Localized salt accumulation: the main reason for cotton root length decrease during advanced growth stages under drip irrigation with mulch film in a saline soil

High salinity in soil can prevent root growth of most plants. To investigate soil salinity dynamics under drip irrigation with mulch film （DI） and its effects on cotton root length, we conducted field experiments in saline soil based on a monolith method using flooding irrigation with mulch film （FI） as a control at the Korla Experimental Station of the Xinjiang Academy of Agricultural Sciences, China in 2009 and 2010. The results showed that the total root length decreased 120 days after sowing （DAS） under DI, and was mainly centered in the 0-30 cm soil layer and at distances of 30-70 cm from the drip-lines. There was almost complete overlap in the area of root length decline and salt accumulation. In the soil depth of 0-30 cm and at distances of 30-70 cm from the drip-lines at 110 to 160 DAS in 2009 and 171 DAS in 2010, the electrical conductivity （EC） in all soil samples was at least 3 mS/cm and in some cases exceeded 5 mS/cm under DI treatment. However, EC barely exceeded 3 mS/cm and no reduction in root length was observed under FI treatment. Correlation analysis of soil EC and root length density indicated that the root length declined when the soil EC exceeded 2.8 mS/cm. The main reason for the decrease of root length in cotton under DI was localized accumulation of salinity.

Cotton's Water Demand and Water-Saving Benefits under Drip Irrigation with Plastic Film Mulch

The primary purpose of this research was to give suitable irrigation program according to the growth period and water requirement.A cotton field experiment with mulched drip irrigation was conducted at the National Field Observation and Research Station for Oasis Farmland Ecosystem in Aksu of Xinjiang in 2008.Water balance method was adopted to study the water requirement and water consumption law of cotton under mulched drip irrigation in Tarim Irrigated Area.Statistical analysis of experimental data of irrigation indicates that the relationship between yield of cotton and irrigation presents a quadratic parabola.We fit the model of cotton water production on the basis of field experimental data of cotton.And the analysis on water saving benefit of cotton under mulched drip irrigation was done.Results indicate that water requirements for the irrigated cotton are 543 mm in Tarim Irrigated Area.The water requirements of seedling stage is 252 mm,budding stage is 186 mm,bolling stage is 316 mm and wadding stage is 139 mm.the irrigation amount determines the spatial distribution of soil moisture and water consumption during cotton life cycle.However,water consumption at different growth stages was inconsistent with irrigation.Quantitatively,the water consumed by cotton decreases upon the increase of irrigation amount.From the perspective of water saving,the maximal water use efficiency can reach 3 091 m3/ha.But the highest cotton yield needs 3464 m3/ha irrigation water.In summary,compared to the conventional drip irrigation,a number of benefits in water saving and yield increase were observed when using plastic mulch.At the same amount of irrigation,the cotton yield with plastic mulch was 30.2% higher than conventional approaches,and the efficiency of water utilization increased by30.2%.While at the same yield level,29.3% water was saved by using plastic mulch,and the efficiency increased by 41.5%.

Water and nitrogen transport characteristics of single-line interference infiltration under film hole irrigation with muddy water and fertilizer

Based on the experimental data,this study investigated the effect of sand content of muddy water on water and nitrogen transport characteristics of the single-line interference infiltration under film hole irrigation with muddy water and fertilizer.The relationship between the single-line interference infiltration parameters,the sand content,the wetting front movement distances,and the sand content were all established.The model of the cumulative infiltration volume of per unit film pore area,the vertical and horizontal wetting front movement distance of the free surface,and the wetting front movement distance of the interference center with sand content and infiltration time were proposed.Reveal the law of the change of soil water content and the distribution of NO_(3)^(-)-N content based on different muddy water sand content.The results indicate that at the same infiltration time,as the muddy water sand content increases,the cumulative infiltration volume per unit pore area decreases.The infiltration index of the free infiltration and the single-line interference vary little when the sand content increases,mainly are around 0.64 and 0.58.The relationship between infiltration parameters a,b and the sand content is linear function.At the same location,the more the sand content,the smaller the wetting front movement distance in free surface and the single-line interference surface,the less the NO_(3)^(-)-N content.

