Preliminary Study On The Water And Fertilizer Coupling Technology Of Chinese Cabbage

There are less research achievements about the water and fertilizercoupling for the outdoor cabbage at present, but more less on precise irrigation watersystem study. With precise control of water and fertilizer，under the same fertility anddifferent irrigation water and fertilizer coupling on cabbage growth, yield and quality,fertilizer use efficiency, plant and soil effects of physiological indexes.The purpose isto find the right growth way of irrigation and fertilization for cabbage, to expound theinteraction between water and fertilization and its physiological mechanism. Thisexperiment results on outdoor vegetable science of integrated water and fertilizermanagement, development technology of comprehensive agricultural. AchievingGood quality and high output, effective way, reasonable irrigation and fertilization isto provide a theory and technical support for saving water and fertilizer.The research that conducted by four fertilization levels (B1、B2、B3、B4) andthree irrigation level（sW1、W2、W3）in the field plot test studied the effect of cabbagewater and fertilizer coupling to the production and quality. Considering that water is aimportant factor, the area required of fertilization is larger and the progressrequirement is higher, so we use the split spot design. Irrigation water is given priorityto handle W, and Fertilizer application as deputy district processing B. The results asfollows:1.Water and fertilizer coupling can significantly change the quality and yield ofcabbage, but the yield and quality are not unlimited increase with the improving waterand fertilizer.2.In this experiment, when the ratio of the organic nitrogen and inorganicnitrogen fertilizer is3:1, the yield of cabbage can significantly increase and thequality can improve remarkably.3. The concentration of nitrate nitrogen in the soil will gradually increase withthe increase of fertilizer, but topsoil nitrate content will gradually decrease with theincrease in amount of irrigation water. However it will increase with the increase offertilizer and irrigation. 4. The effect of water and fertilizer coupling to the crop yield mainly reflects inthe water supply level. In different levels it crop yield will have a different yield. Inthe case of lack of water, it can increase yield when we supply water, but the yieldeffect on fertilizer is greater than the water. In the case of low levels of natural soilfertility, the yield will be increased significantly when fertility be supplied. With theimprovement of natural soil fertility, the water’s influence is getting bigger. Inaddition water and fertility will have a coupling effect to the yield. Fertilization hasobvious effect on water diversion and vice versa. When there is few irrigation water,the interaction of water and fertility will increase with the increasing fertilizer,however it will have a opposite trend with the increasing irrigation water. The waterand fertilizer coupling has a threshold effect, when below this threshold, the yield willbe increased dramatically by increasing water and fertilizer, on the contrary, it willhave little effect.5. Tests showed that soil moisture content mainly increase as the irrigation wateramount is increasing, then slowly reduce during the whole cabbage growth period.The more irrigation water, the lower water use efficiency. For example in which highirrigation water processing is about1562.5m3/hm2, and the water use efficiency is56.2kg/m3. By contrast, the stress treatment irrigation water is937.5m3/hm2, theirrigation water efficiency is66.34kg/m3.6. There are diminishing returns relationship between crop yield and amount offertilizer; cabbage in the nitrate content is positively correlated with the use ofnitrogen into a result.Many studies have shown that ‘parabolic relationship’ betweencrop yields and the amount of fertilizer. When a fertilizer value is greater than aspecific value, if we still increase the amount of fertilizer, the production will have adownward trend, and in vivo nitrate content of vegetables always have an upwardtrend. So we should reduce the nitrogen fertilizer use to bring down the accumulationnitrate based on maintaining the production of cabbage.