Effects Of Ratio Of Nitrogen, Phosphorus And Potassium On Grain Yield And Quality In Malting Barley Yangnongpi 6

The study was conducted on the Experimental Farm of Jiangsu Provincial Key Lab of Crop Genetics & Physiology, Yangzhou University in 2007 - 2009. The tested malting barley cultivar was Yangnongpi6, which was developed by Agricultural College, Yangzhou University. The effects of the ratio of N, P, and K on crop population development, the production and accumulation of photosynthate grain yield, grain quality, and malting quality were studied. The main results were as follows.1. The management of N, P, and K for obtaining high yield in Yangnongpi 6 was identified as: 210 kg/hm2 nitrogen accompanied with N: P2O5: K2O ratio of 1:0.5:0.5, applied at seeding, tillering, and jointing stage at the ratio of 7: 1: 2. Under these conditions, the nutritional quality and grain malt quality of Yangnongpi 6 were in line with national and corporate standards.2. Nitrogen, phosphorus, and potassium produced profound effects on the grain yield and yield components in Yangnongpi 6. When the applied N amount was between 150 kg/ hm2 and 270 kg/ hm2, the grain yield was positively correlated with the applied N amount. At the same applied N amount, the application of phosphorus produced better effects on grain yield than potassium. The highest grain yield was obtained when the ratio of N, P, and K fertilize was 1:0.5:0.5. More phosphorus and potassium made no marked improvement in grain yield. Path analysis showed that the most powerful contributor to grain yield was spike number, followed by the number of grain per spike and 1000-grain weight.3. The yield of protein increased at the increased N applied amount. At the same N applied amount, the yield of protein also increased as the increase of applied P and K amount. Path analysis showed that the yield starch was a more powerful contributor to yield than protein yield. The yield of both starch and protein was positively correlated to grain yield. The application of N, P, and K promoted the accumulation of starch and protein in wheat grain, leading to a high grain yield.4. The grain uniformity of Yangnongpi 6 was in line with Chinese national standard when treated with different ratios of N, P, and K. When treated with 210 kg/hm2 nitrogen and the N: P2O5: K2O ratio of 1:0.5:0.5, the grain uniformity of Yangnongpi 6 was in line with the best Chinese national standard. The grain uniformity of Yangnongpi 6 decreased as the increase of applied N amount. The ratio of N, P, and K produced profound effects on grain volume weight. The germination rate and germination potential decreased as the increased applied N amount. When the applied N amount was less than 210kg/hm2, the germination rate and germination potential were in conformity with the Chinese national standard. At the applied N amount less than 210kg/hm2, the germination rate and germination potential decreased as the applied P and K amount.5. The malting quality of Yangnongpi 6 was affected by N applied amount and the ratio of N, P and K. When the applied N amount ranged between 150 kg/hm2 and 270 kg/hm2, the steeping rate and kolbach index decreased with the increased applied N amount, the saccharogenic power andα-Amino-nitrogen, however, increased. At the 210kg/hm2 nitrogen level, the steeping rate and kolbach index decreased with the increase of the ratio of P and K, but the saccharogenic power andα-Amino-nitrogen increased.6. Correlation analysis showed that the steeping degree and steeping rate decreased and the saccharogenic power increased as the increased protein content. The kolbach index was negatively correlated to the content of protein, and positively correlated to the total nitrogen content in malt.7. The application of P and K increased LAI, SPAD reading, the net photosynthetic rate of flag leaves, and the accumulation of biomass after anthesis, reduced the senescence rate of leaf area and the decline rate of SPAD reading.8. The recommended fertilizer management for obtaining a high yield of 7000 kg/hm2 in Yangnongpi 6 was identified as: 210 kg/hm2 nitrogen accompanied with N: P2O5: K2O ratio of 1:0.5:0.5, applied at seeding, tillering, and jointing stage at the ratio of 7: 1: 2.