Effects Of Different Fertilizer Treatments On Soil Ecological Factors And Tomato Growth In Protected Cultivation

To get high profits, excessive fertilizers were applied in greenhouse, resulting in decline of vegetable quality, the changes of soil ecological factors and soil quality. This research studied the soil ecological factors and the growth of tomato using a laboratory incubation experiment and cultivation experiment. Soil enzymatic activities (urease, hydrogen peroxidase, invertase and alkaline phosphatase), microbial biomass carbon, pH, EC and the contents of soil nutrient were determined in soils under different fertilizer treatments. The growth and yield of tomato wered also calculated. Main results were summarized as follows:1. The activities of soil enzyme wered affected by different fertilizer treatments and water regimes in culture condition. Soil urease and alkaline phosphatase activities increased significantly in the M and MCF-treated soils compared with C-treated soil. At the early of incubation, soil invertase activity was lower in M and MCF than in CK, after 28 days, significantly increased. Under water-surplus conditions and chemical fertilizer, soil urease, hydrogen peroxidase and alkaline phosphatase activities were reduced, but invertase activities was stimulated. It was also found that soil urease and alkaline phosphatase activities reminded higher in organic amended soils than chemical fertilizer was added under water-surplus conditions.Soil urease activities under different treatments increased at first and then decreased, and soil alkaline phosphatase activities showed the trend of gradually decreasing. Soil hydrogen peroxidase activities and invertase activities had the fluctuation changes during incubation.2. Soil microbial biomass carbon (MBC) was significantly affected by the types and amounts of fertilizer under cultivation condition.MBC increased in soils treated with organic fertilizer (M), organic fertilizer applied combining with inorganic fertilizer (MCF) and controlled-release fertilizer (CRF) compared with the CK-treated soil. However, MBC decreased in soil treated with the higher application of chemical fertilizer, as well as MBC obviously decreased with the increase of fertilizer application. MBC in soils treated by CRFs increased significantly in comparison with that treated by CFs.3. The activities of soil enzyme wered affected by the types and amounts of fertilizer under cultivation condition. The effect of different fertilizer treatments on soil enzyme activities was showed: organic fertilizers>inorganic fertilizer. The Manure could significantly increase soil enzyme activities. Soil enzymatic activities (urease, hydrogen peroxidase, invertase and alkaline phosphatase) increased in soils treated with M, CRF (fertilizer application of low and middle), CF (fertilizer application of low and middle). In the same fertilization application, soil urease, hydrogen peroxidase and invertase activities in CRFs were lower than those in CFs, but alkaline phosphatase activity were increased.4. Soil chemical properties were significantly enhanced by fertilization. Soil nutrient contents and EC increased with the amount of fertilizer. The CRF treatments received better results than CF treatments by increasing soil EC, TN, alkaline N, available P, NO3--N, NH4+-N, but pH decreased.5. The correlation between soil MBC, enzyme activities and soil nutrient contents were showed: Positive correlation was found in MCFs between soil MBC, soil urease, invertase, alkaline phosphatase and the contents of organic matter, TN, alkaline hydrolytic nitrogen, available P. In addition, the correlation between hydrogen peroxidase and soil nutrient content was not obvious. However, negative correlation were observed in CRFs between soil hydrogen peroxidase activity and soil TN, EC, available P, NO3--N and NH4+-N.6. The growth and yield of tomato wered affected by the types and amounts of fertilizer. There was a significant increase of plant height, stem diameter, chlorophyll content and fresh fruit weight of tomato in CF1, CF2, CRF1, CRF2, CRF3, M, MCF1 and MCF2. The the highest yield of different treatments was observed in CRF1. The growing of tomato increased in the proper amount fertilizer application, but decreased in the higher application of fertilizer.