Studies On Chemical Control Of Weed And Cultivation Technology Of High Yield For Saving-water And Drought-tolerance Rice

Drought is one of main nonbiological limiting factors reducing yield,how to improve or increase the ability of drought tolerance for rice;obtain the varieties that have strong drought-resistance ability and high yield,improve the culture environment, increase the yield of saving-water and drought-tolerance cultivated rice,all these are one of important problems faced and concern focus in the research field of drought for breeder and cultivator.This research is mainly aimed at economizing on water and the detailed research of some key technology problems faced in the drought-resistant study, meanwhile,study in environmental protection of drought-resistant rice,establish the foundation of theory and practice for the large area of applying for drought-resistant rice. The main result of study is as follows:1.The two DT varieties huhan No3 and Huhan No15 used as the materials,the survival number undergone the herbicides was investigated for three treatments,the three treatments is applying herbicides for three time including before planting,between planting and seedling,and after seedling.The data were collected after spraying drug for 15,30 and 60 days.The results from the remained weeds found,the treatment that the stubble-cleaning was dealt with before seeding,the drug effect for 20%grams no-track AS600-900 g a.i./hm~2 is fast,it prevented and killed off more than 95%weeds in 5 days after medicine,so it is suitable for applying between two short stubble,but 20%grams no-track AS to hold the drug-effect shorter.The treatment that the seedling is dealt with after sowing,we screened tentatively and clearly confirmed the two herbicides mending-grass and clever-land-weeds.The two herbicides have the advantages including excellent killer weed,and holding the long time for drug-effect,and safety for saving-water and drought-tolerance rice.So it can consider that further study as disposable weed killer of upland field.In addition,grass-amine, high-efficient benthiocarb and oxyfluorfen have excellent result of defending to Leptochloa chinensis,Excellent-killer-weeds and Oxyfluorfen have excellent result of defending to the broadleaf weeds,which can further study as formula screening.So,if we consider synthetically from the factor of preventing and killing off the result,security,holding the drug-effect and using cost etc,the best formula of weed killer which prevents and kills off the upland field weeds is mending-grass EC495g a.i./hm~2 and 33%adding mending-grass EC495 and 10%clever-land-weeds WP15-22.5g by 23.5% Oxyfluorfen EC123.4+33%s A.i./hm~2. 2.Integrating study on high-yield and managing of water and fertilizer for water-saving and drought-tolerance rice.Hanyou No3,Zhonghan No3 and other three varieties from Guangxi used as marterials,carried on the test in 5 tests of Guangxi.The experiment of high-efficient cultivation technique mainly including two kinds of modes of culture,one is sowing under well-water and growing under drought condition,the other is sowing and managing both under drought condition,and also,different level of fertilizer and different method of applying fertilizer and different method of irrigating were studied in this research.Among them,the different manuring amount carried on hanyou No3,the result showed that yield is stable under high and medium fertilizer,the yield can reach about 6750.0-7500.0kg per hm~2,but the output drops by about 10%under the low fertile condition,,the fall is not obvious;the yield changes range is higher obveriously sowing under well-water than under drought conditions as the fertility influence.The applying fertilizer amount should be 165-180kg per hm~2 pure nitrogen level,in the meanwhile matched with phosphorus and potassium level.Attention should be payed to increase the fertility amoun on the paddy field with low fertility.3.Study on covering saving-water and water-conservation Three varieties from Shanghai agri-biological gene center were used as material,carried on the comparing test for the dropouts of water and soil in the interplanting between DT rice with young orchard,founded out the corresponding relationship between growth duration and raining course,study the ability of firming soil and transforming the fertility(organic matter).We found the upland rice grows very fast and the roots are developed,it can cover all of ground since seeding 15-21d,and the growth period is long,so it can protect the ground to avoid the rain drops spatter in rainy season,the upland rice demonstrates the better function on water and soil conservation;it also have good function of retaining the rainwater,improve soil conservation storage ability;change surface flow properties,so, it is the crop that have good ability on water and soil conservation.4.Interplanting orchard of mountain with DT rice.Considerable yield in two years for DT rice interplanting orchard of mountain,the output even exceeded the single DT rice without interplanting in the field according to the actual output,the reason may be that the pear tree can ward off the wind,sunshade and preserve soil moisture in the high-temperature season for the saving-water and drought-tolerance rice.