Irrigation Patterns Research Articles

Effect of Different Irrigation Patterns on Fish Assemblages in Agricultural Canals

Effect of Different Irrigation Patterns on Fish Assemblages in Agricultural Canals

Liquid–solid mass transfer in a tubular reactor with solid foam packings

Catalytically active open-cell solid foam packings are promising replacements for conventional randomly packed catalyst particles due to their low pressure drop and high specific surface area. The liquid–solid mass transfer was studied with a modified electrochemical limiting diffusion current method for different packings and flow rates. The effective liquid–solid mass transfer coefficients (ϕkLS) were determined at two different axial packing positions. In particular, the effects of gas and liquid superficial velocities and the pre-wetting modes of the packing (LEVEC and KAN-LIQUID) were researched. The results reveal that higher liquid superficial velocity increases the liquid–solid mass transfer, while increasing foam pore density lowers the mass transfer rate. The strong multiplicity behavior known from the hydrodynamic study of Mohammed et al. (2013) was not obtained for the liquid–solid mass transfer. However, the type of liquid distributor providing the initial irrigation pattern had a significant effect on the effective liquid–solid mass transfer coefficient. A new correlation is proposed to predict the effective liquid–solid mass transfer coefficient.

New model for sustainable management of pressurized irrigation networks. Application to Bembézar MD irrigation district (Spain)

Pressurized irrigation networks require large amounts of energy for their operation which are linked to significant greenhouse gas (GHG) emissions. In recent years, several management strategies have been developed to reduce energy consumption in the agricultural sector. One strategy is the reduction of the water supplied for irrigation but implies a reduction in crop yields and farmer's profits.In this work, a new methodology is developed for sustainable management of irrigation networks considering environmental and economic criteria. The multiobjective non-dominated Sorting Genetic Algorithm (NSGA II) has been selected to obtain the optimum irrigation pattern that would reduce GHG emissions and increase profits. This methodology has been applied to Bembézar Margen Derecha (BMD) irrigation district (Spain).Irrigation patterns that reduce GHG emissions or increase actual profits are obtained. The best irritation pattern reduces the current GHG emissions in 8.56% with increases the actual profits in 14.56%. Thus, these results confirm that simultaneous improvements in environmental and economic factors are possible.

IB-ICCMSP: An Integrated Irrigation Water Optimal Allocation and Planning Model Based on Inventory Theory under Uncertainty

In this study, an inventory-theory-based inexact chance-constrained multi-stage stochastic programming (IB-ICCMSP) model under multi-uncertainties is developed. IB-ICCMSP integrates inventory theory into an inexact chance-constrained multi-stage stochastic optimization framework. This method can not only effectively address system multiple uncertainties (e.g. discrete intervals and probability density functions) and dynamic features, but also provide water transferring and allocating schemes among multiple stages. The developed model is applied to irrigation water allocation optimization system in Zhangye City, Gansu province, China. Based on the runoff simulation prediction of Yingluo Gorge and water supply–demand balance analysis of the 12 irrigation areas in Zhangye City, different optimal irrigation water measures are generated under different flow levels and different probabilities in the planning year. The obtained results are valuable for supporting the adjustment of the existing irrigation patterns and identifying desired water-allocation plans for irrigation under multi-uncertainties.

EFFECT OF RIDGE SPACING AND IRRIGATION PATTERNS ON GROWTH, GRAIN YIELD, YIELD COMPONENTS, AND WATER PRODUCTIVITY FOR MAIZE CROP

