Effects of Irrigation Schedules on Photosynthetic Carbon Assimilation of Winter Wheat (Triticum aestivum L.) in North China Plain:from Leaf to Population

A field experiment was conducted to elucidate the regulation mechanism of different irrigation schedules on population photosynthetic of winter wheat. The experiment included five irrigation schedules, such as no irrigation （W0）, irrigation once at jointing （W1j） or at booting （W1b）, irrigation twice at jointing and booting （W2）, and irrigation three times at jointing, booting and grain-filling （W3） and three planting densities, such as 180 （D1）, 300 （D2） and 450 （D3） seedlings per square meter. The results indicated that irrigation significantly improved population photosynthesis. The relationship between population photosynthesis and irrigation time/volume was to some extent parabolic. Improvements in population photosynthesis （resulting from more irrigation time/volume） were mainly related to increase in leaf area index and population light interception. Population photosynthesis exhibited a significantly negative correlation with canopy light transmittance. Population photosynthesis at grain filling stage was significantly positively correlated with dry matter accumulation at post-anthesis and grain yield. Main effects and partial correlation analysis showed that population photosynthesis of W0, W1j, W1b and W3 were regulated by canopy light transmittance and leaf area. On the other hand, population photosynthesis of W2 was mainly influenced by flag leaf photosynthetic rate. On this basis, planting 300 seedlings per square meter was the optimum combination. The combination of W2D2 increased population photosynthesis during mid-late growth stages and extended high population photosynthesis duration, which ultimately increased grain yield.

The Effect of Water Saving and Production Increment by Drip Irrigation Schedules

Drip irrigation system can achieve high uniformity. When the system is designed for uniformity coefficient equal or more than 70%, the water application in the field can be expressed as a normal distribution and further simplified to a linear distribution. This paper will describe the irrigation scheduling parameters, percent of deficit, application efficiency and coefficient of variation by simple mathematical model. Using this effective model and the irrigation application, the total yield affected by the total water application for different uniformity of irrigation application can be determined. More over, this paper uses the cost of water, price of yield, uniformity of the drip irrigation system, crop response to water application and environmental concerns of pollution and contamination to determine the optimal irrigation schedule. A case study shows that the optimal irrigation schedule can achieve the effect of water saving and production increment compared with the conventional irrigation schedule in which the whole field is fully irrigated. Key words drip irrigation - linear cumulative frequency curve - optimal irrigation schedule - water saving - production increment CLC number TV 139.1 Foundation item: Supported by the National Natural Science Foundation of China (59379407)Biography: QIU Yuan-feng (1973-), male, Ph. D, research direction: water saving irrigation theory and techniques.

Effect of irrigation schedule on growth and seed yield of camelina(Camelina sativa L.)in Tarai region of central Himalaya

Camelina(Camelina sativa)has emerged as a potential biofuel crop globally with its suitability even as a jet fuel source with 75–80%less greenhouse gas emissions compared to common petroleum fuels.The crop has originated from Mediterranean region and belongs to Brassicaceae family.DIBER,DRDO has made initial and pioneer efforts in successful introduction of this crop to India and its agro-technology standardization.Being a short duration crop with lesser input requirement,it fits well in the cropping pattern of hilly states of Indian Himalaya.These areas experience fallow land due to shortage of irrigation water for growing other crops.The present study revealed that irrigation at flowering stage is more beneficial.Irrigation at this stage(if only one irrigation is available)exhibited grain yield of 1.004 kg·m^(-2)which was 21 and 80%higher over pod setting and rosette stage irrigation,respectively.The maximum seed yield was observed under treatment where irrigation was provided at all three crop growth stages(2.044 kg·m^(-2)).It was 50%higher over T6 treatment(where two irrigations were given at rosette and flowering stage)and 104%higher over T3(where only one irrigation was given at flowering stage).

