覆土浅埋滴灌玉米分阶段亏水条件下AquaCrop与Dual Crop Coefficient模型精度对比研究

近年来,西辽河流域地下水超采问题日益突出,改进灌溉技术降低农业用水可有效解决这一问题,但该技术缺乏科学的水分管理方法及适宜的理论模型。基于单阶段及多阶段亏水情形试验,对比同类农田水分模型精度,优选阶段性亏水管理辅助模型。研究设置7个玉米分阶段亏水调控处理,于2018、2019年进行田间小区试验,取得2个同类模型的本地化参数并比较其模拟精度。结果表明,AquaCrop和双作物系数模型可相近表达玉米冠层发育到最大而未开始衰减期间土壤水分的消耗过程,而对快速生长期与后期1m土层贮水量的模拟差异大。AquaCrop模型在土壤贮水量偏低时高估其实测值,其他情形正负偏差分布相对均匀,双作物系数模型多数情形低估其实测值。AquaCrop模型描述玉米各阶段蒸散量因亏水情形而变化能力优于双作物系数模型。AquaCrop模型和双作物系数模型的标准均方根误差平均值在模拟1 m土层贮水量时分别为4.494%~8.443%、6.017%~8.626%,在模拟蒸散量时分别为8.158%~9.510%、5.980%~15.022%。综合来看,AquaCrop模型表现更好,推荐作为适宜西辽河流域覆土浅埋滴灌玉米水分管理模型。研究可为该区域覆土浅埋滴灌种植玉米选出适宜的水分管理模型,理解新技术条件下玉米分阶段亏水调控机制及田间灌溉管理优化提供参考。

Evaluation of Actual Evapotranspiration and Crop Coefficient in Carrot by Remote Sensing Methodology Using Drainage and River Water to Overcome Reduced Water Availability

Searching for alternative methods for traditional irrigation is World trend at days due to a reduction in water and increased of drought due to climate changes therefore farmers need use modern methods of scheduling water and minimizing water losses while also increasing yield. To meet the future increasing demands water and food there is a need to utilize alternative methods to reduce evaporation, transpiration and deep percolation of water. Any countries use recycled water (drain and sewage) and desalination water from the sea or drains to irrigate crops plus computing actual crop evapotranspiration (ETc) so as to calculate the amount of water to apply to a crop. The paper aims to assess the actual evaporation and evaporation coefficient of carrots, by planting carrots in a field and the crop was exposed to several sources of water (DW and RW) and comparing ETc, Kc and production among plots of three sites (A, B and C). The study used two types of irrigation water (drain water (DW) and river water (RW)). The results were to monthly rate and accumulated actual evapotranspiration to C (irrigation by RW only) more than A (67% RW and 33% DW) and B (17% RW and 83% DW) via 7% and 58%, respectively. The yield to C more than A and B by 17% and 75%, respectively. In conclusion the use of DW can cause a reduction in crop consumptive of carrot crops also causes a reduction in yield, crop length, root length, root size, canopy of crop, number of leaves and biomass of the plant therefore, the drainage water needs to treated before irrigating crops And making use of it to irrigate the fields and fill the shortfall in the amount of water from the river. The drain water helped on filling the water shortage due to climate changes and giving production of carrot crop but less than river water.

南方丘陵区油茶蒸散量SIMdualKc模型估算

为探究SIMdualKc模型在南方丘陵区油茶林地的适用性,利用2 a油茶的野外实测生长季数据,率定和验证了双作物系数SIMdualKc模型在南方丘陵区油茶林地的各参数。率定后作物系数K_(cbini)=0.9,Kcbmid=0.92,K_(cbend)=0.77,土壤含水率验证结果R^(2)为0.918~0.979,MAE为0.019~0.021,RMSE为0.021~0.026,EF为0.876~0.957。通过叶面积指数数据输入方式的模拟效果比较,得出日变化叶面积指数模拟效果稍好,确定了Logistic生长函数计算得到叶面积指数的可靠性与适用性,并校准了油茶在水分胁迫条件下土壤含水率的模拟值。油茶夏梢期末以及秋梢期容易产生水分胁迫影响,2021年水分胁迫系数K的范围为[0.478,1],2022年为[0.182,1]。将水量平衡法计算得到的蒸散量作为实测值与模拟值进行比较,两者具有良好的一致性,R^(2)为0.52~0.61。研究结果可为南方丘陵地区油茶林地针对夏秋季节易发生高温干旱的自然灾害制定高效节水的灌溉制度提供理论依据。