A Field trial was conducted in Gemmeiza Agricultural Research Station (Middle Nile Delta, Egypt) in 2011and 2012 to study the effect of four irrigation patterns under two ridge spacing on maize growth, grain yield, yield components, saving of applied irrigation water, and water productivity(WP). The assessed irrigation patterns were: 1) Control where all of furrows were irrigated (ALL), 2) irrigating via every other furrow starting at the 3rd irrigation (EOF3), 3) irrigation via every other furrow technique starting from the 4th irrigation (EOF4), and 4) irrigating with every other furrow starting from the 5th irrigation (EOF5). Irrigation patterns were evaluated under two ridge spacing (70 and 80 cm). The experimental design was randomized complete block arranged in incomplete block design, where replications were nested within ridge spacing and irrigation pattern treatments were randomly arranged within ridge spacing treatments. The most important findings could be as follows:- *Under 80-cm ridge spacing both days to 50% tasseling and 50% silking were significantly decreased, but 70-cm ridge spacing reduced ear height, and ear position (%). * Ridge spacing did not significantly affect plant height, grain yield, number of kernels per row, ear length, ear diameter, kernel depth, and 100-kernel weight. However, 80-cm ridge spacing was associated with higher ear length, ear diameter, kernel depth, and 100-kernel weight. *Irrigation pattern (EOF3) had significantly higher days to 50% tasseling than the control (ALL). Treatment EOF4 had the highest plant height. The lowest plant height was linked to EOF5 treatment but the highest ear height and ear position resulted from application of EOF3. *Grain yield was not significantly affected by irrigation patterns. Irrigation patterns EOF4 and EOF5 were associated with the lowest number of kernels per row. * Effect of ridge spacing x irrigation pattern Interaction was significant for plant height, ear height and kernel depth. *Applied irrigation water decreased, while water productivity increased under 80-cm comparing with 70-cm ridge spacing. The highest value of applied water was recorded for (ALL) irrigation pattern treatment with 70-cm ridge spacing. Application of EOF3, EOF4, and EOF5 patterns reduced applied irrigation water and improved water productivity. *The highest WP was recorded under the interaction of planting maize crop in 80-cm ridge spacing with EOF3 and EOF4 irrigation patterns. Saving irrigation water was higher at EOF3 followed by EOF4, then EOF5. This study strongly suggest applying every other furrow irrigation technique starting from the 3rd irrigation (EOF3) with planting maize crop on 80-cm ridge spacing to save more irrigation water without concomitant reduction in grain yield.

Economic impacts on irrigated agriculture of water conservation programs in drought

The need to adapt irrigation patterns to water shortages in the world’s dry regions continues to inspire economically attractive measures to sustain food security and improve farm incomes. Ongoing evidence of climate variability and growing populations amplify the importance of this search. Motivated by recent severe drought in the southwestern United States, this study analyzes vulnerability, impacts, and adaptability by irrigation technology in a sub-basin of North America’s Rio Grande. The study accounts for economic incentives affecting choices on irrigation technology, crop mix, and water source in the face of water conservation subsidies under various levels of surface water shortage. Findings show that when surface water supplies are reduced, farmers shift to aquifer pumping even when pumping raises the cost of production or reduces yield. An important on-farm drought adaptation mechanism comes by converting from surface irrigation to water conserving irrigation technologies when faced with lower financial costs for conversion. Public subsidies to convert from flood to drip irrigation offset many of the negative impacts of drought on farm income. These subsidies also raise the value of food production, reduce the amount of water applied to crops, but can increase crop water depletions. Our approach for analyzing drought adaptation impacts and adjustment mechanisms can be applied where water shortages loom, food security is important, and water conservation policies are under debate. Results provide insights for the design of adaptation mechanisms for the world’s dry regions for which policymakers need to reduce economic damages from future climate variability and change.

Multiscale spectral analysis of temporal variability in evapotranspiration over irrigated cropland in an arid region

