Influence of boundary plantation of poplar (Populus deltoides M.) on soil–water use and water use efficiency of wheat

Study was undertaken to assess the water use, moisture extraction and water use efficiency (WUE) of irrigated wheat, when grown in association with boundary plantation of poplar, at different distances (0–3, 3–6, 6–9, 9–12, 12–15 and >15 m (control)) from poplar (Populus deltoides M.) tree line. Presence of 3-year old poplar plantation at the boundary of wheat field caused 7.5% higher water use than control (plots having no effect of tree line) up to 3 m distance from tree line which further intensified up to 12.7% and extended up to 6 m distance with 4-year old plantation. Similarly, maximum moisture extraction, both laterally and vertically, observed near the tree line. Contrary to this, WUE of wheat was reduced by 4.6% between 0 and 3 m distance from tree line with 3-year old plantation, decline intensified further to 18.6% with 4-year old plantation. However, wheat was benefited by boundary plantation of trees between 3 and 9 m distance from the base of the tree line which resulted in increased WUE of the wheat crop up to 9%.     

1989年度水利部科学技术进步奖获奖成果题目汇编(续)

<正> (四)四等奖1.WDT—G型PID微机电液调速器 (吴应文、涂健和王永骥等)2.KD型大流量系列孔口滴头的研制 (张祖新、岳荣贵和王万欣等)3.巧溪水库灌区节水灌溉综合技术应用研究 (刘泰湖、王志浩和王盛庆等)     

Comparative Analysis of Comprehensive Water Quality Identification Index Method Based on Different Weighting Method北大核心CSCD

【Objective】In order to analyze the water quality distribution characteristics of each water quality monitoring section of Qingshui River in Ningxia, provide a basis for water quality assessment, based on three water quality section monitoring data on Qingshui River in Ningxia from 2014 to 2016. 【Method】Using the method of Principal Component Analysis to select the evaluate data and choose representative water quality indicators to issue Comprehensive Water Quality Identification Index evaluation and combined with 3 weighting methods to do further comparative analysis.【Result】The comprehensive water quality identification index show that the Ershilipu section water quality evaluation results for class II water and remained stable. The Sanying section evaluation results meet the class III water in 2014 and 2015 years, the evaluation results meet class IV water in 2016, It shows that the water quality of this section has a trend of decrease. The Quanyanshan section evaluation results for the class II water and reduced year by year, the water quality has become the trend of further good. 【Conclusion】The three section water quality evaluation using different weighting methods reached the water function zoning requirements, there were some defects in the Standard Multiple Method and the Entropy Weight Method, and the Variation Coefficient Method was more suitable than the other two weighting methods. © 2019 Office of Journal of Irrigation and Drainage, Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences. All rights reserved.     

1989年(第20卷)1至4期总目次

期数轮式拖拉机座位悬架系统动态参数的优化设计··················……马伟赵性黄礼彬利用模态技术及多自由度振动模型分析上海一50变速箱的动态响应······……葛屯宫镇轮胎动刚度特性的初步探讨·,······4································……彭超英喻谷源余群双风道贯流风机的试验研究·······“···~···……王成芝刘简周天培陶南施德芝径向进气风机流场的试验研究·······································……师清…     

Use of a covariance variogram to investigate influence of subsurface drainage on spatial variability of soil–water properties

Knowledge of the spatial variability of soil–water properties is of primary importance for management of agricultural lands. This study was conducted to examine which spatial structure measure, the semi-variogram or the covariance variogram, is appropriate for inference of the spatial structure and performing interpolation of soil–water properties from sample data sets. Using the appropriate spatial structure measure, the spatial variability of these properties (saturated hydraulic conductivity, water table depth, groundwater salinity, and soil salinity and sodicity) as affected by subsurface drainage is also evaluated. The soil–water properties were sampled before and after the installation of subsurface drainage on a regular square grid of 500 m at 61 locations within 1470 ha in the Nile Delta of Egypt. The results showed that the covariance variogram reveals the character of spatial structure and that it is more appropriate for interpolation than the semi-variogram. Subsurface drainage has highly affected the spatial variability of soil–water properties. On average, the spatial correlation range increased by approximately 29%, whereas the ratio of structural heterogeneity to the total variation (relative structured heterogeneity) was doubled 4 years after drainage installation. Moreover, the nugget effect increased and was present for all soil–water properties with noticeably high values. Uneven spatial distributions were also observed. Further study of long-term spatial variation of soil–water properties as affected by subsurface drainage is suggested.     