The Study of Condensation Processes in the Low-Temperature Short Heat Pipes with a Nozzle-Shaped Vapour Channel

The results of researches of condensation processes in the vapour channel similar to the Laval nozzle of short linear heat pipes are presented. Capacitive sensors are additionally installed in cooled top covers of the heat pipes, and electromagnetic pulses were supplied to them from the external generator. At heating the heat pipe evaporator, starting from a certain thermal power threshold value, electromagnetic pulses became modulated. It is related with the formations of the boiling process in the capillary-porous evaporator and large amount of vapour over it. Boiling process results in rapid increase of the pressure under which the average temperature of the evaporator occurs to be less than the boiling temperature of the working fluid under increased pressure. Considering condensation of excess vapour, this leads to repeated initiation and extinction of the boiling process in the evaporator, which reflects in pressure pulsations in the vapour channel. Pressure pulsations cause modulating effect on electromagnetic impulses. Pulsations frequencies are measured as well as their dependence from overheating of the evaporator. Using the capacitive sensors and a special electronic equipment we measured the local thickness of the working fluid at the condensing surface inside the heat pipes. Time-averaged values of the condensate film thickness are measured, depending on the heat load on the capillary-porous evaporator. The measurement error does not exceed 2 × 10–3 mm. It is demonstrated that the condensate film thickness lessens sharply with the increase of the heat load on the evaporator of a Laval-like low-temperature heat pipe, while the heat resistance of the film on the condensing surface reaches 60% of the total heat resistance of heat pipe with the capillary-porous evaporator.

膜下滴灌不同灌水下限对花生生长发育的影响及DMA数字模型构建

探究辽西地区花生膜下滴灌最佳灌溉制度,建立以有效积温为自变量的不同灌水下限花生干物质积累动态模型,以期为花生高产节水节效栽培管理提供参考依据。采用大田试验以花生白沙1016为试验材料,设置4个灌水处理,雨养处理(CK)、W50、W60、W70(灌水下限分别为田间持水率的50%、60%、70%),通过观测花生株高、LAI和干物质积累量(DMA)变化,分析不同灌水下限对花生生长发育的影响,并建立基于有效积温为自变量,DMA为因变量的花生生长动态模型。结果表明:花生在花针期、结荚期的生长速度较快,对水分的敏感度较高,生育后期的生长速度较慢,W70处理较其他处理的花生株高、LAI和DMA有显著的提高,其产量最高达到5 181.81 kg/hm^(2)、水分利用效率最大为1.79 kg/m3。所以田间持水率70%为该地区膜下滴灌条件下花生最适宜的灌水参数,并建立了其基于归一化的有效积温为自变量的相对DMA预测的Gompertz方程:■。

Measuring and modeling two-dimensional irrigation infiltration under film-mulched furrows

Furrow irrigation with film-mulched agricultural beds is being promoted in the arid region of northwest China because it improves water utilization. Two-dimensional infiltration patterns under film-mulched furrows can provide guidelines and criteria for irrigation design and operation. Our objective was to investigate soil water dynamics during ponding irrigation infiltration of mulched furrows in a cross-sectional ridge-furrow configuration, using laboratory experiments and mathematical simulations. Six experimental treatments, with two soil types （silt loam and sandy loam）, were investigated to monitor the wetting patterns and soil water distribution in a cuboid soil chamber. Irrigation of mulched furrows clearly increased water lateral infiltration on ridge shoulders and ridges, due to enhancement of capillary driving force. Increases to both initial soil water content （SWC） and irrigation water level resulted in increased wetted soil volume. Empirical regression equations accurately estimated the wetted lateral distance （Rl） and downward distance （Rd） with elapsed time in a variably wetted soil medium. Optimization of model parameters followed by the Inverse approach resulted in satisfactory agreement between observed and predicted cumulative infiltration and SWC. On the basis of model calibration, HYDRUS-2D model can accurately simulate two-dimensional soil water dynamics under irrigation of mulched furrows. There were significant differences in wetting patterns between unmulched and mulched furrow irrigation using HYDRUS-2D simulation. The Rd under the mulched furrows was 32.14% less than the unmulched furrows. Therefore, film-mulched furrows are recommended in a furrow irrigation system.

