Effects Of Long-term Fertilization On Crop Photosynthesis And Protective Enzyme Activities Under Wheat-maize Double-cropping System

The effects of different fertilization treatments on growth development, photosynthesis, protective enzyme, and yield of winter-wheat and summer-maize were studied in a long-term field experiment. The long-term field experiment is carried out to evaluate nutrition equipoise of farmland ecosystem in fluvo-aquic soil by the National Agro-Ecological Experiment Station in Fengqiu, China. Through the study of these parameters under different fertilization treatments, we try to explore the inherent mechanism between crop growth characteristics and yield. This study also could provide a scientific basis for the coordinated development between achieving high and stable yield and efficiently using of resources in this area. The main results are as follows:1. Effects of different fertilization on matter produce and photosynthesis and senescence characteristics of winter-wheat and summer-maize.(1)Effects of different organic and inorganic fertilizer treatments on height increase of winter-wheat and summer-maize is not significant. Application of inorganic fertilizers can increase in LAI rapidly, promote the content of chlorophyll and soluble protein, pick up speed of Pn, Gs and Tr, and enhance the activity of SOD, POD, and CAT during earlier growing stage. Enhancing photosynthetic capacity can help to the rapid accumulation of dry matter. During later growth stage, the decline of LAI, photosynthetic physiological parameters, and activity of protective enzymes lead to reduce photosynthetic capacity and slow accumulation of dry matter. The function of promoting growth is weak during earlier growing stage, and amount of photosynthetic physiological parameters and activity of protective enzymes are lower, and accumulation of dry matter is slow. But during later growth stage, all of these parameters are better.(2)Long-term application of inorganic fertilizers (including nitrogen and phosphorus) and organic fertilizer could promote winter-wheat and summer-maize growth and development, optimize the ear structure, and finally improve the yield significantly. Application of organic fertilizer could improve the thousand kernel weight of winter-wheat and kernels per row and hundred kernel weight of summer-maize significantly, while application of inorganic fertilizers could improve panicles per unit area of winter wheat and kernel rows of summer-maize. Annual output on different treatments exhibit that 1/2NPK+1/2OM >NPK >OM treatment.2. Effects of deficiency fertilization on matter produce and photosynthesis and senescence characteristics of winter-wheat and summer-maize.(1)The NPK treatment could improve the increase of height and LAI, promote the content of chlorophyll and soluble protein, pick up speed of Pn, Gs and Tr, and enhance the activity of SOD, POD, and CAT during earlier growing stage. Enhancing photosynthetic capacity can help to rapid accumulation of dry matter. The decrease of height, amount of LAI and photosynthetic physiological parameters, activity of protective enzymes are lower, and accumulation of dry matter. This is related to this kind of soil which is rich in potassium. The restrain on these parameters of N deficiency treatment is serious. The influence on these parameters of P deficiency treatment is the most serious, almost the same as CK.(2)In these deficiency fertilization treatments, yield of both winter-wheat and summer-maize exhibit that NPK>NP>PK>NK>CK treatment, and the same as annual output.