On-farm Irrigation Management Research Articles

Evaluating the Effects of Deficit Irrigation and Mulch Type on Yield and Yield Components of Onion in Fogera, Ethiopia

Water scarcity is a challenge for current irrigated agriculture globally. Under these circumstances, new on-farm irrigation management strategies should be established. An experiment was conducted at Fogera in 2021 to evaluate the effects of deficit irrigation (DI) and mulch type on onion yield and yield components. A factorial combination of three levels of DI (100%ETc, 75%ETc, and 50%ETc) and three mulch types No Mulch (NM), White Plastic Mulch (WPM), and Rice Straw Mulch (RSM)) were evaluated in RCBD with three replications. Monthly ETo, ETc, and irrigation scheduling were computed using CROPWAT 8.0 model. These studies showed that the onion yield and yield components were significantly affected by the main and the interaction effects. The maximum average plant heights (PH), leaf heights (LH), and number of leaves per plant (LNP) of 51.7 cm, 38.0cm, and 10.4 respectively, were recorded from 100%ETc whereas the minimum PH, LH, and LNP of 39.5 cm, 29.0cm, and 6.9 were recorded from 50%ETc treatment respectively. The highest average bulb weight (BW), bulb diameter (BD), and bulb height (BH) were 117.9gr, 6.4, and 5.7 cm recorded from 100%ETc treatment respectively. In contrast, the minimum average BW, BD, and BH were 79.9gr, 4.8, and 5.0cm recorded from 50%ETc respectively. The highest PH, LH, and LNP of onions were 51.9cm, 40.6cm, and 10.1 respectively recorded from RSM treatments. In contrast, the minimum PH, LH, and LNP of onions were 41.5cm, 31.1cm, and 7.5 respectively, recorded from WPM treatments. Similarly, the highest mean BW, BH, and BD 106.2gr, 5.8cm, and 6.0cm were obtained from the treatments of RSM respectively. In contrast, the lowest mean BW, BH, and BD 100.7gr, 5.0cm, and 5.3cm were obtained from NM treatments respectively. The interaction effects of DI and mulch showed that the onion yield at 100%ETc with RSM was 7.5% higher than that at 100%ETc with NM and 15.1% higher than the yield at 100%ETc with PM. The highest BW, BH, and BD of the onion 121.8 gr, 6.2, and 6.8 were obtained when the onions received 100%ETc and mulched with RS while the lowest average BW, BH, and BD of the onion were 77.3gr, 4.6cm and 4.1cm were obtained from 50%ETc with NM treatment combination. These results showed that RSM with 75%ETc improves onion yield and yield components.

A simulation tool to optimize the management of modernized infrastructures in collective and on-farm irrigation systems

Irrigated areas face new, pressing challenges due to escalating energy costs for pumping, increasing cost of seeds, fertilizers and agrochemicals, volatility of agricultural commodities, pressure of environmental regulations, water scarcity and mounting cost of irrigation infrastructure investments. At the same time, from the technical standpoint, farmers can chose from a wide array of irrigation design and operation alternatives for collective and on-farm systems, with variable effects on crop yield and profitability. These factors are often subjected to quick changes, complicating decision making. Simulation models have proven useful to support decision making in irrigation infrastructure, water / energy use, crop agronomy and soil management. In this research, new capacities of the Ador-Simulation software are reported, targeting comprehensive analyses of irrigation modernization. The model implements additional on-farm irrigation methods (low-pressure solid-set, center-pivot and drip irrigation); crop intensification (double cropping in the same season); and crop response to different on-farm irrigation management options (timing and frequency). Model performance was verified using a set of theoretical case studies. Finally, the model was applied to the optimization of irrigation design and management (water and energy) in the Bardenas XI project of northeastern Spain. Water application in center-pivot and drip irrigation were simulated using a normal distribution characterized by a user-defined Distribution Uniformity. In center-pivot, the application depth was randomized in every irrigation event, reproducing the random nature of wind disturbances. In drip irrigation, the application depth followed the same random distribution in all irrigation events, reproducing the deterministic effect of manufacturing and hydraulic variability. According to the literature, the effect of irrigation timing was treated differently for two key sprinkler irrigated crops: corn and alfalfa. Differences in water application and crop yield between on-farm methods resulted in different gross and net income. In the Bardenas XI project, irrigation performance indicators showed different patterns of inter-annual variability. Deep percolation was strongly affected by the amount of seasonal precipitation and by Distribution Uniformity. Indicators at the plot level were strongly determined by the on-farm irrigation method, the soil type, and the crop. In the conditions of Bardenas XI, the design option without pumping station was the most adequate. Natural pressure proved sufficient for a combination of low-pressure sprinkler irrigation, pivot and drip irrigation methods, distributed throughout the irrigated area. Escalating energy costs emphasize the need for careful assessment of pumping requirements at the design phase of irrigation projects.

