The Relationship Between Solar Greenhouse Soil Environment And Cucumbers' Quality And Yield

The characteristics of soil and fertilization of fruit vegetable in solar greenhouse in Beijing were investigated. Based on it, the influence of fertilization on cucumbers' quality and yield was researched. The results indicated that most of the solar greenhouses in Beijing now were builted in recent years, soil pH ranged from litmusless to alkalescent, the soil bulk density was on the high side, and soil pH of more than 70% greenhouses investigated was suitable for cucumber cultivation. The EC in 0-20 cm soil depth was higher than 20-40 cm depth. It was showed that salinity accumulated in soil surface of greenhouses tested, the salinity was too high for cultivating cucumber in about 15.8% greenhouses. The soil organic matter, available N, P, K were all at a middle or low level of soil fertility, whereas, all available micror.utrients, except boron, were at high level. The soil nutrients content in solar greenhouse increased with the number of cultivation years. Soil organic matter, total nitrogen, available phosphorus and zinc were significantly related to the number of greenhouse cultivation years, correlations were 0.675 (P<0.01), 0.690(P<0.01) 0.523 (P<0.05) and 0.528 (P<0.05), respectively. The bulk density of greenhouse soil were negatively related to the number of greenhouse cultivation years (r=-0.509, P<0.05). After fruit vegetables were cultivated for a season, the soil nutrients content in solar greenhouse, except boron, increased, but soil salinity problem increased by more than 50%. The soil NO3-N was the primary reason for the soil salinity problem, and it significantly related to soil EC as well.The organic manure fertilization rate of greenhouse fruit vegetable was excessive in greenhouses investigated. The average quantities of organic N, P and K applied on greenhouse fruit vegetables were 2373.0kg/hm2, 2040.9 kgm/hm2 and 1494.9 kg/hm2. It was a problem that the sort of organic manure was not diversity, chicken manure account for more than 70% of the organic manure. The chemical fertilization rate of greenhouse fruit vegetable was different in different greenhouse, some of them was too much for vegetable to uptake and the other was zero. The ratio of chemical N, P and K applied on greenhouse fruit vegetables was 1: 0.63: 0.76, and it was relatively reasonable for fruit vegetable to uptake. The agronomic efficiency of chemical N, P and K was 24.2%, 14.3% and 49.1%, respectively. There were a lot of fertilizers were left over soil.With the increase of fertilizer application rate, the nutrient quality and flavor quality as well as market quality of cucumber increased. But cucumber yield, quality characteristics, including crispness and market ratio of cucumber, and morphological and physiological characteristics including cucumbers' development height, leaves area, net photosynthetic rate, leaves and stems' dry and fresh weight, roots' volume and absorbency, decreased by excessive fertilizer application on greenhouse cucumber, whereas NO3-N concentration increased. In poor light and low temperature season, the effects were more significant, and it was recommended that less fertilizers should be applied in that season.The results showed that in current soil fertility level in Beijing, cucumber yield was significantly related to soil organic matter, available K, Fe, B, total nitrogen and available Zn Cu. There was a parabola relationship between soil NO3-N and cucumber's yield according to field experiments. The soil NO3-N and EC were main factors which affect cucumber's quality, and dissociative amino acid and organic acid were main factors which were affected. The NO3-N of cucumber was significantly related to soil NO3-N and EC, but the ratio of NO3-N which was distributed to fruit of cucumber is little.The problems in fertilizer application on fruit vegetable in Beijing and scientific soil management methods were discussed in the dissertation.