ABSTRACT
To be green and sustainable are essential requirements for modern agriculture in China, with fertilizer input being one of the keys. Developing and extending organic fertilizer has become a basic national policy for agricultural production in China for its eco-friendly and advantages in fertile farmland nurture. Organic fertilizer has wide source and variety. The conditions for agricultural production are also largely different. We analyzed the status of organic fertilizer products and stan-dards, physical and chemical properties differences, differences of carbon and nitrogen mineralization characteristics and their influencing factors. Meanwhile, we reviewed the effects of application of organic fertilizer on basic soil fertility of cultivated land. Due to the differences in source and production process, different organic fertilizers differ in the four main internal factors (the content of organic carbon fractions, total N, active nitrogen and C/N) affecting carbon and nitrogen mineralization characteristics, including mineralization rates and the amount of available nitrogen release. With the influence of external conditions such as edatope, different organic fertilizers vary in nutrient supply characteristics. Overall, organic fertilizer significantly increases soil organic matter content, especially for labile organic matter content and carbon management index (CMI). Moreover, soil contents of nitrogen, phosphorus and potassium are expanded. As a result, nutrient loss caused by crop growth is reduced, with positive consequences on soil quality. The application of organic fertilizer on fertile farmland nurture, the theoretical study of organic fertilizer, and the development of safe and efficient organic fertilizer products should be strengthened in the future, promoting the efficient recycling of organic fertilizer resources which could be an important agricultural resource.
Subject(s)
Manure , Soil , Agriculture , China , Fertilizers , Nitrogen , NutrientsABSTRACT
The variety of the contents of N, P, K and photo-biological characters in a bud and two leaves tea tree new shoots were determined to investigate the effects of different fertilization ways, i.e., single or combined N, P, K fertilizer. The regression equations of net photosynthetic rate (Pn) of tea tree in spring, summer and autumn were set up by stepwise regression analysis. The results showed that fertilization ways significantly affected the contents of N, P, K in new shoot. In the same fertilization ways, the contents of N, P in the new shoot was less in summer and autumn than in spring, but the content of K was in contrast. Combined application of N, P and K fertilizer improved Pn of the tea trees in spring. Single application of P fertilizer inhibited the Pn of the tea trees in summer and autumn, while single application of N fertilizer significantly improved it. In the same fertilization ways, the Pn of the tea trees in summer and autumn was higher than in spring. The stomatal conductance (g(s)) and transpiration rate (T(r)) had positive correlations to P, in summer and autumn. Regression and correlation analysis showed that the physiological factors affecting Pn of the tea trees varied with seasons, and the common factors were the Ci and the content of P. Ci had some subduction to Pn, and it was improved by the content of phosphorus.
