Applied Irrigation Water Research Articles

Model based irrigation water application of maize (zeamays l.) to improve water productivity in irrigated agriculture

Under the semiarid and arid climate of Eastern Europe, accurate estimation of crop water requirement and irrigation scheduling is important for water management and planning. The objectives of this study were to estimate maize water requirement and irrigation scheduling in variable climatic conditions. CROPWAT model is decision support system developed by United Nations Food and Agriculture Organization (FAO) and it is used as a practical tool to carry out standard calculations for reference evapotranspiration, crop water requirements, irrigation scheduling, and also allows helps in planning and decision making in the areas where water resource availability is varying and scarce. The study result indicated that Maize seasonal amounts of irrigation requirements varied from 439.5 to 615.0 mm. Maize actual daily evapotranspiration (ETa) varied from 0.12 to 4.13 mm and from 0.27 to 4.68 mm in 2010 and 2011 respectively. Net irrigation schedule for all growing periods in 2010 was zero for initial and late but for development 138.9 mm and 45.9 mm for mid-stage of the growing period. However, 2011 were zero, 83.7 mm, 178 mm, and 98.2 mm in initial, mid, and development and late stages respectively. Besides in the study area, 2010 was the wettest year but 2011 was determined as the driest year this may cause adverse conditions on maize crop yields quantity and quality. Irrigation requirements for maize should be adjusted to the local meteorological conditions for optimizing maize irrigation requirements and improving maize water productivity under such climatic variable conditions.

Optimum Operating Conditions for Impact Sprinkler

Sprinkler irrigation systems can be managed and designed by only conducting an individual sprinkler test in no wind conditions. The present work was conducted to study the effect of different operating pressures and riser heights to determine optimum operating conditions that achieve high application efficiency and wheat production in impact sprinkler system. The coefficient of uniformity (CU,%) was evaluated within the operating pressure range from 100 to 350 kPa, riser heights 1.0, 1.5 and 2.0 m, overlapped from 100 to 20% under square and triangular layouts sprinkler. It was concluded that the operating conditions that achieved high CU was operating pressure of 250 kPa and 1.5 m riser height for impact sprinkler. Information from individual sprinkler test was established to carry out the corresponding overlapping ranged from 20 to 100% in square and triangular layouts sprinkler. Optimal spacing between sprinklers was found to be as 50 to 70% from diameter of throw in square layout. It was found in range of 50 to 80% from diameter of throw in triangular layout sprinkler. The wheat yield was highly affected by water requirements (100, 80 and 60% ETc). The results showed that the average values of total grain and straw yield/fed, increased with increasing ETc from 60 to 100%. The highest yield was achieved with 100% ETc, while, WUE with 80% ETc was the highest value. It could be recommended to apply irrigation water to 100% ETc that has the highest yield of wheat under operating pressure of 250 kPa with good CU for impact sprinkler. On the other hand, adding 80% ETc applied gave the highest values was preferred when the priority to save on the applied water and increase water productivity. Also, layout spacing ≥ 50% from diameter of throw was recommended.

Role of deficit irrigation strategies on ET partition and crop water productivity of rice in semi-arid tropics of south India

Crop water productivity (CWP) is a measure of crop yield per unit of water consumed and plays a crucial role in evaluating the role of alternate management practices for sustainable production. This study investigates the crop water and yield dynamics of rice (Oryza sativa L.) subjected to three (low, moderate, and high water stress) deficit irrigation scenarios. Factorial experiments were conducted in four paddy fields in a command area of south India during the 2017–18 growing seasons with farmers’ current irrigation practice used as the control (T1). Seasonal total and irrigation water application of rice was ranged from 803 and 175 mm for high stress to 978 and 350 mm for T1 conditions. Cumulative potential evapotranspiration (ETo) for the growing seasons was observed to be 326.65 ± 2.51 mm. The FAO-56-based SIMDualKc model was parameterized to partition the evapotranspiration (ET) fluxes and to obtain site-specific crop coefficients for each scenario. Model-simulated root zone soil moistures were in agreement with the observations for all irrigation treatments (R2 > 0.80, RMSE < 0.04 cm3 cm−3, n = 20). Stage-specific single (Kc) and basal crop (Kcb) coefficients for rice with T1 are, respectively, 1.1, 1.09, 0.79, and 0.9, 0.97, 0.57, which are slightly lower than FAO tabulated values. The calibrated soil–water balance model was further applied to simulate crop yield using a simple crop growth algorithm. Our results conclude that crop yield is sensitive to water stress during vegetation (ky = 1.14 ± 0.10) followed by transplantation (ky = 1.07 ± 0.16) and reproduction stages (ky = 1.02 ± 0.17). We observed a marginal increase in CWP (12% in 2017 and 3% in 2018) and a reduction in deep percolation losses (29% in 2017 and 14% in 2018) through controlled water-saving strategies.

