Effects Of Different Mulch,Sowing Date And Density On Cotton Yield Characteristics

This experiment was carried out in 2018-2019 in the field of science and Technology Demonstration Park of Dezhou Academy of Agricultural Sciences,the cotton test base of Shandong Agricultural University.In the experiment,the polyethylene plastic film was used as a control,and the whole biodegradable plastic film covering treatment was adopted.The split zone design was adopted.In the main areas with different plastic film covering,the whole biodegradable plastic film covering(DF)and polyethylene plastic film covering(CF)were set.The sowing date is sub-area,and the seeds will be sown on April 20(S1),April 30(S2)and May 10(S3)respectively.In the sub-sub-area,planting density was set at 52,500 plants/ha(D1),67,500 plants/ha(D2)and 82,500 plants/ha(D3).The effects of different mulch,sowing date and density on growth process,growth and development characteristics,leaf physiological characteristics,boll-forming spatial and temporal distribution,fiber quality,yield and its components of cotton were studied.The main results are as follows:1.Effects of different mulching,sowing date and density on growth process of cottonCompared with the ordinary membrane treatment,the catmulling stage was the same or delayed by 1-3 days at the same sowing date.The length of each birth stage is the same or extended by 1-3 days,except for the shortened bud stage in 2018.2.Effects of different mulch,sowing date and density on growth and development of cottonThe effects of different mulching films on the height of first fruit branch,number of fruit nodes and boll formation rate of cotton were not significant.The plant height of degraded film treatment was significantly lower than that of ordinary film treatment,and the number of fruit branches of degraded film treatment was significantly lower than that of ordinary film treatment.The sowing date had very significant or significant influence on all characters,and the influence trend was not the same.There were significant or significant differences in density for all traits,plant height decreased with the increase of density,number of branchesand nodes decreased with the increase of density,and boll formation rate decreased with the increase of density.3.Effects of different mulch,sowing date and density on physiological characteristics of cotton leavesThe effects of different mulching films on chlorophyll content,Fv/Fm,Fv/Fo and MDA content did not reach a significant level,and the effects of different mulching films on photosynthetic rate were different from year to year.The effects of sowing date on Fv/Fo,photosynthetic rate,SOD and POD all reached significant or extremely significant levels.The effects of density on photosynthetic rate and SOD were significant or extremely significant.4.Influence of different mulch,sowing date and density on boll-forming spatial and temporal distribution of cottonDifferent mulching films had no significant effect on boll forming spatial and temporal distribution of cotton.With the delay of sowing date,the proportion of fuqian peach decreased significantly,and the proportion of Fuqian peach and Autumn peach increased significantly.The density had no significant effect on the proportion of three peaches.With the delay of sowing date,boll number of inner fruit nodes of cotton base and middle branch decreased significantly,boll number of upper branch increased significantly.The density increased,the lower branch boll fell off seriously,and the boll concentrated to the middle and upper branch.5.The influence of different mulch,sowing date and density on cotton fiber quality was studiedThe influence of plastic film on fiber specific strength,micronaire value and fiber uniformity did not reach significant level.With the delay of the sowing date,the fiber length,fiber specific strength,fiber elongation and fiber uniformity all tended to increase,while the Macron value tended to decrease.The influence on the fiber length did not reach a significant level,but the influence on the Macron value,fiber specific strength and fiber elongation reached a significant or extremely significant level.With the increase of density,fiber length and fiber uniformity tended to increase,and the influence on fiber uniformity reachedsignificant or extremely significant level,but the influence on fiber specific strength,micronaire value and fiber elongation was not significant.6.Different mulch,sowing date and density interacted on cotton yield and its component factorsIn the two-year experiment,the seed cotton yield was lower than that of normal film under the condition of degradation film cover,but it did not reach a significant level in2019.The boll number,boll weight,seed cotton yield and lint yield decreased with the delay of sowing date.The population boll number tended to increase with the increase of density,while the single boll weight tended to decrease with the increase of density.In addition to D3 density in 2019,seed cotton and lint yield tended to increase with the increase of density.