Effects of Four Kinds of Fertilizers on Soil Properties and the Growth of Brassica chinensis L. in Vegetable Greenhouses

Objective The study was conducted to explore the effects of four kinds of fertilizers on soil properties and Brassica chinensis L. yield and quality in vegetable greenhouses in order to provide reference basis for scientific improvement of soil in vegetable greenhouses.

Method Sheep manure, bio-organic fertilizer, mineral potassium humate and acidified soil conditioner were used as tested fertilizers and B. chinensis L. was used as tested crop. The effects resulting from the four kinds of fertilizers on the pH value, EC value and contents of alkali-hydrolyzed nitrogen of soils in vegetable greenhouses were studied. Meanwhile, the variations of B. chinensis L. yield and quality were studied.

Result The application of sheep manure with 5 000 kg/hm² and 10 000 kg/hm² increased the soil pH value by 0.58 and 0.81, and increased the available potassium content by 43.0% and 78.2% respectively compared with conventional fertilization(CK). The EC value and alkali-hydrolyzed nitrogen contents of the soil increased significantly with the application of sheep manure doubled. The application of bio-organic fertilizer with 3 000 kg/hm² and 6 000 kg/hm² increased the soil pH value by 0.71 and 0.81 respectively compared with CK. The application of "mineral potassium humate 300 kg/hm² + acidified soil conditioner 1 200 kg/hm² " and "mineral potassium humate 600 kg/hm² + acidified soil conditioner 2 400 kg/hm² " increased the soil pH value by 0.99 and 1.00 respectively compared with CK. The EC value, alkali-hydrolyzed nitrogen content, available phosphorus content and available potassium content of the soil significantly rose with the increase of "mineral potassium humate + acidified soil conditioner" application, but the only application of mineral potassium humate had no significant effect on soil basic properties. The application of sheep manure increased the yield of the first crop of B. chinensis L. by 33.7% and 11.6%, and reduced the nitrate content by 23.4% and 8.3%. The application of "mineral potassium humate + acidified soil conditioner" significantly increased the Vc content in B. chinensis L. by 66.6% and 105.1%. The increase of fertilizer application had no significant improvement on Brassica chinensis L. yield and quality, and the effects on which from the four kinds of fertilizers were not significant in the second crop.

Conclusion The application of sheep manure or "mineral potassium humate + acidified soil conditioner" as base fertilizer in vegetable greenhouses has better effects on soil properties and B. chinensis L. yield and quality. The suitable application amount is 5 000 kg/hm² sheep manure or "600 kg/hm² mineral potassium humate + 2 400 kg/hm² acidified soil conditioner".