Difference between Responses of Potato Plant Height to Corrected FAO-56-recommended Crop Coefficient and Measured Crop Coefficient

This study was conducted to establish a simple convenient method for calculating crop coefficient, and provide a certain basis for the research of the empirical formula for calculating crop coefficient with plant height which could be measured conveniently with regional differences, especially for the establishment of accurate irrigation schedule of potato in Yunnan. By the field experiment on potato under the condition of drip irrigation, it was found that the models of plant height with corrected FAO-56-recommended K and measured K were a quartic polynomial and a cubic polynomial, respectively, and the polynomial of potato plant height with measured crop coefficient was simpler with higher degree of fitting; and the differences between the period with the highest change rate of potato plant height and the periods with the greatest FAO-56-recommended K and measured K exhibited a differences of 3 d. In conclusion： In the future study of simple or empirical formula calculation of crop coefficient, plant height should be considered as a main dependent variable in that the calculation result would be closer to the measured crop coefficient with the problem of regional difference existing in the FAO method solved and the formula might be simpler; and the irrigation time of potato should be 3 d earlier than the irrigation time determined according to the corrected FAO-56-recommended crop coefficient, especially in the key water requirement stages of potato.

Determining Crop and Pan Coefficients for Cauliflower and Red Cabbage Crops Under Cool Season Semiarid Climatic Conditions

The aim of this study was to estimate the evapotranspiration of cauliflower and red cabbage crops grown under cool season semiarid climatic conditions from Class A pan evaporation. Actual evapotranspiration （ETc） of cauliflower and red cabbage crops was calculated according to the water balance approach. Reference evapotranspiration （ETo） was calculated with FAO Penman-Monteith equation. Pan evaporation （Epan） was measured by using Class A pan. Seasonal ETc was determined as 475 mm for cauliflower and 556 nun for red cabbage. Seasonal pan coefficient （kp=ETo/Epan） was determined as 0.82, and the seasonal crop coefficient （kc=ETc/ETo） was determined as 0.84 for cauliflower and 0.83 for red cabbage. So the evapotranspiration of cauliflower and red cabbage crops was estimated as 70% Class A pan evaporation.

Evapotranspiration, Yield and Crop Coefficient of Irrigated Maize Under Straw Mulch

Maize (Zea mays L.), a staple crop grown from June to September during the rainy season on the North China Plain,is usually inter-planted in winter wheat (Triticum aestivum L.) fields about one week before harvesting of the winterwheat. In order to improve irrigation efficiency in this region of serious water shortage, field studies in 1999 and 2001, twodry seasons with less than average seasonal rainfall, were conducted with up to five irrigation applications to determineevapotranspiration, calculate the crop coefficient, and optimize the irrigation schedule with maize under mulch, as well asto establish the effects of irrigation timing and the number of applications on grain yield and water use efficiency (WUE)of maize. Results showed that with grain production at about 8 000 kg ha-1 the total evapotranspiration and WUE ofirrigated maize under mulch were about 380-400 mm and 2.0-2.2 kg m-3, respectively. Also in 2001 WUE of maizewith mulch for the treatment with three irrigations was 11.8% better than that without mulch. In the 1999 and 2001seasons, maize yield significantly improved (P = 0.05) with four irrigation applications, however, further increases werenot significant. At the same time there were no significant differences for WUE with two to four irrigation applications.In the 2001 season mulch lead to a decrease of 50 mm in the total soil evaporation, and the maize crop coefficient undermulch varied between 0.3-1.3 with a seasonal average of 1.0.