Land use efficiency and productivity of rice (Oryza sativa) under various irrigation regimes and intercropping system

A field experiment was conducted at Tamil Nadu Rice Research Institute, Aduthurai to assess the land use efficiency and productivity of rice under intercropping system. Treatments consisted of six irrigation regimes viz., IW (depth of irrigation water) / CPE (Cumulative pan evaporation) ratio 1 up to harvest, IW/CPE 0.75 up to 60 days thereafter IW/CPE 1, IW/CPE 0.75 up to 60 days thereafter IW/CPE 1.25, IW/CPE 0.75 up to 60 days thereafter IW/CPE 1.50, IW/CPE 1 up to 60 days thereafter IW/CPE 1.25 and IW/CPE 1 up to 60 days thereafter IW/CPE 1.50 and three cropping system viz., Rice alone, Rice + Blackgram and Rice + Greengram. Results revealed that application of irrigation water at different levels and cropping systems markedly influenced the growth, yield components and yield of rice. The maximum value of growth and yield components were recorded with the application of irrigation IW/CPE ratio of 1 up to 60 days thereafter IW/CPE ratio of 1.50 and among the cropping systems aerobic rice alone showed significantly higher growth and yield. Water productivity is higher in irrigation with IW/CPE ratio of 1 up to 60 days thereafter 1.50. The land equivalent ratio (LER) also revealed both the intercropping systems were advantageous. The results encourage the options of pulses could be grown as inter crop in rice.

Use of copper in pine nurseries

Copper has been used by nursery managers for more than 100 years to suppress fungi and as a fertilizer for more than 50 years. Consequently, nursery seedlings with copper deficiencies are rare, especially for broadleaf species. In many nurseries, soil contains <10 μg-Cu g-1 and in greenhouse trials, pine seedlings are relatively tolerant of soil levels with 35 μg-Cu g-1. A million bareroot pine seedlings may contain 50 to 100 g-Cu and, when soil tests indicate low copper levels, managers might apply 1 kg-Cu per million seedlings. In contrast, it may take only 15 g-Cu to produce one million container-grown seedlings. Copper fertilization is typically not required when 30 cm of applied irrigation water contains 0.1 μg-Cu g-1 (supplying 0.3 kg-Cu ha-1). This review highlights some of the past and current uses of copper in bareroot and container nurseries with a focus on deficiency and toxicity effects as well as the impact of various copper-based products and provides recommendations on ideal soil and foliar ranges.

Effect of mycorrhiza application and different irrigation level on yield and yield components of cucumber grown in late period

Bu çalışmanın amacı, mikoriza uygulamasının farklı sulama seviyelerinde hıyar bitkisinin verim ve verim bileşenleri üzerine etkisinin belirlenmesidir. Şanlıurfa ilinde 2017 yılı güz döneminde (ağustos-ekim) yürütülen bu araştırma, tesadüf blokları bölünmüş parseller deneme desenine göre 3 tekerrürlü olacak şekilde kurulmuştur. Ana parsel mikoriza uygulaması, alt parseller ise sulama suyu seviyelerinden olmuştur. Sulama suyu miktarı A sınıfı buharlaşma kabına göre hesaplanmış ve damla sulama yöntemi ile parsellere uygulanmıştır. Araştırmadan elde edilen sonuçlara göre, hıyar bitkisine güz dönemde uygulanan sulama suyu miktarı 334-673 mm, bitki su tüketim değerleri ise 379-673 mm arasında değişmiş, bitki su tüketim değerleri ile sulama suyu miktarları paralellik göstermiştir. Hıyar bitkisinin güz dönemindeki verimi 20.54-33.66 t ha-1 arasında değişmiştir. En yüksek verim mikoriza uygulamasının yapıldığı ve sulama suyu ihtiyacının %133’ünün karşılandığı konudan elde edilmiştir. Meyve çapı, meyve boyu ve meyve ağırlığı değerleri; sırasıyla 29-36 mm, 134-161 mm ve 103-135 g arasında değişmiştir. Çalışma sonucunda, mikoriza uygulamasının hıyar bitkisinin verim ve verim parametreleri üzerinde önemli bir etkiye sahip olduğu tespit edilmiştir.