Performance Evaluation of Gated Pipes Technique for Improving Surface Irrigation Efficiency in Maize Hybrids

Waterlogging and low application efficiency are the main problems inherent with surface irrigation in the Nile Delta. Develop surface irrigation using gated pipes (GP) is a new method to be used to distribute water into furrow irrigated fields as strategy based on water saving. Laboratory calibration was conducted out to evaluate the hydraulic characteristics of pipe gates. Field experiments were conducted at the Experimental Farm of the Agriculture Faculty, Minufiya University during 2013 and 2014 seasons to evaluate the performance of utilize gated pipes technique for irrigating five maize varieties (S.C 10, S.C 130, S.C 131, S.C 2031 and T.W.C 321). The results revealed that the highest amount of water applied was with traditional surface irrigation (6423.81 m3·ha-1. Use of gated pipes system GP1 as compared to traditional irrigation reduced water application by 923.81 m3·ha-1 with grain and stover yields increases of 5.7% and 3.4%, respectively. Traditional irrigation system achieved lowest irrigation performance parameters compared to gated pipes systems. Maize physiological attributes, yield, water use efficiency (WUE) and nitrogen accumulation were significantly decreased by either deficit or surplus irrigation than of GP1 rate. S.C 2031 variety significantly surpassed other varieties in abovementioned traits. Significant interaction effects were detected in both seasons. Maize varieties respond differently to irrigation systems. The highest values of grain yield (11062.6 and 10911.8 kg·ha-1 and stover yield (13639.0 and 13902.2 kg·ha-1) were obtained by S.C 2031 irrigated with GP1 system in both seasons. From the above mentioned results, it is concluded that the gated pipes technique is better than traditional irrigation for improving WUE and maize productivity under Nile Delta conditions.

运用DRAINMOD_NII分析排水暗管布置对水稻产量及氮素流失量的影响

合理的排水暗管布置,可以有效提高水稻产量、减少氮素流失量。运用DRAINMOD_NII模型分析竹络坝灌区不同排水暗管布置对水稻产量和氮素流失量的影响。结果显示暗管间距90 m、埋深90 cm时,水稻产量最高;随排水暗管间距增大,氮素累积流失量减小,同一排水间距,埋深越深,氮素累积流失量越大。

Effects of combined drip irrigation and sub-surface pipe drainage on water and salt transport of saline-alkali soil in Xinjiang, China

Developing effective irrigation and drainage strategies to improve the quality of saline-alkali soil is vital for enhancing agricultural production and increasing economic returns. In this study, we explored how irrigation and drainage modes (flood irrigation, drip irrigation, and sub-surface pipe drainage under drip irrigation) improve the saline-alkali soil in Xinjiang, China. We aimed to study the transport characteristics of soil water and salt under different irrigation and drainage modes, and analyze the effects of the combination of irrigation and drainage on soil salt leaching, as well as its impacts on the growth of oil sunflower. Our results show that sub-surface pipe drainage under drip irrigation significantly reduced the soil salt content and soil water content at the 0–200 cm soil depth. Under sub-surface pipe drainage combined with drip irrigation, the mean soil salt content was reduced to below 10 g/kg after the second irrigation, and the soil salt content decreased as sub-surface pipe distance decreased. The mean soil salt content of flood irrigation exceeded 25 g/kg, and the mean soil desalination efficiency was 3.28%, which was lower than that of drip irrigation. The mean soil desalination rate under drip irrigation and sub-surface pipe drainage under drip irrigation was 19.30% and 58.12%, respectively. After sub-surface drainage regulation under drip irrigation, the germination percentage of oil sunflower seedlings was increased to more than 50%, which further confirmed that combined drip irrigation and sub-surface pipe drainage is very effective in improving the quality of saline-alkali soil and increasing the productivity of agricultural crops.

