Study On Paper Making Waste Water Irrigation In Winter-wheat And Rice Rotation System

Experiment of mid-stage effluent ammonium sulfite method irrigation on wheat and paddy was conducted to study the effect on crop,soil and ground water. The feasibility of treating mid-stage effluent with soil and plant system was discussed. From the results of this experiment, we can gain the amount of effluent on irrigation , rational consumptiom of fertilizers and economic analysis on best treatments. The main conclusions are as follows:1.The growth of wheat was accelerated markedly as the amount of effluent increased, and yields improved from 5.56% to 18.51% after the application of mid-stage effluents .However, the content of total soil salinity was elevated as mid-stage effluents helped to increase the content of organic matters and total nitrogen in tested soil. Therefore, further researches should be conducted to study the most effective amount and modes of irrigation to inhibit the extra accumulation of total salinity in soil.2.The irrigation of mid-stage effluent promoted the growth of paddy markedly and increased heigth,rate of dispart and yields.Yields improved from 20.38% to 106.8% in different waste-water treatments.Treatment 3 was the best of all.There were very significant differences in different treaments. Orgnism,total N,available N,P,K of tested soils were increaced in different extent .Meanwhile,the content of salinity and pH were improved as the accretion of mid-stage effluent.3.CODcr of mid-stage effluent can be removed markedly with treatment of soil.Though the removal rate of CODcr would decline as the process of irrigation,90.48% and 86.39% had reached in treatment 1/2 and treatment 1 finally.The content of total nitrogen in extravasate was influenced by the content of total nitrogen in mid-stage effluent.Removal rate of total nitrogen was declined as the amount of irrigation ,but stabilized comparatively in different treaments.Such as treatment 1/2 and treatment 1 which removal rate kept from 60% to 80%.Total salinity in extravasate was increased as the process and the amount of irrigation. 4.Nutrient balance in wheat showed that nitrogen and potassium waned,but phosphorus was surplus with the irrigation of mid-stage effluent.Nitrogen,phosphorus and potassium were surplus in paddy stage.In wheat-paddy system, Nitrogen,phosphorus and kalium were surplus too.The rate of surplus of nitrogen,phosphorus and potassium reached 5.21%,60.10%and 37.36% in the best treatments of system.Because nitrogen loss easily,so,we should use some fertilizer in wheat stage.The recommend application of nitrogen fertilizer is 286.8 kg/ha ,phosphorus fertilizer is 64.2 kg/ha,no potassium fertilizer in wheat stage.In paddy stage,nutrient of waste water can satisfy the demand of paddy.So,we shouldn't use fertilizers in this stage.5.With irrigation of mid-stage effluent of ammonium sulfite method,each hectare soil can treat 19200m3 waste water,save $ 17280 expense of treatment,gain $28893 production value of crop and $38482.50 economic benefits every year.Because the amount of irrigation is very little in wheat stage,so,we can resolve the problem of superfluous waste water with wetland.