Study On The Safty Of Winter Wheat With Reclaimed Water Irrigation

The reclaimed water is a kind of water resource, which is reusable by recycling the sanitary sewageand industrial waste. Under the situation of serious water shortage, realizing the safe utilization ofreclaimed water will open a new channel for using agricultural water. So, what effect the reclaimedwater irrigation can bring to the crop yield, quality and agricultural environment will get a wide attention.This study takes winter wheat as object, reclaimed water of different degrees of processing (Secondaryeffluent, Tertiary effluent) as irrigation-water. By pot experiment and field experiment, the effect ofgrowth, yield and quality of winter wheat and soil environment caused by the reclaimed water werestudied.The results showed that irrigation with reclaimed water was helpful to the growth of winter wheatto some extent. From the morphological appearance, it can be seen that the effect of the reclaimed waterirrigation on the height of winter wheat is very significant, and the difference get more significant in thelater growing period. The height of the winter wheat irrigated by the reclaimed water is 2.2～6.1％higher than CK and the leaf area of winter wheat irrigated by reclaimed is also significant than CK.From the measurement of biochemical index, it can be seen that the effect of the Antioxidase on thewinter wheat is mostly demonstrated on the seedling stage. During the Winter-growing stage, the SODaction of the winter wheat is 14.54～16.44％higher than CK, but later it became less significant. Thechlorophyll content of the first leaf of the winter wheat irrigated by reclaimed water is a little higher thanCK, later it was improved 6.70～16.75％during the Jointing stage and Heading stage. The difference ofdifferent treatments became insignificant when it get the later Flowering stage. From the measurement ofwinter wheat's photosynthesis, it can be seen that winter wheat's photosynthetic rate by reclaimed waterirrigations is lower than fresh water irrigations in jointing stage and earning stage, but leaf blade'stranspiration rate by tertiary effluent are higher than those by fresh water treatments in jointing stage,secondary effluent treatments transpiration rate are lower than those of fresh water treatments, bothtreatments are lower than fresh water treatments in earning stage. Through analysis, it is considered thereclaimed water irrigation has not had the advert impact on the winter wheat's physiological function.The reclaimed water irrigation can improve the yield of winter wheat to some extent and alsoimprove the quality of winter wheat. Yield of wheat processed by tertiary effluent for two years wereimproved 8.94％and 4.12％respectively; which is very significant. Yield of wheat by secondary effluentirrigations is not remarkable: winter wheat yield is 4.79％higher than CK by fresh water irrigation in the1st year, and no difference the 2nd year. Grain protein and gluten content of winter wheat by reclaimedwater irrigation is relatively higher than those by fresh water; and the composing and stabilizing time ofthe wheat powder index is elongated, which is helpful to improve the nutritional value and processingquality of the winter wheat. Through measurement of the five kinds of heavy metal of Cr, Pb, Cd, Cu, Zn,it can be seen that the accumulation of heavy metal is not remarkable and has no significant advertimpact to the crop. The accumulation of heavy metal cadmium is comparatively higher than CK butwithin the National Food Health Standard. Through analysis it is thought that resurgent water irrigationmay not cause the over standard of heavy mental in the grain for short term, but accumulation of heavy metal cadmium should be pay more attention, especially in the long-term reclaimed water irrigated area.The reclaimed water has some nutritional substances which can nourish the soil and improve thenutritional status, for example the Available N Available P Available K was improved, but the effect toorganic matter is small. The edaphon are remarkably improved; the pot experiment shows that the soilbacterium and the fungus were improved significantly; field experiment shows that Azotobacter andNitrosobacteria was remarkably increased. The microorganism increase will make the soil microecology system more abundance and more standardized function, so that improve the bio-action andbuffering capacity and has beneficial effect on the physical and chemical nature of the soil, and furthermore improve the enabundance of the soil. The 5 heavy metals are different in the different layer of thesoil, most of them distributed in the 20～40cm depth. The difference between the same heavy metalswithin the same treatments is not so different. The reclaimed water irrigation didn't caused accumulationof heavy metals.So it can conclusion that irrigation with reclaimed water is helpful to the growth of winter wheat,and also improved the yield and quality of winter wheat. Reclaimed water irrigation can nourish the soiland improve the nutritional status, for example the Available N Available P Available K was improved.The edaphon are remarkably improved. There's no grain and soil polluted with heavy metals byreclaimed water irrigation in trial period, but there is some accumulation of heavy metals.