The temporal patterns of evapotranspiration (ET) and its biophysical and physiological controls (e.g., soil water content, solar radiation, and canopy conductance) occur over a wide range of time-scales ranging from seconds to decades. Thus, there is increasing interest in understanding at which scales the main temporal correlations between ET and its controlling factors occur across different ecosystems. For this study, we used eddy covariance measurements of ET over 2 years at an irrigated maize field in an arid inland region of northwest China. We applied the wavelet transform as a novel technique to examine spectral characteristics of ET and its controlling factors. The ET power spectra displayed a −1 power law in turbulent inertial subrange at <1-h time-scale, and showed substantial power at daily, seasonal and annual time-scales. The cospectra of ET and soil water content (SWC) showed significant temporal correlation at 5-days, which has implications for calculation of ET using the soil water balance method in this region. We found that ET synchronized with the change of net radiation, and led vapor pressure deficit and air temperature for ∼2h at the 1-day time-scale (i.e., positive lags), but the phase relationship between ET and SWC was influenced by irrigation patterns. Canopy conductance influenced ET variability at the 1-day time-scale, but the effect was not consistent across the growing seasons. Our results show the importance of irrigation practices and its influence on the multi-temporal correlations of ET and its controlling factors. Irrigation can sharply change the phase angle relationship of ET and SWC from −10h to 10h. These results are important for understanding water cycle processes, improving water management, and address food security issues across irrigated croplands in arid regions.

A multistage irrigation water allocation model for agricultural land-use planning under uncertainty

In practical agricultural water management problems, fluctuating water availabilities and demands, varying crop yields and economic profits, as well as changing irrigation patterns in both temporal and spatial scales are challenged decision makers. These challenges are being further compounded by rapid socioeconomic development associated with increased food requirement and decreased resources accessibility. A multistage irrigation water allocation (MIWA) model is developed for agricultural water management and cropland use planning in response to such complexities. The MIWA model is derived from incorporating interval parameters within a multistage stochastic programming (MSP) framework, such that uncertainties expressed as interval parameters and probability distributions can be tackled, and the real-time dynamic irrigation water management can be conducted. It can also support the analysis of various policy scenarios that are associated with different levels of economic consequences when the pre-regulated crop targets are violated over a multistage context. The MIWA model is then applied to a real case of planning agricultural water management and cropland use pattern in Zhangweinan River Basin, which is one of the driest regions in China and faces serious water scarcity. Solutions of irrigation targets for multiple crops as well as actual water-allocation patterns in different growth stages can help determine optimized water and land use in agricultural system, which could hedge appropriately against future available water levels in more profitable and sustainable ways.

Entropy Coefficient Assessment of Mulch Drip Irrigation Scheme in Tobacco Fields

In order to find the optimum mulch drip irrigation scheme in tobacco fields of southern China plain, the flue-cured tobaccos were treated with different water and nitrogen levels, the yield, WPc, and the economic benefits (EIRR, ENPV, EBCR) were calculated, then the PCA model and the entropy weight coefficient method were introduced in order to select the preferable pattern of mulch drip irrigation. Results showed that: the application of mulch drip irrigation obtained the predicted effects, which improved the yield of flue-cured tobaccos and achieved satisfactory economic benefits; the entropy weight method was appropriate for the comprehensive evaluation of the mulch drip irrigation scheme in tobacco fields of southern China, which could combine the objective weight with the subjective weight, reducing the arbitrariness of using only objective weight or only the subjective weight; the optimum mulch drip irrigation treatment was T5, with the entropy weight value of 0.921; followed by T9; T2 was the poorest. Therefore, drip irrigation with 12mm, 16mm, and 12mm each time during root-extending stage, vigorous stage and maturity stage, and N fertilizer amount with 83.3kg/hm2could be applied as the water-nitrogen scheme, serving for the production of tobaccos with good quality and high yield under mulch drip irrigation construction in southern China plain.

The Economic Size of The Irrigated Agricultural Tenure Planted With Vegetables in The Southern Jordan Valley / Jordan