Parameters for Use of BEWAB＋ Programme to Schedule Irrigation of Pea （Pisum sativum L,）

A large portion of irrigation farmers make use of subjective （intuition） irrigation scheduling methods as supposed to objective or scientific irrigation scheduling methods, which need to be changed. The BEsproeiingsWAterbestuursprogram （BEWAB＋） irrigation scheduling programme is based on the water balance equation and needs： （1） a crop production function; （2） a relative consumptive water demand curve and （3） an allowable depletion subroutine. The objective of this paper was to describe research aimed at obtaining information on （1） and （2） for pea and also to describe the effect of water application on yield and water use of pea. BEWAB＋ uses this information to estimate the daily irrigation water requirements for a particular soil-crop-atmosphere system under irrigation. A field experiment, based on published line-source irrigation methodology, was conducted on a 3 m deep loamy fine sand Bainsvlei or Ustic Quartzipsamment soil near Bloemfontein （26°08′S; 29°01′E） in South Africa. Results showed that there is a linear relationship of the form Ys = 8.07ET - 249 （r2 = 0.91）, where Ys is the seed yield of pea （kg/ha） and ET is evapotranspiration for the growing season （mm）. The relative consumptive water demand curve is represented by the following third order polynomial function that describes the relationship between time and relative ET for a pea growing season of 120 days： ETrelx = 0.09419646 - 0.01302413x ＋ 0.00059008x2 - 0.00000371x3. ETrelz denotes relative ET and x denotes time in days. A workable balance between practical problem solving and advanced irrigation science has been established with BEWAB＋. Pre-plant irrigation schedules can be made for semi-arid areas with the BEWAB＋ programme using easily obtainable inputs, like target yield, soil depth and soil particle size distribution information.

Assessing Suitability of Irrigation Scheduling Decision Support Systems for Lowland Rice Farmers in Sub-Saharan Africa—A Review

Irrigation in lowland rice production systems in Sub-Saharan Africa (SSA) is mainly based on traditional surface irrigation methods with continuous flooding practices. This irrigation method ends up using a lot more water that would have otherwise been used to open more land and be used in other water-requiring sectors. Various studies suggest Alternate Wetting and Drying (AWD) as an alternative practice for water management that reduces water use without significantly affecting yield. However, this practice has not been well adopted by the farmers despite its significant benefits of reduced total water use. Improving the adoption of AWD using irrigation Decision Support Systems (DSSs) helps the farmer on two fronts;to know “how much water to apply” and “when to irrigate”, which is very critical in maximizing productivity. This paper reviews the applicability of DSSs using AWD in lowland rice production systems in Sub-Saharan Africa.

Drip Irrigation Scheduling for Tomato Grown in Solar Greenhouse Based on Pan Evaporation in North China Plain

This study has investigated the suitable drip irrigation scheduling for tomato grown in solar greenhouse based on 20-cm pan evaporation （Epan） in North China Plain. Irrigation treatments included three irrigation frequencies （11 10, 12 20 and 13 30 mm, and irrigation interval of 2-6 d for 11, 4-9 d for 12 and 8-12 d for 13） based on accumulated pan evaporation （Epan）, and four plant-pan coefficients （Kcp1 0.5, Kcp2 0.7, Kcp3 0.9 and Kcp4 1.1）. Results indicate that total irrigation amount, seasonal crop evapotranspiration （ET） and tomato yield （Y） were 185.1-365.8 mm, 249.1-388.0 mm and 99.6-151.8 t ha^-1, respectively. Irrigation frequency and amount increased the yield, and second-degree polynomial relationship was found between Y and ET （R2=0.8671）. Irrigation frequency did not increase mean fruit weight, diameter and length significantly but increased fruit number, total soluble solids content （TSS）, TSS yield, fruit firmness and water use efficiency （WUE） and irrigation WUE （IWUE） significantly. Irrigation amount increased external quality of tomato but reduced TSS content, TSS yield, fruit firmness, WUE and IWUE significantly. Kep3 and gep4 treatments had the highest fruit yield, but Kep2 and Kep3 treatments had the highest WUE. 11Kcp3 treatment （irrigation interval of 2-6 d, and Kop=0.9） had higher IWUE, WUE, external quality, yield, and TSS yield, so it is recommended as the suitable irrigation scheduling for tomato grown in solar greenhouse in North China Plain.