Systematic review: Effect of Irrigation Water Quality and Deficit Irrigation on Crop Yield and Water Use efficiency

The main purpose of this paper is to review on the effect of irrigation water quality and deficit irrigation on crop yield and water use efficiency. Low quality water for irrigation can impose a major environmental constraint to crop productivity. If salts become excessive, losses in yield will result. To prevent yield loss, salts in the soil must be controlled at a concentration below that which might affect yield. Irrigation application below the full evapotranspiration requirement is termed as deficit irrigation. Deficit irrigation consists of deliberately applying irrigation water in amounts below the plant‘s water requirements. Deficit irrigation can be applied at certain periods during the crop‘s growing season or throughout its growing season. Yield reductions also occur in a number of crops when subjected to water stress. Yield reductions depend on the crop‘s sensitivity to water stress at its various growth stages. In order for deficit irrigation to be an economically viable practice, the revenue lost due to yield reduction should be lower than savings in total cost of production. The goal of deficit irrigation is to increase crop water use efficiency by reducing the amount of water that is applied or by reducing the number of irrigation events. The interaction effects of water quality and DI illustrated that when the two types of stresses; saline and DI were coupled together, a serious reduction occurred on total dry biomass and total yield. The interaction effects of water quality and deficit irrigation illustrated that when the two types of stresses; saline and deficit irrigation were coupled together, a serious reduction occurred on total dry biomass and total yields.

Effects of Salinity on Producers’ Livelihoods and Socio-economic Conditions; the Case of Afar Region, Northeastern Ethiopia

This study was done to assess the effects of salt-affected soils on the livelihoods and socio-economic conditions of the farming communities in Afar National Regional State, Northeaster Ethiopia. Primary data were collected from Amibara and Dubti districts sample respondents selected using multi-stage sampling techniques. Descriptive statistics (mean, frequency, percentage) and inferential statistics (t-test and Chi-square test) were employed to analyze the quantitative data. The results of the study showed that in the study areas, the farming communities have been negatively impacted by soil salinity. According to the study, soil salinity has made deterioration of both livestock rearing (reduced in number) and crop production (low to complete loss) activities, which in turn lead to livelihood vulnerability of the household. The results of the study showed that due to soil salinity, land less ness and food insecurity have becoming the common manifestation of the areas under study. Hence, the quality of irrigation water used for irrigation, the land leveling problem and the method of irrigation water application have to be given due attention to halt further expansion of soil salinity. On the other hand, wider promotion and popularization of proven practices as well as innovating new ones need to be strengthened. Trainings and awareness creation on soil and water management practices could also be taken as an immediate solution.

Spice crops tolerant to salinity and alkalinity

Tolerance and yield of a crop are complex genetic traits, which are difficult to maintain simultaneously since salt stress may occur as a catastrophic agent, be imposed continuously or intermittently or become gradually more severe. Salinity and alkalinity stress have a major impact on spices in the form of their growth, development and yield.Adverse effects of salinity might be due to ion cytotoxicity and osmatic stress, which disrupt homeostasis in water potential and ionic distribution due to disordering in cohesions of membrane lipids and proteins and influence various physiological and biochemical processes. To review the tolerance of spices to salinity and alkalinity, the present paper collates the existing experimental data sets, establishing the salt tolerance limits under saline or alkali environment either in soil root zone or which is created due to the application of saline or alkali irrigation water for crop production. Studies show that the salt affected areas and saline irrigation water can be utilized satisfactorily to raise forest and fruit tree species, forage grasses, conventional and non-conventional crops, oil seed crops, spice crops of high economic value, petro-crops and flower plants.

