Effects of planting patterns on yield, quality, and defoliation in machine-harvested cotton

The aim of this study was to elucidate the effects of different machine-harvested cotton-planting patterns on defoliation,yield,and fiber quality in cotton and to provide support for improving the quality of machine-harvested cotton.In the 2015 and 2016 growing seasons,the Xinluzao 45(XLZ45)and Xinluzao 62(XLZ62)cultivars,which are primarily cultivated in northern Xinjiang,were used as study materials.Conventional wide-narrow row(WNR),wide and ultra-narrow row(UNR),wide-row spacing with high density(HWR),and wide-row spacing with low density(LWR)planting patterns were used to assess the effects of planting patterns on defoliation,yield,and fiber quality.Compared with WNR,the seed cotton yields were significantly decreased by 2.06–5.48%for UNR and by 2.50–6.99%for LWR,respectively.The main cause of reduced yield was a reduction in bolls per unit area.The variation in HWR yield was–1.07–1.07%with reduced bolls per unit area and increased boll weight,thus demonstrating stable production.In terms of fiber quality indicators,the planting patterns only showed significant effects on the micronaire value,with wide-row spacing patterns showing an increase in the micronaire values.The defoliation and boll-opening results showed that the number of leaves and dried leaves in HWR was the lowest among the four planting patterns.Prior to the application of defoliating agent and before machine-harvesting,the numbers of leaves per individual plant in HWR were decreased by 14.45 and 25.00%on average,respectively,compared with WNR,while the number of leaves per unit area was decreased by 27.44 and 36.21%on average,respectively.The rates of boll-opening and defoliation in HWR were the highest.Specifically,the boll-opening rate before defoliation and machine-harvesting in HWR was 44.54 and 5.94%higher on average than in WNR,while the defoliation rate prior to machine-harvesting was 3.45%higher on average than in WNR.The numbers of ineffective defoliated leaves and leaf trash in HWR were the lowest,decreased by 33.40 and 32.43%,respectively,compared with WNR.In conclusion,the HWR planting pattern is associated with a high and stable yield,does not affect fiber quality,promotes early maturation,and can effectively decrease the amount of leaf trash in machine-picked seed cotton,and thus its use is able to improve the quality of machine-harvested cotton.

A Study of Mechanization of Cotton Harvesting in India and Its Implications

Cotton is one of the most important crops throughout the history of India and it also plays an important role in social and economic aspects of the Indian society in the present age. Recent technological advances and trade liberalization have made India a major player in international cotton markets. In the year 2011-2012, India was the world＇s second largest producer, consumer and exporter of cotton. The increasing role of the Indian cotton sector in international markets is a direct challenge to other major players like the US. Within this context, a better understanding of the Indian cotton sector and the impact of mechanization on cotton cultivation are needed. The overall objective of this paper is to assess the competitiveness of Indian cotton producers and potential implications for India as a competitor in the world cotton market if it mechanizes harvesting of cotton. The results demonstrate that the net income of the Indian cotton farmers will increase considerably with the mechanization of cotton harvesting. But the adoption of the practice of harvesting cotton by mechanical means is possible only if efforts from many private and public agencies come together. In that scenario, the cotton production in India can increase considerably which can impact the international markets.

Fiber damage of machine-harvested cotton before ginning and after lint cleaning

Machine harvesting increases the foreign matter content of seed cotton. Excessive cleaning causes fiber damage and economic loss. Most trading companies in the Xinjiang Uygur Autonomous Region, China have indicated reluctance to use machine-harvested cotton. The first objective was to determine how the fiber quality was affected by the ginning and lint cleaning and how the fiber damage during levels of lint cleaning changed. The second objective was to determine the optimum number of lint cleaners for machine-harvested cotton based on fiber damage. Cotton samples were collected from 13 fields and processed in seven ginneries between 2013 and 2015. The results indicated that ginning and lint cleaning didn＇t have significant effect on fiber strength and significantly affected both fiber length and short fiber index. Fiber length was reduced by more than 1.00 mm from six of 13 fields after lint cleaning, then the damage rate on short fiber index from 11 of 13 fields was more than 20%. The third lint cleaning caused great fiber damage, reducing fiber length by 0.35 mm and increasing short fiber index by 0.65%. So, the lint should be cleaned by one lint cleaner in the Xinjiang, however, the stage of lint cleaning was sometimes omitted when the foreign matter content of lint was little.

