清、洪水灌溉条件下土壤中盐分运移规律的试验研究

在大同县罗庄村玉米地进行洪水灌溉与清水灌溉的大田灌水试验,研究在不同的灌水定额下,用洪水与清水灌溉后,土壤剖面上盐分的运移规律。研究结果表明:用洪水与清水灌溉后,土壤中盐分的运移规律基本相同;盐分随水分运动而向下运移的深度随灌水定额的增大而增大。     

畦灌条件下苹果树根区速效磷运移规律的试验研究

通过测定不同生育期不同深度土壤中速效磷的含量,研究在不同水肥条件下土壤中速效磷的变化规律,为确定合理的灌水定额和合理的施肥方式提供理论依据和技术参数。结果表明:在幼果生长期需要的速效磷最多,在开花发芽期需要的较少;在灌水量为8 400m3/hm2和施肥量为1 104kg/hm2时,磷肥发挥的效益最好。     

东营引黄灌区波涌灌溉对田间泥沙运移影响研究

作为缓解引黄灌区泥沙淤积问题的一种解决方案,引泥沙入田值得作更深入的研究。分析了灌水定额对土壤颗粒级配的影响以及在传统灌溉和波涌灌溉2种灌溉处理下,引黄泥沙在田间的运移规律。结果表明,浑水灌溉可以提高土壤中沙粒、黏粒含量,降低粉粒含量,改善土壤结构性,并且灌水定额越大,变化越大。波涌灌溉可使入田泥沙运移更加均匀,有利于整体改善土壤结构。     

干旱区滴灌棉田生育期节水控盐灌溉模式研究

开展作物节水控盐研究,对于实现水资源的高效利用与农业的可持续发展意义重大。以新疆孔雀河流域为研究区域,采用两种灌溉定额研究了棉花在不同盐渍化程度土壤中的生长特性,结果表明:灌水频次相同时,灌溉定额和株高成正相关性;灌溉定额相同时,灌水频次和株高成正相关性;高盐渍化土壤,小灌溉定额时大灌水次数棉株成铃数多,且单铃较重。大灌水定额时,小灌水次数棉株成铃数多,但单铃重小;低盐渍化土壤,小灌溉定额时小灌水次数棉株成铃数多,但单铃重小。大灌水定额时大灌水次数棉株成铃数多,但单铃重小;从水分生产效率角度考虑,在盐渍化土壤中种植棉花,大频率灌水有利于提高棉花水分生产率。     

干旱绿洲区膜下滴灌棉田土壤盐分时空变化特征研究

基于Penman-Monteith公式设计一定梯度的灌水定额和灌水次数双因素组合试验,通过2012—2014年连续3a免冬、春灌膜下滴灌棉花田间定位试验研究,测定分析土壤盐分时空变化规律及其对棉花产量的影响。结果表明:膜下滴灌棉花生育期0~30 cm土壤盐分变幅大于40~100 cm,较小的灌水定额和灌水次数使0~30 cm盐分变幅增大,棉花苗期和花铃期变幅最为明显。灌水定额对土壤剖面盐分变异程度影响弱于灌水次数。增加灌水定额有利于减小棉花各生育阶段0~30 cm土壤盐分含量。土壤剖面盐分呈"C"形分布,0~40 cm土壤盐分含量灌水12次比灌水16次大1.74%,50~80 cm土层土壤盐分含量灌水16次比灌水12次大1.71%,灌水次数对90~100 cm土层土壤盐分影响不明显。同一灌水次数下,460 mm灌溉定额籽棉产量最高,适宜灌溉定额下,16次灌水次数籽棉产量高于灌水12次籽棉产量。灌溉水利用效率随灌水定额的降低和灌水次数的增加而提高,在南疆水资源短缺情况下高频次小定额灌溉可获得最大的灌溉水利用效率。当0~30 cm初始土壤含盐量(2.03 g/kg)小于3.0 g/kg时,棉花生育期460 mm灌溉定额、16次灌水次数,不会产生土壤盐分累积情况,可作为南疆干旱区免冬、春灌适宜棉花灌溉制度。     

