The Impact Of Pig Farming Waste Water Irrigation On Soil Physical And Chemical Properties

Water is the most basic element for human survival and development, as well as thepower for agriculture and industry production. Since the1970s, with the booming ofurbanization and industrialization, many countries and regions pay attention to therecycle of aquaculture wastewater, because it can contribute to the agricultural irrigation.However, using aquaculture wastewater to irrigate the crops brings up manyenvironmental problems. To some extent, aquaculture wastewater irrigation has becomea world major issues of sustainable human development.Aquaculture wastewater is powerful for agricultural irrigation water-saving,pollution reduction, the efficiency of triple effect。Aquaculture wastewater is rich inmany nutrients, however, there may be other potentially harmful substances may play anegative role on soil ecosystem, therefore, to explore the impact of aquaculturewastewater irrigation on soil physical and chemical properties, refining science,aquaculture wastewater irrigation methods applicable to ensure the safety of food andwater environment are of great significance for achieving the safe irrigation ofaquaculture wastewater.Based on the theory of soil physochemistry, we carried out our experiments atExperiment Station in East Stream Town of Jianyang City, which belongs toWater-Saving Key Laboratory of Sichuan Province. Three different waters are used toirrigate and we sampled soil at the seedling stage, the jointing stage, heading stage andthe filling stage. Based on the analysis of the soil physochemical parameters andcomparisons, the following conclusions are put forward.Judging by the changes of soil physical parameters, we discover that when weirrigate with clean water, the soil bulk density increases and the soil porosity decrease.This is because that the clean water does not bear organic substance and cannot improve the soil quality. For the low organic matter content, the treated aquaculture wastewaterafter does not improve soil physical properties noticeably, such as soil bulk density.When we irrigate using untreated aquaculture wastewater, the soil bulk density decreases,the porosity increases and the field water-holding capacity is also enhanced. This isbecause that the high content of organic substance of untreated aquaculture wastewaterwhich may provide food to the microorganism in soil. It is obvious that untreatedaquaculture wastewater can improve the soil quality much more significant than theother two types water.Judging by the changes of soil chemical parameters, we discover that when weirrigate with clean water, the decline obviously, this is because the clean water does notcontain organic substance which will be consumed by plant. When we irrigate usingtreated aquaculture wastewater, the soil nutrient decrease noticeably, except the increaseof soil total nitrogen, total potassium, and nitrate, all other chemical parameters decrease.This is because after a series of treatment, a large amount of organic substance lost.Situations are different with the untreated aquaculture wastewater. All chemicalindicators are enhanced. Therefore, untreated aquaculture wastewater can improve thechemical quality of the soil much more obvious than the two other types of waters.In short, according to the soil physical and chemical indicators, after untreatedaquaculture wastewater irrigation, soil physical properties has been some improvement,soil bulk density lower capillary water holding capacity increases, the capillary porosityincreases, the organic matter content has improved, the degree of soil loose soilstructural and ventilation accordingly been improved and enhanced. Soil plant is easy toabsorb and use a variety of carbon, nitrogen, phosphorus, potassium nutrient elements;particularly the plant can directly absorb nitrogen, phosphorus, and potassium contentwhich have been some improvement. There is little number of bacteria after disposal ofhazardous soil ecological environment caused by the impact. This study shows, usingthe treated aquaculture wastewater irrigation, the overall fertility level is not high on thesoil to retain water and and fertilizer in general no obvious improvement.