Studies On The Nitrogen Loss In Sunlight Greenhouse Under Different Water And Nitrogen Management During Cucumber Growing Season

Our country is power in the vegetable planting, but also vegetable consumption and export power. To meet the increasing demand of vegetables, sunlight greenhouse developing rapidly, China has become the world’s largest country facility culture area. Due to the influence of the traditional vegetable planting mode, there is a widespread use of water and fertilizer plant of excessive way in our current vegetable production system, it lead to the water and nitrogen waste of resources and environmental pollution, become the main facilities vegetables the key to the sustainable development of factors. Therefore, the study of leaching nitrogen of cucumber season growth period in sunlight greenhouse under different water and nitrogen management have the important meaning for sunlight greenhouse of nitrogen use science. To solve the problem of soil nitrogen leaching in sunlight greenhouse in the effects of different water and nitrogen amounts, set up different processing field experiment in a greenhouse in Xinji, Hebei province in2010, for the research of effects of different water and nitrogen management on nitrate leaching in sunlight greenhouse and the yields during cucumber growing season. The study was conducted in Xinji, Hebei province, design different nitrogen (urea) processing under two level of water, study nitrate nitrogen leaching during cucumber growing season to determine the effects of water and nitrogen management on yields, dry matter accumulation and nitrogen utilization, we can finally get the best water and nitrogen management mode. The main results were as follows:1. With the increase of irrigation water, the value of soil moisture content rise. The water-saving treatments reduce the soil moisture content in the whole period with the conventional water treatment, especially in seeding stage and primary fruit stage. The water-saving treatment which maintains soil moisture contents at about20%in the whole period can meet the demand of water for cucumber growth, the treatment can save water30%with the conventional water treatment.2. The same irrigation water, with the increase of nitrogen, the values of soil nitrate nitrogen contents were increased. The treatment with25%～50%reduction in nitrogen can reduce soil nitrate nitrogen contents by18.0～50.8%. The soil nitrate nitrogen contents maintain at low levels.The same nitrogen used, with the increase of irrigation water, the values of soil nitrate nitrogen contents were reduced. It show that it’s easy to cause soil nitrate nitrogen into deep soils. The value of soil nitrate nitrogen contents of95cm depth in soil is rising steadily along with the growth of the crop and the increase of number of fertilization.All treatments of nitrogen used, the treatment is W2N600with30%reduction in water and50%reduction in nitrogen in soil nitrate nitrogen contents. It’s therefore the treatment W2N600was the recommend treatment which can reduce the soil nitrate nitrogen contents.3. The same nitrogen used, with the increase of irrigation water, the values of nitrate nitrogen contents leaching amount were increasing. The value of W1N1200(the conventional treament) increased by34.7%than W2N1200(30%reduction in water, conventional nitrogen); The value of W1N900(conventional water,25%reduction in nitrogen) increased by24.1%than W2N900(30%reduction in water,25%reduction in nitrogen). The nitrate nitrogen contents leaching amount was increasing with the increasing of irrigation water. They are stay at low level wtth no nitrogen used.The same irrigation water, with the reduce of nitrogen, the values of the nitrate nitrogen leaching amount were reduced. At seeding stage、 primary fruit stage、 full fruit stage、 last fruit stage, The value of W1N900(conventional water,25%reduction in nitrogen) respectively reduced by23.1%、22.0%、20.5%、11.2%than W1N1200(the conventional treament). The value of W2N600(30%reduction in water,50%reduction in nitrogen) respectively reduced by68.2%、61.6%、54.8%、46.0%than W|N|200(the conventional treament). The nitrate nitrogen leaching amount of W2N600(30%reduction in water,50%reduction in nitrogen) is reduced by57.8%in the whole period. The lowest values of nitrate nitrogen leaching amount is184.3kg/hm2, the processing is W2N600(30%reduction in water,50%reduction in nitrogen)4. The nitrate nitrogen leaching amount in the depth of95cm is closely related to soil moisture during cucumber growing season, especially of the full fruit stage under1200kg/hm" nitrogen treatment and the seeding stage、 full fruit stage、 last fruit stage under900kg/hm" nitrogen treatment. With certain nitrogen amount, the soil moisture can significantly affect the nitrate nitrogen leaching amount, especially of the full fruit stage.The nitrate nitrogen leaching amount increase with the soil nitrate nitrogen contents in the depth of95cm during cucumber growing season, they are linear positive correlation. The nitrate nitrogen leaching amount in the depth of95cm is closely related to soil nitrate nitrogen contents during primary fruit stage、 full fruit stage、 last fruit stage, the highest values was in full fruit stage.5. The same irrigation water, with the increase of nitrogen amount, the loss of nitrogen was increased, the utilization of nitrogen was reduced. In all processing, the utilization of nitrogen with the treatment W2N600was top.6. The yields of treatments W2N600was the highest compared with the conventional treatment in2008. But, the yields of W2N600with30%reduction in water and50%reduction in nitrogen have no significantly reduced with the conventional treatment in2009、2010.In conclusion, the treatment W2N600was much more reasonable management approach. Because this treatment with30%reduction in water and50%reduction in nitrogen can make the nitrate nitrogen leaching amount reduced by35.0%-57.8%in the whole period without the yields’reduce. The treatment W2N600can increase the utilization of nitrogen and reduce the nitrate nitrogen leaching amounts compared with the conventional treatment. So, the treatment W2N600with30%reduction in water and50%reduction in nitrogen was the best management approach.