Effect Of Different SAP, Water And Nutrition On Growth And Water Use Efficiency Of Jatropha Curcas L.

Abstract:As a kind of multi-functional tree species, Jatropha curcas not only become the important raw material for biodiesel species by its high oil content of seed, but show great research value in the field of medicine and the ecological environment.At present, yunnan province has China’s largest Jatropha curcas planting area with good development trend. Since Jatropha curcas were usually planted in sloping fields, they were often facing the problems of lack of water and fertilizer, while complex terrain and climate made it difficult to full irrigation and fertilization. It is the urgent problem to be solved that the crop yield should not be affected or suffered only minimal impact on the conditions of saving the manpower, irrigation water and fertilizer in the region.Based on the above backgrounds, we choose Jatropha curcas as the research object,introduce two new methods (Regu-lated Deficit Irrigation and Super absorbent polymer) to investigate the effects of different RDI and SAP modes on growth regulation and water use efficiency of Jatropha curcas L. respectively.(1) In the regulated deficit irrigation (rdi) test, compared to CK treatment, as W2D3treatment saved irrigation water by11.2%, mean significantly reduced the leaf dry mass and petiole dry mass,reduced the root dry mass, stem dry mass and total dry mass slightly, Meanwhile, mean significantly increased base stem diameter-plant height ratio and root-shoot ratio, thus significantly increased irrigation water use efficiency and healthy index of sapling.(2) In the different water,nitrogen and SAP test, the obtained best treatment of Jatropha curcas growth was SAP(2g·g-1), high-moisture (80%ET) and high level of Nitrogen(5g·g-1). Under N2level, compared to S1W2treatment, S2W1treatment saved irrigation water by35.1%. As the applying of SAP reduced the evapo-transpiration quantity, the suitable water content and nitrogen form a coupling effect, which increased the dry mass by20.3%and raised the water use efficiency significantly.(3) In the different irrigation cycle and applying ways of SAP test, on condition of same irrigation amount, effects of different applying way of SAP on growth regulation and water use of Jatropha curcas L. were:ring>half ring>hole; effects of different irrigation on growth regulation and water use of Jatropha curcas L.were:10d>5d>15d. Ring SAP applying and10d cycle irrigation can reduce the evapo-transpiration quantity, increase the soil water content, and raise the total dry mass.According to the above conclusion,when plant Jatropha curcas in yunnan province,we could employ deficit irrigation method. We should ensure a good supply of water before the roots growing well and reduce the supply when they get a good healthy index of seedlings. We can also use SAP to keep water and fertilizer. When Jatropha curcas saplings grow in the soil with SAP, we could lengthen its irrigation cycle and reduce irrigation amount to achieve the goal of saving water while increase production and improve WUE.