Effects Of Density And Row Spacing Configuration On Growth Development And Yield Quality Of Cotton

Selecting suitable cultivation mode is one of the important means to improve crop yield.In the traditional research methods,the basis of improving technique is too single,which is based on yield and basic agronomic characters,it is difficult to analyze the main characteristics of cotton population affecting yield.In order to explore the effects of different density and row spacing on growth and development,population photosynthetic characteristics,yield and quality of cotton,CCRI641 cotton with compact plant type was used as material in this study,The planting patterns of 76cm equal row(SP)and(66cm 10cm)wide narrow row(DP)were adopted,and three treatments were set.The planting densities of three treatments were I low density 1.2×10~5plants/hm~2,II mid density 1.8×10~5plants/hm~2and III high density2.4×10~5plants/hm~2respectively.The experiment was conducted at the Cotton Research Institute of the Chinese Academy of Agricultural Sciences,Xinjiang Production and Construction Corps,Aral,Xinjiang,China(40°51′N,81°30′E).Based on the study of cotton growth and development,boll-forming characteristics,yield and quality,canopy light distribution in 2020 and 2021.The following conclusions were drawn:1.The increase of planting density will lead to the delay of cotton growth period,and the plant height of cotton with different row spacing configuration shows a downward trend,equal row will weaken the elongation of internodes after cotton topping.The number of fruit branches of cotton with low density treatment is the largest,and the dry weight ratio of above ground and underground parts is the first to stabilize.High density SP treatment had the highest biomass accumulation and the highest dry matter growth rate for two consecutive years.The response intensity of dry matter accumulation to LAI was significant in different treatments,and the fitting curve P value was less than 0.01 under the difference of row spacing.However,the fast accumulation of biomass showed that the dry matter accumulation time of low density treatment with fixed row spacing was the longest.In order to obtain high yield in production practice,equal row spacing should be selected,the best planting density was between 1.8×10~5plants/hm~2and 2.4×10~5plants/hm~2.2.The boll shedding area of cotton was affected by the difference of density and row spacing.The distribution area of peach before cotton was covered by SP was wider than that of DP,and the longitudinal area was longer.In the full boll stage,the boll forming distribution of single plant of SP treated cotton was slender ellipse as a whole,and the boll forming distribution of DP treated cotton was short flat ellipse.With the narrowing of plant spacing and plant width,the boll is close to the middle and lower fruit branches of the main stem.DP treated cotton is more prone to abscission and high incidence branches,and the increase of density will increase the high incidence sites of Boll abscission.Wide row configuration helps to reduce boll shedding.With the increase of planting density,the distribution of reproductive organs in SP treated cotton concentrated at the first and second fruit nodes of middle and lower fruit branches,and the distribution probability of reproductive organs in DP treated cotton increased first and then decreased with the increase of density.In the two-year experiment of medium density SP treated cotton,the yield of seed cotton is the highest,which is 5359.5 kg/hm~2in 2020,5151.0 kg/hm~2in 2021.The planting density and row spacing configuration have a significant impact on the fiber breaking ratio strength in the middle of cotton and the elongation length of upper and lower fibers,but have no significant impact on the single boll weight of cotton,but there is an interaction effect on the number of bolls in the upper and lower parts of cotton.The research shows that the equal row(SP)treatment has high yield and good fiber quality of cotton seed cotton.3.The Leaf Area of all treatments were different at seedling stage,bud stage,initial stage of flower and Boll,Full Boll stage and boll opening stage.The Leaf Area reached its maximum at 90 days of the growth period.2020 and 2021 had the highest Leaf Area,which were 348.29 dm~2and 347.53 dm~2respectively.The light interception ability of canopy was highly correlated with leaf area,and the response of light interception ability of canopy to leaf area was higher than that of row spacing.The light interception rate of cotton canopy increased at first and then decreased in different treatments,among which fixed row spacing and low density treatment had lower interception in canopy and fixed row spacing at early growth stage.The light energy conversion ability of low density treatment was stronger than other treatments in the development stage of cotton vegetative organs.The light utilization efficiency of population can be improved by adjusting the difference of row spacing.High-density and fixed-row-spacing treatments were the first to construct high-quality canopy structure,and v-shape light distribution appeared in the other treatments at full boll stage,which was beneficial to improve light resource utilization efficiency.The interception rate of PAR in the canopy showed that the equal row was more beneficial to maintain the high light efficiency population structure and improve the fiber quality of CRRI 641.