Spice crops tolerant to salinity and alkalinity

Tolerance and yield of a crop are complex genetic traits, which are difficult to maintain simultaneously since salt stress may occur as a catastrophic agent, be imposed continuously or intermittently or become gradually more severe. Salinity and alkalinity stress have a major impact on spices in the form of their growth, development and yield.Adverse effects of salinity might be due to ion cytotoxicity and osmatic stress, which disrupt homeostasis in water potential and ionic distribution due to disordering in cohesions of membrane lipids and proteins and influence various physiological and biochemical processes. To review the tolerance of spices to salinity and alkalinity, the present paper collates the existing experimental data sets, establishing the salt tolerance limits under saline or alkali environment either in soil root zone or which is created due to the application of saline or alkali irrigation water for crop production. Studies show that the salt affected areas and saline irrigation water can be utilized satisfactorily to raise forest and fruit tree species, forage grasses, conventional and non-conventional crops, oil seed crops, spice crops of high economic value, petro-crops and flower plants.

Examination of drought stress of two genotype maize hybrids with different fertilization

In the growing season of 2019, we analysed stress resulting from climatic factors on maize hybrids of different genotypes, with the aim of gaining a better understanding of the physiological responses of each hybrid, which might support the elaboration of a cost-effective irrigation plan.&#x0D; Our experiments were carried out at the Látókép Experimental Station of the University of Debrecen on calcareous chernozem soil in a small-plot long-term field trial with strip plot design. In the scope of the experiment, N-fertilizer doses were applied as basic fertilizer and top-dressing in addition to the non-fertilized (control) treatment. The 60 and 120 kg N/ha doses applied as basic fertilizers in the spring were followed by top-dressing in the V6 phenophase with a +30 kg N/ha dose. Measurements were carried out with the involvement of the Renfor early (FAO 320) and Fornad (FAO 420) late maturity hybrids-&#x0D; The stomata of the plants became more and more closed with the progression of the phenological phases; their stomatal conductance decreased. However, the hybrids responded differently to environmental stress. In the case of the Renfor hybrid, the highest conductance (669 mmol/m2-s) was recorded in the V12 phenophase with the 150 kg N/ha treatment. The stomata were more open due to the high turgor pressure, allowing plants to evaporate properly. The plant was in its worst physiological condition on 2nd July, at the time of the appearance of the last leaf in the case of the 120 kg N dose (224 mmol/m2-s). The value measured in the V12 phenophase has already shown that the stomata were closing due to the self-regulating system of the plant. It would have been necessary to dispense irrigation water following the measurement. This confirms the finding that water stress can be prevented by measuring stomatal conductance.&#x0D; In the case of the Fornad hybrid, stomatal conductance was the highest on 12th June (630 mmol/m2-s) in the 90 kg N/ha treatment and it was the lowest (183 mmol/m2-s) in VT (emergence of the last leaf) phenophase in the 60 kg N/ha treatment. In this case, the appropriate time for applying irrigation water would have been early July, when the conditions for the plants were still adequate. Subsequently, the stomata began to close due to a reduction of the water resources available to them.&#x0D; There was a significant correlation between soil moisture and stomatal conductance, as well as between temperature and stomatal conductance.

Exogenously applied growth promoters modulate the antioxidant enzyme system to improve the cotton productivity under water stress conditions

Great climatic inconsistency and increased frequent occurrences of severe conditions results in plants being exposed to water stress at various growth stages, thus adversely affecting the productivity. This investigation was planned to minimize the water stress induced-losses to cotton plants with the exogenous application of growth promoters i.e. distilled water, salicylic acid (0.5 mM), jasmonic acid (50 μM) and moringa leaf extract (MLE30) including control (un sprayed). Cotton plants were exposed to water stress with the application of irrigation water at 10 (well watered) and 30 day intervals (severe water stress). Results indicated that water stress severely reduced the cotton productivity. It was observed that exogenous application of salicylic acid and moringa leaf extract improved the productivity both under well watered and water stress conditions as compared to other treatments. However, exogenous application of salicylic acid had greater influence on the studied parameters than MLE, although the insignificant differences were documented in most of the traits. Exogenous application of salicylic acid reduced the cell injury percentage, improved the cell membrane thermostability and produced significantly higher content of leaf protein, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) that modulated the negative influence of water stress on yield contributing attributes and produced maximum seed cotton yield. These results indicate that exogenous application of SA and MLE helped the cotton plants to become more tolerant to water stress-induced losses by adjusting the membrane characteristics and improving their antioxidant defense mechanism.