《排灌机械》1989年总目次(1—4期)

一渭﹃J 1.“J月.门丁日泥”........ 水泵技术 期水泵苏特坐标曲线非单一性的探讨·...·...························,·········……龚时宏1推导外混式自吸泵自吸性能的计算公式····································……陈茂庆1离心泵抽送固液混合物时的能量损失··················……〔西德〕K·Holxenbergl涡壳面积比原理讨论···············一妇······························1··~··…     

Tank performance and multiple uses in Tamil Nadu,South India–comparison of 2 time periods (1996–97 and 2009–10)

Irrigation tanks in India are common property resources. Tanks provide not only for irrigation, but also forestry, fishing, domestic water supply, livestock, and other uses. Using empirical results from a study of tank performance from 80 tanks in Tamil Nadu, South India in two time period: 1996-97 and 2009-10, this paper evaluates tank irrigation system performance in terms of economic output and revenue generation forirrigation and other uses. The results indicate that irrigation and other productive uses put together raised the total value of output at tank level by 12 % in 1996-97 and just 6 % in 2009-10. This may suggest that tank multiple use values are small and getting smaller, and therefore not worth consideration. However, it was also found that, while declining in absolute terms, non-irrigation uses provided the majority of tax revenues and still more than cover government's operation and maintenance expenditure (O&M) budget. This finding provides another reason to consider multiple use values and their linkage with overall system viability.     

Simulations on direct and cyclic use of saline waters for sustaining cotton–wheat in a semi-arid area of north-west India

A validated agro-hydrological model soil water atmosphere plant (SWAP) was applied to formulate guidelines for irrigation planning in cotton–wheat crop rotation using saline ground water as such and in alternation with canal water for sustainable crop production. Six ground water qualities (4, 6, 8, 10, 12 and 14 dS/m), four irrigation schedules with different irrigation depths (4, 6, 8 and 10  cm) and two soil types (sandy loam and loamy sand) were considered for each simulation. The impact of the each irrigation scenario on crop performance, and salinization/desalinisation processes occurring in the soil profile (0–2 m) was evaluated through Water Management Response Indicators (WMRIs). The criterion adopted for sustainable crop production was a minimum of pre-specified values of ET_rel (≥0.75 and ≥0.65 for wheat and cotton, respectively) at the end of the 5th year of simulation corresponding to minimum deep percolation loss of applied water. The extended simulation study revealed that it was possible to use the saline water upto 14 dS/m alternatively with canal water for cotton–wheat rotation in both sandy loam and loamy sand soils. In all situations pre-sown irrigation must be accomplished with canal water (0.3–0.4 dS/m). Also when the quality of ground water deteriorates beyond 10 dS/m, it was suggested to use groundwater for post-sown irrigations alternately with canal water. Generally, percolation losses increased with the increase in level of salinity of ground water to account for leaching and thus maintain a favourable salt balance in the root zone to achieve pre-specified values of ET_rel.     

