Effect Of Salts Content In Irrigation Water And Accumulation In Soil On The Growth Potential Of Crops

Salinity is one of the major abiotic stress limiting agricultural production. It is also a serious problem in world irrigated farming in nowdays. In recent years with the industry and agriculture development, the irrigation water quality unceasingly dropped, the soil salinification unceasingly aggravated. The northwest arid and half arid region in our country, the rainfall is specially small, the evaporation is intense, the irrigation water source is short. With the irrigated farming development, people directly or indirectly used waste water and sewage irrigation which is from industrial and agricultural production, wild flooding irrigation, the unreasonable irrigation method, the backward irrigation technology, ignored supporting irrigation infrastructure and so on to cause some region water level ascension, the soil salt content to increase, the salinity accumulates continually, land productivity reduces, it is very harmful to the agricultural production. Therefore aims at the Shaanxi Guanzhong the main grain crops wheat and corn, a culture experiment indoor and a pot experiment were conductered on study effect of different NaCl content stress on the seed germination and seedings growth of wheat and corn, and so on the Wei river water quality was investigated and evaluated. The purpose of this experiment finds out salinity affects corn growth, seeks suitable irrigation condition of wheat and corn in Shaanxi Guanzhong, offers scientific basis to enhance corn yield, breed and cultivate salt tolerance seed. Simultaneously also for instructs the Weihe River basin specially is the Guanzhong irrigation area farmer reasonably using the Wei river water irrigation and the investigation, deals with the Weihe River basin water pollution issue to provide the theory reference, and provides the scientific basis for the Weihe River basin water environment protection. The results showed as follow:1. Effect of salt sress on seed germination and seedings growth of corn:≤0.5 g/LNaCl was benefical to enhance corn seed germination rate , the growth of root and sprout, and increase the number of roots, With an increased salt content, the adverse effect of salt stress on corn became more obvious. Which decreased seed germination rate , restrained the growth of root and sprout.≤0.5 g/LNaCl is probably the threshold content which effect corn seed germination. Using salt content(≥0.5 g/LNaCl)water solution long?term irrigation will enhance soil salt concent thus hinder corn growth, decrease survival rate and corn seedings show salt injury effect in form shape, According to five physiology indexes, such as the dry weight of shoot and root, water concent of plants and so on were valued. The result showed that the corn seedings were treated by tap water (0.1 g/LNaCl) reached significant level than other treatments. This also indicated a low salt content (0.1 g/LNaCl) can promote the growth of corn seedings, thereby enhance corn yield.2. Effect of salt sress on seed germination and seedings growth of wheat:≤0.5 g/LNaCl was benefical to enhance corn seed germination rate, the growth of root and sprout, and increase the number of roots, with an increased salt content, the adverse effect of salt stress on corn became more obvious. Which decreased seed germination rate, restrained the growth of root and sprout. The salty stress on wheat seed sprouts mainly is the low flow of water hinders absorbing water≤0.5 g/LNaCl is probably the threshold content which effect corn seed germination. Using salt content(>0.5 g/LNaCl)water solution long?term irrigation will enhance soil salt concent thus hinder corn growth and corn seedings show salt injury effect in form shape, According to four physiology indexes, such as the dry weight of plant , plant height, spike length and so on were valued. The result showed that the wheat seedings were treated by tap water (0.1 g/LNaCl) reached significant level than other treatments. This also indicated a low salt content (0.1-0.5 g/LNaCl) can promote the growth of corn seedings, thereby enhance corn yield.3. Indicated to the Weihhe river water diagnosis that, the Wei river water pH value maintains between 6 -9, Range of variation increases unceasingly from the upstream to the downstream, it conforms to (GB3838-2002) water quality requirement. In the Weihe river water the total phosphorus content all > 0.1 mg/l, It increases gradually in the middle stream and downstream, the change scope enlarge gradually and has surpassed (GB3838-2002)Ⅳ(The forth kind of water quality requirement), it is only suitable for the agricultural irrigation water used. The nitric nitrogen is the source of Weihe River nonpoint pollution, mainly comes from the farmland and the water and soil leaching outflow nitrate nitrogen. In the Weihe river water the nitric nitrogen and entire sulfur content very are all high, change tendency basic consistent, all is the content has lowered in the middle stream and downstream of Weihe river, but change scope increased. Middle and upper reaches Weihe River the nitric nitrogen content on all > 2.1 mg/l, the entire sulfur content all basically reaches > 2.5 mg/l in the entire Weihe River basin, from this we might infer in middle and upper of the Weihe River the entire nitrogen and the sulfide content have all surpassed (GB3838-2002)Ⅴ(The fifth kind of water quality requirement), couldnot be used in the agricultural irrigation water. In the Weihe river water the special ion sodium content <200 mg/l, Iit is lower than the irrigation water quality request, Potassium, calcium, magnesium ion change tendency basic consistent, all is the changes scope in middle and downstream of the Weihe River to enlarge unceasingly, also the entire basin threecontent overall change tendency basic assumes identically: Sodium>calcium>magnesium ion; In Wei river water heavy metal element: Copper, the cadmium, the chromium content very is all small, is insufficient to harm surface water quality. The total quantity size is in turn: The copper>chromium>cadmium. but if we use this kind of water quality long-term irrigation , it will became harmful to the soil or the crops.