Estimating Crop Coefficient in Intermittent Irrigation Paddy Fields Using Excel Solver

The current study proposes a novel method using Excel Solver to estimate, from limited data, crop coefficient （Kc） in paddy fields under intermittent irrigation （11）. The proposed method was examined in a field experiment conducted at Karang Sari Village, Bekasi, West Java, Indonesia during the first rice season of 2007/2008 （December 2007 to April 2008） in the rainy season. As the control, continuous flooding irrigation （CF） was applied to the conventional rice cultivation fields. Based on the observed water storage, Excel Solver was used to estimate crop evapotranspiration. Estimated crop evapotranspiration was used to compute Kc value, then the average Kc values at each growth stage were compared with that for the CF treatment. The estimation method was evaluated by comparing estimated crop evapotranspiration and the crop evapotranspiration derived by the well established FAO procedure. Excel Solver estimated crop evapotranspiration accurately with R2 values higher than 0.81. Accordingly, more than 81% of the FAO crop evapotranspiration was described by the proposed method. Thus, Kc value could be well determined from those estimated crop evapotranspiration. Under the II treatment, the average Kc values were 0.70, 1.06, 1.24 and 1：22 for the initial, crop development, reproductive and late stages, respectively. These values were lower than those under the CF treatment for initial and crop development stages because of a minimal soil evaporation and intense dryness during these stages. However, average Kc values under the II treatment were higher than those under the CF treatment at the reproductive and late stages, indicating that the II treatment promoted more plant activity particularly for dry biomass production as indicated by a greater number of tillers per hill.

Water requirements and single and dual crop coefficients of sugarcane grown in a tropical region, Brazil

A field experiment was conducted throughout 2009/2010 in a sugarcane field of a commercial distillery located on the coastal area of Paraiba state, Brazil. The objectives were to determine sugarcane water requirements and to test the single and dual crop coefficients by comparing the calculated values of ET with measured ones. Crop evapotranspiration was determined by field water balance, reference evapotranspiration (ETo) by the Penman-Monteith approach, while single and dual crop coefficients were computed through the standard FAO-56 methodology. The experimental area was cultivated with irrigation applied weekly by a centre pivot system in addition to rainfall and the irrigation scheduling was based on 100% ETo. Three statistical tests, mean bias difference (MBD), normalized root mean square difference (NRMSD) and regression analysis, were used to evaluate the performance of single and dual crop coefficients. Results showed that there was a notable symmetry between ET measured and ET calculated by Kc dual. The ET values, calculated from Kc single, underestimated those obtained from soil water balance measurements by 36%.

Spectral Crop Coefficient Approach for Estimating Daily Crop Water Use

While the amount of water used by a crop can be measured using lysimeters or eddy covariance systems, it is more common to estimate this quantity based on weather data and crop-related factors. Among these approaches, the standard crop coefficient method has gained widespread use. A limitation of the standard crop coefficient approach is that it applies to “standard conditions” that are invariant from field to field. In this article, we describe a method for estimating daily crop water use (CWU) that is specific to individual fields. This method, the “spectral crop coefficient” approach, utilizes a crop coefficient numerically equivalent to the crop ground cover observed in a field using remote sensing. This “spectral crop coefficient” Ksp is multiplied by potential evapotranspiration determined from standard weather observations to estimate CWU. We present results from a study involving three farmers' fields in the Texas High Plains in which CWU estimated using the Ksp approach is compared to observed values obtained from eddy covariance measurements. Statistical analysis of the results suggests that the Ksp approach can produce reasonably accurate estimates of daily CWU under a variety of irrigation strategies from fully irrigated to dryland. These results suggest that the Ksp?approach could be effectively used in applications such as operational irrigation scheduling, where its field-specific nature could minimize over-irrigation and support water conservation.