Soil Enzyme Activities with Greenhouse Subsurface Irrigation

Various environmental conditions determine soil enzyme activities, which are important indicators for changes of soil microbial activity, soil fertility, and land quality. The effect of subsurface irrigation scheduling on activities of three soil enzymes (phosphatase, urease, and catalase) was studied at five depths (0-10, 10-20, 20-30, 30-40, and 40-60 cm) of a tomato greenhouse soil. Irrigation was scheduled when soil water condition reached the maximum allowable depletion (MAD) designed for different treatments (-10, -16,-25,-40, and-63 kPa). Results showed that soil enzyme activities had significant responses to the irrigation scheduling during the period of subsurface irrigation. The neutral phosphatase activity and the catalase activity were found to generally increase with more frequent irrigation (MAD of -10 and -16 kPa). This suggested that a higher level of water content favored an increase in activity of these two enzymes. In contrast, the urease activity decreased under irrigation, with less effect for MAD of -40 and -63 kPa. This implied that relatively wet soil conditions were conducive to retention of urea N, but relatively dry soil conditions could result in increasing loss of urea N. Further, this study revealed that soil enzyme activities could be alternative natural bio-sensors for the effect of irrigation on soil biochemical reactions and could help optimize irrigation management of greenhouse crop production.

Saline Water Irrigation Scheduling Through a Crop-Water-Salinity Production Function and a Soil-Water-Salinity Dynamic Model

Using a crop-water-salinity production function and a soil-water-salinity dynamic model, optimal irrigation scheduling was developed to maximize net return per irrigated area. Plot and field experiments were used to obtain the crop water sensitivity index, the salinity sensitivity index, and other parameters. Using data collected during 35 years to calculate the 10-day mean precipitation and evaporation, the variation in soil salinity concentrations and in the yields of winter wheat and cotton were simulated for 49 irrigation scheduling that were combined from 7 irrigation schemes over 3 irrigation dates and 7 salinity concentrations of saline irrigation water (fresh water and 6 levels of saline water). Comparison of predicted results with irrigation data obtained from a large area of the field showed that the model was valid and reliable. Based on the analysis of the investment cost of the irrigation that employed deep tube wells or shallow tube wells, a saline water irrigation schedule and a corresponding strategy for groundwater development and utilization were proposed. For wheat or cotton, if the salinity concentration was higher than 7.0 g L-1 in groundwater, irrigation was needed with only fresh water; if about 5.0 g L-1, irrigation was required twice with fresh water and once with saline water; and if not higher than 3.0 g L-1, irrigation could be solely with saline water.

Water Requirements and Irrigation Scheduling of Spring Maize Using GIS and CropWat Model in Beijing-Tianjin-Hebei Region

Due to the over use of available water resources, it has become very important to define appropriate strategies for planning and management of irrigated farmland. In this paper, Beijing-Tianjin-Hebei (Jing-Jin-Ji) region was chosen as the case study area for its special political and economic status and its severe water problem. To achieve effective planning, the information about crop water requirements, irrigation withdrawals, soil types and climatic conditions were obtained in the study area. In the meantime, a GIS method was adopted, which extends the capabilities of the crop models to a regional level. The main objectives of the study are: 1) to estimate the spatial distribution of the evapotranspiration of spring maize; 2) to estimate climatic water deficit; 3) to estimate the yield reduction of spring maize under different rainfed and irrigated conditions. Based on the water deficit analysis, recommended supplemental irrigation schedule was developed using CropWat model. Compared to the rainfed control, the two or three times of supplemental water irrigated to spring maize at the right time reduced the loss of yield, under different scenarios.

Advanced Irrigation Engineering： Precision and Precise

Irrigation advances in precision irrigation （PI） or site specific irrigation （SSI） have been considerable in research; however, commercialization lags. SSI/PI has applications when soil texture variability affects soil water holding capacity or when crop yield or biotic stresses （insects or diseases） are spatially variable. SSI/PI uses variable rate application technologies, mainly with center-pivots or lateral-move or linear irrigation machines, to match crop needs or soil water holding constraints. Variable rate applications are achieved by variable nozzle flow rates, pulsing nozzle flows, or multiple nozzles on separate submains. Newer center pivot and linear machines are controlled by on-board microprocessor systems that can be integrated with supervisory control and data acquisition controllers for both communication and control of the variable rate application for specific sets of nozzles or individual nozzles for management zones. Communication for center pivot or linear controllers typically uses radio telemetry, wireless interact links, or cellular telephones. Precision irrigation has limited utility without precise irrigation scheduling （temporally and spatially）. Plant or soil sensors are used to initiate or complete an irrigation event. Automated weather stations provide site information for determining the irrigation requirement using crop models or simpler reference evapotranspiration （ET）, data to be used with crop coefficients. Remote sensing is being used to measure crop water status or crop development from spectral reflectance. Near-surface remote sensing with sensors mounted on moving irrigation systems provide critical spatial integration from point weather networks and feedback on crop ET and irrigation controls in advanced automated systems for SSI/PI.

