The Research On Threshold Value Of Phosphate Fertilizer In Helio-Greenhouse

Tomato (Lycopersicum esculentum Mill.) is one of the most yield of crops for annual production. It is distributed widely and consumed most in the world. With the constant expanding of tomato cultivating areas, quantity of phosphate fertilizer increased gradually for tomato high yield, but utilization ratio of phosphate fertilizer decreased, only 10～25% phosphorus is absorbed and utilized by crops in the season, other majority are fixed by soil, large amount of phosphorus is wasted. Consequently, it is necessary that how to apply phosphate fertilizer rationally and raise the utilization ratio of phosphate fertilizer.The calcium superphosphate was regarded as the source of phosphate fertilizer in the tests, helio-greenhouse structure tomato was the research object, the purpose was to study the effects of different phosphate fertilizer on the growth, the chlorophyâ…¡, the soluble sugar, MDA, the electric conductance value content influence in the tomato seedling stage. Both laboratory and helio-greenhouse pop-experiment were carried out to reseach systematically the effects of different phosphate fertilizer on tomato physiological characteristics, growth, yield and quality. The influence on soil of urease, sucrase, catalase activity, EC value, rapidly available phosphorus was also studied.The conclusions as follows:1. The suitable phosphate fertilizer can promote the growth of tomato seeding. It also stimulates the accumulation of the sugar in the leaf blades, enhances the resistance. It has the positive role to cultivate the tomato strong sprout.2. The suitable phosphate fertilizer can increase the height, the stem thick and the number of tomato leaf. The phosphate fertilizer (P₂O₅) of 150～200 mg·kg^-1 has better effect. The biomass of tomato plant increases with phosphate fertilizer, but phosphate fertilizer of 1000mg kg^-1 is the best. The suitable phosphate fertilizer (150～200mg kg^-1) can promote the plant to absorb the nitrogen and the potassium. The quality and the output are also enhanced.3. The suitable phosphate fertilizer can enhance tomato nutritional value, when used phosphate fertilizer as 200mg kg^-1, the quality is the most best. However, used excessive phosphate enhanced the fruit acidity, the nitrate content but reduced the saccharinic acid ratio.4. The phosphate fertilizers execute the amount used and the rapidly available phosphorus, the EC value assume remarkably are being connected. The soil urease, the sucrase, the catalase activity had negatively correlated with the amount of phosphate fertilizers. The soil enzyme has promoted action in the suitable phosphate fertilizer(150～300mg kg^-1), but the excessive phosphorus had the certain inhibitory action to the soil enzyme activity.The phosphorus excessively used can reduce the soil enzyme activity, enhance the soil EC value, and destroy the soil environment.The result indicated that the suitable phosphate fertilizer may promote the tomato growth and output In the helio-greenhouse production, the excessive phosphate fertilizer could decrease the fruit quality and reduce the output. It also created the unbalanced of soil nutrient and caused phosphate waste and environment deterioration. It was not suitable for the helio-greenhouse vegetables good quality, high output and the soil sustainable use. Therefore, using the phosphate reasonably in the helio-greenhouse vegetables production is important for the environmental protection and high production, high quality, effective technical system of appling fertilizer.