微咸水灌溉对作物生长及土壤盐分

在田间试验条件下,采用正常灌溉定额和淋洗灌溉定额两种灌溉水平,对小麦进行了不同灌溉水浓度处理的灌溉试验,并对其生长过程、地上部干物质积累规律、产量、土壤盐分等进行了研究。研究发现灌溉水浓度达到某一临界值时,盐分在一定深度的土层内聚集明显增大。这一临界浓度值与使作物生长、产量受到抑制的灌水浓度基本一致。在淋洗灌溉定额下作物的耐盐能力增大,由于较大定额的淋洗灌溉将盐分淋洗到深层,在排水作用下从土层中排出,使作物根区盐分降低。应用产量与灌水浓度的相关关系预测出小麦的耐盐度阈值为正常灌溉定额下为4.0g/l,淋洗定额下为4.5g/l。预测值与研究发现的灌水浓度临界值基本吻合。     

滴灌条件下酿酒葡萄园土壤速效养分和水分迁移特征

为了寻求红寺堡地区酿酒葡萄园的最佳灌水量,解决葡萄园合理灌水问题,以4年生酿酒葡萄"赤霞珠"为供试材料,以滴灌为灌水方式,设计6个不同灌水量梯度,分析不同灌水量下葡萄园土壤刨面水分含量、碱解氮、有效磷、速效钾含量变化趋势,研究不同灌水量对土壤速效养分和水分在土壤迁移中的影响。结果表明,酿酒葡萄园土壤养分的空间迁移受不同灌水量的影响较为明显,随着灌水量的增加,土壤中速效养分向深层迁移的量也随之增加。在灌水量为2.85×10~3m~3/hm~2时,酿酒葡萄的产量最高,土壤养分向下迁移的量相对较少,为最优处理。     

CROPWAT模型在滇中南部灌水量模拟中的应用研究

滇中是云南主要高原特色作物主产区,开展灌溉制度研究对当地水资源优化配置、高效利用具有重要意义。基于滇中南部建水(102°50′E、23°56′N)2016～2018年灌溉试验数据,对CROPWAT模型中灌水量计算模块所涉及的作物、土壤参数进行了校准,并应用该模型模拟了水稻和马铃薯全生育期的灌水量过程。结果显示,模拟的水稻泡田水量在192.3～195.0 mm之间,本田期灌水次数在8～11次、灌水定额在20.9～45.9 mm、灌溉定额在288.3～414.4 mm之间,全生育期灌溉定额在483.3～609.7 mm之间,与试验观测的灌溉定额相差在±6%以内;马铃薯全生育期灌水次数在7～8次、灌水定额在12.7～38.3 mm、灌溉定额在181.5～201.0 mm之间,与试验观测的灌溉定额相差在±12%以内。灌水次数模拟与试验观测值接近,灌水定额水稻模拟值略偏小、马铃薯模拟值略偏大,灌水时间虽然略有差异但总体相应性较好。结果表明,该模型在滇中南部水稻和马铃薯灌水量过程模拟中的应用效果较好,用于制定灌溉制度可更好地把握灌水时间,提高制定灌溉制度的精度。     

引黄灌溉对黄河下游盐碱地土壤水盐含量的影响研究

为探究引黄灌溉对黄河下游盐碱地土壤水盐运移的影响,选择4种典型的灌水定额(570、780、990、1 200 m~3/hm~2),通过田间试验与室内试验,从土壤含水率与全盐量综合调控的角度,对比分析灌溉前后0～100 cm土层土壤的水盐变化。结果表明:灌溉前土壤含水率较低不适宜作物生长,灌溉后较灌溉前土壤含水率增加7%～12.07%,达到作物生长需求;灌溉前,1 m内土壤盐渍化等级为中度盐渍化,灌溉后土壤盐渍化等级由中度盐渍化降为轻度盐渍化。综合考虑灌溉对土壤水盐含量的影响,确定780～990 m~3/hm~2的灌水定额既能有效地增加土壤含水率,又能减少土壤含盐量,为灌区理想的水盐调控灌水定额。     

