Studies On Soil Nutrient And Heavy Metal Accumulation Effects Under The High Amount Of Organic Fertilizer Input

Due to the food quality requirement, organic agriculture was developing quicklyin China in recent years. But over-use organic fertilizer in the organic vegetableproduction may cause a series of problems, such as low vegetable quality, the soilenvironment quality decreasing and environment pollution. In order to found therational application of organic fertilizer on vegetable cultivation, a long-term locatedfield experiment with4treatments of different organic fertilizer amount was carriedout in green house in Beijing suburb. The effects of organic fertilizer application oncrop yield, quality, nutrient absorption characteristics and nutrient use efficiency, soilnutrient and heavy metal accumulation results showed as follows:1. The results showed that the crop yield was increased with the organic fertilizerapplication amount increasing when it was lower than the best fertilizing amountpoint (85.5t/hm~2). But the crop yield began to decline when the organic fertilizationinput was high than85.5t/hm~2.2. The nitrate content of vegetables were increased with the increasing of organicfertilizer amount at beginning, then, it will decreased. But it was no significantinfluence on Vc and soluble sugar content. The reasonable application of organicfertilizer can obtain a better sugar acid ratio of tomato.3. N and K uptake amount of vegetables was higher than P uptake. The apparentuse efficiency of N, P and K was obviously decreased with the organic fertilizer inputamount increasing.4. The high organic fertilizer lead to a high residual of soil Nmin, Available P,Available K in0~30cm soils. The content of soil Nmin, Available P and Available Kafter experiment finish increased2.9folds,2.6folds,3.1folds than the beginning.That would lead to high risk potential of soil nutrition loss and environmental pollution under the heavy rainy or unreasonable irrigation conditions.5. Different treatments of organic fertilizer application was little effect on soilheavy metal content of Cr, Hg, As and Pb; But it had significant effect on soil heavymetal content of Cd, Cu and Zn. The correlations between organic fertilizerapplication and soil heavy metal content of Cd, Cu and Zn, all reached a significantpositive liner relationship.