| In order to establish suitable row spacing patterns for different plant types of cotton,this study used the looser plant type Zhongmiansuo 96 A and the compact plant type B9 as materials,and set up three row spacing patterns under the same density: one film with three rows(76+76)cm,row spacing was 76 cm and plant spacing was 6 cm,one film with four rows(76+10+66)cm,the average row spacing was 57 cm and the plant spacing was 8 cm,one film with six rows(10+66+10+66+10)cm,the average row spacing was38 cm and plant spacing was 12 cm.To study the differences in the canopy structure and micro-environment of different plant types of cotton under different row spacing patterns.Explore the effects of different row spacing on the plant morphological,accumulation of photosynthetic substances,and yield of different plant types of cotton,and provide theories for high-efficiency and high-quality cultivation techniques for machine-picked cotton in accordance with.The main results are as follows:1.Different row spacing patterns have different effects on the canopy micro-environment of different plant types.Compared with the loose type of cotton Zhongmiansuo 96 A,the temperature of the middle and lower part of the canopy treated with compact B9 is higher,and the change of the humidity of the middle and lower canopy is smaller among the row spacing.After the blooming period,the lowest temperature and the highest humidity were found in the treatment of one film and six rows.From full bloom to boll opening stage,the shedding rate of buds and bolls was negatively correlated with canopy temperature and positively correlated with canopy humidity.The highest photosynthetically active radiation(PAR)interception rate of Zhongmiansuo 96 A was in the treatment of one film and six rows before and after row closure.The PAR interception rate of B9 was higher under the treatments of three rows with one film and six rows with one film before the row closure of cotton plants at flowering stage.After the row closure at full boll stage,the PAR interception rate of B9 with three rows and one film was lower,resulting in a waste of light resources.2.The plant height,the height of the first node of the fruit branch,the average internode length,the average length of the fruit branch and the angle between the fruit branches of the two varieties were the highest of one film and three rows.Compared with compact B9,the fruit branch angle of loose Zhongmiansuo 96 A was more easily affected by row spacing.The nodal branch ratio of Zhongmiansuo96 A of one film with three rows increased by 9.46% and 9.80% respectively compared with one film with four rows and one film with six rows;the leaf area index(LAI)of Zhongmiansuo 96 A of one film with three rows was higher before the full boll stage,but after the full boll stage,the LAI of one film with three rows decreased slowly,the diffusion non-interceptance(DIFN)was lower,and the duration of photosynthesis was prolonged.The nodal branch ratio of B9 of one film with six rows increased by 3.61%and 4.27% respectively compared with one film with three rows and one film with four rows;the LAI of one film and six rows was the highest and the DIFN was the lowest during the growth period,while the LAI of one film with three rows was the lowest and the DIFN was the highest,which was not conducive to improving the utilization rate of light energy.3.The net photosynthetic rate of loose Zhongmiansuo 96 A with one film and three rows were higher.Compared with one film four rows and one film six rows,the total leaf area duration(LAD)of Zhongmiansuo 96 A with one film and three rows increased by 7.82% and 9.46% respectively,and the dry matter accumulation of single plant increased by 4.76% and 6.74% respectively,and the duration of dry matter accumulation in reproductive organs was prolonged for about 5 days,and the dry matter distribution ratio of reproductive organs was 1.17 and 2.06 percentage points higher,respectively.Compared with the other two treatments,the total LAD of the compact B9 with one film and six rows increased by 1.67% and3.57% respectively,and the dry matter accumulation per plant increased by 9.17% and 8.11%,respectively,the duration of dry matter accumulation in reproductive organs prolonged about 2 days,and the proportion of dry matter in reproductive organs increased by 3.87 and 2.57 percentage points respectively.4.Boll formation was mainly located in the inner fruit nodes of the middle and lower fruit branches.The boll formation rates of loose Zhongmiansuo 96 A and compact B9 were the best under the treatments of three rows with one film and six rows with one film,respectively.The boll shedding parts of each treatment were mainly located in the second fruit node of each fruit branch,and the boll shedding rates were all more than 50%,and the treatment of six rows of one film was the highest.The number of bolls per plant of Zhongmiansuo 96 A was the highest of one film with three rows,and its seed cotton yield increased by4.76% and 6.73% respectively compared with the one film with four rows and one film with six rows.The higher boll forming rate of B9 with one film and six rows made up for the loss caused by the shedding of buds and bolls.The seed cotton yield of one film with six rows was 9.00% and 12.16% higher than that of one film with three rows and one film with four rows,respectively.In conclusion,under the condition of density,the loose Zhongmiansuo 96 A and compact B9 were suitable for one film with three rows and one film with six rows respectively,which can increase production significantly. |
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