Research,Extension,and Good Farming Practices Improve Water Quality and Productivity

Agriculture in southeastern Oregon and southwestern Idaho known collectively as the Treasure Valley has depended on furrow irrigation using heavy inputs of water and nitrogen （N） fertilizer. Crop rotations include onion, corn, wheat, sugar beet, potato, bean, and other crops. By 1986 groundwater had become contaminated with nitrate and residues of the herbicide chlorthal-dimethyl （DCPA）; an official groundwater management area was established by the Oregon Department of Environmental Quality along with an action plan and well monitoring network. The action plan allowed for a trial period to see whether voluntary changes would improve trends. Researchers, producers, and agencies cooperated to develop production options that had the possibility of being both environmentally protective and cost effective. Options were tested to improve irrigation practices, increase N fertilizer use efficiency on several rotation crops, and find a cost effective replacement for DCPA. Research demonstrated the opportunity for increased productivity through both irrigation scheduling and the adoption of drip and sprinkler systems. Fertilizer research demonstrated that smaller, more frequent N applications were more efficient than a single large application. Effective, lower cost herbicides replaced DCPA. Research results were effectively delivered through many means and voluntarily adopted. Both groundwater nitrate and DCPA residues are declining. Productivity has increased.

Root length density distribution and associated soil water dynamics for tomato plants under furrow irrigation in a solar greenhouse

Furrow irrigation is a traditional widely-used irrigation method in the world. Understanding the dynamics of soil water distribution is essential to developing effective furrow irrigation strategies, especially in water-limited regions. The objectives of this study are to analyze root length density distribution and to explore soil water dynamics by simulating soil water content using a HYDRUS-2D model with consideration of root water uptake for furrow irrigated tomato plants in a solar greenhouse in Northwest China. Soil water contents were also in-situ observed by the ECH_2O sensors from 4 June to 19 June and from 21 June to 4 July, 2012. Results showed that the root length density of tomato plants was concentrated in the 0–50 cm soil layers, and radiated 0–18 cm toward the furrow and 0–30 cm along the bed axis. Soil water content values simulated by the HYDRUS-2D model agreed well with those observed by the ECH_2O sensors, with regression coefficient of 0.988, coefficient of determination of 0.89, and index of agreement of 0.97. The HYDRUS-2D model with the calibrated parameters was then applied to explore the optimal irrigation scheduling. Infrequent irrigation with a large amount of water for each irrigation event could result in 10%–18% of the irrigation water losses. Thus we recommend high irrigation frequency with a low amount of water for each irrigation event in greenhouses for arid region. The maximum high irrigation amount and the suitable irrigation interval required to avoid plant water stress and drainage water were 34 mm and 6 days, respectively, for given daily average transpiration rate of 4.0 mm/d. To sum up, the HYDRUS-2D model with consideration of root water uptake can be used to improve irrigation scheduling for furrow irrigated tomato plants in greenhouses in arid regions.

Evapotranspiration and Above Ground Biomass of Acer rubrum from Liners to 8 m Tall Trees

To meet minimum spring flows, water management districts in Florida sought to make both agriculture and urban landscapes water efficient, which includes tree farms. Acer rubrum L. (red maple) trees are endemic to Central Florida and native to the eastern portion of the United States. Urban and suburban expansion has increased use of A. rubrum in landscape plantings and their production in nurseries. In Florida A. rubrum is planted around stormwater retention areas, but also in urban landscapes. To provide a basis for irrigation allocations both during production and in landscapes, daily actual evapotranspiration (ETA) for three red maple trees were measured with weighing lysimeters, beginning with rooted cuttings and continuing until trees averaged 8 m in height. Empirical models were derived to calculate ETA based on crown horizontal projected area or trunk caliper, adjusted daily by changes in reference evapotranspiration (ETo). Water use efficiency, based on carbon sequestered in above ground wood mass, was calculated at the end of five growing seasons. Average ETA to produce these maples was 29,107 L over 4.75 years, with an average water use efficiency of 1 kg dry mass of wood per 709 L of water lost by transpiration.