Effects of plant density and mepiquat chloride application on cotton boll setting in wheat–cotton double cropping system

Sowing cotton directly after harvesting wheat in the Yangtze River Valley of China requires early mature of cotton without yield reduction.Boll-setting period synchronisation and more yield bolls distributed at the upper and middle canopy layers are also required for harvesting.The objective of this study is to quantify the individual and interaction effects of plant density and plant growth regulator mepiquat chloride(MC)on temporal and spatial distributions of yield bolls,as well as yield and yield components.During the 2013–2016 cotton growing seasons,the experiments were conducted on a shortseason cotton cultivar CRRI50 at Yangzhou University,China.Various combinations of plant density(12.0,13.5 and 15.0 plants m^(–2))and MC dose(180,270 and 360 g ha^(–1))were applied on cotton plants.The combination of 13.5 plants m^(–2)and 270 g ha^(–1)MC resulted in the greatest boll number per unit area,the highest daily boll setting number and more than 90%of bolls positioned within 45–80 cm above the ground.In conclusion,appropriate MC dose in combination of high plant density could synchronize boll-setting period and retain more bolls at the upper and middle canopy layers without yield reduction in the system of direct-seeded cotton after wheat harvest,and thus overcome the labor-intensive problem in current transplanting cropping system.

Effects of Different Drip Irrigation Modes on Growth and Yield of Cotton

This study aimed to explore the optimum drip irrigation belt arrangement mode for mechanically-harvested cotton in Xinjiang. The Xinluzao 61 was selected as the experiment material, and the effects of two different drip irrigation modes（6 cotton rows with 2 drip irrigation pipes under plastic film, 6 cotton rows with 3 drip irrigation pipes under plastic film） on the growth and yield of Xinluzao 61 were investigated under mechanical harvest. The results showed that under the mode of 6 cotton rows with 2 drip irrigation pipes, the growth rate of edge-row cotton was lower in the early growth period, and its emergence rate and agronomic traits were all lower than those of the interior-row cotton; under the mode of 6 cotton rows and 3 drip irrigation pipes, the difference in cotton growth between edge and interior rows was smaller. The yield and benefit under the mode of 6 cotton rows with 3 drip irrigation pipes were higher than those under the mode of 6 cotton rows and 2 drip irrigation pipes by 255 kg/hm^2 and 1 500 yuan/hm^2, respectively. Therefore, the cultivation mode of 6 cotton rows with 3 drip irrigation pipes under plastic film should be promoted in the production.

压缩籽棉对棉籽破碎率及纤维品质的影响

为探究压缩对籽棉品质的影响因素与规律,以含水率、含杂率及压缩密度为试验因素,以棉籽破碎率、纤维长度、马克隆值、伸长率、反射率、黄度、整齐度、纤维强度为指标进行研究。结果表明:含水率、含杂率及压缩密度对棉籽破碎率影响显著(P<0.05),棉籽破碎率随压缩密度增大而增大,随含水率增加而降低;压缩密度仅对棉籽破碎率和反射率有显著影响(P<0.05);纤维长度随压缩密度、含水率增加而增加,随含杂率增加而减小;马克隆值随含杂率及含水率增加而增加,随压缩密度增加而减小;伸长率随含杂率增加而增加,随压缩密度及含水率增加而减小;反射率随压缩密度增大而增大,随含杂率增大而减小;黄度随含杂率增加而降低,随含水率增大而增大。

牧神4MJZ-3600型自走式落地棉花收获机的研制

针对机采棉后自然落地棉花、机采损失棉花及未开棉铃等残留的棉花(棉桃)收获难、浪费大的问题,开展落地棉花和未开棉铃的一次性收获技术研究。通过研制出的不对行仿形浮动采摘割台、柔性输送器、静液压驱动系统和自走式落地棉花收获装备,提高棉花综合性机械化收获质量和采摘水平,实现了棉花收获全程机械化的节本增效。经过田间试验,使用采棉机收获后的棉田通过落地棉花收获机再次采摘可收获大量遗留在棉田里的落地棉花和未开棉铃,棉桃采净率为98.49%,落地棉花采净率为91.66%,检测数据达到设计要求。

