种植密度和缩节胺调控对麦后直播棉产量和冠层特征的影响

2013―2014年以早熟棉(中棉所50)为材料,采用裂区设计,在江苏省南京市研究了种植密度(7.50万、9.75万和12.00万株·hm~(-2))和缩节胺(DPC)调控(0,52.5和105.0 g·hm~(-2))对麦后直播棉产量和冠层特征的影响。结果表明:皮棉产量在不同种植密度下以12.00万株·hm~(-2)处理最低,在不同DPC用量水平下以0 g·hm~(-2)处理最低;种植密度与DPC调控存在互作效应,以种植密度9.75万株·hm~(-2)、DPC用量52.5~105 g·hm~(-2)处理产量较高,且产量构成中以铃数对产量的直接效应最大。对冠层特征影响表明,下部果枝夹角和长度随种植密度增加而降低,而中、上部果枝的夹角和长度、叶面积指数均以种植密度9.75万株·hm~(-2)处理较高;不同部位果枝夹角和长度、叶面积指数均随DPC用量增加而降低,而透光率则相反。相关分析表明,下部果枝夹角大、中部果枝较长及上部果枝夹角小且叶面积指数和透光率较高,有利于提高产量和霜前花率。综上,该棉区麦后直播棉种植密度9.75万株·hm~(-2)、DPC用量52.5~105 g·hm~(-2)(蕾期、开花期和打顶后用量比例为1∶2∶4),有利于改善棉花冠层特征,实现早熟高产。     

氮素对滨海盐土棉花产量、品质及生物量的影响

为研究不同施氮量对滨海盐土花后棉株生物量、生物量累积特征及其与产量、品质的关系,于2010年和2012年在江苏滨海盐土设置了氮肥水平试验。结果表明:在0~600 kg·hm-2范围内施氮量越大棉株总生物量累积越多,而皮棉产量2010年和2012年分别在施氮375 kg·hm-2和300 kg·hm-2时达到最大;成铃数在施氮300~375 kg·hm-2范围内达到最大;铃重和衣分随施氮量增加而增加,达到最大值后(≥300 kg·hm-2)差异不显著。在300~375 kg·hm-2施氮量范围内纤维比强度最高;高氮有利于上部、顶部果枝纤维长度、比强度、伸长率的提高和马克隆值的优化,但显著降低中下部果枝棉纤维比强度,导致中部纤维马克隆值变劣、下部果枝纤维伸长率下降,说明高氮对中下部果枝棉纤维品质的形成利弊各半,适量高氮可提高上部及顶部果枝产量、品质。在滨海盐土条件下,利于产量、品质及氮素利用效率提高的适宜施氮量为375 kg·hm-2。     

Nitrogen Fertilizer and Its Residual Effect on Cotton Yield and Biomass Accumulation

[Objective] The optimum nitrogen rate of 300 kg·hm^－2 is well documented for cotton in the Yangtze River Valley, China. It can be reduced to 225 kg·hm^－2 without reducing yield in late sowing under high planting density. The aim of this study was to determine the possibility of further reducing the nitrogen application rate at the first flower stage, its residual effects and influence on cotton yield formation rule. [Method] A pot experiment was conducted with five nitrogen levels (120, 150, 180, 210 and 240 kg·hm^－2) in 2014, but only 180 kg·hm^－2(for studying nitrogen residual effect) in 2015, to study the cotton growth process, yield and its components and biomass accumulation. [Result] Nitrogen levels significantly affected the yield and biomass accumulation, but not the growth process and nitrogen residual effect. Maximum seed cotton yield (30.5 g·plant^－1), boll weight (3.8 g) and biomass accumulation, especially in the reproductive and vegetative organs, was recorded in the 180 kg·hm^－2 nitrogen treatment. In the rapid accumulation period, the proportion of biomass accumulation in the reproductive organs was the highest. [Conclusion] In a soil with medium fertility level, the application of 180 kg·hm^－2 nitrogen was optimal, because the strength of biomass accumulation in reproductive organs increased during the rapid accumulation period.     