Determination of Upland Rice Cultivar Coefficient Specific Parameters for DSSAT (Version 4.7)-CERES-Rice Crop Simulation Model and Evaluation of the Crop Model under Different Temperature Treatments conditions

To develop basis for strategic or arranged decision making towards crop yield improvement in Thailand, a new method in which crop models could be used is essential. Therefore, the objective of this study was to measure cultivar specific parameters by using DSSAT (v4.7) Cropping Simulation Model (CSM) with five upland rice genotypes namely Dawk Pa-yawm, Mai Tahk, Bow Leb Nahng, Dawk Kha 50 and Dawk Kahm. Experiment was laid out in a Completely Randomized Design (CRD) with split plot design. Results showed that five upland rice genotypes had significantly affected each other by different temperature treatments (28°C, 30°C, 32°C) with grain yield, tops weight, harvest index, flowering, and maturity date. At the same time, all the phenological traits had highly significant variation with the genotypes. The cultivar specific parameters obtained by using a temperature tolerant cultivar (Basmati 385) with five upland genotypes involved in the DSSAT4.7-CSM. Model evaluation results indicated that utilizing the estimated cultivar coefficient parameters, model simulated well with varying temperature treatments as indicated by the agreement index (d-statistic) closer to unity. Hence, it was estimated that model calibration and evaluation was realistic in the limits of test cropping seasons and that CSM fitted with cultivar specific parameters can be used in simulation studies for investigation, farm managing or decision making. This electronic document is a “live” template. The various components of your paper [title, text, heads, etc.] are already defined on the style sheet, as illustrated by the portions given in this document.

Seasonal variation of evapotranspiration,Priestley-Taylor coefficient and crop coefficient in diverse landscapes

Priestley-Taylor equation(PT)and the Penman-Monteith equation(PM)are commonly used methods for regional evapotranspiration monitoring,using the PT coefficient(α_(a))and PM crop/vegetation coefficient(K_(c)).This paper investigates the seasonal changes inα_(a)and K_(c)at five sites in Australia and China,to understand the relation-ship between environmental conditions and evapotranspiration when applying different evaporation estimation methods.The research shows that higher actual evapotranspiration does not lead to higherα_(a)and K_(c)values.α_(a)and K_(c)perform similarly in cropland and forest environments in both China and Australia.Bothα_(a)and K_(c)continuously increase to a peak during the growing season and then decrease to their lowest values during the winter season.Considering K_(c)’s similar performance toα_(a)and its greater data processing requirements,K_(c)has few advantages for estimating regional evapotranspiration.Applying the Priestley-Taylor equation with a regional𝛼indicator will enhance the accuracy and reduce the workload when estimating regional evapotranspiration for similar landcover types based on remote sensing.

拱架送/回风方式对日光温室冬季作物冠层区热环境的影响

传统日光温室被动的热环境调控模式难以满足温室作物冠层区空气温度和速度调控需求,且能源利用效率低下。为了改进日光温室热环境精准调控方法和提高温室能源利用效率,该研究结合日光温室围护结构特点,提出了一种日光温室拱架的送/回风方法,并基于温室作物多孔介质模型,建立了拱架送/回风系统温室的数值传热模型。采用空气温度与速度不均匀系数、气流速度适宜区面积比、能量利用系数以及累计有效积温等评价参数,研究了下送上回、中间回风和上送下回等3种温室拱架送/回风方式对日光温室冬季作物冠层区热环境的影响。结果表明,与中间回风和上送下回通风方式相比,下送上回通风方式对不同作物冠层高度处的空气温度和速度调控的结果最优,且不同作物冠层高度处气流速度适宜区面积比和累计有效积温都最大。当采用下送上回通风方式时,与送风干管风速为9、11和12 m/s相比,送风干管风速为10 m/s的能量利用系数最大,在作物冠层高度0.4、0.6、0.8和1.0 m处的能量利用系数分别为0.976、0.982、0.985和0.987,并且不同作物冠层高度处的空气温度不均匀系数和速度不均匀系数也都最小。因此,下送上回通风方式的推荐送风干管风速为10 m/s。该研究可为日光温室热环境的精准调控提供参考。