Comparison between Hydro-Flume and Open Field Head Ditch Irrigation Systems at Kenana Sugar Scheme, Sudan

A study was undertaken in Kenana Sugar Scheme, Sudan during 2009/2010 and 2010/2011 seasons. In this study, the gated pipe (hydro-flume) for ?furrow irrigation was compared with the conventional open field head ditch irrigation system concerning the volume of irrigation water applied to the field, irrigation efficiencies, the time of cutoff, water and irrigation time saved and the irrigation production efficiency (IPE). To achieve these objectives, two commercial cane fields having the same furrow lengths (2100 m) and slopes were chosen. The study shows that in the open field head ditch irrigation, the irrigation water added was 69.1 mm in the top, 75.7 mm in the ?middle and 66.1 mm in the end of the furrow. Whereas, the irrigation water added in the gated pipe system was 132.7 mm, 46.1 mm and 101.9 mm, respectively. The present study indicates that the gated-pipe system has a high value of application efficiency (79% - 88%) compared with the open field head ditch (69% - 71%). The percent of deep percolation (PDP) for the gated-pipe system is greater than the PDP obtained under open field head ditch irrigation conditions. Also the percent of runoff (PRO) is higher under the open field head ditch system and the water conveyance efficiency for the open field head ditch is 88%. While the gated pipe needs more advance time but can save 20 to 65 m3 of water/irrigation cycle with better uniformity coefficient (CU) and irrigation production efficiency (IPE) compared with the open field head ditch. From the above mentioned results, it is concluded that under Kenana conditions the gated-pipe system is better than the open field head ditch irrigation system keeping in mind that for more uniform water distribution through irrigated furrows of the long fields of Kenana, increased pressure head at the inlet and/or larger openings of the hydro-flume gates may be necessary.

Numerical Modeling of the Vapour Vortex Formation in the Short Heat Pipes

The results of the numerical studies of vortex formation inside short heat pipes (HP’s) with profiled vapour channel in the Laval-liked nozzle form are presented. For the first time, it was found that the vapour vortex of moist compressible vapour flow in the cooled part of vapour channel changes its rotational motion direction. The rotation direction of the toroidal vapour vortex, obtained by solving the Navier Stokes equations is dependent on the heat power value, entering to the HP’s evaporator. With low heat power loads the rotational direction of the circular toroidal vapour ring due to the Coanda effect and sticking moving vapour jets to the channel’s walls occurs from the periphery to the longitudinal axis of the vapour channel. While the heat power load increasing, the direction of the circular toroidal vapour ring rotation changes to the opposite, from the longitudinal axis to the periphery of the vapour channel. The thickness of the formed working fluid condensate film located under the toroidal vapour vortex also related to the evaporator heat power load and the associated toroidal vapour vortex rotation direction. The numerical thickness calculation of the formed working fluid condensate film located under the toroidal vapour vortex was compared with experimental values, obtained by capacitive sensors. The thickness values of the calculated condensate film thickness and experimentally measured values using capacitive sensors are close in magnitude order.

Green Control Measures of Weeds in Wheat Fields in Hetao Irrigation Area along the Yellow River

This study was conducted to solve the problem of green weed control in wheat fields in Hetao irrigation area among the Yellow River.Based on the observation of the competition between wheat and weeds in areas where weeds occurred seriously in wheat fields in Hetao irrigation area among the Yellow River,we measured the effects of green weed control measures and wheat yield using different wheat varieties,planting densities,different organic fertilizers,different ploughing times,and different mulching methods.The results showed that the emergence of weeds in wheat fields dominated by Chenopodiaceae weeds,grain amaranth and barnyard grass was more than 10 d later than wheat.Weeds were mainly distributed between rows(holes),and the number of plants accounted for 66.6%(drill seeding)and 97.6%(hole seeding),respectively.And the growth of weeds in rows(holes)was weaker,and the fresh weight of individual plants was 39.3%-41.9%lower than that between rows(holes).The ecological weed inhibitory effect was significant in the early stage of wheat growth;and among the green weed control measures,except that different varieties and planting densities caused no significant difference in weed control effect,other measures had obvious weed control effects.Comprehensive comparison showed that the control effects of plant number in black film full-covered hole seeding,conventional film-covered hole seeding,increasing ploughing times,and applying organic fertilizer free of weed seed pollution were 82.3%,71.7%,22.0%,and 8.6%,respectively;the fresh weight control effects of black film full-covered hole seeding,conventional film-covered hole seeding,increasing ploughing times,and applying organic fertilizer free of weed seed pollution were 98.0%,97.1%,23.9%,and 9.6%,respectively;and the fresh weight control effects of black film full-covered hole seeding,conventional film-covered hole seeding and increasing ploughing times increased wheat yield by 69.4%,56.4%and 21.1%,respectively.The technologies in this study can realize the purposes of mechanized green weed control in organic wheat production and low-cost,high-yield,large-scale production.

