Characteriaztion Of Phosphorus Forms In Environmental Materials And Their Transformation In Soils By³¹Phosphorus Nuclear Magnetic Resonance Spectroscopy

Large amount of organic wastes can be produced every year because of the urbanization, such as sewage sludge from sewage treatment plants, animal manure, household rubbish and greenery waste. Disposal of growing organic wastes has become a problem we must face to. At the same time soils in China are generally deficient in phosphorus. These organic wastes are rich in nutrition elements such as nitrogen, phosphorus and organic matter. If these organic wastes can be applied to soils, then the problem of phosphorus deficiency and disposal of organic wastes would be solved or relieved simultaneously, and it coincides with the concept of circular economy. However, too much phosphorus in soil would become potential pollution sources to the surrounding environment. Besides, phosphorus with different forms in soil tend to have different chemical behaviors. In this article, the typical phosphorus forms in the organic material and their changes after being applied into the soil were studied by the NaOH/Na2EDTA-3!P-NMR technology, which would provide technical basis for scientific and reasonable application of organic materials in soil.In order to understand the phosphorous forms from different sources, the31P-NMR technology was used in3kinds of typical zonal soils and23kinds of organic materials by compared with the traditional NaOH digestion method determining the total phosphorus and ignition method determining the organic phosphorus. Compared with the traditional methods, the percentages of total phosphorus are39.18%～134.43%and that of organic phosphorus are0.00%～134.43%by31P-NMR technology, which are very significant correlation(R2=0.8433, p<0.01), and significant correlation(R2=0.6621, p<0.05) respectively. For three soils, black soil shown higher phosphorus proportion and dominate in organic phosphorus by31P-NMR analysis. Almost all organic materials are rich in organic phosphorus except the aged refuse. Among the organic materials, monoester-P is the primary phosphorus form, only few samples can find the pyrosphosphate, phospholipids and DNA, polyphosphate and phosphonate are absent in all samples. The phosphorus forms and compositions can clearly indicate the circumstance and deposit situation of these organic materials. This31P-NMR method is effective to most of the environmental samples, especially those with high organic matters and low content of Fe, Mn and Al metals.Application of different organic materials into soil exerted obvious effect on soil pH value, organic matter, total phosphorus and organic phosphorus content. Organic matter content and total phosphorus content of soil increased when more organic material were applied, No obvious change of organic phosphorus was observed, and greenery waste had best capacity of organic phosphorus fixation compared with other organic materials. Latosol generally tended to have lower pH values, which were helpful for fixation of organic phosphorus. Black soil tended to higher content of organic phosphorus.Soil types and organic materials exerted obvious effects on phosphatase activities. Generally speaking, phosphatase activities in latosol and calcareous alluvial soil increased with growing organic material. However phosphatase activities in black soil dropped down when organic materials were applied perhaps because of0.96g·kg-1of organic phosphorus in the soil. Greenery waste had best positive effect on phosphatase activities and organic phosphorus fixation compared with other organic materials, and next one was combination of greenery waste and0.96g·kg-1of KH2PO4, and aged refuse decreased phosphatase activities.From the figure of phosphorus forms distribution it can be seen, all kinds of soil phosphorus compounds increased when the materials were applied into soil. The transformation of phosphorus forms mainly happened fourteen day to eighteen days after application of organic materials, and orthophosphate diesters disappeared. The proportion of inorganic phosphorus increased gradually with training time, while orthophosphate monoester decreased. Organic phosphorus transformed to the inorganic phosphorus, and content of the latter increased, which was beneficial to the growth and development of the plant and could also cause some environmental problems because of too much inorganic phosphorus, which should be paid much attention. After the pot experiments, available phosphorus content in soil decreased obviously. Different prescription exerted different effects on plant growth, and plant generally grew better when cow manure and greenery waste were applied. Special attention should be paid to the prescriptions that would cause slight decrease of available phosphorus content since excessive phosphorus would cause leaching and eutrophication of water.The results of different dosage of exogenous phosphorus and their transformation in soil implied that, excessive phosphorus was not favorable to fixation of organic phosphorus. Organic materials were rich in organic phosphorus, but it can be easily transformed to inorganic phosphorus in soil, and therefore it might be a good idea that small amount of organic materials were applied in multi-times, which would be helpful to reduce possibility of potential pollution to the environment.At the same time, according to different types of soils we should adopt different measures, we should try to increase the soil which bottom phosphorus content is higher, we should increase the first phosphorus quantity.