非充分灌溉对地表双元覆盖黄瓜养分吸收的影响

在温室中,以地表双元覆盖条件下黄瓜为试材,探讨在常规灌水量80%、60%和40%的非充分灌溉条件下对黄瓜土壤和植株养分分布的影响。结果表明:在地表双元覆盖条件下,适度非充分灌溉提高非根际土壤全磷、全钾和根际土壤速效钾含量,同时,降低植株根和茎部氮含量,提高果实磷和茎部钾含量。在相对常规灌溉水量的80%条件下(每次灌溉量344m3/hm2)的处理效果较为明显,与对照相比,分别显著提高根际土壤全氮、非根际全磷和果实磷的含量11.36%、28.79%和19.21%,并提高果实氮含量14.86%和钾含量2.72%。     

Assessment of drip and flood irrigation on water and fertilizer use efficiencies for sugarbeets

Mismanagement of nitrogenous fertilizers has caused serious nitrate (NO₃) contamination in many flood-irrigated regions of the western US. Low-volume irrigation practices, such as drip irrigation, can offer an alternative approach for controlling NO₃ leaching and agricultural water use. The objectives of this study were to compare NO₃ movement through soils under flood and drip irrigation practices for sugarbeet production, and to evaluate the agronomic feasibility of implementing drip irrigation. A field experiment was conducted during the sugarbeet (Beta vulgaris L.) growing seasons of 1996 and 1997 in southeastern Wyoming, where NO₃ contamination is a continued concern and sugarbeet is a major cash crop. Three drip irrigation regimes, corresponding to 20, 35, and 50% water depletion of field capacity (designated as D1, D2, and D3, respectively), were compared against flood irrigation. The irrigation plots were treated with 112, 168, and 224 kg N ha⁻¹ (designated as F₀, F₁, and F₂, respectively). Sugarbeet (SB) yields and sugar contents under drip irrigation were higher (3–28%) than those with flood irrigation; yields and sugar contents for the drip systems were in the order of D1>D2>D3. For all of the irrigation applications, there was an increasing trend in yields with increasing fertilizer rates. Drip regime resulted in greater residual soil NO₃ (RSN) for both 1996 and 1997 seasons as compared to flood practices. Values of RSN in both years followed the trend: F₂>F₁>F₀. Soil NO₃ in all three drip regimes was higher (1.6–2.4 times) than that with flood irrigation. In the overall root zone, NO₃ concentrations between D1 and D2 were comparable, whereas both of those levels were lower than D3. Greater NO₃ concentrations with D3 were observed at all depths. The amount of applied irrigation water with the drip system was lower than that for flood irrigation. Agronomic water use efficiency (WUE) and fertilizer use efficiency (FUE) for drip irrigation were always higher than those for flood irrigation. In 1996, WUE and FUE maintained an order of D1>D2>D3. There was a decreasing pattern in FUE values with increasing fertilizer rates. The overall results indicated that SB production could be sustained with lower water and fertilizer use by using drip irrigation. The p-values (≤0.05), based on both F-test (p_f) and two-tailed student’s t-test (p_t), suggested a significant difference between the yield means obtained under drip and flood irrigation practices. As compared to the flood irrigation, the least p-values were obtained with D1 followed by D2 and D3, respectively, thus, confirming that D1 was the most effective treatment. The p-values for SB yields under comparative fertilizer treatments and same drip application showed no significant difference between the means, thus, suggesting the feasibility of using lower fertilizer rate while sustaining the targeted yield under drip irrigation. The comparative estimation of water losses by drainage between flood and drip irrigation suggested that the later practice reduced the quantity of water leaching beyond the root zone. Among the three drip treatments, the lowest drainage amount was observed with D1 as a result of its higher irrigation frequency and smaller quantity of water input during each application.     

矿区农田土壤重金属分布特征与污染风险研究

对渭北旱原矿区130个农田土壤样品的Cd、Cr、Cu、Pb、Zn含量进行了测定,结果显示,Cd、Cu、Pb平均含量均高于陕西省土壤背景值,而Cr和Zn含量低于背景值。利用地统计方法得到的土壤重金属含量分布图显示,土壤各重金属含量由西向东呈下降趋势,水泥厂周边土壤重金属含量最高。相关性分析和主成分分析结果表明,5种重金属之间呈极显著正相关,说明其存在较高的同源性或复合关系。第1主成分主要由Cd构成,且主要反映了人为活动的影响,而第2主成分中的Cr所占负荷最高,体现了成土母质的作用,Cu、Pb和Zn含量受人为活动和成土母质共同影响。分别利用污染负荷指数(PLI)法和潜在生态危害指数(PER)法对研究区域土壤污染风险进行了评价,评价结果为煤矿区呈无污染或轻微到中度污染,水泥厂区土壤呈中度污染水平,单一元素污染程度由高到低依次为Cd、Pb、Cu、Cr、Zn。     