Optimizing water management practice to increase potato yield and water use efficiency in North China

Potato is one of the staple food crops in North China.However,potato production in this region is threatened by the low amount and high spatial-temporal variation of precipitation.Increasing yield and water use efficiency(WUE)of potato by various water management practices under water resource limitation is of great importance for ensuring food security in China.However,the contributions of different water management practices to yield and WUE of potato have been rarely investigated across North China’s potato planting region.Based on meta-analysis of field experiments from the literature and model simulation,this study quantified the potential yields of potatoes without water and fertilizer limitation,and yield under irrigated and rainfed conditions,and the corresponding WUEs across four potato planting regions including the Da Hinggan Mountains(DH),the Foothills of Yanshan hilly(YH),the North foot of the Yinshan Mountains(YM),and the Loess Plateau(LP)in North China.Simulated average potential potato tuber dry weight yield by the APSIM-Potato Model was 12.4 t ha^(–1)for the YH region,11.4 t ha^(–1)for the YM region,11.2 t ha^(–1)for the DH region,and 10.7 t ha^(–1)for the LP region,respectively.Observed rainfed potato tuber dry weight yield accounted for 61,30,28 and 24%of the potential yield in the DH,YH,YM,and LP regions.The maximum WUE of 2.2 kg m^(–3)in the YH region,2.1 kg m^(–3)in the DH region,1.9 kg m^(–3)in the YM region and 1.9 kg m^(–3)in the LP region was achieved under the potential yield level.Ridge-furrow planting could boost yield by 8–49%and WUE by 2–36%while ridge-furrow planting with film mulching could boost yield by 35–89%and WUE by 7–57%across North China.Our study demonstrates that there is a large potential to increase yield and WUE simultaneously by combining ridge-furrow planting with film mulching and supplemental irrigation in different potato planting regions with limited water resources.

秸秆复合管地下灌溉对冬小麦生长与水分利用效率的影响

为了推进秸秆复合管地下灌溉技术的应用,以冬小麦为供试作物,通过田间试验,研究了秸秆复合管地下灌溉对冬小麦生长及水分利用效率的影响。结果表明,与无灌溉对照相比,秸秆复合管地下灌溉、地表滴灌和地下滴灌对冬小麦的生长与产量的提升均有促进作用,其中秸秆复合管地下灌溉的提升效果最显著。与地表滴灌相比,秸秆复合管地下灌溉显著提升了冬小麦起身期至抽穗期的株高、开花期之后的叶面积指数及地上干物质量,冬小麦穗长和穗粒数分别增加了5.84%和9.23%,产量提升了15.55%,水分利用效率与灌溉水利用效率分别提高了21.88%与15.55%,净收益提高了77.95%。与地下滴灌相比,秸秆复合管地下灌溉提高了冬小麦返青期后的株高、叶面积指数与开花期后的地上干物质量,冬小麦穗长和穗粒数分别增加了5.15%和9.8%,产量提高了5.11%,水分利用效率与灌溉水利用效率分别提高了8.81%与5.11%,净收益提升了23.53%。秸秆复合管地下灌溉有助于促进拔节期以后冬小麦生长,提高冬小麦的产量与水分利用效率,经济效益较高,在补充灌溉区对大田密植作物具有较好的推广应用前景。