基于SIMDualKc模型估算非充分灌水条件下温室番茄蒸发蒸腾量

为了探讨SIMDual Kc模型在西北地区温室环境不同水分处理的适用性,以番茄为材料,于2013-2015年在陕西省杨凌区温室内进行亏水处理试验,设置全生育期充分灌水处理、仅发育期亏水50%处理、发育期中期连续亏水50%和全部亏水50%共4种水分处理,通过2013-2014年试验数据对SIMDual Kc模型进行率定,采用2014-2015年试验数据对模型进行验证,并通过模型将土壤蒸发量和番茄蒸腾量分开,利用模拟结果分析不同水分处理对土壤蒸发量和番茄蒸腾量的影响。结果表明:模型模拟不同水分处理蒸发蒸腾量与实测值有较好的一致性,其绝对误差为0.22~0.33 mm/d,均方根误差为0.26~0.48 mm/d、决定系数为0.51~0.81。该模型可以准确的将不同水分处理土壤蒸发量和作物蒸腾量分开,且土壤蒸发量模拟值与实测值有较好的一致性,其绝对误差为0.016~0.024 mm/d,均方根误差为0.013~0.034 mm/d和决定系数为0.63~0.84;通过模拟得到的番茄蒸腾量计算不同水分处理的水分亏缺系数,研究表明水分亏缺系数随亏水时间的增加而降低,复水后水分亏缺系数有不同程度的增加,且发育期、中期和后期连续亏水50%时,后期时水分亏缺系数降到最低,为0.63。因此该模型在西北地区温室环境下非充分灌溉条件下有一定的适用性。除此之外,研究通过模拟结果分析非充分灌水下番茄的响应及复水后的补偿机制,为非充分灌水条件下番茄栽培提供理论依据。

双作物系数模型SIMDual_Kc的验证及应用

为了将棵间蒸发与叶面蒸腾有效地分开,该文利用3 a冬小麦的田间实测数据(土壤含水率和实际腾发量),率定和验证双作物系数模型SIMDual_Kc在华北地区的适用性,并计算各生育阶段以及整个生育期冬小麦棵间蒸发量占作物腾发量比例。结果表明,模型模拟土壤含水率及实际腾发量的效果均比较好,拟合度较高。模型所模拟的棵间蒸发变化过程趋势明显,与作物生长阶段密切相关,整个生育期棵间蒸发量占作物腾发量比例在17%～22%左右变化,此模型在华北地区具有一定的适用性。

基于单作物系数法的温室秋季生菜蒸散量估算及验证

【目的】基于单作物系数法估算温室秋季生菜蒸散量。【方法】通过2021—2022年温室秋季生菜试验,根据各生育期影响因素修正FAO-56推荐作物系数值,即生育前期根据ET0值和灌溉频率修正,生育中期和生育后期根据气象因素和株高修正,并采用单作物系数法对温室生菜蒸散量进行估算,以称重式蒸渗仪实测蒸散量ETcm为标准值对蒸散量估算值ETcs进行验证。【结果】不同试验年度逐日ET0均呈逐渐降低变化趋势,介于1.18~2.44 mm/d。温室生菜作物系数修正值(Kc adj)和实测值(K_(c loc))均在生育前期最高,2 a均值分别为0.74±0.13和0.76±0.13;进入快速发育期后二者均呈降低趋势,并在生育中后期逐渐稳定在0.5~0.6。各生育阶段的Kc adj较FAO推荐值(Kc FAO)更接近实测值(K_(c loc)),Kc adj和K_(c loc)相对误差介于-6.7%~5.4%。应用修正单作物系数法估算温室秋季生菜ETcs与实测ETcm的日均值分别为1.310 mm/d和1.283 mm/d,决定系数(R^(2))、平均绝对误差(MAE)、均方根误差(RMSE)、一致性指数(d)分别为0.975、0.176 mm/d、0.222 mm/d、0.955。【结论】修正单作物系数法能够较为准确的估算温室秋季生菜蒸散量。

