Study On The Effect Of Biochar On Greenhouse Soil Properties And Crop Growth Under Different Water And Nitrogen Conditions

The mode of single fertilizer and flood irrigation in north China has reduced the utilization rate of water and fertilizer,which futher caused soil carbon and nitrogen imbalance, environmental problem and yieldreduction. This paper explored the optimal application level of biological carbon via filed trails in Wuqing, Tianjin. The effect of different levels of biological carbon on the soli properties and crop growth were explored under trational water nitrogen and optimal water nitrogen conditions. Futhermore, the optimal management of water & nitrogen was explored under organic fertilizer with different levels of biological carbon conditions. Finally, the summer catch corn planting and biological carbon application were used to study the absorption of nutrient in maize, prevention of the accumulation of nitrogen and phosphorus downward movement in the soil and the mechanism of reducation on the risk of soil environment. The results are as follows:There is significant difference between two kinds of water and fertilizer management with different levels of biochar on soil physical properties. Bulk density treatment of earthworm manure application and optimization of water and nitrogen combined with biological carbon has a certain reduction, with the increase of the amount of biological carbon application, bulk density decreased. The 0.5%~2% biochar application trestments improved significantly soil aggregate structure. The application of 0.5%~4% biochar was beneficial to increase soil moisture and soil temperature, but the field water holding capacity and soil temperature decreased when the biochar application level was 8%. Conventional water and nitrogen with application of biochar on soil water holding capacity enhanced the role of good to optimize fertilizer with biochar treatment, vermicompost with biochar on field water holding capacity was better in chicken manure application of biochar.Different levels of biochar with two fertilizer management obviously affected the soil chemical and biological properties. With the increasement of biochar levels, the contents of soil organic mater and soil DOC showed a rising trend, chicken manure with biochar management showed better effect on improving the content of soil organic mater than vermicompost with biochar, especially the chicken manure with 4% biochar treatment. While the concentration of biochar was higher than 2%, the soil DOC unsteady changed, which need to be further studied. Optimal water nitrogen and chicken manure with 0.5%~4% biochar could adjust the C/N in facility farmland in order to maintain a desirable level of crop growth. Optimal water nitrogen fertilizer with biochar could reduce the leaching of nitrate nitrogen. In the late stage of crop growth, 0.5% biochar was the most effective in improving the content of surface soil nitrate nitrogen. The 4% biochar could reduce the effective phosphorus content in the surface of the soil, which could help to reduce the environmental risk of phosphorus. Biochar could improve soil cation exchange capacity, 8% and 0.5% of carbon was the best, however, two water and nitrogen conditions showed no difference. The quantity of biochar application showed positive correlation with soil cellulase activity and soil microbial biomass carbon, while the amount of 4% biochar appear to be abnormal, which needs to be further explored. Biochar could improve soil urease activity, urease activity was mainly affected by nitrogen content in soil.Different levels of biochar caused significant effect on the growth of crops, quality and yields. The cucumber grew well in the initial period under optimal water nitrogen and chicken manure with 0.5%~2% biochar conditions. The growth in late period was the same with vermicompost and 0.5%~2% biochar, 4% ~ 8% biochar inhibited the growth of cucumber. The 2% biochar was the most effective on the waxy maize only in early growth period. The 0.5%~4% biochar was benefit for the growth of waxy maize in late period. The 0.5%~2% biochar was benefit to improve the tomato yield and biomass. Meanwhile, 0.5%~2% biochar could improve the quality of tomato and cucumber. Chicken manure with biochar had better effect on improving the yield than vermicompost fertilizer with biochar. The 2%~4% biochar showed some advantages on both total fresh biomass and total dry biomass in waxy corn.The biochar was positioned for 1.5 years under optimal water nitrogen conditions and the result indicated that, the chicken manure with 0.5%~2.0% biochar + summer catch waxy corn plant could improve the crop yields, quality and the quality of facility soil. As well as reduce the risk of nitrogen and phosphorus in environment and guarantee the development of sustainable agriculture.