The aim of this study was mainly to economic analysis and descriptive standard functions vegetable production under style drip irrigation, and under typical protected cultivation and exposed in the southern Jordan Valley, and determine the volumes achieved economic efficiency and maximize the profit and the extent of justice in the distribution of agricultural tenure and the degree of fragmentation of these tenure. The primary data collection through personal field interview with farmers. Divided tenure agriculture by Pattern of agriculture and the method of irrigation into two groups, group crop vegetative planted exposed were irrigated drip and a crop vegetative protected cultivation been irrigated drip, and results showed the economic analysis descriptive The most important crops which recorded the highest net returns melon (434.9) dinars, and beans (318.6) JD / donum and eggplant record lowest rate of net returns by (15.11) dinars/ donum in the pattern of agriculture convertibles and style drip irrigation while the cucumber recorded highest rate of net return (700.2) JD / donum in the pattern of protected cultivation and drip irrigation. Using the measurement model economic Multiple cost function shows that the areas that ensure economic efficiency away from the average area of ​​agricultural holdings present in the study area and adult (20) without much (-35.6) donum as away areas property that ensures achieving maximization profit for this rate by (-47) donum, in the pattern of cultivation of a crop that was planted was exposed drip irrigated. either in the pattern of protected agriculture and the use of drip irrigation, the area property to ensure economic efficiency away from this rate by (9) donum, property also turned away an area that guarantee achieving maximization Profit (3) donum, ranging degree of fragmentation of agricultural holdings irrigated in the study area between (0.009-0.02) In addition to the apparent deviation from the baseline level of justice by (0.64), and the high proportion of multiple pieces tenure and low area per possession . The study recommended directing farmers about agricultural cooperative work, and the establishment of a company to market agricultural production and facilitate the consolidation procedures smallholder through swap between farmers, and the development of national guidance programs for the introduction of modern technologies in production, such as protected cultivation and use of drip irrigation technology .

Role of Irrigation Patterns in Reducing Harms of High Temperature to Rice

Possible irrigation patterns to reduce the injury of high temperature to rice growth and development were studied using two mid-season indica cultivars of Huanghuazhan and Shuanggui 1.Both high temperature(mean temperature during the day/night at 35.1℃/20.8℃) and normal temperature(mean temperature during the day/night at 29.0℃/20.8℃) treatments and three irrigation patterns,including alternate wetting and moderate soil drying(MD,plants were re-watered when soil water poten-tial reached to 15 kPa),alternate wetting and severe soil drying(SD,plants were re-watered when soil water potential reached to 30 kPa),and well-watered(control,continuously flooded),were conducted during heading and grain filling.The grain yield and quality of rice were investigated.The results showed that under either normal or high temperature,compared with the control,the MD significantly increased seed-setting rate,1000-grain weight,grain yield,brown rice,milled rice and head rice,and reduced chalky grains and chalkiness degree.The MD also increased the break down viscosity and decreased the setback viscosity.The SD showed the opposite effects.The two cultivars behaved the same.These results indicated that the MD may maintain a higher grain yield and better quality of rice under high temperature.The reduction of relative humidity in the panicle canopy,decreased reac-tive oxygen(O2?) production rate,elevated contents of ascorbic acid,reduced glutathione,and increased concentrations of cyto-kinins in leaves and spermidine and spermine in grains are the ecological and physiological reasons for reducing harms of high temperature to rice by the MD regime.

Water and fertilizer use efficiency of potato under different irrigation patterns in North Yin Mountain Region

为明确内蒙古阴山北麓马铃薯主产区不同灌溉模式对水肥利用效率以及土壤无机氮残留的影响, 2009-2010年进行了漫灌(农民习惯)、喷灌、露地滴灌、膜下滴灌4种灌溉模式对比研究, 分析了不同灌溉模式对马铃薯产量形成、水分利用效率、养分偏生产力、经济净收益以及土壤无机氮残留的影响。结果表明: 膜下滴灌马铃薯的产量、水分利用效率、氮磷钾肥料的偏生产力以及经济净收益均显著高于其他3种灌溉模式。其中, 膜下滴灌的马铃薯产量分别比漫灌、喷灌和露地滴灌增加35.7%、26.0%、12.9%, 水分利用效率和经济净收益分别增加200.2%、91.8%、23.7%和37.7%、30.1%、10.7%; 氮肥偏生产力膜下滴灌比漫灌、喷灌和露地滴灌分别增加50.6 kg·kg^-1、39.8 kg·kg^-1、22.0 kg·kg^-1, 磷肥偏生产力分别增加126.6 kg·kg^-1、99.4 kg·kg 1、55.0 kg·kg^-1, 钾肥偏生产力分别增加42.3 kg·kg^-1、33.2 kg·kg^-1、18.4 kg·kg^-1。漫灌马铃薯收获后60~120 cm土层无机氮残留量达102.95 kg·hm^-2, 分别是喷灌、露地滴灌和膜下滴灌的1.36倍、2.11倍和2.28倍。由此可见, 露地滴灌和膜下滴灌不仅节水, 且马铃薯高产、养分资源和经济高效, 可显著减少薯田氮素淋洗, 从而降低环境污染的风险。