The Plant Architecture of Direct-Sowing Cotton Planted after Barley Harvested with High Yield and Centralized Boll-Setting

[Object] The study was conducted to investigate the plant architecture characteristic of direct sowing cotton planted after barely harvested with high yield and centralized boll-setting in the Yangtze River basin. [Method] In 2014, the cultivars Guoxin 12-1, Yijimian and Lumianyan 36 were used and the two conventional fertilizer (CF) application rates (namely pure nitrogen 45 kg·hm^－2, 150 kg·hm^－2) and Guoxin 12-1 was used in 2015. Two slow release fertilizer (SR) utilization rates (namely pure nitrogen 150 kg·hm^－2 and 225 kg·hm^－2) and two SR topdressing at different growth stages (namely 100% topdressing at seedling stage, 70% topdressing at seedling stage + 30% at flowing stage) were set with CF (pure nitrogen 150 kg·hm^－2) and no fertilizer treatment as the controls. [Result] While the pure nitrogen (CF) amount was 150 kg·hm^－2, the seed cotton yield of Guoxin 12-1 were 4 014.72 kg·hm^－2. In 2015, the seed cotton yield for the treatment, application SR (pure nitrogen 150 kg·hm^－2)and application ratios of seedling stage and flowering stage of 100% and 0, respectively, increased by 30.96%. The ratios of bolls setting from 08-15 to 08-30 to total bolls (RBT) for the two treatments were 31.8% and 26.1%, respectively. Then a significantly positive correlation between the seed cotton yield and RBT was found（r2014＝0.948^**, r2015＝0.976^**）. Based on the analysis of relationship between the plant architecture indexes and RBT, plant architecture characteristics of cotton population with high yield and centralized boll-setting was proposed. [Conclusion] These indexes would be used to supervise the cotton culture management to achieve high yield and centralized boll-setting for the direct sowing cotton planted after barely harvested.     

整枝方式与种植密度对蒜套棉产量和品质的效应

以棉花抗虫杂交种鲁棉研15号(F1)为材料,在鲁西南3个不同的地点,研究了整枝方式(去叶枝、留叶枝)与种植密度(2.7、3.3、3.9、4.5万株·hm-2)对棉花产量和纤维品质的影响。结果表明,整枝方式和种植密度对棉花纤维品质的影响不显著,但对棉花产量有显著的互作效应,3.3万株·hm-2×留叶枝、2.7万株·hm-2×留叶枝和3.3万株·hm-2×去叶枝的组合比传统栽培(2.7万株·hm-2×去叶枝)分别增产20.4%、9.2%和10%,也显著高于其他处理组合;生物产量分别提高了13.7%、27.8%和11.6%,而经济系数只降低了5.3%、11.5%和4.5%。在维持较高经济系数和铃重的基础上增加生物产量和铃数是该3个处理组合显著增产的原因,适当提高密度并配合简化整枝是实现蒜套棉高产高效的重要技术途径。     

Effects of Density and Miantaijin Chemical Control on Boll Characteristics and Physiological Activity of Direct-Seeded Cotton after Wheat Harvest

[Objective] The aim of this research is to study the effects of planting density and Miantaijin(diethyl aminoethyl hexanoate·mepiquat chloride of mass fraction 27.5%) chemical control on physiological leaf characteristics and boll setting characteristics of direct-seeded cotton after wheat harvest. [Method] In 2011―2012, the early-maturing variety Guoxinzao 11-1 was used as the experimental material. The study was conducted in Yangzhou University in 2011―2012 under the direct-seeded after wheat harvest cropping system, and the randomized complete block design was arranged with planting densities and Miantaijin rates. [Result] Under the density 105 000 plant·hm^－2 combined with 1 170 mL·hm^－2 Miantaijin, the boll setting was mainly concentrated before August 31. The SPAD value, soluble sugar content, soluble protein content, free amino acid content on July 15, July 30, August 15 of direct-seeded cotton after wheat harvest showed significant or extremely significant open-down parabola relationship with the number of bolls before August 31. It indicates that keeping the appropriate level of carbon and nitrogen physiological activity in cotton leaves is beneficial to high-quality bolls. [Conclusion] High density (105 000 plant·hm^－2) combined with proper Miantaijin control (1 170 mL·hm^－2) would contribute to forming quality bolls of direct-seeded cotton after wheat harvest, and the physiological activities of leaf carbon and nitrogen are suitable.     

