Effects Of Irrigation Water Amount At Chemical Detopping Cotton On Growth,Plant Type And Physiological Features

Chemical detopping is the important technology to realize xinjiang cotton planting mechanization,while will be beneficial to reduce artificial labor intensity,reduce the cost of cotton,resolve the artificial detopping seasonal labour shortages,intensive and time-consuming,and so on.Now,now it has been widely applied.At present,there is less research about irrigation water volumes to the chemical detopping cotton yield formation and physiological response.Therefore,the experiment was laid out in a split-plotdesign,main-plot treatments were irrigation volumes,6150 m~3/hm~2,4400 m~3/hm,2650 m~3/hm~2(Consistency in the amount of cotton field before chemical detopping);detopping ways were deputy district,chemical detopping,artificial detopping and no detopping.Aim to provide some theoretical basis for northern Xinjiang cotton irrigation technology,we study the comprehensive influence of different irrigation water to the chemical detopping cotton,including cotton growth,yield,quality formation,physiological response,plant type characteristics and so on.The main findings are as follows:1.Under the condition of same irrigation quantity,compare with artificial detopping cotton,the chemical detopping cotton's leaf area index are higher at growth anaphase(after detopping 32 d and later),the rapid dry matter accumulation time of ground part and reproductive organs reproductive organ time(?t)extended 11 d,9 d respectively.It is conducive to the accumulation of photosynthetic products.Under the condition of same irrigation quantity,the chemical detopping cotton's fiber yield and the percentage of pre-frost lint are lower than artificial detopping cotton,single boll weight and seed index weightier than artificial detopping cotton and no-topping cotton,seed cotton yield is basically similar to artificial detopping cotton under medium and low irrigation amount,reduce 555.15 kg/hm~2 under the high irrigation amount condition,increase only 101.20 kg/hm~2 from condition 4400m3/hm~2 to condition 6150m~3/hm~2,significantly less than 675.54 kg/hm~2 of artificial detoppping.Compare with other detopping cotton,the chemical detopping cotton's fiber quality is similar,but the Micronaine is better.2.The whole plant type of cotton is mainly important impact by detopping way,and the influence of irrigation water is smaller.The amount of irrigation negatively correlated to the plant type control ability of chemical detopping cotton,the control for the growth of plant height,branch length is reduced with the increasing of irrigation water.Under the condition of same irrigation quantity,compare with other detopping cotton,the chemical detopping cotton's length of internode,length of branch and length of leaf branch were significantly lesser,at the same time the plant height shorten 18%~26%less in artificial detopping cotton.Chemical detopping agent can effectively control the length of the top branch,more than48%~51%less in artificial detopping cotton upper branch.Inner boll is the main factors of chemical detoppping cotton yield,the boll to each branch first fruit nodules accounted for over 61%~82%of the whole plant boll.Along with the decrease of irrigation water,boll position will be toward to fruit section of the lower plant and near the main stem.It will ensure the normal growth and development of boll and obtain adequate nutrients,reduce the production due to lack of irrigation water.Chemical detoppping could minimize the top branch length and the growth of the invalid branch,avoid the waste of nutrients,improve cotton production;at the same time,the shape of compact plant type and reasonable spatial distribution because of chemical detopping are also conducive to cotton boll mechanized harvesting.3.Under different irrigation amount,chemical detopping can improve the chlorophyll content in cotton leaves,superoxide dismutase(SOD)and peroxidase(POD)also has a strong regulatory role,Low content of malondialdehyde(MDA)proves the argument from the side.Under different irrigation amount,chemical detopping cotton's osmotic regulation substances proline PRO all has the good adjustment ability,although soluble sugar(SS)and soluble protein(SP)have good performance to adjust the action of osmotic potential and turgor pressure under the condition of high irrigation quantity,the adjustment ability relatively weak at airtificial detopping cotton under low irrigation quantity.