Effects of Drip Irrigation Patterns on Wheat Yield and Water Use Efficiency in Heilonggang Region

A field experiment with different drip irrigation patterns was conducted in Heilonggang region,Hebei Province,China in the 2010–2011 and 2011–2012 winter wheat growing seasons to develop suitable drip irrigation schedule in this region.The yields and water use efficiencies(WUE) of wheat in different drip irrigation treatments with flood irrigation as control were compared under total water supplies of 225,180,150,and 120 mm,respectively.Under the condition of 225 mm irrigation,drip irrigation and irrigation frequency(1–3 times) had no significant difference in effect on yield and WUE.Drip irrigation resulted in 45–105 mm reduction of irrigation amount as compared to the control,with no significant yield loss,and a significant increase of WUE.Correlation analysis indicated that the contribution of yield components showed a sequence of spike number1000-grain weightgrain number per spike.These results showed that drip irrigation technique should have potentials of water saving and yield stability in wheat production of the experimental region.

Estimating soil wetting patterns for drip irrigation using genetic programming

Drip irrigation is considered as one of the most efficient irrigation systems. Knowledge of the soil wetted perimeter arising from infiltration of water from drippers is important in the design and management of efficient irrigation systems. To this aim, numerical models can represent a powerful tool to analyze the evolution of the wetting pattern during irrigation, in order to explore drip irrigation management strategies, to set up the duration of irrigation, and finally to optimize water use efficiency. This paper examines the potential of genetic programming (GP) in simulating wetting patterns of drip irrigation. First by considering 12 different soil textures of USDA–SCS soil texture triangle, different emitter discharge and duration of irrigation, soil wetting patterns have been simulated by using HYDRUS 2D software. Then using the calculated values of depth and radius of wetting pattern as target outputs, two different GP models have been considered. Finally, the capability of GP for simulating wetting patterns was analyzed using some values of data set that were not used in training. Results showed that the GP method had good agreement with results of HYDRUS 2D software in the case of considering full set of operators with R2 of 0.99 and 0.99 and root mean squared error of 2.88 and 4.94 in estimation of radius and depth of wetting patterns, respectively. Also, field experimental results in a sandy loam soil with emitter discharge of 4 L h-1 showed reasonable agreement with GP results. As a conclusion, the results of the study demonstrate the usefulness of the GP method for estimating wetting patterns of drip irrigation.

Effects of Irrigation Patterns and Nitrogen Fertilization on Rice Yield and Microbial Community Structure in Paddy Soil

Water and nitrogen (N) are considered the most important factors affecting rice production and play vital roles in regulating soil microbial biomass, activity, and community. The effects of irrigation patterns and N fertilizer levels on the soil microbial community structure and yield of paddy rice were investigated in a pot experiment. The experiment was designed with four N levels of 0 (N0), 126 (N1), 157.5 (N2), and 210 kg N ha−1 (N3) under two irrigation patterns of continuous water-logging irrigation (WLI) and water-controlled irrigation (WCI). Phospholipid fatty acid (PLFA) analysis was conducted to track the dynamics of soil microbial communities at tillering, grain-filling, and maturity stages. The results showed that the maximums of grain yield, above-ground biomass, and total N uptake were all obtained in the N2 treatment under WCI. Similar variations in total PLFAs, as well as bacterial and fungal PLFAs, were found, with an increase from the tillering to the grain-filling stage and a decrease at the maturity stage except for actinomycetic PLFAs, which decreased continuously from the tillering to the maturity stage. A shift in composition of the microbial community at different stages of the plant growth was indicated by principal component analysis (PCA), in which the samples at the vegetative stage (tillering stage) were separated from those at the reproductive stage (grain-filling and maturity stages). Soil microbial biomass, measured as total PLFAs, was significantly higher under WCI than that under WLI mainly at the grain-filling stage, whereas the fungal PLFAs detected under WCI were significantly higher than those under WLI at the tillering, grain-filling, and maturity stages. The application of N fertilizer also significantly increased soil microbial biomass and the main microbial groups both under WLI and WCI conditions. The proper combination of irrigation management and N fertilizer level in this study was the N2 (157.5 kg N ha−1) treatment under the water-controlled irrigation pattern.