An assessment of water footprint for irrigated rice in Punjab


 Water scarcity has become one of the highest risks for environmental and economic security worldwide. The water footprint for rice production, i.e., the total volume of freshwater consumed to produce a unit quantity rice has been estimated for three different agroclimatic zones of Punjab for the years 2000 to 2017. The results revealed that effective rainfall (Peff) improved in later years due to a change in crop calendar,legally enforced by an Act prohibiting the transplanting of paddy before a specified date. During the period of study, minimum crop evapotranspiration (ETc) was 4645 and maximum was ETc of 9511 m3ha-1 during 2014 and 2011, respectively. The green water footprint (WFgreen) for rice varied from 646litreskg-1of rice during low rainfall years (2012) to 1149 litre kg-1 of rice during heavy rainfall (1192 mm) during 2011.Out of a total water footprint (WFtotal) of 2650 litre kg-1, the share of blue water footprint (WFblue) was higher 1804 litre kg-1 (68%), indicating a need to improve on-farm irrigation management to conserve water resources.

Crop Row Detection through UAV Surveys to Optimize On-Farm Irrigation Management

Climate change and competition among water users are increasingly leading to a reduction of water availability for irrigation; at the same time, traditionally non-irrigated crops require irrigation to achieve high quality standards. In the context of precision agriculture, particular attention is given to the optimization of on-farm irrigation management, based on the knowledge of within-field variability of crop and soil properties, to increase crop yield quality and ensure an efficient water use. Unmanned Aerial Vehicle (UAV) imagery is used in precision agriculture to monitor crop variability, but in the case of row-crops, image post-processing is required to separate crop rows from soil background and weeds. This study focuses on the crop row detection and extraction from images acquired through a UAV during the cropping season of 2018. Thresholding algorithms, classification algorithms, and Bayesian segmentation are tested and compared on three different crop types, namely grapevine, pear, and tomato, for analyzing the suitability of these methods with respect to the characteristics of each crop. The obtained results are promising, with overall accuracy greater than 90% and producer’s accuracy over 85% for the class “crop canopy”. The methods’ performances vary according to the crop types, input data, and parameters used. Some important outcomes can be pointed out from our study: NIR information does not give any particular added value, and RGB sensors should be preferred to identify crop rows; the presence of shadows in the inter-row distances may affect crop detection on vineyards. Finally, the best methodologies to be adopted for practical applications are discussed.

Evaluation of remote sensing-based evapotranspiration models against surface renewal in almonds, tomatoes and maize

Evapotranspiration (ET) is a major hydrologic flux in water resources planning and irrigation management. While recent advances in remote sensing (RS) have enabled availability of high spatial and temporal resolution ET data, a lack of information related to error in the estimations has made it challenging to use this data for on-farm irrigation management decision making. In this study, three commonly used single-source RS based ET models (pySEBAL — a new version of the Surface Energy Balance Algorithm for Land; SEBS — Surface Energy Balance System algorithm; and METRIC — Mapping Evapotranspiration at High Resolution with Internalized Calibration) were used to estimate daily actual evapotranspiration (ETa) for almonds, processing tomatoes, and maize in the Central Valley of California. Model evaluation was conducted by comparing the predicted ETa from RS with in-situ measured ETa using surface renewal. Results indicated that the RS-based ETa estimations for all three models were within acceptable levels of uncertainty and agreed well with surface renewal estimates except for the underestimation by pySEBAL and METRIC during early season growth stages of processing tomatoes. This underestimation was attributed to the lack of accuracy when using single source ET models under lower vegetation cover condition (when ET is dominated by soil evaporation). Better estimates of ETa with pySEBAL and METRIC were detected at full cover, which explains the applicability of these two models to irrigation management during peak crop water demand. SEBS performed the best among the three RS-based models for daily ETa estimation for all crops. This suggests that SEBS-based ETa estimates can be adopted in operational irrigation management programs for farms that have not installed in field ETa sensors such as Tule Sensors (Tule Technologies Inc.). In addition, RS based ET is spatially distributed which can help to identity spatial variability between different irrigation zones.

Benchmarking irrigation water use in producer fields in the US central Great Plains

Efficient use of freshwater resources is necessary to balance food production and long-term sustainability of irrigated agricultural systems. Here we developed a framework to benchmark irrigation water use relative to crop yield for individual fields based on site-specific weather and soil. Subsequently, we used the framework to diagnose on-farm irrigation management, in relation to crop production, in maize and soybean producer fields in Nebraska (USA). We found actual irrigation to be similar to estimated irrigation water requirement in about half of the fields (i.e. small water surplus). Remarkably, these fields attained yields similar to fields where actual irrigation exceeded water requirements (i.e. large water surplus). Underlying causes for water surplus included producer risk aversion in soils with low water storage capacity, use of coarse methods for scheduling irrigation, and tillage. Scenario assessment indicated that total irrigation volume could potentially be reduced up to 25%–40%, without hurting crop yields, by reducing current irrigation surplus in years with above- or near-average seasonal precipitation. About a third of the producer fields already achieved high yields with little water surplus, supporting the contention that achieving high productivity with less irrigation by better matching irrigation amounts in relation with crop water requirements are compatible goals. The proposed framework can be applied to other crops and regions provided there are well-validated models, local soil and weather datasets, and reliable field-level irrigation, yield, and management records.

