentation value and hardness decreased with the rate of K fertilizer, but the starch content was improved. Except for hardness, there had no significant differences of the quality parameters among the different K treatments both in low-potassium soil and in medium-potassium soil. The treatment with application of K fertilizer had notable effects on development time, stability time, degree of softening and valorimenter value of weak gluten wheat, but no obvious effect on water absorption. Within optimized usage of K fertilizer, the development time,stability time,degree of softening and valorimenter value of weak gluten wheat were improved with increase of K fertilizer usage, but the threshold of farimograph index was exception one,and at the same time, those indexes were effected by the content of K in soil. There's no significant differences for starch paste trait of weak gluten wheat between different usage of K fertilizer, furthermore, there was difference among the soil with different basic fertility. The basic fertility of the test soil had certain effects on the quality, farimograph index and starch paste trait of weak gluten wheat under the experimental condition.2.Effects of combined application of N and K fertilizer on grain yield and quality of wheat for different end usesCombined application of N and K fertilizer could improve grain yield of strong gluten wheat significantly by 61.3%～110.9%.Firstly, the combined application of N and K fertilizer improved the grains per spike of strong gluten wheat. Secondly, it improved 1000-grain weight. Although no sole effect on quality of the strong gluten wheat, K fertilizer could notably enhance the quality improvements of N fertilizer. The protein content, wet gluten content and sedimentation of the wheat treated with N and K nutrition significantly increased by 19.4%-39.5%,23.5%-51.4% and 20.8%-27.3% respectively compared with N0K0. The regression analysis indicated that the positive interaction of N and K had significant effects on the grain yield, protein content, protein amount and wet gluten content. Treatment of N3K2 had the highest yield and better indexes of quality.The rational combination of N and K fertilizer also significantly improved yield of weak gluten wheat. In low-potassium soil, the maximum yield of 5023 kg/hm2 was reached at the treatment of N180K150, while, the maximum yield of 5145 kg/hm2 at the treatment of N180K90 in medium-potassium soil. The yield response of N fertilizer was bigger than that of K fertilizer both in low-potassium soil and in medium-potassium soil. The significant positive interaction of N and K fertilizer on the grain yield was found in low-potassium soil. Spike number was the major contributing factor to the grain yield. Combined application of N and K fertilizer could significantly increase the protein content, wet gluten content, sedimentation value and hardness of wheat grain in low potassium soil. The effect of N fertilizer on quality was bigger than that of K fertilizer, but K fertilizer was also helpful to the quality optimization of N fertilizer. N and K fertilizer had a significant positive interaction on the quality of weak gluten wheat. In medium-potassium soil, the increasing of N fertilizer usage still could promote the improvement of quality indexes. The quality improvements were declined and became negative with the increase of K fertilizer usage. N and K fertilizer had a notable negative interaction. N fertilizer had notably significant effects on the farimographic index of weak gluten wheat. Within optimized usage(90kg/hm2), the increasing K fertilizer usage could enhance valorimenter value, e.g. increasing water absorption, prolonging development time and stability time and having lower degree of softening. There was no significant difference between different usage of K fertilizer. A same tendency existed both in low-potassium soil and in medium-potassium soil. N and K fertilizer had no significant effect on starch paste trait of weak gluten wheat. The basic fertility of soil had a notable effect on the quality of weak gluten wheat.3.Effects of N and K nutrition on nutrient absorption and distribution of wheat for different end usesDuring the whole growth period, the content of N, P and K in wheat had a declining tendency, the cumulative absorption of N, P and K had a increasing tendency and the content of N, P and K reached maximum during Jointing- heading stage. The changing of the N, P and K content in wheat plants for different end uses was different. The N content in strong gluten wheat had graph curve, the peak values at tillering and heading stage respectively,but the content of P and K had a declining tendency. The N content of weak gluten wheat declined from tillering stage to filling stage, but increased slightly during the period of maturity. The content of P had wave-like change, however, K had a continuous declining tendency. The treatment of K fertilizer improved the K content and the absorption of N, P and K. The content of K and the absorption of N, P and K in strong gluten wheat, and weak gluten wheat in low-potassium soil, had significant relevance with the increase of K fertilizer usage during different growing stage. In medium-potassium soil, the usage of K fertilizer had significant relevance with the cumulative uptake of K nutrition, but no significant relevance with the accumulation of N and P. Combination of N and K fertilizer promoted the increments of N, K content and the absorption of N, P and K. There was a positive interaction of N and K on nutrient absorption. Under our experimental condition, the NK interaction had more notable effects on increasing cumulative uptake of K than that of N and P. In medium-potassium soil, the positive NK interactions on nutrient absorption were more obvious. Within optimized usage of N fertilizer, the distribution of N, P and K during the period of maturity was improved with the increasing rate of N fertilizer. At the same time, the total N contribution rate from vegetative tissues to gain had an increasing tendency. If the usage of N fertilizer was excessive, the distribution of N, K and P and total contribution of N had declining tendency. In low-potassium soil, the total contribution rate of N in weak gluten wheat had increasing tendency with the increasing of N fertilizer. Within optimized usage of K fertilizer, the distribution of N, P and K and total contribution rate of N during the period of maturity was improved with the increasing of K fertilizer. However, the effect of K fertilizer was also affected by the usage of N fertilizer and K content in soil. N and K fertilizer had definite effect on total contribution rate of P. P content in strong gluten wheat mostly came from the redistribution of P storage in earlier stage, while P content in weak gluten wheat came from P absorbed and assimilated in later stage.The plants with N fertilizer had an improvement of N nutrition, which promoted correlation of N with grain quality parameters. And the relevance of K and grain quality also had improvement after K fertilizer applied.4.Identification of optimized usage of N, K fertilizer of wheat for different end usesUnder our experimental condition, at the N fertilizer usage of 1.4g/pot and K fertilizer usage of 1.0g/pot (N:K=1.4:1), strong gluten wheat accessed to maximum yield and better indexes of quality. While weak gluten wheat obtained maximum yield at K fertilizer usage of 120kg/hm2 in low-potassium soil and of 90 kg/hm2 in medium-potassium soil respectively. Treated with N180K150 in low-potassium soil, weak gluten wheat obtained maximum yield when N: K was 1.2: 1. But in medium-potassium soil treated with N180K90, weak gluten wheat reached maximum yield when N: K was 2:1. The wet gluten content, ratio of water absorption and stability time of weak gluten wheat all met current state standard of high-quality weak gluten wheat when the N fertilizer usage below 120kgN/hm2.