Effect of Irrigation Water Containing Iodine on Plant Physiological Processes and Elemental Concentrations of Cabbage (Brassica oleracea L. var. capitata L.) and Tomato (Solanum lycopersicum L.) Cultivated in Different Soils

Iodine uptake and translocation was studied in cabbage and tomato cultivated on different soil types (sand, sandy silt, silt) by applying irrigation water containing iodine at concentrations of 0.1 and 0.5 mg/L. Iodine treatment at the concentrations applied did not significantly influence the photosynthetic efficiency and chlorophyll concentration of cabbage and tomato leaves. The growth of cabbage leaves cultivated on sand and sandy silt soil with iodine treatment was slightly stimulated, while, on silt soil, it remained unchanged; for tomato plant parts, independent of the soil-type, the dry mass values remained constant. It can be concluded that iodine treatment had no negative effect on the physiological characteristic of cabbage and tomato plants. Applying 0.5 mg/L in the irrigation water, the highest biofortification with iodine was achieved in plants cultivated in sandy soil and the iodine concentration calculated in the dry matter amounted to 10 and 3.6 mg/kg in the leaves and fruits of cabbage and tomato, respectively. Considering the iodine and moisture content of cabbage leaves and tomato fruits, the consumption of 100 g of fresh vegetable would cover about 80% and 15% of the recommended iodine intake, respectively. The presence of iodine resulted in a reduction in Fe and P concentrations in tomato fruits independent of the soil-type; however, the concentration of Mg, Cu, Mn, Zn, and B remained practically unchanged. However, for cabbage, no similar trend for Fe and P was observed.

Irrigation and nutrition as criteria for adequate management of Tahiti acid lime trees affected by a physiological disorder in tropical conditions

In Colombia, Tahiti acid lime production value ranks among the most important fruits in the country. Despite its economic importance, productivity loss in Tolima department orchards has been reported due to a physiological disorder or “phisiopathy”, related to water and nutrition stress which causes descending tissue death. This study aimed to assess the response of Tahiti acid lime trees to three irrigation treatments (based on water retention curve) combined with two nutrition doses (based on balance index between soil and leaf nutrient concentration). Variables of photosynthesis, yield, and symptom expression caused by the phisiopathy were monitored during three experimental years. The number of affected order-5 branches was quantified in five trees per treatment on a biweekly frequency. Assessment of physiological behavior of Tahiti acid lime was conducted by monitoring leaf gas exchange. The results of the water retention curve indicated that the soil moisture must be maintained above 15.6 % (at 0.5 bars) and preferably at field capacity (FC), in order to avoid water stress and thus physiological disorder. Results showed that no treatment was highlighted in terms of reducing significantly the number of affected order-5 branches for trees without phisiopathy (WOP, classified as trees with less than 50 % of branches affectation). However, in trees with (WP, trees with more than 50 % of branches affectation), a decrease in affected order-5 branches was observed as a response to T2 (applied irrigation water is between 0.33−0.5 bars with 150 % of nutrients), T3 (applied irrigation water is between 0.5−1.0 bars with 100 % of nutrients), and T6 (applied irrigation water is between 1.0–3.0 bars with 150 % of nutrients) treatments.For trees WP and WOP, the highest yield was observed by applying T2 treatment where yield value reached 2.91 t ha−1 and 5.02 t ha-1, respectively. T2 generated an improvement of the functional response of Tahiti acid lime trees represented in the increase of Gs and A, which in turn, increased fruit yield and renewed foliage during the crop season. Significant statistical differences were found in average yield (t ha-1) in tress WP and WOP, over the three experimental years (p < 0.05). The application of the different treatments generated a positive productive response and maybe used as a guideline for Tahiti acid lime farmers in Tolima region.

Optimization of applied irrigation water and nitrogen fertilizer for barley in a semi‐arid region: a case study in Iran

AbstractThis study was conducted to estimate the optimal amounts of water and nitrogen of barley production under water‐ and land‐limited conditions. Two years of field experiments were performed with two treatments using a spilt plot design with three replications. The treatments included four levels of irrigation regimes (0, 50, 75 and 100% of water requirement) as the main plots and four nitrogen fertilizer levels (0, 70, 140 and 210 kg N ha−1) as the subplots. Straw yield income was about 35% of total income, indicating the important role of both grain and straw yield in the economic analysis. The optimal amounts of water and nitrogen considering the rainfall and residual amount of nitrogen in the soil were estimated using a generalized reduced gradient nonlinear method as 0.758 m and 236 kg N ha−1 for maximum income per unit area, while these values were obtained as 0.758 m and 232 kg N ha−1 for maximum profit under land‐limited and 0.56 m and 293 kg N ha−1 for maximum profit under water‐limited conditions, respectively. The results show that the highest profit was obtained under land‐limited, maximum income and water‐limited criteria, respectively. © 2020 John Wiley &amp; Sons, Ltd.

