Effects Of Carbon Regulator Application On Secondary Salinization Degree And Nitrogen Transformation Of Soil

This study employed field sample analyses and laboratory pot cultivation, in order to study the improvement effect of carbon regulator (wheat straw with fast decomposing bacteria) on the soil secondary salinization degree and nitrogen transformation. By investigating water-soluble salts at different depths of the soil secondary salinization degree, we study the component characteristics and spatial distribution of water-soluble salt and provide the basis for the improvement of the soil secondary salinization; At the same time, we add different amounts of carbon regulator to the soil secondary salinization, in order to study the improvement effect of carbon regulator on the soil secondary salinization degree and nitrogen transformation;The results are as follows:(1) Ca2+ and NO3- were the main components of the soil soluble salt ions, accounting for 59.71% of the total cations and 65.95% of the anions respectively. Soil soluble salts were mainly distributed in soil surface layer (0～10cm).(2) In both short-term and long-term culture experiments, the concentrations of water-soluble salts were significantly reduced by adding the carbon regulators in the soil. Within a certain range, total amount of water-soluble salts was reduced with the increase of carbon regulator addition. The concentration of water-soluble salts could be reduced up to 33.95%.(3) Soil pH, organic matter and available potassium content were significantly increased, and available phosphorus content was compensated to a certain level by addition of carbon regulators. The increase of pH and nutrient factors were beneficial for the improvement of soil properties overall.(4)Total acid-soluble nitrogen was significantly increased by adding carbon regulators to the salinized soil, with sharp decrease in acid-soluble nitrogen (up to 42.26%). Microbial nitrogen content was also increased significantly with carbon regulators addition. With the increase ratio or carbon regulators, the microbial nitrogen increases first and then decreased.(5) The growth experiment showed carbon regulator addition improved the growth the Chinese white cabbage. When considering the six common physiological and production index, including the germination rate, the number of root tips, root length, root surface area, root volume and total average root diameter, the optimal dosage of carbon regulators is 40g/kg (T4).Conclusively, the recommended carbon regulator dosage is 40g/kg, in order to achieve the best results in water-soluble salt reduction, the optimal nitrogen transformation and soil physical and chemical properties, as well as the best growth of Chinese white cabbage. Note that this experiment was conducted under the laboratory conditions, which differs from the field in many aspects. Therefore, further studies are needed to investigate the effects of the suggested dosage of carbon regulators in actual farming practice.