Field Comparison of Soil Moisture Sensing Using Neutron Thermalization, Frequency Domain, Tensiometer, and Granular Matrix Sensor Devices: Relevance to Precision Irrigation

The efficient use of irrigation water requires several kinds of information. One element of efficient irrigation scheduling is monitoring the soil moisture to assure that the crop irrigation goals are being met. Various soil moisture sensing devices were tested for irrigation scheduling in silt loam at the Malheur Agricultural Experiment Station, Oregon State University between 2001 and 2004. Neutron probes, frequency domain probes, tensiometers, granular matrix sensors, and Irrigas were compared as to their performance under field conditions at Ontario, Oregon, USA. Granular matrix sensors were tested as read automatically by a datalogger and read manually with a hand-held meter. Practical suggestions are provided to use soil moisture sensors to the benefit of crop production and water conservation.

An Assessment of Potential Economic Gain from Weather Forecast Based Irrigation Scheduling for Marginal Farmers in Karnataka, Southern State in India

This study is aimed to assess the usefulness of weather forecasts for irrigation scheduling in crops to economize water use. The short-term gains for the farmers come from reducing costs of irrigation with the help of advisory for when not to irrigate because rain is predicted (risk-free because the wrong forecast only delays irrigation within tolerance). Here, a quantitative assessment of saving (indirect income) if irrigation is avoided as rain is imminent (as per forecast), using a five-year archived forecast data over Karnataka state at hobli (a cluster of small villages) level is presented. Estimates showed that the economic benefits to the farmers from such advisories were significant. The potential gain in annual income from such forecast-based irrigation scheduling was of the order of 10% - 15%. Our analysis also indicated that the use of advisory by a small percentage of more than 10 million marginal farmers (landholding < 3 acres) in Karnataka could lead to huge cumulative savings of the order of many crores.

Simulation and optimization of irrigation schedule for summer maize based on SWAP model in saline region

In order to explore the appropriate irrigation schedule for summer maize,a field experiment was conducted in 2013 in Lubotan of Shaanxi Province.Soil water content,soil salinity,soil hydraulic parameters,crop growth parameters and summer maize yield were measured in the experiment.The SWAP model was calibrated based on field experiment observation data in 2013.The SWAP model was used to simulate and optimize irrigation schedule for summer maize after calibration.The results showed that model simulation results of soil water content,soil salinity and summer maize yield agreed well with the measured values.The Root Mean Square Error(RMSE)and Mean Relative Error(MRE)were within the allowable error ranges.The RMSE values were all lower than 0.05 cm3/cm3 and the MRE values were lower than 15%in soil water content calibration.The RMSE values were all lower than 0.1 mg/cm3 and the MRE values were lower than 20%in soil salinity calibration.The RMSE and MRE values were 1299.6 kg/hm2 and 15.26%in summer maize yield calibration.The model parameters suitable for the study area were obtained in calibration.The SWAP model could be used to simulate and optimize irrigation schedule for summer maize after calibration.The SWAP model was used to simulate soil water-salt balance,summer maize yield and water use efficiency under different irrigation schedules.The model simulation results for different irrigation schedules indicated that the optimal irrigation schedules of summer maize were three times each for jointing stage(July 5),heading stage(August 5)and grain filling stage(August 30)with irrigation amount of 128 mm,128 mm and 96 mm,respectively.The optimal irrigation quota was 352.0 mm for summer maize in the study area.

Collaborative operation and application influence of sprinkler drip irrigation:A systematic progress review

Considering the high-quality requirements related to agricultural crop production,the collaborative operation and application influence of sprinkler drip irrigation is an important issue in precision agriculture.The objective of this review is to give a comprehensive demonstration focusing on the subject of collaborative operation and application influence of sprinkler drip irrigation,by using a set of comparative analysis and literature bibliometric maps,therefore the sprinkler drip irrigation quality considering actual influential factors could be determined and analyzed.This review establishes on a broad spectrum of agricultural drip irrigation performance,throughout its whole procedure of collaborative monitoring,irrigation scheduling,application efficiency,and environmental influence,covering such aspects as soil physicochemical quality,irrigation scheduling,water resource redistribution,crop productivity,tillage management,climate adaptation,and environmental monitoring,etc.This review indicates that,the irrigation efficiency and drip infiltration quality of soil field can be planned precisely and allocated reasonably by sprinkler drip irrigation,which has extraordinary infiltration capability and enables much better performance,than that of other ordinary irrigation approaches in accuracy,stability,regularity,and efficiency.Thereafter,the investigation on the collaborative operation and application influence of sprinkler drip irrigation can be used to ensure the infiltration uniformity of moisture distribution,and then the high-quality requirements of practical irrigation performance can be met,too.This systematic review facilitates the productive soil-moisture-environment management for precision irrigation and agricultural production.