不同矿化度水源膜下滴灌对棉花土壤盐分分布及生长的影响

利用微咸水膜下灌溉是缓解干旱区农业灌溉资源短缺的有效途径之一,分析不同矿化度水源膜下滴灌对土壤盐分分布及作物生长的影响对于确定灌溉水源矿化度阈值具有重要意义。开展4 a不同梯度矿化度水源膜下滴灌棉花测坑试验,设置6个处理矿化度分别为1 g/L(CK)、2 g/L(A)、3 g/L(B)、4 g/L(C)、5 g/L(D)和6 g/L(E),分析不同梯度矿化度水源膜下滴灌土壤盐分累积及棉花生长特征,确定微咸水膜下滴灌棉花灌溉矿化度阈值。结果表明:2019-2022年,0~100 cm平均土壤电导率以每年0.920 dS/m、0.995 dS/m、1.196 dS/m和1.188 dS/m的速率呈线性增长的趋势。随着灌溉年限增加,不同梯度微咸水膜下滴灌下土壤电导率呈现增加趋势。5 g/L和6 g/L处理土壤盐分累积最大,分别为38.70%和39.19%;灌水12 h后,宽行表层20~40 cm土壤盐分累积最为明显,土壤电导率为0.30~2.1 dS/m;窄行土壤盐分在40~60 cm土层处出现累积,土壤电导率为1.26~1.93 dS/m。矿化度为3 g/L水源膜下滴灌棉花土壤盐分累积量较小,对棉花叶片光合作用指数影响最小,生长指标和产量达到最大,微咸水膜下滴灌棉花适宜的灌溉水源阈值为3 g/L。

膜孔灌溉单孔入渗Kostiakov模型建立与验证

以非饱和土壤水分运动理论为基础,研究膜孔灌单孔入渗土壤水分运动的数学模型,用SWMS-3D软件对多种典型土壤的单点膜孔入渗特性进行模拟.结果表明:单点膜孔的累积入渗量变化过程符合Kostiakov模型.提出包含膜孔直径、灌溉水深的单点膜孔Kostiakov入渗模型参数计算方法,采用多种土壤单点膜孔入渗室内试验结果与已有文献资料对所建模型进行验证,结果表明,所建模型能较准确地反映单点膜孔入渗特性,可为确定合理的膜孔灌灌水技术要素组合提供理论依据.

PBAT生物降解膜覆盖对绿洲滴灌棉花土壤水热及产量的影响

为应对农田残膜污染,探明基于聚己二酸丁二醇酯-对苯二甲酸丁二醇酯(PBAT)材料的完全生物降解地膜代替普通塑料地膜与滴灌结合在棉花滴灌上应用效果,于2015—2016年在新疆石河子大学节水灌溉试验站,分别设置4种不同厚度和降解诱导期生物降解地膜和普通塑料地膜共5种不同处理,研究不同覆盖对滴灌棉花土壤温度、水分及产量的影响,并对可降解膜降解性能和经济效益对比分析。2 a试验结果表明,覆膜60~80 d开始出现降解,至覆盖180 d后出现均匀细纹并未完全降解,0.012 mm可降解地膜覆膜180 d仅仅出现裂纹,降解速度较慢。0.010 mm和0.012 mm厚完全生物可降解地膜处理棉花苗期土壤0~25 cm平均温度较对照分别低0.94℃和1.34℃(P<0.05),但随着作物生长两者差异逐渐减小。4种类型可降解膜覆盖在棉花生长前期均能提高土壤土壤水分,但随地膜降解和棉花生长后期则显著降低,与普通塑料地膜相比土壤水分显著降低1%~3%。总体而言,覆盖完全生物可降解地膜处理2 a平均产量较CK减少2%~3%,水分利用效率减少4%左右(P<0.05),净收入少1 858.5元/hm2(10.2%),4种类型可降解地膜产投比相比,厚度较薄0.010 mm处理应用经济效果较好。可见,目前全生物降解地膜若要代替普通地膜,解决残膜污染,仍需进行较大的改善。