宁夏沿黄绿洲参考作物蒸散演变特征及其归因

参考作物蒸散(Reference crop evapotranspiration,ET_(0))是生态水文过程中的关键因子,研究ET_(0)在干旱绿洲区的演变,不仅有助于理解气候变化背景下的绿洲水文过程响应,亦对绿洲水土资源高效配置和生态系统稳定性维持有指导意义。以宁夏沿黄绿洲为例,基于1960—2019年的气象资料和Penman-Monteith模型计算ET_(0),利用Mann-kendall突变检验、相对敏感系数和Morlet小波分析等方法,对宁夏沿黄绿洲近60 a的ET_(0)演变特征及其归因进行研究。结果表明:(1)宁夏沿黄绿洲ET_(0)年内呈单峰形态,ET_(0)在5—7月间较高,累积ET_(0)占年总ET_(0)的43.6%;近60 a的ET_(0)年均值为1226.38 mm,并以1.66 mm/a(P<0.01)幅度上升,但年际波动特征明显,其中在1988年突变之前,ET_(0)无显著变化趋势,而突变之后则以每10 a左右的周期显著增加或降低。(2)年ET_(0)主要以20—40 a和50—60 a周期振荡,且有多重时间尺度的复杂嵌套现象,不同季节的周期振荡差异较大,夏、秋季振荡幅度较强,其周期接近于年ET_(0)规律,而冬、春季振荡幅度较弱。(3)虽然ET_(0)与6种气象因子均存在显著相关性,但ET_(0)对不同气象因子的敏感性存在差异,其中对最高温度和相对湿度的敏感性较高,敏感系数分别为11.58%和8.40%。(4)宁夏沿黄绿洲ET_(0)与区域气候变化特征有较强的耦合性,区域气候的持续升温和相对湿度持续降低、以及由此引发的饱和水汽压亏缺持续增强是推动ET_(0)上升的重要原因,而气候由湿润向干旱的突变和平均风速的异常波动是诱发ET_(0)突变的原因。

海东市平安区土壤与农作物Se含量分布特征

为探究青海省海东市平安区的土壤及农作物的硒含量及富集特征,系统地采集分析了平安区七个乡镇152份0~50 cm深度土壤样品及1161份植物样品,采用氢化物-原子荧光光谱法测定土壤及作物硒含量。结果表明,平安区表层硒含量平均值为0.27 mg/kg,高于全国及世界土壤硒平均值,有75.36%的地区处于适量硒状态,且三合镇的土壤硒含量最高,古城乡最低,总体上各乡镇采集的0~10 cm、10~20 cm、20~30 cm、30~50 cm土层之间的硒含量差异不显著,但随土壤深度的增加,硒含量逐渐降低。在几种作物中,油菜的平均硒含量最高,达到富硒标准,小麦、玉米、豌豆、燕麦、马铃薯硒含量平均值均达到足硒标准,青稞和蚕豆在土壤硒含量较高的三合镇达到足硒标准以上。综合分析,土壤硒含量与相应的作物籽粒硒含量呈正相关,油菜、小麦、玉米硒的富集系数较高,对硒具有良好的吸收能力,因此适宜在相应的富硒地发展富硒农产品,豌豆、蚕豆、燕麦、青稞属于中等富硒作物,马铃薯的富集系数最小而变异系数最高,适合在硒含量较高的地方种植马铃薯。