Timing of phenological stages for apple and pear trees under climate change in a temperate-continental climate.

The study examines the consequences of climate change in Malus (apple) and Pyrus (pear) on four phenological stages: bud swelling (code 51 BBCH Monograph), budburst (code 53), beginning of flowering (code 61), and end of flowering (code 69) in the temperate-continental climate of southern Romania. The hypothesis tested is how much the onset dates (TOD) of phenology stages moved earlier due to climate change. Weather and phenological data were collected from 1969 to 2018 and were statistically processed. There was an increase in air temperature (T) during the first 5months in the year, with a significant rise in March and April; significant linear relationships show an advance in TOD with the years elapsed. Inverse linear relationships were found between TOD, maximum (Tmax), mean (Tmean), minimum (Tmin) temperature, and sunshine hours (Sh). The relationships between TOD and Tmax were the strongest. The early stages of flowering phenology are advancing more strongly than later flowering stages. For apple, in the last 50years, there was an advance of 13.8days for stage 51, 14.8days for stage 53, 10.7days for stage 61, and only 7.3days for stage 69; for pear trees, the advance was lower: 10days for stage 51, 9days for stage 53, 6.7days for stage 61, and only 2.1days for stage 69. These findings, which might be extrapolated to similar environments, have important consequences in fruit growing, like the occurrence of climate accidents due to late frost, insect pollination, and application of pesticides and irrigation water.

Evaluation of Some Water Management Methods on Water Productivity and Its Saving Under Onion Crop Production at Dugda District, Rift valley of Ethiopia

The limitation in water availability as well as salinity and waterlogging related to over application of irrigation water resulted in low crop water productivity, which obliges to select alternative water management methods. The work compared Wetting Front Detector against Crop Water Requirement and farmers practice under onion production. A field experiment was designed in Randomized Complete Block Design, replicated five times on farmers' fields. Results were compared on the basis of application, distribution, storage and water use efficiencies, and water productivity. The results illustrate that there was a significant difference between the water used in the three methods of irrigation water management used in this manuscript. In comparison with farmer method, Crop Water Requirement saved irrigation water by 35%. The Wetting Front Detector technology also saved the irrigation water by about 16% than the farmer method. On the basis of these values, the water saved by the Crop Water Requirement technique could irrigate 16.5% and the Wetting Front Detector 6-8% more area of onion field than the farmer practice. The differences between the water optimization techniques can be accounted for by to differences in the efficiencies of application, storage and irrigation water use which vary considerably from one type of irrigation water management to another at p&lt;0.05. Generally, Crop Water Requirement technique is more application efficiencies (59.06) followed by the Wetting Front Detector technique (53.78%) and farmer practice (49.26%). The mean Irrigation Water Use Efficiency of Crop Water Requirement, Wetting Front Detector and Farmer Practice were 114.79, 78.38 and 54.38 respectively. The Crop Water Requirement had an storage efficiency of 65.09% which can be beneficially used by the crops while the Wetting Front Detector has efficiently store 59.78%. Based on this study, Crop Water Requirement technique appears to be a promising alternative for water saving without negligible trade-off in yield. Keywords : crop water productivity, water use efficiency, water saving, onion DOI: 10.7176/JNSR/10-7-04 Publication date: April 30 th 2020

Wheat yield response and seasonal salt profile evolution under irrigation with saline waters in a semi-arid region

Scarcity of fresh water resources is the major constraint for agricultural development in Iran as in many other regions with arid and semi-arid climate. With the pressure on fresh water resources, the use of un-conventional water resources including brackish, saline and sewage water has received greater attentions in recent years. The objective of this study was to assess the impact of farmers' practices using saline groundwater on wheat yield and soil salinity in a Mediterranean cli-mate of Fars province in southern Iran. The study was carried out in several commercial wheat production regions for two years. Chemical analysis of irrigation waters, volume of applied irrigation water, electrical conductivity of soil saturation extract (ECe) and yield were measured in each field. General information on agronomic practices was also collected using a questionnaire. Results demonstrate that waters with salinities higher than what has been classified as “suitable for irriga-tion” are being used for the production of wheat crop. Analysis of wheat yield response to saline irrigation water showed that for water salinities up to 10.7 mS∙cm–1 (threshold value) variation in yield was relatively minor, above which wheat yield decreased at a greater rate. Root zone salinity profiles showed the effect of winter rainfall in reducing soil salinity. It is concluded that although acceptable yields are obtained with some of the highly brackish waters, over application of these waters would threaten the sustainability of crop production in the region.