《农田水利与小水电》1989年第1～12期要目(总第75期～86期)

·农田水利·聚苯乙烯板在渠道衬砌防冻害中的应用··············································,·············……董勤瑞I一(5)加强水利管理增强农业后劲······,·····,···························································……杨忍劳I一(9)芦秆暗管排水的经济效益分析·······················································…     

Wet soil volume and strategy effects on drip-irrigated olive trees (cv. ‘Arbequina’)

The effect on productive and vegetative behavior and on the quality of oil from Olea europaea L. when applying two distinct irrigation techniques, full irrigation (FI) and regulated deficit irrigation (RDI), was studied. A total of five wet soil volumes (WSVs, 12, 24, 35, 47 and 59%) expressed in terms of the potential root exploration volume were established for each strategy. The experiment was performed on cv. ‘Arbequina’ in an olive grove in Tarragona (Spain). Results obtained suggest that a 20% reduction in the irrigation dose (RDI) had no significant effect either on olive fruit and oil production or on oil content. Likewise, no significant increase in irrigation water-use efficiency was observed for FI with respect to RDI. A tendency for olive and oil production per hectare to increase with increased WSV percentage was observed, although there were no significant differences between FI and RDI except for 59% WSV in the RDI strategy, producing the best response.     

Soil–plant water status and yield of sweet corn (Zea mays L. cv. Saccharata) as influenced by drip irrigation and planting methods

A field experiment was conducted during summer season of 1998 at the Main Research Station, University of Agricultural Sciences, Hebbal, Bangalore. Experiment consisted of four irrigation levels and two methods of planting. Drip irrigation at 0.8 Epan with normal planting recorded significantly higher green cob (20.07 t ha⁻¹) and fodder yield (24.87 t ha⁻¹) compared to either drip at 0.6 Epan or weekly surface irrigation at 0.8 Epan, while drip at 0.4 Epan under paired planting (10.53 and 15.23 t ha⁻¹, respectively registered the lowest. Drip at 0.4 Epan with normal planting recorded higher WUE of green cob and fodder (48.21 and 61.22 kg ha mm⁻¹) with total water requirement of 330.46 mm. With increase in water use (drip at 0.6 Epan, drip/surface irrigation at 0.8 Epan) the water use efficiency decreased. Drip irrigation at 0.8 Epan resulted in higher leaf water potential (−4, −7, −8 bars) at 20, 40 and 60 DAS before irrigation. Consequently, the RWC in the leaf was 81.10% and the available soil moisture ranged from 55.62 to 61.91%.     

Using the DRAINMOD-N model to study effects of drainage system design and management on crop productivity,profitability and NO3–N losses in drainage water

The environmental impacts of agricultural drainage have become a critical issue. There is a need to design and manage drainage and related water table control systems to satisfy both crop production and water quality objectives. The model DRAINMOD-N was used to study long-term effects of drainage system design and management on crop production, profitability, and nitrogen losses in two poorly drained soils typical of eastern North Carolina (NC), USA. Simulations were conducted for a 20-yr period (1971–1990) of continuous corn production at Plymouth, NC. The design scenarios evaluated consisted of three drain depths (0.75, 1.0, and 1.25 m), ten drain spacings (10, 15, 20, 25, 30, 40, 50, 60, 80, and 100 m), and two surface conditions (0.5 and 2.5 cm depressional storage). The management treatments included conventional drainage, controlled drainage during the summer season and controlled drainage during both the summer and winter seasons. Maximum profits for both soils were predicted for a 1.25 m drain depth and poor surface drainage (2.5 cm depressional storage). The optimum spacings were 40 and 20 m for the Portsmouth and Tomotley soils, respectively. These systems however would not be optimum from the water quality perspective. If the water quality objective is of equal importance to the productivity objective, the drainage systems need to be designed and managed to reduce NO₃–N losses while still providing an acceptable profit from the crop. Simulated results showed NO₃–N losses can be substantially reduced by decreasing drain depth, improving surface drainage, and using controlled drainage. Within this context, NO₃–N losses can be reduced by providing only the minimum subsurface drainage intensity required for production, by designing drainage systems to fit soil properties, and by using controlled drainage during periods when maximum drainage is not needed for production. The simulation results have demonstrated the applicability of DRAINMOD-N for quantifying effects of drainage design and management combinations on profits from agricultural crops and on losses of NO₃–N to the environment for specific crop, soil and climatic conditions. Thus, the model can be used to guide design and management decisions for satisfying both productivity and environmental objectives and assessing the costs and benefits of alternative choices to each set of objectives.