Cotton-harvester-flow simulator for testing cotton yield monitors

An experimental system was developed to simulate the pneumatic flow arrangement found in picker-type cotton harvesters.The simulation system was designed and constructed for testing a prototype cotton yield monitor developed at Mississippi State University.The simulation system was constructed to approximate the pneumatic cotton flow system of a cotton picker,and was capable of operating with varying cotton flow rates.The simulator was tested with different cotton flow rates,and the relationship between feeder rate and amount of conveyed seed cotton was found to be consistent.Further,the simulator was used to conduct tests with the novel optical cotton yield monitor,which proved accurate at measuring the amount of seed cotton flowing through the simulator.Finally,some differences between laboratory testing and field-testing were noted:seed cotton becomes fluffed and twisted when recycled through the simulator,and seed cotton stored in the laboratory tends to be of lower moisture content than cotton during harvest.These differences should be considered when using a laboratory simulator to test cotton yield monitors.

缩节胺运筹对夏直播棉熟相的影响

为明确缩节胺运筹对夏直播棉熟相形成的影响,2018-2019年于扬州大学实验农场以中棉425为材料,设缩节胺用量0、180、360 g·hm^(-2)3个水平,施用时期分别设盛蕾期+初花期(施用比例1∶2)、盛蕾+初花期+盛花期(施用比例1∶2∶3) 2个运筹方式,同时设常规施用方式(初花期,缩节胺120 g·hm^(-2))为对照,探讨缩节胺施用量和施用时期处理对此种植方式下熟相的调节。结果表明:缩节胺用量180 g·hm^(-2)并于盛蕾期+初花期或盛蕾+初花期+盛花期使用后再通过脱叶催熟吐絮率均能达到90%以上,且吐絮强度高,较对照显著提高46.6%~71.4%。进一步回归分析表明,黄叶率保持在9.0%~12.8%之间,主茎红茎比为52.8%~53.1%,倒1果枝红茎比为28.3%~34.3%,倒2果枝红茎比为27.5%~39.8%,倒3果枝红茎比为34.3%~8.5%,倒4果枝红茎比为49.1%~51.5%,吐絮倒序位为7.1~8.1台最有利于集中吐絮。因此,缩节胺合理运筹能形成集中吐絮的熟相,为实现机采提供技术支撑。

采棉机三角履带行走装置设计与仿真

为了适应长江、黄河流域棉区的棉花机械化采收需求,设计了一款采棉机三角履带行走装置。分析棉田工况、整车接地比压和车速等参数,确定了三角履带行走装置的主要技术参数;通过有限元分析,对基架、驱动轮和摆动销轴等关键部件进行了强度校核计算。结果表明:所设计结构与材料选用均能满足使用要求,单轮承载最高可达8 t。该装置可与原车轮胎快速互换,对于推进长江、黄河流域棉花收获机械化具有一定意义。

胶棒滚筒棉花采摘头的设计与试验

为确定胶棒滚筒棉花采摘头运动参数对新疆机采棉种植模式下的棉花采摘质量的影响,该文阐述了胶棒滚筒棉花采摘头的工作原理及其关键部件、总体结构。基于运动学分析,建立了采摘速比K值与采棉工艺速度、采摘工作角、滚筒转速之间的相应的函数关系,分析了其对棉花采摘性能影响规律。田间试验表明,当采棉机作业速度0.83 m/s,滚筒转速在450 r/min时,棉花采净率达95%以上,含杂率小于15%,落地棉小于2%,达到了棉花收获机械作业的技术要求。

棉花秸秆剪切力学性能试验

为了获取棉花秸秆低茬切割力学特性参数,采用微机控制电子式万能试验机(WDW-5E),对棉花秸秆剪切力学性能进行了研究。对棉花秸秆在不同时间、不同含水率的剪切强度和剪切功的变化进行了试验研究。试验结果表明:棉花秸秆剪切强度与含水率密切相关,棉花秸秆含水率在30%～50%之间时剪切强度和剪切功均是较低的,而当含水率过高或者过低时剪切强度和剪切功较高,含水率在60%左右时达到高峰。棉花秸秆的剪切强度在0.6～1.8 MPa范围内,棉花秸秆剪切功在1～4.5 Nm范围内。由此可以确定出在12月中下旬的一个月内为收获棉花秸秆的最佳时期,此时收获可节省16.4%的剪切功。