Irrigation Module and Sowing Date Affect Seed Cotton Yield, Quality, Productivity Indices, and Economics of Cotton in North-western India

ABSTRACTDelayed sowing and imprecise application of irrigation water to cotton has been the major hurdle in sustaining cotton yield in north-western India. Therefore, studies were initiated to ascertain the impact of heavy or normal level of presowing irrigation (PSI), scheduling time of first postsowing irrigation (POSI) under two sowing dates (SDs) on cotton arranged in a split block design replicated thrice. PSIh (100 mm) recorded 23.2% higher seed cotton yield over PSIn (70 mm) owing to better yield attributes and higher stand. First POSI at 4 weeks after sowing (WAS) resulted the highest yield (3072 kg ha−1), while one at 6 WAS (POSI6) recorded least due to poor population and reduced yield attributes. Water productivity under POSI6 was lesser by 29.1%, 25.2%, and 16.2% as compared to POSI3, POSI4, and POSI5, respectively. April sown crop out yielded the May sown cotton crop by 939 kg ha−1 due to better yield attributes. Nitrogen factor productivity (NFP) among SD remained higher by 23.3% for April as compared to May sowing. PSIh exhibited better NFP over PSIn. POSI6 recorded least NFP by 24.4%, 28.5%, and 16.3% as compared to POSI3, POSI4, and POSI5, respectively and was indicative of relatively poor utilization of N under delayed schedules. Therefore, planting in April after heavy PSI and scheduling first POSI at 4 WAS is best strategy for sustaining cotton yield and maximizing farmer profitability.

Evaluation of Wetting Front Detector on Water Productivity and Its Savings Under Pepper Production at Dugda District, East Shoa Zone of Oromia Region

The limitation in water availability and also salinity and waterlogging related to over application of irrigation water resulted in low crop water productivity, which obliges to adopt alternative water management techniques. The work compared a simple on-farm water optimization technology called Wetting Front Detector (WFD) against computer program to estimate Crop Water Requirement (CWR) and farmers practice (FP). A field experiment was designed in Randomized Complete Block Design, replicated six times on farmers' fields. Results were compared on the basis of application, distribution, storage and water use efficiencies, and water productivity. The results illustrate that there was a significant difference between the water used in the CWR, WFD and FP. In comparison with FP, CWR saved irrigation water by 37% under pepper field. The WFD technology also saved the irrigation water by about 16% than the farmer method. The differences between the water optimization techniques can be accounted for by to differences in the efficiencies of application (E a ), storage (E r ) and irrigation water use which vary considerably from one type of irrigation water management to another at p&lt;0.05. Generally, CWR technique is more efficient (E a is 66.76%), followed by the WFD technique (E a is 62.32%) and farmer practice (E a is 55.74%) under pepper. On the basis of these values, the water saved by the CWR technique could irrigate 16.5% and the WFD 6-8% more area than the FP. Implicitly better crop production, also less competition between head and tail irrigators. The mean IWUE of CWR, WFD and FP were 3.67, 3.08 and 1.52. Based on this study, CWR technique appears to be a promising alternative for water saving without negligible trade-off in yield. The CWR had an E r of 66.42% which can be beneficially used by the crops while the WFD of 50.85%. As a result, yield of the crop from the CWR exceeds both techniques as it can provide sufficient amount of water for plants at their root zones. Considerable amount of water in FP is lost to Deep Percolation (D p ) and this has environmental and economic implications. Although many indicators confirm the importance of CWR approach, its practicality at farmers level is questioning as it is computer based. Thus, WFD would be an important tool to be considered to improve the current on farm water optimization by smallholder irrigators. DOI: 10.7176/JNSR/10-5-02 Publication date: March 31 st 2020