Effects Of Long-Term Fertilizations On Grain Yield And Quality In Different Quality Wheat Varieties

Formation of wheat grain quality is determined genotype, growth condition such as soil fertility, management such as fertilization regime. With long-term fertilization experiment, varied soil fertility in different plots were given with the same type of soil, which provided with very useful tools for studying effects of soil fertility and fertilization on wheat quality. Till now, however, no specialty wheat variety was selected in the existed long-term fertilization experiments. Few physiological mechanisms on effects of long-term fertilization on wheat quality and yield were supported in previous studies. Based on a 20-year long-term fertilization experiment with wheat-corn double cropping system in the present dissertation, super strong gluten and weak gluten specialty wheat varieties were used to study the effects of long-term fertilization on wheat quality and yield, flag leaf photosynthetic properties, cell membrane lipid peroxidation as well as GS activity. This could help illustrate physiological mechanism of changes in grain yield and quality under long-term fertilization experiment, and improve wheat fertilization technique.The present study was conducted at the long-term fertilization experiment in Xuzhou Agricultural Science Institute, Jiangsu Province. The long-term experiment commenced in 1980, with a spit design. The main factor was manure treatment, with two levels of apply (M) or not apply. The sub-factor was fertilizer treatment with four levels of no fertilizer (CK), N-fertilizer (N), N and P-fertilizer (NP), and N, P and K-fertilizer (NP). The plot size was 33.3m2 with four replications. From fall of 1995, two replications of N treatment were changed to N and K-fertilizer (NK) treatment. Wanmai 38 and Yan 2801 were used in the 2000-2001 season, while Yan 2801, Xuzhou 25 and Xuzhou 26 were selected in the 2001-2002 season. Variety was set as the sub-sub-factor. The main results are listed as follows.Effects of combined application of manure and fertilizers. The main effort of organic fertilizer was significant on grain yield, while insignificant on most grain quality traits. The main effects of inorganic fertilizer and the interaction betweenorganic and inorganic fertilizer were significant oh both grain yield and major grain quality traits. Compared with corresponding inorganic fertilizer application treatments, the long term application of combining inorganic with organic fertilizers enhanced most of the quality traits, which could favor the quality improvement of strong-gluten wheat varieties, however infavor quality of weak-gluten wheat varieties.Effects of combined application of N, P and K fertilizers. When no manure was used, compared with the non-fertilizer treatment, N fertilizer significantly increased yield and grain protein content of wheat, Grain yield increased while grain protein content decreased with the combined application of N and P fertilizers, and N, P and K. fertilizers, compared with the single N treatment. The combined application of N and K fertilizers increased gluten and grain protein content, but reduced the gluten index and yield obviously, indicating that the nutrient element balance in soil was very important for formation of grain quality. High N combined with moderate P and K fertilizers favored quality formation of strong-gluten wheat, while moderate N combined with high P and K fertilizers favored quality formation of weak-gluten wheat.Effects of long-term fertilization on leaf photosynthetic characteristics in wheat. At the 20 or 23 days post anthesis (DPA), the mid grain filling stage, - photosynthetic rate (Pn), the maximal photosystem II (PSII) capacity (Fv/Fm) and chlorophyll content (SPAD value) of flag leaves and leaf area index (LAI) were much higher, while at the late grain filling stage (30 DPA), the declining of the above four traits were slower with the treatments combination organic manure and inorganic fertilizers, compared with the treatments of only inorganic fertilizers were applied. The maximal canopy photosynthetic traits expressed as Pn*LAI and...