The Study On Saving Water Culture Of Radish And Cabbage By Plastic Film Mulching In High Cold Region Northwest Of Hebei Province

In high cold region northwest of Hebei Province where it is drought and less rainfall.the vegetables were planted by irrigating with the water under ground,so the water level under ground decreased;the research on saving water of Radish and Cabbage under PFM(PFM) was conducted, in order that the aim at saving water ,high yield and good quality of vegetables under PFM could be realized.This experiment was studied on the saving water of Radish and Cabbage under PFM and appropriate irrigation in High Cold Region Northwest of Hebei Province,and on the character of resisting drought of radish seedling by soaking seed with CaCl₂. were conducted on Zhang Bei's experiment station of agriculture university of HeBei from June to September in 2004 and 2005, with radish variety and cabbage variety which were all the main varieties in Bashang Region. And drought- resisting experiment of radish seedling experiment was conducted from July to September in 2005. The saving-water effect of Radish and Cabbage under PFM and appropriate irrigation,and the drought-resisting of radish seedling which seed was soaked by CaCl₂ were systematicly reseached by field observation and the experiment in door.The main results were summaried as follows:The soil temperature of 0²0cm cultivated layer was increased 3-4.5℃ in early growth period was only 1℃ in late growth period by PFM;there was more water saved up to 20.84mm in 0⁶0cm soil layer by PFM than no PFM in the early growth period of Radish;the yield and water use efficiency of Radish in L4 were exceeded respectively 10.1% and 21.9% of that contrast, the yield and water use efficiency of Cabbage in G4 were exceeded respectively 8.7% and 26.58% of that contrast, under PFM and appropriate irrigation.The aim at saving water, high yield and good quality of Radish could be attainded by PFM and no irrigation, if the Radish growth period was arranged in rainy season. Under PFM and excessive irrigation, the leaves above ground were flourishing, the numbers of leave were increased, root length and root diameter reduced;leaf chlorophyl content ,Pn, and WUE decreased, while Tr increased;dry matter which distributed to root was reduced, quality, yield and economic benefit decreased, while water- consumed increased;and water resource use efficiency decreased.The effect of soil drought on Radish seeding growth can be improved by soaking seed with CaCl₂. Under light drought and heavy drought condition, the decrease of relativelywith CaCl₂. Under light drought and heavy drought condition, the decrease of relatively water content, water potencial, transpiration intensity, chlorophyl content, photosynthetic rate and respiration rate of Radish seedling leaf which seed was soaked with CaCl₂ was smaller than contrast, and the water- keeping ability of Radish seedling leaf which seed was soaked with CaCl₂ was better than contrast.The result of water saving, high yield and high quality of Cabbage could be realized by PFM and one time irrigation. Water- consumed was increased with irrigation times, if the irrigative water under PFM was the same as no PFM. The young plant in leaf growing stage would flourish and short of controlling, leaf growth period was prolonged and shaping leaf ball was delayed as well, if the irrigation was excessive under PFM in seedling stage . Under PFM and excessive soil water content in shaping leaf ball period, the root under ground was restrained, root dry matter density decreased, leaf Chl contents, Pn, and WUE decreased, while Tr increased;dry matter which was distributed to leaf increased, yield and economic benefit decreased, and water resource use efficiency decreased. Under PFM and no irrigation, water- consumed was reduced, but WUE was exceeded of that contrast, which root growth was accelerated, dry matter distributed to root was no apparent difference between PFM no irrigationand and no PFM three times irrigation, which photosynthetic character and dry matter content and yield were under contrast.In high and cold region in northwest of Hebei province, radish and cabbage were planted under PFM and water resource used effectively, which decreased two times irrigation, the aim at saving-water and high yield could be come ture as well.