| In this study different years of cultivating greenhouses were used to investigate the fertilizer input, different vegetables and their output and soil nutrition of inside and outside of each greenhouse surface soil, to discuss the fertilizer utilization and the soil nutrition difference between inside and outside of each greenhouse and different greenhouses with different vegetables, to analysis the relationship between the cultivating year and soil nutrition accumulation characteristics and curing fitting the soil nutrition with different vegetables and their cultivating year, to study the dynamic changes of soil nutrients and the reason of soil acidity, the results are described as below:1.The average inputs of N, P2O5 and K2O were respectively 2683.6 kg·hm-2,1964.9 kg·hm-2,2375.1kg·hm-2(with a ratio of 1:0.73:0.89),among which N, P2O5 and K2O provided by chemical fertilizers took up 45.6%,75.4%,60.8% of the total nutrients. In terms of the vegetable varieties, the inputs of N, P2O5 and K2O in different greenhouses were in the order of cucumbers>tomatoes>sweet peppers. A common problem was that there was a higher proportion of phosphorus input while a relatively lower input of potassium. It was also discovered that there was a big surplus of nutrients of Nitrogen, phosphorus and potassium in the greenhouse system. The theoretical application of them was 18.6%,7.3%,31.4%. Differences existed in the application of fertilizers to different vegetables, with 14.4% of nitrogen 9.9% of phosphorus and 27.4% of potassium in the cucumber greenhouse, 17.7%,5.1%,32.1% in the tomato greenhouse and 29.6%,7.2%,41.3% in the sweet pepper greenhouse .2.In comparison, the contents of hydrolysable nitrogen, available phosphorus, available potassium, organic matters and electrical conductivity in greenhouse soil were much higher than those in the open field soil. To be exact, they were increased respectively by 135.3%,475.2%,290.1%,97.7%,188.7%, on the other hand, the PH value decreased by 0.31. The frequency curve of various nutrients was observed in a normal distribution. Differences were observed in the amount of nutrients in greenhouses for different vegetables. The amount of hydrolyzable nitrogen and electronical conductivity lay in the order of tomato > cucumber >sweet pepper, cucumber>sweet pepper>tomato. as for organic matters and pH value, cucumber>tomato>sweet pepper for available phosphorus and tomato>cucumber>sweet pepper for available potassium, whose frequencies were all in a normal distribution. The results also revealed a mild tendency of acidification in greenhouse soil and an increasing gravity of soil salinization, primarily caused by the accumulation of hydrolysable nitrogen and available potassium. The decrease of PH value was closely related to the accumulation of hydrolysable nitrogen..3.The soil nutrients in greenhouses displayed an accordance with accumulation characteristics of cultivating years. They tend to accumulate rapidly in the first two years and slow down in the third and fourth year. Later they fell into a stable scale with slight fluctuations, but demonstrated a dynamic balance in the greenhouse soil system on the whole. All the contents were in positive accumulation except the pH value. There was significant relevance between soil nutrients in greenhouses of different vegetables and cultivating years, which could be fitted by conic curve or cubic curve.4.After the basal manure was applied, there showed a sharp increase in hydrolysable nitrogen, available phosphorus, available potassium and electrical conductivity, a moderate rise in organic matters and a slow decrease in the pH value. Planted in the greenhouses, vegetables fell into a highly- fertilized environment. Compared with the nutrient levels after the application of basal manure in the previous year, a dramatic fall down was observed in various nutrients before the use of basal manure in the following year. Apart from an average declining tendency in available phosphorus, hydrolysable nitrogen, available potassium, electrical conductivity and organic matters all went up by less than 20% with an exception of 42.3% increase in the electronical conductivity in sweet pepper greenhouse. Meanwhile a modest declining tendency was shown in the PH compared with the value before the vegetables were planted last year.
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