蒸发和灌水频率对土壤中NO_3~-运移影响的研究

通过室内均质土柱试验,对不同灌水频率下有、无蒸发土壤中NO3-运移规律进行了研究。结果表明,有、无蒸发条件下土壤NO3-峰均随灌水频率增加而变陡、变窄,峰值增高,向下运移变缓;随灌水频率增加蒸发条件下溶质峰和溶质锋深度明显浅于无蒸发条件;蒸发量越大,灌水频率越高,有效淋洗水量越少;灌水间隔期蒸发与灌水淋洗共同决定着不同灌水频率土壤中溶质的运移和分布。     

对节水灌溉的再思考

华北地区农田灌溉的节水潜力问题,在“七五”期间对其研究过程中存在着两种截然不同的观点。一种观点认为灌溉水资源在地区内利用率已相当高,节水潜力有限,另一种观点认为由于灌区内的设施年久失修,灌溉输水过程中存在着严重的水量损失现象,且灌水定额控制不严,大水漫灌时有发生,因此农田灌溉节水大有潜力可挖。本文通过对节水潜力进行分析,初步提出了农田灌溉节水潜力的计算方法,指出了节水措施的有限性和制定节水灌溉措施规划的重要性。文章最后提出了当前急需认真研究的与此有关的几个问题,并就这些问题谈了自已的看法。     

A modified checkbook irrigation method based on GIS-coupled model for regional irrigation scheduling

In this study, a regional irrigation schedule optimization method was proposed and applied in Fengqiu County in the North China Plain, which often suffers serious soil water drainage and nitrogen (N) leaching problems caused by excessive irrigation. The irrigation scheduling method was established by integrating the ‘checkbook irrigation method’ into a GIS-coupled soil water and nitrogen management model (WNMM) as an extension. The soil water and crop information required by the checkbook method, and previously collected from field observations, was estimated by the WNMM. By replacing manually observed data with simulated data from WNMM, the application range of the checkbook method could be extended from field scale to regional scale. The WNMM and the checkbook irrigation method were both validated by field experiments in the study region. The irrigation experiment in fluvo–aquic soil showed that the checkbook method had excellent performance; soil water drainage and N leaching were reduced by 83.1 and 85.6%, respectively, when compared with local farmers’ flood irrigation. Using the validated WNMM, the performance of checkbook irrigation in an entire winter wheat and summer maize rotation was also validated: the average soil water drainage and N leaching in four types of soils decreased from 331 to 75 mm year⁻¹ and 47.7 to 9.3 kg ha⁻¹ year⁻¹, respectively; and average irrigation water use efficiency increased from 26.5 to 57.2 kg ha⁻¹ mm⁻¹. The regional irrigation schedule optimization method based on WNMM was applied in Fengqiu County. The results showed a good effect on saving irrigation water, decreasing soil water drainage and then saving agricultural inputs. In a typical meteorological year, it could save >110 mm of irrigation water on average, translating to >7.26 × 10⁷ m³ of agricultural water saved each year within the county. Annual soil water drainage was reduced to <143 mm and N leaching to <27 kg ha⁻¹ in most soils, all of which were significantly lower than local farmers’ flood irrigation. In the mean time, crop yield also had an average increase of 2,890 kg ha⁻¹ when checkbook irrigation was applied.     