基于AquaCrop模型的南疆无膜滴灌棉花灌溉制度优化

为探究AquaCrop模型对南疆地区无膜滴灌棉花种植的适用性、寻求最优灌溉制度,以2018—2019年田间实测数据对模型进行校验,并利用校准模型分别模拟2种不同灌水情景下的棉花冠层覆盖度、生物量及产量的变化规律。结果表明:采用AquaCrop模型模拟2019年冠层覆盖度的均方根误差(RMSE)、拟合指数(d)、标准均方根误差(NRMSE)及决定系数(R2)分别为6.03%、0.12、13.08%和0.97,生物量模拟的各参数分别为810 kg/hm^(2)、0.93、6.41%和0.80,产量模拟的各参数分别为751 kg/hm^(2)、0.84、14.02%和0.87,说明AquaCrop模型可以较好地模拟南疆地区无膜滴灌棉花的生长与产量。基于1960—2019年的气象数据,利用AquaCrop模型对无膜滴灌棉花进行情景模拟:灌水周期相同时,无膜滴灌棉花产量随灌溉定额的增加呈先增加、后减小的变化趋势,总灌水量为7 200 m3/hm^(2)时产量达到最大值(5 398 kg/hm^(2)),水分利用效率(WUE)为0.75 kg/m3;灌溉定额相同时,无膜滴灌棉花产量随灌水周期的增加而增加,总灌水量为5 400 m3/hm^(2)、灌水周期为5 d时,产量达到最大值(5 315 kg/hm^(2))、WUE为0.98 kg/m3。研究表明,灌水周期5 d、灌溉定额540 mm的灌溉制度可保证无膜滴灌棉花具有较高的产量和水分利用率,可作为无膜滴灌棉花的参考灌溉制度在南疆地区推广应用。

膜下滴灌对麦茬夏花生土壤理化性状及肥料农学效率的影响

为保障夏花生出苗和高产高效,本研究采用漫灌和膜下滴灌两种灌溉方式,系统研究了不同灌溉方式对夏花生田土壤理化性状、植株养分积累、肥料利用率及花生产量的影响。结果表明,膜下滴灌各土层地温在昼间7:00、9:00、11:30及14:30均高于漫灌,但滴灌处理土壤容重在0~15 cm土层显著低于漫灌。滴灌处理显著增加了0~30 cm土壤含水量,且提高了各土层的有机质含量和花生茎、叶、果壳中氮和磷含量,显著提高了花生荚果氮含量及积累量和花生茎、叶中磷和钾的积累量。与漫灌相比,滴灌处理氮、磷、钾肥的农学效率分别提高33.0%、33.9%、36.4%;夏花生产量显著提高,达17.8%。综合分析表明,膜下滴灌提高了花生产量,增加了经济效益,增强了作物对土壤养分与水分的有效利用。

滴灌水盐氮调控对棉田水肥盐运移及棉花产量的影响

为明析覆膜滴灌条件下水盐氮调控对土壤水盐养分运移变化、棉花生长指标及产量的影响,通过两年三因素全组合大田试验,设置灌水量三水平(W1:2700 m^(3)·hm^(-2)、W2:3600 m^(3)·hm^(-2)和W3:4500 m^(3)·hm^(-2))、含盐量三水平(S1:3 dS·m^(-1)、S2:6 dS·m^(-1)和S3:9 dS·m^(-1))、施氮量三水平(F1:105 kg·hm^(-2)、F2:210 kg·hm^(-2)和F3:315 kg·hm^(-2)),研究了不同水盐氮组合对土壤水分、盐分、氮素分布及植株生长、产量的影响。结果表明:土壤水分主要聚集在30~40 cm土层,不同土层深度的含水率基本呈先增大后减小的变化趋势;蕾期和花铃期的S3F3W1和S2F3W1比S1F3W1的0~40 cm土层平均含水率增大1.3%~21.8%;同一灌溉量下S1F3组合的平均含水率比S1F2和S1F1增大1.39%~13.83%。土壤盐分生育期内呈现先减少后增加的变化趋势;S1土壤盐分随施氮量的增大而先增大后减小,S2、S3土壤盐分随施氮量的增加而减少。W2、W3处理中,氮素在40~60 cm土层中缓慢积聚;S1处理的氮素含量明显高于S2、S3。土壤水分、盐分、氮素含量交互影响,在适宜的土壤水分、氮素条件下,较低的土壤含盐量,能使植株更好地利用养分,利于植株的生长进而促进产量的形成。为获得较高的经济效益,低、中盐土壤推荐灌溉量为3600 m^(3)·hm^(-2),施氮量为210 kg·hm^(-2);高盐土壤推荐灌溉量为4500 m^(3)·hm^(-2),施氮量为315 kg·hm^(-2)。研究为探索干旱区多年膜下滴灌棉花农田生态系统水盐养分运移机制及水肥高效利用提供科学的理论依据。