基于不同滴灌定额的压砂瓜需水规律

在田间试验条件下,采用随机区组设计,灌溉定额设置4个处理:高水600 m^(3)/hm^(2)(A1)、中水450 m^(3)/hm^(2)(A2)、中水300 m^(3)/hm^(2)(A3)、低水150 m^(3)/hm^(2)(A4)和1个不灌水对照(CK),研究不同灌溉定额下压砂瓜田间土壤含水率、作物系数、产量、水分利用效率和需水规律。结果表明,压砂瓜随着灌溉定额的增加,土壤含水率、耗水量和产量均增加。0~40 cm土层土壤含水率在A1处理下最高,CK最低,对比不同土层土壤含水率变化,0~10 cm波动最明显,10~20 cm和20~30 cm波动次之,30~40 cm波动最小;不同处理各生育阶段耗水量表现为果实膨大期>开花坐果期>伸蔓期>苗期>成熟期,日耗水量表现为开花坐果期>果实膨大期>伸蔓期>苗期>成熟期;各生育阶段作物系数表现为开花坐果期>果实膨大期>伸蔓期>苗期>成熟期。水分利用效率在一定范围内随灌溉定额增加而增大,但灌溉量过高,水分利用效率反而会降低。中水处理A2水分利用效率最高,水资源被充分利用。兼顾节水、水分利用效率、经济价值三方面综合考虑,中水处理A2(450 m^(3)/hm^(2))为最适宜的灌溉定额。

水足迹视角下黄土丘陵区农业水土资源匹配格局——以山西省和顺县为例

从水足迹视角出发,运用CROPWAT及标准差椭圆模型分析2010—2019年山西省和顺县乡镇域主要农作物生产水足迹和耕地面积的时空变化,运用基尼系数及空间失配指数深入研究2010年、2014年、2019年乡镇域农业水土资源时空匹配格局,并明确调控方向。结果表明,研究期间,和顺县作物生产水足迹、蓝水足迹、绿水足迹和耕地面积总体上均呈下降趋势;绿水足迹对各区域作物生产水足迹的构成贡献最大,占比均超过62.0%;和顺县西部地区作物生产水足迹和耕地的空间聚集性不断增强;和顺县作物生产水足迹、蓝水足迹、绿水足迹与耕地之间的空间失配均逐渐加剧,中部和东部地区农业水土资源分别为中度失配和重度失配,是和顺县未来农业水土资源调控的重点地区;可以将县域10个乡镇分别划分为水源涵养调蓄、水土优化调控与引水节水灌溉3个调控区。总的来说,受社会经济、生产要素投入和气候条件的影响,和顺县农业水土资源匹配协调水平处于失衡状态,但在调控区划分的基础上,有针对性地进行人工调控,仍可实现农业水土资源匹配协调水平的较大提升。

基于结构方程模型下滇中鲜食玉米耗水规律及其影响因素研究

旨在深入了解滇中高原地区鲜食玉米的生育期耗水量与规律,明确耗水量与其影响因素之间的关系,为鲜食玉米的推广种植和灌溉管理提供科学支持。进行了为期2年的鲜食玉米田间灌溉试验,参考农民种植经验管理试验小区,安装了自动气象站和土壤墒情自动观测设备,用于采集土壤墒情和气象数据。分析了鲜食玉米全生育期土壤水分动态、日耗水量和作物系数,同时研究了气象、土壤和作物因素对耗水量的影响。发现鲜食玉米在10~30 cm土层水分变化较大,生长后期根系吸水最深可达40 cm土层。2022—2023年鲜食玉米生育期耗水量分别为182.32 mm和175.84 mm,平均耗水强度分别为2.40 mm/d和2.31 mm/d。耗水量及强度在不同年份和生育阶段表现不同,2022年,由大到小表现为灌浆乳熟期>苗期>拔节期>抽雄吐丝期,而在2023年表现为抽雄吐丝期>灌浆乳熟期>拔节期>苗期。两年鲜食玉米全生育期Kc平均值分别为0.65和0.44,变化趋势随作物生长发育逐渐增大,在灌浆乳熟期达到峰值;土壤因素和气象因素对鲜食玉米耗水量存在路径系数为0.38、0.34的正相关关系,而鲜食玉米耗水量与作物生长特性存在路径系数-0.46的负相关关系。鲜食玉米耗水量较小,且受土壤和气象因素影像较大,本次研究结果为滇中地区鲜食玉米的灌溉定额和灌溉管理提供了科学依据。