Yield response of a semi-dwarf wheat variety to irrigation on a calcareous brown flood plain soil of Bangladesh

Field studies were conducted to determine the yield performance of a semi-dwarf high yielding variety of wheat (Triticum aestivum L., cv. ‘Sonalika’) in response to irrigation provided at various critical stages of growth. Determination of an irrigation schedule for most efficient water management was attempted. The study, conducted on a calcareous brown flood plain soil, comprised a randomized block design experiment with eight irrigation treatments applied at critical growth stages.The yield of wheat was the highest and the irrigation efficiency maximum, when two irrigations, totalling 9.5 cm, were given at tillering and booting stages. The quantity of irrigation water applied was calculated on the basis of deficit from field capacity level of soil water content. The lowest grain yields were obtained in treatments receiving either no irrigation or only one irrigation at the grain-filling stage. The percent increase over control (no irrigation) in grain yield, due to various irrigation treatments, ranged from 21 to 92%. The data revealed that the depletion of soil water increased as the amount of irrigation water increased.The results indicate that the present yield levels of wheat in Bangladesh can easily be increased by 50–100% by irrigating with only one-third to one-half of the water currently being used, provided it is scheduled and managed efficiently, keeping in view the need of the crops as well as the soils.     

保水材料对河套灌区土壤硝态氮和铵态氮动态变化的影响

为了研究内蒙古河套灌区农业化肥面源污染检测和治理措施,采用大田土壤淋溶试验,分析了河套灌区农田在保水材料处理下,玉米生育期内土壤硝态氮、铵态氮累积量及动态变化特征。结果表明,与CK相比,保水材料处理玉米苗期土壤NO_3~--N累积量平均提高20.49%,收获期平均降低13.98%;苗期土壤NH_4~+-N累积量平均提高35.21%,收获期平均降低28.93%。保水材料有效地抑制了氮素的淋溶损失,提高了氮素利用率,同时保证了玉米生育后期有效氮的供应,避免短时间内氮素的大量累积,在一定程度上减少了化肥面源污染,为农业面源污染治理提供有力措施。     

脱硫石膏淋洗次数对铵态氮迁移特征的影响

基于室内土柱穿透试验,设置4组试验处理:3组施加脱硫石膏,不同次数淋洗处理;1组无脱硫石膏无淋洗对照处理。通过分析NH+4、Ca2+、Na+3种离子相互关系及土壤水力传导度的变化情况,研究脱硫石膏及不同淋洗次数对碱土养分离子铵态氮迁移转化的影响。结果表明:碱土混合脱硫石膏后未经淋洗的情况下会抑制碱土对NH+4的吸附效果,但随着穿透前被淋洗次数的增加,NH+4在盐碱土中穿透曲线的斜率减小,吸附作用增强。从节水控盐、促进土壤肥力吸收、抑制土壤次生盐碱化的因素来看,根据试验结果推测铵肥不适合与脱硫石膏同时施加到碱土土壤中。建议在施肥前,拌施脱硫石膏的碱土宜采用秋浇与春灌相结合的方式,每次淋洗662.7 m3/hm2水量,这种淋洗方式在保证改良效果,促进肥料吸收的基础上,还可以适当减少秋浇灌水量,合理分配灌区有限的淡水资源。     

景电灌区利用回归水灌溉的潜力分析

景电灌区灌溉回归水指灌溉农业土壤深层渗滤水、农田尾水、渠道渗漏水、退水及少量的工业废水和城镇生活污水,年排量达1亿m3.针对灌区灌溉回归水的特点,分析回归水的水质、水量,研究其产生的负面影响,得出利用回归水灌溉的潜力.     

Drip irrigation water and salt flow model for table grapes in Coachella Valley,California

Unlike annual crops where reclamation leaching of salts can be readily conducted between cropping, leaching of salts in permanent crops that are drip irrigated pose challenges. A need exists to formulate and test a management-type of salinity model for drip irrigation of table grapes. The model reported herein predicts the distribution of salts along the vine row and between the rows during the growing season, as affected by reactivity of salts of the applied irrigation water as well as rate and duration of drip application. The calibrated model reproduced the initial field salinity profiles after repeated irrigation cycles by adjusting only the routing factor α which is the ratio of horizontal to vertical water flow. After eight cycles the profiles stabilized and the calibrated horizontal to vertical flow routing ratio was 0.6. There is remarkable agreement between measured and simulated salinity. Corresponding soil moisture profiles show the expected high water content with depth at the emitter, the decrease in surface water content with radial distance and the increase with depth, at the distal end of the wedge. Although the model is location specific it can be applied knowing soil, initial and boundary conditions, as well as irrigation application quantity and quality and as such can be applied location by location in order to assess flow and quality of deep percolation recharging the groundwater system. With this capacity the model can predict soil water quantity and quality outcomes for possible land and water management scenarios.