棉花短季直播栽培模式对产量构成及纤维品质的影响

为探索棉花短季直播高产栽培技术模式,2014年在湖南农业大学浏阳试验基地,采用"311"最优回归设计方案研究了播期、密度和施氮量对早熟品种JX0010的产量构成及纤维品质的影响。对不同处理的棉铃时空分布、棉花产量及纤维品质的分析结果表明:不同处理棉铃时间分布上以秋桃比例最大,空间分布上纵向分布以中下部成铃数所占比例大,横向分布以内围铃为主。根据结果,建立了3个栽培因子施氮量(x1)、密度(x2)、播种期(x3)与子棉产量的多项式回归方程:y=213.522+3.9331x1+6.414x2-21.4619x3-5.7541x12-4.321x22-7.5348x32~(-1)1.982x1x2-0.1645x1x3+3.5747x2x3。分析回归方程得出,单因子效应表现为播种期密度施氮量,交互作用表现为施氮量与密度的互作效应密度与播种期的互作效应施氮量与播种期的互作效应,根据回归方程得到子棉高产的最佳组合为施氮量202.35 kg·hm-2、密度6.20万株·hm-2、播种期5月19日,产量为5510.25 kg·hm-2。棉花纤维品质性状受影响的顺序为马克隆值断裂伸长率断裂比强度上半部平均长度长度整齐度指数。     

Cotton Chemical Topping by Applying DPC in Different Cotton-Growing Regions

[Objective] The objective of this study was to investigate the stability and universality of cotton chemical topping by applying mepiquat chloride (1,1-dimethyl-piperidinium chloride, DPC) in different cotton-growing regions. [Method] Field experiments were conducted in 2018 at 10 locations in the Yellow River basin (Hejian and Handan, Hebei province; Dezhou and Wudi, Shandong province), the Yangtze River basin (Dafeng, Jiangsu province; Huanggang, Hubei province), and Xinjiang area (Shihezi location I and loacation II, northern Xinjiang and Luntai and Shaya, southern Xinjiang). Local cultivars/lines were used, and the experiments were performed using a randomized complete block design with three or four replicates. Accompanied with typical DPC multi-application in each location, chemical topping was conducted at 10 days before manual topping (T1) or at the same time with manual topping (T2) by applying four dosages of DPC (0, 90, 180, 270 g·hm^－2), manual topping was used as the first control and non-topping as the second control. [Result] The time of chemical topping significantly affected cotton plant height (except for the results in Handan, Dezhou and Wudi) and the number of fruit branches (except for the results in Dafeng and Huanggang). It was observed that earlier chemical topping would result in lower cotton plant height and a fewer fruit branches. In Hejian and Shihezi location I, the average plant height across DPC chemical topping at T1 stage was not only lower than that of T2 stage but also 3.3 cm and 4.6 cm lower than that of manual topping, respectively. In most locations, chemical topping at T1 stage increased around two fruit branches per plant compared with manual topping, while in T2 stage the increased fruit branches per plant ranged from 2.3 to 7.7. Also, we found that a higher dosage of DPC resulted in shorter plant height (except for that in Huanggang). In some locations, plant heights of chemical topping with 180 g·hm^－2 or 270 g·hm^－2 DPC were even shorter than that of manual topping. The number of fruit branches per plant of 0 g·hm^－2 DPC increased by 2.4-8.3 compared with manual topping. However, chemical topping with 90-270 g·hm^－2 DPC significantly reduced the number of fruit branches compared with 0 g·hm^－2 DPC. There were no significant differences in the number of fruit branches among three DPC dosages (90, 180, and 270 g·hm^－2). In Handan, seed cotton yield of chemical topping at T2 stage was significantly lower than that of manual topping due to the decreased boll number, which is possibly associated with the high temperature and drought weather after chemical topping. While at other locations, most treatments of chemical topping by using DPC did not produce significant effects on yield. In addition, chemical topping by using DPC did not delay cotton maturity, characterized by their similar boll-opening rate and the first harvest rate to those of manual topping before spraying harvest aids. [Conclusion] Cotton chemical topping with DPC is more stable and universal across different cotton-growing regions. We suggest that 90-180 g·hm^－2 DPC could be used at the same time with manual topping for cotton chemical topping.     

