Sludge For Agricultural Research, The Status Of Vegetable Growth And Heavy Metal Security

The sludge outlet of municipal wastewater treatment plant has been the focus of attention, sludge is an effective biological resources and a good soil amendment, because it contains rich essential plant nutrients, for instance N, P and K etc. But the local soil of Kunming can not meet demand of crop planting soil, because the soil quality is poor, especially low content organic matter, N and P, in addition, soil is tinged with acidity. Sludge compost land use can improve the physicochemical properties of Kunming local soil, but sludge also contains some refractory organics, heavy metal, pathogenic microorganism and parasites etc, organic compounds mainly includes protein, oil, crude fiber and humic acid etc, inorganic matter mainly includes metallic compounds and inorganic salts, and that may bring harmful effect on sludge compost land use, so we need considering in many respects, the sludge must be innocent and stable before utilization.By researching the effect of mixed soil with sludge compost, local soil and some fly ash and lime on growth status, heavy metal absorption and safety of vegetables, for find some law of the effect of sludge compost land use on growth status and heavy metal absorption of vegetables, meanwhile, evaluating the heavy metal safety of vegetables, to provide scientific basis for sludge compost land use.The results showed that the plants need nutritional components of local soil are very poor and the local soil is acid, but sludge contains rich plants need nutritional components, such as organic matter, N, P and K etc, and the sludge presents alkaline, so the physicochemical properties of sludge compost and local soil have very strong complementarities. After sludge compost mixed with local soil, the pH of local soil can neutralize, EC can improve, N, P, and organic matter can supplement and the physicochemical properties of local soil can modified excellently. It can neutralize the pH and impove the plant growth need nutritional components by adding a certain amount of sludge compost, so it can increase the organic matter, TN, TP, TK, AN, AP and AK, furthermore those are effective components mostly, so very good for plant growth.The fresh biomass and plant height of pakchoi as well as the total fresh biomass and fresh biomass of fruits are all great degree impoving after adding sludge compost, and the addition of sludge by 5%-10% had the best effect, after the addition of sludge higher than 10%, the growth of vegetables were inhibited because of the poisoning effect of heavy metal, so we should control the addition quantity of sludge rang from 5%～10% when added sludge to local soil, like this can get best effects. Adding fly ash and lime in sludge compost modified soil can reduce vegetables uptake heavy metal, such as Cu,Zn,Pb,Cr, and it's effect is good, the heavy metal content can come up to the sanitary standard of food, so it ensure the safety of heavy metal content. Adding different amount fly ash and lime get different effects for vegetables uptake Cu,Zn,Pb,Cr, the effects improved with the addition quantity of fly ash and lime increased, so fly ash and lime can reduce vegetables uptake heavy metal and raise the edible safety significantly.