Photosynthetic characteristics of cotton are enhaneed by altering the timing of mulch film removal

Background:The photosynthetic parameters of cotton plants may be modified by the timing of film removal during their growing period.This study was undertaken during 2015-2017 in Xinjiang,China,to determine to what extent the film mulching removal time,1 and 10 days before the first irrigation and 1 day before the second irrigation after seedling emergence,influenced cotton's photosynthetic characteristics.The control group(CK)was film-mulched throughout the growth stages.Results:The results suggested the following:(1)Removing mulching-film within 50 days since seedling emergence had adverse effects on soil temperature and moisture.(2)Film-removal before the first or second irrigation after emergence improved the net photosynthetic rate in cotton's later flowering stage and its transpiration rate in mid and later flowed ng stages while enhancing the actual electron transport rate(ETR)and maximum electron transfer rate(ETRmax)between cotton photosystems I and II.(3)Film-removal treatment also increased cotton plants'toleranee to high irradiation after emergence,the trend was more pronounced in the early flowering stage in wetter years.(4)Leaf area index(LAI)of cotton was reduced in the film-removal treatment for which the least accumulation of dry matter occurred in a drought year(i.e.,2015).(5)Film removal caused a yield decrease in the dry year(2015),and the earlier the film was removed,the more seriously the yield decreased.Removing mulching film before the second irrigation could increase the yield of XLZ42 in the rainy year(2016)and the normal rainfall year(2017).Early film removal can in crease the yield of XLZ45 in the rainy year(2016).Conclusions:Collectively,our stud/s experimental results indicate that applying mulch film removal at an appropriate,targeted time after seedling emerge nee had no adverse effects on soil moisture and temperature,and improved the photosy nthetic performance of cotton,thus in creased cotton yield and fiber quality,but no significant difference was reached.

Nutrient Accumulation and Distribution in Cotton Promoted by Removal of Mulch Film

Plastic film mulching affects changes in nutrient contents in soil and absorption and utilization of nutrients in plants were by changing hydrothermal condition of soil.The temporal and spatial variation of the total soil salt and nutrient contents with mulch film removed at three different times during the early cotton growth stage and its effects on nutrient absorption and accumulation in cotton plants were studied over 2015-2017.The film removal treatments reduced salt accumulation in normal rainfall year(2017).Film removal increased contents of soil organic matter,the total phosphorus and available potassium at the end of growth stage,increased contents of soil hydrolyzable nitrogen and the total nitrogen in the surface soil layer(0-10 cm),and increased the total nitrogen contents in the deep soil layer(40-50 cm).Film removal increased accumulation of nitrogen and phosphorus nutrients in cotton plants in 2017 and accumulation of nitrogen,phosphorus and potassium nutrients in cotton plants in heavy rainfall year(2016).These experimental results indicated that removal of mulch film at an appropriate and targeted time in the bud stage of cotton promoted nutrient absorption.

The technology and mechanism of removal of plastic mulch and land preparation

In this article,the characteristic of the field plastic mulch, the craft for mechanization removal and land preparation of plastic mulch and the mechanism frequently used in the removal and land preparation of plastic mulch were introduced, which offered references for the design of removal mechanism and land preparation of plastic mulch and structural optimization combination of working components.

Design and experiment of nail tooth picking up device for strip type residual film recycling and baling machine

In order to solve the problem of residual film pollution caused by large area of cotton mulched planting in Xinjiang,a strip type residual film recycling and baling machine was designed,which can complete mulching film picking up,impurities separation,baling and other operations.The picking up device,as the key part of residual film recycling machine,was designed and analyzed.The kinematics of the pick-up nail tooth was analyzed,and its motion equation,motion trajectory and the conditions for completing the film pick-up were determined.And the key parameters were determined by analyzing the conditions of no missing picking and the stress of the residual film.According to the Box-Benhnken test design principle,field experiments were carried out with the forward speed of machine,the pickup speed ratio and the number of auxiliary film removing mechanisms as the key experimental factors,and the residual film pickup rate,the cotton stalk content and the residual film winding rate as the operation performance indexes of the picking up device.The mathematical models between the experimental factors and indexes were established,and the effect of each factor was analyzed.Through multi-objective parameter optimization and field experiment,the optimal combination of operation parameters was obtained as follows:the forward speed of machine of 1.67 m/s,the pickup speed ratio of 1.13,and the number of auxiliary film removing mechanisms of 6.Under this parameter combination,the pickup rate of residual film was 88.9%,the cotton stalk content in recycled residual film of 3.9%,and the residual film winding rate of 1.5%.The absolute error with the theoretical value was less than 0.6%.The research results show that the picking up device has stable operation performance and good residual film recycling effect,which meets the design and practical operation requirements.