黄河流域棉区秸秆还田下机采棉的氮肥用量和利用率研究

提高种植密度、优化缩节胺(1,1-dimethyl-piperidinium chloride,DPC)化控技术是黄河流域棉区机采棉田的基本管理措施,秸秆还田则是实现农作物化肥零增长的技术途径之一。于2013―2014年在河北省河间市秸秆还田地块,研究了密度、DPC化控和氮(Nitrogen,N)肥用量对棉花产量及其构成因素、干物质和N的积累与分配以及N肥利用率的影响,其中2013年蕾期和花铃期降水量大,2014年比较干旱。研究结果表明,与低密度(6.75×10~4株·hm~(-2))相比,高密度处理(11.25×10~4株·hm~(-2))在干旱年份的籽棉产量和N肥偏生产力分别显著提高8.1%和7.4%,N回收率也显著增加25.5百分点,达到41.6%。与清水对照相比,DPC化控的籽棉产量、N肥偏生产力和农学效率在多雨年份分别显著提高39.2%、43.3%和212.8%,N回收率略增加但差异不显著。提高密度促进了干物质积累,但降低了多雨年份的收获指数;DPC化控的生物量较低,但在多雨和干旱年份均可提高收获指数。N肥用量对棉花产量的影响不显著,但表现出低N处理(105 kg·hm~(-2))的产量高于中N处理(210 kg·hm~(-2))和高N处理(315 kg·hm~(-2))的趋势。低N处理2年的N肥偏生产力分别为24.5 kg·kg~(-1)和54.4kg·kg~(-1),回收率分别为45.2%和41.0%,显著高于中N处理和高N处理。综上所述,增密和DPC化控相结合,有利于机采棉田干物质的积累及向产量器官的分配,有利于维持产量的稳定性;在秸秆还田条件下,棉田的适宜施N量可降至105 kg·hm~(-2)。     

中国北方主要棉区土壤供钾能力及其与产量和品质的关系

2012―2013年在山东平原县、河北威县、新疆昌吉市代表性棉田上采集土壤(0~20 cm)和棉花样品,分析北方棉区土壤钾素状况、供钾能力及其与棉花产量和纤维品质的关系。结果表明,平原、威县、昌吉棉田速效钾含量平均分别为217、128、232 mg·kg-1,供钾能力平均分别为128.2、105.1、213.6 kg·hm-2,每生产100 kg皮棉棉花地上部分别吸收K 9.77、7.82、12.25 kg。不同棉区土壤速效钾含量与皮棉产量和地上部吸钾量相关性不同,在平原和昌吉,当土壤速效钾含量分别小于123 mg·kg-1和220 mg·kg-1时,与皮棉产量和地上部吸钾量具有显著正相关。3个植棉区棉花的吸钾量与子棉产量、皮棉产量都呈显著的正相关。棉花地上部吸钾量、纤维吸钾量和纤维含钾量与纤维品质指标的相关性不同地点差异大。     

Effects of Planting Density and Chemical control on Yield and Mineral Elements Accumulation of Cotton Direct-Seeded after Wheat