Risk assessment of agricultural irrigation water under interval functions

In recent years, water shortages and unreliable water supplies have been considered as major barriers to agricultural irrigation water management in China, which are threatening human health, impairing prospects for agriculture and jeopardizing survival of ecosystems. Therefore, effective and efficient risk assessment of agricultural irrigation water management is desired. In this study, an inexact full-infinite two-stage stochastic programming (IFTSP) method is developed. It incorporates the concepts of interval-parameter programming and full-infinite programming within a two-stage stochastic programming framework. IFTSP can explicitly address uncertainties presented as crisp intervals, probability distributions and functional intervals. The developed model is then applied to Zhangweinan river basin for demonstrating its applicability. Results from the case study indicate that compromise solutions have been obtained. They provide the desired agricultural irrigation water-supply schemes, which are related to a variety of tradeoffs between conflicting economic benefits and associated penalties attributed to the violation of predefined policies. The solutions can be used for generating decision alternatives and thus help decision makers to identify desired agricultural irrigation targets with maximized system benefit and minimized system-failure risk. Decision makers can adjust the existing agricultural irrigation patterns, and coordinate the conflict interactions among economic benefit, system efficiency, and agricultural irrigation under uncertainty.

Effect of planting pattern and drought stress on amylase content in rice grain

In order to determine the effects of planting pattern and drought stress on rice in Western Iran during 2005 to 2006, this research was performed. Experiment form was split plot in randomized complete block design with four replications. In this research, patterns of irrigation (I1, I2 and I3 = 10 cm water irrigation, five-dayalternate irrigation, and five-day alternate irrigation until the beginning of heading with 10 cm flooding till it gets to the ripening time, respectively) were the major factors and rice variations (Anbar boo, Tarem, Neda,Line 6 and Kadoos as V1, V2, V3, V4 and V5, respectively) were the minor factors. The results of this research showed that water limitation in procreative period and loading of seed induced decrease in the time required for it to reach the maximum weight and maximum amount of amylases, and also, water limitation in this period of growth and germination, decreased seed weight and amount of amylase in rice. The time of reaching tthe maximum amount of amylases in all treatments was less than the time of reaching the maximum seed weight. Also, water limitation in vegetable growth period is not efficient on seed weight and amount of amylases.

Water Level Variations in Fractured, Semi-Confined Aquifers of Anantapur District, Southern India

Abstract The study on water level conditions of fractured aquifer system in northeastern part of Anantapur district is of immense importance as the area is covered by varied geological formations and has different irrigation patterns. The monthly groundwater level data of 154 observation wells for five year period (2001-06) is analyzed to decipher the behavior of water levels in different seasons and geo-environments. The hydrographs of the average water level data of each Mandal (group of villages) indicate steady declining trend ranging from 0.50 to 2.91m/yr. Yellanuru Mandal has both the shallowest and the deepest water levels among eight Mandals, highly undulating terrain could be one of the reasons for this contrasting condition. The pre-monsoon water levels show decline of 8.22 m in one year from May 2002 to 2003. A negative seasonal fluctuation of -1.49m has occurred in the year 2002 during which the area received 32% less than normal rainfall. The mean water levels are deeper by 42% in areas covered by sedimentary formations than those of granite terrain. Raise in water levels is significant where monthly rainfall is more than 200 mm. Due to erratic rainfall in space and time, deeper water levels are noticed even in post-monsoon period and shallow in February month at some locations. The water levels in command areas are deep and exhibit falling trend as the area forms the tail end part of the Tunga Bhadra High Level Canal. The deeper water level conditions and its declining feature is directly related to groundwater development in the form of increased agriculture activity, reduced area under rain-fed crops, high horticulture development. Arid climatic conditions, low precipitation and continuous exploitation of groundwater resources could be other factors contributing for steady decline in water levels in the area. The wide variations in groundwater levels could be due to uneven topography, heterogeneous and anisotropic conditions of granites and poor porosity - permeability of shales, lack of vegetation, and increased groundwater extraction.

