04 Jan 2017
Effects of long term application of organic and inorganic fertilizers on the fertility Properties of Reddish Paddy Soil
Fertilization is the most important measure for improving farmland soil fertility. Different fertilization patterns resulted in different soil productivities and soil fertility levels. Soil microbe and soil enzymatic activities played an important role in soil fertility improvement and plant nutrient uptake. They also often be used as the indicators of soil fertility. Reddish Paddy Soil (typical Haplic-Stagnic Anthrosis) is one of the most important rice soil in south China and its soil fertility improvement is always be encouraged by local governments.
To study the effects of long-term application of chemical fertilizers (CF) and combined application of CF with pig manure (PM) and/or rice straw (RS) on the chemical and biochemical properties of the reddish paddy soil, under the support of IPNI China Program, the Soil and Fertilizer Institute of Hunan province conducted a research project based on a 30-year long-term field experiment, which was designed to examine long-term effects of application CF, PM and RS on soil properties and rice productivity. In this research project, some important soil fertility properties such as total soil organic carbon (TOC), total N (TN), available N, available P, microbial biomass C (Cmic), N (Cmic), soil respiration (SR), enzymatic activities (urease, acid phosphatase, invertase, and dehydrogenase) were determined.
Results showed that the soil pH values with long-term application of CF, PM and/or RS were significantly decreased compared with the original soil, but the changes of electrical conductivity (EC) were not significantly different between CF and organic manure application. The contents of TOC, TN, available N, available P, soil respiration, Cmic, Nmic and enzymatic activities were higher in the treatments of combined application of CF with PM and/or RS than those in CK treatment and treatments with CF application only. The chemical fertilizer qCO2 showed a progressive increase in various treatments during the 27 years, especially the qCO2 in treatments with CF. The Cmin/Nmic ratios were higher in treatments with combined application of CF with PM and/or RS compared to treatments with CF application only. Biochemical properties were positively correlated with TOC and nutrient contents in the soil. Long-term application of CF combined with PM and/or RS improved soil chemical and biochemical properties, which was one of the effective measures to improve soil fertility for the reddish paddy soil.