[Objective] The effects of planting density and Miantaijin treatment on yield and nitrogen, phosphorus and potassium uptake and accumulation in cotton direct-seeded after wheat in the Yangtze River basin were studied in order to clarify the high-yield cultivation techniques under this cropping system. 【Method】 In 2011 and 2012, Guoxinzao 11-1 at the experimental material, and adopted three densities (75 000, 90 000 and 105 000 plants·hm^－2) and three Miantaijin doses (0 mL·hm^－2, 1 170 mL·hm^－2 and 2 340 mL·hm^－2). 【Result】 The results showed that the highest yield was 3 551.3～3 687.5 kg·hm^－2 under 90 000～105 000 plant·hm^－2 density combined with 1 170 mL·hm^－2 Miantaijin (seedling stage: 90 mL·hm^－2, peak squaring stage: 180 mL·hm^－2, peak flowering stage: 360 mL·hm^－2, peak boll-setting stage: 540 mL·hm^－2). Under these conditions, the highest uptake of nitrogen, phosphorus and potassium was 117.8 kg·hm^－2, 77.4 kg·hm^－2, 116.4 kg·hm^－2, respectively. Among them, nitrogen uptake was the highest in the peak-squaring stage to peak-flowering stage, while the highest phosphorus and potassium uptake were both detected in the peak-flowering to boll-opening stage. The correlation analysis showed that there was a significant linear positive correlation between the yield of direct seeded cotton after wheat and the total absorption and accumulation of nitrogen, phosphorus and potassium, especially during the peak flowering to boll-opening stage. 【Conclusion】 The suitable application dose of Miantaijin under medium and high density could enhance the absorption of nitrogen, phosphorus and potassium in the whole growth period of cotton, especially in the peak flowering to boll-opening stage. and thus result in the high yield of direct-seeded cotton after wheat in the Yangtze River basin.     

调亏灌溉与合理密植对旱区棉花生长发育及产量与品质的影响

为明确合理密植条件下调亏灌溉的节水增产效果,在新疆干旱区大田研究了灌溉量(饱和灌溉、正常灌溉、调亏灌溉)和种植密度(12万、18万、24万株·hm-2)对棉花生长发育和产量品质的影响。结果表明,灌溉量和种植密度对棉花生物产量、经济系数、经济产量有显著的互作效应,但对纤维品质没有影响。调亏灌溉显著抑制营养生长,但提高了收获指数;调亏灌溉下适当提高密度,显著提高了生物产量和单位面积铃数。调亏灌溉下高密度处理组合在用水量减少20%的情况下,棉花产量与正常灌溉下中、高密度以及饱和灌溉下低密度等高产组合的产量相当。调亏灌溉配合合理密植是旱区棉花节水增产的有效栽培途径之一。     

Response of Enzyme Activity of Soil to Urea Application Rate in a Cotton Field Trial

We studied the response of urease activity of soil in cotton field to different long-term urea (amide nitrogen) application (N application rates were 0, 90, 180, 270, 360, 450 kg·hm^－2), as well as responses of dehydrogenase and proteinase activity of soil at the harvest stage of cotton. The results showed that urease activity of soil increased with increased urea application rate, and urease activity at 0-20 cm soil depth were close to those at 20-40cm soil depth. In contrast, urease activity of soil greater than 40 cm soil depth decreased with increased soil depth. There was a significant positive correlation between urease activity and total N content, organic matter content, and available N content of soil. Dehydrogenase and proteinase activities increased with increased urea application rate (0-360 kg·hm^－2); however, at the urea application rate of 450 kg·hm^－2, dehydrogenase and proteinase activities declined. When the urea application rate was 270-360 kg ·hm^－2, urease, dehydrogenase and proteinase activities were much higher than those of the urea application rate less than 270 kg ·hm^－2, and there was no significant effect on urease, dehydrogenase and proteinase activities when urea application rate was 270-360 kg·hm^－2 in the cotton field.     

