Effects Of Green Manures On Soil Properties And Afterreap Eggplant Output And Quality In Greenhouse

With the development of facility agriculture, greenhouse has become an important part of vegetable production. Because of the greenhouse soil conditions in a relatively special ecological environment, how to maintain and improve soil fertility under greenhouse conditions is a difficult problem in production. To understand the characteristics of soil nutrition, leaching conditions of dissolved maters (DOC, DON and Nmin) and aferreap eggplant yield and quality responding to different green manures used as summer catch crops, six species of green manures were chosen in this study. These species belong to three families of Leguminosae,(Mung bean, Sesbania, India cowpea), Gramineae (Sweet corn, Gaodan grass) and Amaranthaceae (Amaranth), respectively. A control treatment without green manure was included. The results shows as follows.1.The biomass of Gramineae and Amaranthaceae was significantly higher than that of Leguminosae at green manure harvest time. Gaodan grass producted the most, fresh biomass was128.17t/hm2, dry biomass was33.57t/hm2. Amaranth contains higher N、P and K, especially the K content reached8.77%, it is significant higher than other green manures. Gramineous green manure contains higher carbon(average content was51.40%) and lower nitrogen(average content was1.85%). Its C/N was significantly higher than Leguminous and Amaranthaceae. Leguminous’s nitrogen content is higher. The average nitrogen content of Leguminous green manure was2.69%, higher than that of Gramineae green manure, and lower than that of Amaranthaceae.2. After all the biomass return to the soil, the surface0～20cm of soil total N and available K content increased significantly. Total N content increased more in Gramineae treatments (32.46%higher than turning over before). Available K increased more in Amaranthaceae treatment increased available potassium content (75.72%higher than turning over before). Available P content changed little. It increased little at the eggplant harvest period, the growth was under9.8%. Organic matters increased slowly during the test. Planting the green manure can also reduce the soil EC. The plot of turning over all biomass of Gramineae crops treatments reduce the soil pH. Thus planting and retuning all the biomass could effectively increase the soil total N, available K and organic matter, and adjust soil pH. Planting green manure can effectively reduce soil EC.3. Planting and turning over green manure could increase the soil SMBC. The average value from183.19mg/kg to211.25mg/kg. The control treatment showed a downward trend. Soil SMBN average content of Mung bean, Sesbania, India cowpea, Sweet corn, Gaodan grass, Amaranth and control treatments was respectively57.04,63.73,55.44,51.50,64.90,51.74,32.01mg/kg in different periods. So planting and turning over all the biomass could increase soil SMBN content, especially for Gaodan grass and Sesbania treatments. After turning over the biomass, soil SMBC content continued to grow until eggplant blossom period and decreased at harvest period. Gaodan grass treatment increased in the whole test cycle, soil SMBC content increased from179.02mg/kg to332.88mg/kg.4.The soil DOC contents increased after planting green manures, especially in0-40cm layer. Planting green manures reduced the soil DON and the Nmin contents. When all biomass returned into the soils, the DOC contents in the whole soil profile were increased in all green manure treatments, and the treatments of Leguminosae and Gramineae enhanced more than the treatment of Amaranthaceae did. Turning over the green manures could increase the soil DON and Nmin contents as well, especially in the treatments of all biomass returned. The soil DON and Nmin contents varied among different treatments with the trend of Leguminosae treatments <Control <Gramineae and Amaranthaceae treatments. When the roots only returned, the soil DOC, DON and Nmin of the green manure treatments were all lower than those in the control treatment. During the eggplant growth period, green manure treatments DOC contents is lower than CK at60-100cm in the plot of roots return. This suggests that return the roots of green manure can effectively reduce the leaching of soil DOC. During the eggplant flowering period, green manure treatments under60cm soil depth DON and inorganic nitrogen content is lower than CK. The plot of roots return have better effect. After returning full amount of amaranth can increase content of soil DOC, DON and Nmin and effective control of nutrient leaching.5.The eggplant yield performs that the plot of turning over all the biomass was better than the plot of turning over the roots. The average values were33164.2kg/hm2and30265.7kg/hm2. The sweet corn treatment shows the best effect. Fruit number and yield were80913per hm2and39534.6kg/hm2, significant higher than other treatments. CK was lower than green manure treatments. Fruit number and yield were65457per hm2and31843.3kg/hm2. Planting and returning all biomass of green manure can obviously increase the number of eggplant fruits and production. It can also improve the eggplant fruit quality. VC content and soluble sugar content of eggplant is shown as:sesbania treatment> Gaodan grass> CK.