基于集中收获的新型棉花群体结构

构建合理群体结构是实现棉花高产优质高效的重要栽培学基础。我国传统棉花群体结构主要有"高密小株类型"、"中密中株类型"和"稀植大株类型"3种,分别在西北内陆棉区、黄河流域棉区和长江流域棉区广泛应用,为实现棉花高产稳产发挥了重要作用。但进入新时期,传统群体结构不利于集中收获和提质增效的弊端凸显,探索新型棉花群体结构成为新时期棉花栽培学的重要研究内容。本文简要评述了传统棉花群体结构的主要特征和弊端;基于新时期轻简节本、提质增效的需要,提出了建立"降密健株型"、"增密壮株型"和"直密矮株型"3种适于集中收获的新型棉花群体结构替代传统群体结构的观点。在此基础上,重点论述了3种新型群体结构的主要指标和调控技术,对新型棉花群体结构的研究与发展趋势进行了展望。

2006～2013年新疆棉花纤维品质变化分析

【目的】各大棉区的公检数量增加迅速,全面覆盖了我国主要棉花主产区。分析自公证检验以来新疆棉区棉花纤维品质变化,了解我国主要棉区棉花纤维品质的整体状况及发展趋势,为育种及相关决策提供参考。【方法】以2006~2013年我国棉花纤维公证检验检测的纤维品质为研究对象,划分不同区域进行分析。【结果】随着国储政策的深入实施,八年来,我国棉花纤维长度、比强度整体呈现下降趋势,年均下降0.1 mm和0.16 c N/tex。新疆地方棉区纤维长度优于内地和新疆兵团棉区,年际间分别较二者高0.2~0.3 mm和0.3~0.6 mm,〉28 mm长度级范围内新疆地方棉区棉花所占比显著高于内地及兵团;在纤维比强度方面,全国平均、新疆地方与兵团年均下降0.16、0.28、0.32 c N/tex。近三年来强度中上水平（〉29 c N/tex）皮棉所占比例明显下降,表现为内地棉区占比较高,新疆地方棉区次之、兵团最低;在纤维整齐度方面,全国平均、新疆棉区总体呈现下降趋势,新疆地方棉花优于内地和兵团;在马克隆值方面,表现出A级所占比整体下滑、B级微升、C级逐年增加趋势。【结论】新疆棉区棉花主要纤维品质下降严重,应启动优质手采、机采棉新品种培育及推广。

采棉机视觉导航路线图像检测方法

采棉机视觉导航路线的检测是实现采棉机自主导航的重要前提。收获时期的棉田中主要有棉秆、棉花、棉桃、棉叶、杂草及田外区域等多种目标特征,并且机械采收会造成已收获区的棉枝上残留少许棉花,对采棉机田间作业路径的检测造成困难。该文主要通过分析已收获区、未收获区、田外区域、田端的不同颜色特征,对采棉机田间作业路径、棉田边缘、田端等的检测算法。首先采用3B-R-G、|R-G|、|R-B|及|G-B|等颜色分量差的方法,针对棉田内、外等不同区域的目标特征分别进行提取,并以设定的步长进行移动平滑处理,而后基于最低波谷点向未收获区方向寻找波峰上升临界点以及与前一帧直线检测结果相关联等方法,确定直线变换的候补点群,最后基于过已知点Hough变换提取导航直线;试验证明,该算法提取的直线能够准确贴合已收获区与未收获区分界、田侧边缘等,处理时间平均为56.10ms/帧,满足采棉机田间实际生产作业的需求。该研究可为小麦、玉米等其他作物机械化收获时视觉导航路线的检测提供参考。

灌溉制度对机采棉生长、产量及品质的影响

1膜2管6行是新疆机采棉的主要种植模式。为确定该模式适宜的灌溉制度，采用田间试验研究了灌溉频率（F5、F8）与灌水定额（180、160和140）对棉花生长、产量、品质及水分利用效率的影响。结果表明，高频高定额（F5180）与高频中定额（F5160）灌溉可有效降低棉花株高，增加叶面积指数，提高蕾铃生物量在地上部中的比例。灌溉频率相同时，灌水量过高-9过低均不利于棉花增产；灌水定额相同时，高频（F5）较低频（F8）灌溉增产0．59％～1．56％。灌溉制度对棉花纤维品质无显著影响。灌水定额显著影响棉花耗水量及水分利用效率，而灌溉频率对二者影响不显著。研究认为高频（F5）和中灌溉定额（160）是南疆地区机采棉种植模式适宜的灌溉制度，即在全生育期内灌水12次．灌溉定额300mm左右。