氮素对棉株上部果枝铃￣叶系统生长及生理特性的影响

以鲁棉研28号为试验材料,不施氮肥为对照,在大田条件下研究低氮(120 kg·hm-2)、中氮(240 kg·hm-2)、高氮(480 kg·hm-2)处理对棉株上部果枝"铃￣叶系统"的形态和生理生化效应。结果表明:1)中氮和高氮显著增加棉花上部果枝的长度、叶面积,高氮显著降低上部果枝近远端直径比;2)与对照相比,中氮上部果枝铃对位叶的叶绿素含量、可溶性蛋白含量显著增加,上部果枝棉子的可溶性蛋白含量也显著提高;3)中氮棉花果枝内外围铃重最大,结铃后期显著大于对照。氮肥提高棉花上部果枝的纤维品质,以中氮内外围棉铃的纤维品质最优。表明施适量氮肥能增强棉花上部果枝的"源￣库"协调性。     

密度对棉花株间小气候、农艺性状及产量的影响

为掌握棉花群体结构中的小气候环境状况,确定棉花不同密度对产量的影响,设计6个不同密度测定农艺性状,选择棉花郁闭度最大的开花盛期,测定不同棉花密度群体田间小气候要素。结果表明,密度不同棉花的农业性状发生很大变化,群体间光、温、湿度等气候因子有较大的改变。随着密度的增加,棉花株高、茎粗、叶片数、果枝数、蕾数、铃数、铃重与株间梯度温度差呈显著负相关,而与透光率呈正相关;最佳密度群体株间梯度温度差应0.3~0.4℃;棉株间地面透光率应在5.5%以上。密度22.5万株/hm²产量表现最佳,其次是27.0万株/hm²,再其次是18.0万株/hm²。在当前栽培管理水平下,北疆早熟棉花品种的种植密度以20万~25万株/hm²为宜。     

行距对机采棉干物质积累及氮磷利用效率的影响

【目的】新疆棉花生产的主要环节均已实现机械化,但采摘环节仍大量使用人工,农机农艺不协调是导致机收比例低的主要原因。优化机采棉行距配置是实现农机农艺融合的有效途径,因此本研究通过设置不同的机采棉行距,探究其对棉花产量形成及养分利用的影响,为机采棉行距配置的优化提供理论依据。【方法】采用随机区组设计,选择生产中最佳密度,在密度一致基础上,设置"一膜三行"(S1,平均行距76 cm)、"一膜四行"(S2,平均行距57 cm)、"一膜六行"(S3,平均行距38 cm)3种行距,其中S3处理为常规机采行距(CK),研究行距对棉花干物质积累、分配以及对产量形成及氮、磷养分吸收利用的影响。【结果】不同行距下棉花干物质的积累符合Logistic生长函数模型。2年均值表明随着平均行距的降低,单株干物质积累总量降低43.3%,干物质最大积累速率降低(1.4 g·株-1·d-1),快速积累期起始时间从出苗后51.4 d逐渐推迟至62.5 d,但快速积累持续时长从19.7 d增加至35.1 d。增加行距显著提高单株成铃(0.9个),对铃重及衣分无显著影响,籽棉及皮棉产量显著增加16.7%和17.4%。行距对植株养分积累与分配有显著的影响,S1处理氮积累总量(907.0 kg·hm-2)、磷积累总量(58.3 kg·hm-2)、吐絮期经济器官氮分配率和磷分配率(N 55.7%和P2O569.1%)、每100 kg皮棉氮素吸收量(32.1 kg)均最高;而S3处理氮积累总量(664.5 kg·hm-2)、磷积累总量(38.9 kg·hm-2)最低,S2处理吐絮期经济器官氮分配率和磷分配率(N 48.5%和P2O560.3%)、每100 kg皮棉氮素吸收量(28.6 kg)最低。【结论】综合来看,一膜三行下植株养分指标及产量均优于其他行距,更适宜作为高效机采的行距。     

套作条件下种植密度对紫色甘薯干物质生产的影响

为了研究川中丘陵区旱地套作条件下种植密度对紫色甘薯干物质生产的影响,在与玉米套作条件下,以鲜食型紫色甘薯品种‘南紫薯008’为材料,设置5个种植密度,测定紫色甘薯叶面积指数、群体生长率、群体光合势、干物质积累、产量等指标。结果表明：在套作条件下,随着种植密度的增加,‘南紫薯008’群体叶面积指数有升高的趋势,群体生长率、群体光合势、商品薯率、干物质率、鲜薯产量、淀粉产量均呈先升后降的趋势,而单株结薯数、单株薯鲜重则下降,群体干物质积累量和T/R则随生育期的推进不同密度间表现有所差异。公顷种植密度在3.5×10⁴~4.0×10⁴株时,群体干物质积累量、鲜薯产量、淀粉产量和商品薯率均较高。套作条件下‘南紫薯008’最高鲜薯产量为11816.9 kg/hm²,约为其净作产量的42.6%~53.1%。川中丘陵区旱地套作条件下紫色甘薯适宜的种植密度为3.5×10⁴~4.0×10⁴株/hm²。     