Reuse of Distillery Wastewater with Designed Dose and Pattern for Sugarcane Irrigation

AbstractThe present investigation aims to optimize dose and pattern of distillery effluent for sugarcane irrigation. The postmethanated distillery effluent (PMDE) was recorded to have significant amount of micro‐ (Na, Zn, Fe) and macro‐ (Ca, Mg, N‐NO3, P, K, S–SO) nutrients and so was utilized for sugarcane irrigation. Lysimetric studies were conducted to assess the impact of PMDE on sugarcane productivity with different concentrations (50 and 75%) and irrigation patterns (intermittent and pre‐sowing). The intermittent pattern of ferti‐irrigation with 50 and 75% effluent dose for sugarcane crop was found to enhance the growth and quality parameters of crop without impairing the groundwater quality. Results were more pronounced with 75% intermittent irrigation as the percent increase with respect to control for plant length, cane girth, cane weight, number of internodes per cane, dry matter accumulation, juice extraction, sucrose content, and available sugar were 28.0, 42.5, 14.6, 40.2, 54.4, 18.9, 44.9, 57.9, and 50.0%, respectively. It is suggested that PMDE can be used as an alternative of fresh water irrigation and also as a fertilizer for sugarcane, provided that the effluent quality and sugarcane quality is continuously monitored to avoid any contamination.

Effect of different levels of irrigation and planting pattern on grain yield, yield components and water use efficiency of corn grain (Zea mays L.) hybrid SC. 704

Corn production management including irrigation and planting pattern might be different under various conditions. This research was conducted to study the effects of different levels of irrigation and planting pattern on grain and biological yield, yield components, and water use efficiency of grain corn (hybrid SC.704) in 2010 cropping season at Natural Resources and Agricultural Researches Center of Khuzestan, south-west Iran. The study was split-plot experiment, using Randomized Complete Block Design (RCBD) with three replicates. Three irrigation levels consisting of optimum irrigation (I1), drought moderate stress (I2) and drought severe stress (I3), (irrigation based on 100, 80 and 60% water requirement, respectively) were considered as main plots and subplots consisted of two planting pattern, planting in furrow (P1) and planting on raised bed (P2). The amount of water applied was determined by Class-A Pan evaporation every day. Required irrigation water was applied as 70 mm of evaporation of Class-A Pan. The total evaporation from Class-A Pan was measured with a manual limnimeter that has 0.1 mm accuracy. These measurements were checked with the readings from the water flow meters mounted in every plot. The results indicated that the effect of drought stress and planting pattern on grain and biological yields was significant at 1% probability level. The maximum grain yield of about 998 gm-2 was obtained from optimum irrigation treatment. Drought severe stress reduced the grain yield by 30% compared to the optimum irrigation condition. This reduction was mainly due to reduction in grain number per ear and average of grain weight. Step-wise regression analysis indicated that about 88% of grain yield variation was related to the grain number per ear. Increasing amount of water applied, while planting in furrow improved economical and biological water use efficiency mainly due to increased grain and biological yields. The results also indicated that selecting suitable treatments )optimum irrigation with planting in furrow system( and change in leaf area index would be optimal for corn grown in semi-arid regions with saline soil similar to the area in south west of Iran where this study was conducted and can cause plant growth increase and high yield access. Key words: Corn, irrigation, planting pattern, water use efficiency.