采棉机摘锭采摘过程的动力学分析

针对采棉机采棉头核心部件摘锭易磨损、易折断的工程实际问题,根据采摘系统的结构特点和振动特性,建立该系统单自由度干摩擦振动模型,考查摘锭在摩擦力作用下的动力学响应,分析了系统运动中存在的黏滑振动,并通过摘锭速度及结构参数的变化揭示了摘锭在工作过程中实际动力学特性,同时探讨了呈现出的动力学行为对摘锭磨损的影响,并提出抑制摘锭磨损的建议。该文的理论分析与数值结果为采棉机摘锭的结构设计及优化提供参考。

基于响应面法的梳齿式采棉机采收台优化设计

为寻求梳齿式采棉机采收台结构与工作参数的最优组合,对其进行了参数优化试验。采用二次回归正交旋转中心组合优化试验方法,以行走速度、梳齿间距、梳齿振动频率为影响因素,以采净率、撞落棉率为目标函数,对影响该机采收性能的结构与工作参数进行优化试验研究。结果表明:当行走速度为0.45 m/s、梳齿间距(轴线距离)为51 mm、梳齿振动频率为2.65 Hz时,采净率为96.5%,撞落棉率为2.8%。

适宜膜下滴灌频次提高北疆机采棉光合能力及产量

在北疆大田条件下,以机采棉品种新陆早57号为供试材料,研究不同灌水分配对机采棉光合特性和产量形成的影响。试验设滴灌定额为4 500 m^3/hm^2,3个灌水分配次数分别为10次(D10)、8次(D8)、6次(D6)。结果表明:D6处理头水时间推迟,由非气孔限制因素导致净光合速率的下降,胁迫程度较高,最大光化学效率、光化学猝灭系数、光化学量子产量显著低于其他处理(P<0.05),非光化学淬灭系数明显增加,同时恢复能力较差,地上部分生物量积累受限。盛蕾后充分供水但并没有较高的补偿强度,且蒸腾速率较高,叶片水分利用效率降低。由于D10处理花铃期灌量分配不合理,净光合速率的下降主要受气孔限制因素影响,棉株受到轻度胁迫,吐絮期的灌水有效提高了其光化学猝灭系数,与D6处理差异显著。降低了非光化学淬灭系数,延长了叶片光合功能期,生物量积累偏向营养生长,使其营养器官显著高于其他处理,但生殖器官差异不显著(P>0.05),不利于产量的形成。而D8处理在整个生育期保证了高效的光合生产能力,明显提高了光合物质向生殖器官运移的比例,比D10、D6处理高出21.1%、23.5%,叶片水分利用效率表现最优,且产量与D10差异不显著,但比D6处理显著高647.4 kg/hm^2(P<0.05)。因此在滴灌定额为4 500 m^3/hm^2的条件下,配合D8处理的灌水分配方式,有利于提高叶片光合能力,促进光合物质优先向生殖器官分配,从而获得高产。由此可见,盛蕾前灌头水且增加盛花期后灌溉定额,同时减少吐絮期水分供应,可有效提高叶片光合生产能力,促进光合物质优先向生殖器官运移,实现机采棉节水高产高效。

不同机采棉行距配置对棉花生长发育及光合物质生产的影响

以新陆早32号为供试材料,在新疆自然生态环境下研究不同机采棉行距配置(66+10 cm、72+4 cm)对棉花生长发育及其光合物质生产的影响。结果表明:72+4模式利于棉花前期生长,因其地膜覆盖率高,采光面积大,地温高;66+10模式利于棉花中后期的生长,因其通风透光性强;其中66+10模式与72+4模式相比,棉花生育时期提前3 d,株高高于72+4模式15.66%,叶片多于72+4模式13.53%,两者差异达到显著水平,以此为基础,66+10模式下棉花营养生长和生殖生长得到有效合理的协调,并促进了生殖器官干物质的积累,且因中后期的通风透光性强,提高了外围铃比例,为增产做贡献。