Much Improved Irrigation Use Efficiency in an Intensive Wheat-Maize Double Cropping System in the North China Plain

Crop yield and water use efficiency （WUE） in a wheat-maize double cropping system are influenced by short and uneven rainfalls in the North China Plain （NCP）, A 2-year experiment was conducted to investigate the effects of irrigation on soil water balance, crop yield and WUE to improve irrigation use efficiency in the cropping system, Soil water depletion （~SWS） by crop generally decreased with the increase of irrigation and rainfall, while ASWS for the whole rotation was relatively stable among these irrigation treatments, High irrigations in wheat season increased initial soil moisture and ASWS for subsequent maize especially in the drought season, Initial soil water influenced mainly by the irrigation and rainfall in the previous crop season, is essential to high yield in such cropping systems, Grain yield decreased prior to evapotranspiraUon （ET） when ET reached about 300mm for wheat, while maize showed various WUEs with similar seasonal ET, For whole rotation, WUE declined when ET exceeded about 650 mm, These results indicate great potential for improving irrigation use efficiency in such wheat-maize cropping system in the NCP, Based on the present results, reasonable irrigation schedules according to different annual rainfall conditions are presented for such a cropping system.

Effect of smart sprinkler irrigation utilization on water use efficiency for wheat crops in arid regions

The smart irrigation system(SIS)developed in this research is a valuable tool for scheduling irrigation and quantifying water required by plants.SIS was implemented and tested under sprinkler irrigation system to irrigate wheat crops(YecoraRojo).Results obtained from this system were compared with the control irrigation system(CIS),whose scheduling method was based on data from an automatic weather station.Results indicated significant savings in applied water using the SIS.In addition,the use of the SIS conserved 12%of irrigation water compared to CIS and obtained an economical yield.The water use efficiency(WUE)under SIS had generally higher values(1.64 kg/m^(3))compared to CIS(1.46 kg/m^(3)).Hence,the application of SIS technology provides significant advantages on WUE and irrigation water use efficiency(IWUE).Relatively high WUE and IWUE were found for the irrigation treatment(80%of evapotranspiration under SIS).Results showed that the irrigation requirements of wheat increased(100%of ETc under CIS)with increasing evapotranspiration(ETc)but excessive irrigation could decrease WUE and IWUE.These results indicated that extreme irrigation might not produce higher yield or optimal economic benefit,thus,suitable irrigation schedules by using SIS must be established and extendable to other agricultural crops.

Effects of timing and duration under brackish water mulch drip irrigation on cotton yield in northern Xinjiang,China

The brackish water is an important potential water source and has frequently been utilized to drip-irrigate cotton due to the water shortage in the arid region of Xinjiang,northwestern of China.The brackish water is usually saline water with salinity ranging from 1 g/L to 5 g/L,which is widely distributed in this area,so the reasonable use of that brackish water may not only play a vital role in the local agricultural production,but also save plenty of freshwater.However,irrigation with brackish water usually causes the reduction of crop yield and soil salinization which can negatively impact plants through three major components:osmotic,nutritious and toxic stresses.Therefore,a field experiment,with eight different time-series irrigation modes using brackish water(3.5±0.2)g/L and freshwater(<1 g/L),beneath a combined film and drip-irrigation system was carried out to study the changes of soil salt content and cotton yield aiming to search for a balanced method during the 2 cotton growing seasons in 2012 and 2013.The results indicated that the time-series irrigation modes determined the soil salinity and moisture distribution based on observed spatio-temporal distribution of water content and electric conductivity,and soil salinity generally gathered at the depth of 0-10 cm and 60 cm of soil with the increase of irrigation quota.Moreover,the results demonstrated that the yields of cotton which was grown using brackish water and freshwater were better than those only using freshwater and the soil salinity with reasonable irrigation timing was not accumulated obviously.