蕾期调亏灌溉对海岛棉棉铃发育及产量的影响

以新海24号、新海35号为材料,设置滴灌定额0 m3·hm-2(重度调亏,土壤含水量10%左右)、900 m3·hm-2(轻度调亏,土壤含水量16%左右)、1800 m3·hm-2(丰水,土壤含水量20%左右)3个处理,研究蕾期调亏灌溉对海岛棉棉铃发育及产量的影响。结果表明:0 m3·hm-2处理的铃直径、铃体积分别在花后10 d内、20 d内快速增大,铃重在花后30 d内增长速度较快;但铃直径、铃体积在开花后30 d,铃重在开花后50~60 d,均较900 m3·hm-2和1800 m3·hm-2处理显著下降。900 m3·hm-2处理的铃直径、铃体积及铃重均与1800 m3·hm-2处理无明显差异。皮棉产量以900 m3·hm-2处理最高,平均为2372.92 kg·hm-2,比1800 m3·hm-2和0 m3·hm-2分别高10.97%和41.78%。因此,海岛棉蕾期滴灌定额以900 m3·hm-2较为适宜。     

缓释氮肥对小麦后直播棉产量及氮素吸收利用的影响

【目的】研究缓释氮肥运筹对小麦后直播棉产量及氮素吸收利用的影响。【方法】2016―2017年以短季棉品种中棉所50为材料,采用小麦后直播的种植方式,设3个缓释肥氮素用量:45、90和135 kg·hm-2,2个施用时期分别为2叶期和4叶期。以常规氮肥尿素(纯氮90 kg·hm-2,CK1)和不施肥为对照(CK2)。【结果】缓释肥氮素90 kg·hm-2,并于2叶、4叶期施用产量较高,其中2017年籽棉产量显著高于其它处理,分别达4198.7和4037.8 kg·hm-2,比对照CK2分别高517.2和356.3 kg·hm-2,干物质积累量也表现为缓释肥氮素用量90 kg·hm-2于2叶、4叶期施用较高,其中2017年分别达到14090.5 kg·hm-2、13564.5 kg·hm-2,分别比对照CK2高12.6%和8.4%。氮素积累量表现相似的结果。氮素利用效率结果进一步表明,2叶期施缓释肥氮素用量45 kg·hm-2的处理氮素回收利用率(NARE)、氮素农学利用率(NAE)及氮素生理利用率(NPE)都最高,2叶期施缓释肥氮素用量90 kg·hm-2的处理其次,如2017年2叶期施缓释肥氮用量45 kg·hm-2处理的上述3个氮素利用效率分别为75.62%、23.68%、77.26%,施缓释肥氮素用量90 kg·hm-2处理则分别为60.9%、19.9%、46.6%,而对照CK2仅为53.79%、14.12%、40.91%。【结论】小麦后直播棉在2叶期一次性施用缓释肥氮素用量90 kg·hm-2能显著提高氮素利用效率,促进群体干物质生产并实现高产,同时达到轻简高效的目的。     

化学打顶对棉花群体容量的拓展效应

以常规人工打顶为对照,在大田条件下设置不同种植密度(18万、22.5万和27万株·hm-2),研究化学打顶对棉株形态、群体器官数量和经济产量等的影响.结果表明,化学打顶棉花株高显著高于人工打顶,平均高出17％,中上部果枝显著变短,尤其是上部果枝平均比人工打顶短75％.冠层中部透光率平均提高约13％.在相同密度条件下,化...