Investigation of irrigation performance at the tertiary canal level in the Nile Delta of Egypt

One of the objectives of the Irrigation Improvement Project (IIP) in the Nile Delta, Egypt, is to facilitate equitable water distribution and improve on-farm irrigation management by improving irrigation infrastructure. Because paddy rice is a major summer crop in Egypt and it consumes the greatest amount of water in comparison with other crops, the authors focused on monitoring and evaluating the irrigation practices of farmers during summer and examined the extent of sufficient and equitable water distribution in the Dakalt branch canal. Three tertiary canals that had been improved under IIP were selected from upstream, midstream, and downstream along the Dakalt branch canal. Two, three, and one pumping stations were selected from the upstream, midstream, and downstream, respectively, for monitoring pump operations in order to quantify the water supply. Cropping patterns and pump operation records were collected. The irrigation water requirement for each crop was estimated using the UN Food and Agriculture Organization Penman–Monteith method. Water sufficiency (WS), which is the ratio of water supply to water demand, was then calculated, and equitable water distribution among the tertiary canals was assessed based on these results. The mean WS during the mid-irrigation season of June, July, and August for two years at the downstream tertiary canal was 0.75, which was considered to be poor sufficiency, whereas the mean WS values at the upstream and midstream tertiary canals were 0.93 and 0.93, respectively, which were considered to be good sufficiency. The downstream tertiary canal received less water than required compared with the others, and this insufficient and inequitable supply affected rice yields because the average yield downstream in 2013 and 2014 was 7.6 t ha−1, while those for upstream and midstream were 10.0 and 10.5 t ha−1, respectively; this difference was significant. However, WS downstream of the upstream tertiary canal in 2013 and WS upstream of the midstream tertiary canal in 2014 were below 0.8. This was attributed to a drastic change in the cropping pattern at the tertiary canal level and to the insufficient water supply to the tertiary canals.

IMPACT OF CLIMATE CHANGE AND AGRICULTURAL PRACTICES ON IRRIGATION WATER REQUIREMENTS UNDER NILE DELTA CONDITIONS

Agriculture in Egypt consumes about 80% of the available water resources. With an ever-increasing demand and a relatively fixed supply of fresh water, every drop of water should be treated as a drop of life. Consequently, effective on-farm irrigation management becomes a must. The present study aims to estimate amounts of irrigation water (IW) requirements for crops grown in the Nile Delta Region over three decades (1985-2015). In addition, the impact of weather variability on the irrigation water needs from year to year is assessed using the FAO CROPWAT 8.0 model. Results showed that the mean IW requirements for winter crops ranged between 3,812 m3ha-1 (kidney beans) and 5,610 m3 ha-1 (sugar beet). On the other hand, IW requirements for summer crops are much higher with mean values ranging between 5,483 m3 ha-1 (kidney beans) to 25,411 m3ha-1 (sugarcane). For orchards, the mean amount of IW requirement ranged between 11,728 m3ha-1 (grapes) to 24,059 m3.ha-1 (banana). Variability of IW requirements due to climate variability ranged between -14% and +27% for winter field crops, between -6% and +17% for winter vegetable crops, between -6% and +19% for summer field crops, between -6% and +20% for summer vegetable crops, and between -5% and +20% for orchards. Summer cultivation of the same vegetable crops results in an increase in water consumption ranging between 44 and 145%. The use of new short duration varieties of rice (120 days instead of 150 days) saves about 4,000 m3ha-1 of irrigation water.

Optimization model for on-farm irrigation management of Mediterranean greenhouse crops using desalinated and saline water from different sources

Desalination is becoming a competitive alternative for supplying quality water to irrigation districts in dry areas. However, its acceptance level among farmers is often low due to its higher price, the need for additional fertilization, and the misconception that it would negatively affect yield and crop quality. This work presents a decision support system that would help them to make irrigation management decisions regarding the optimal combination of saline and desalinated seawater (DSW), which would provide maximum economic profit. The model has been specially designed for Mediterranean greenhouse cropping systems. The proposed model was validated by applying it to a real watermelon crop which was experimentally monitored. A sensitivity analysis was then conducted in order to analyze the effect of different limiting factors on the optimal combination of water and the optimal profit for farmers.The application of the model to the case study demonstrated that it is profitable to use a blend of DSW and brackish water for irrigation of greenhouse crops. Despite the higher cost of the DSW, the economic optimum was achieved for higher DSW fractions than those which are used today. This sensitivity analysis has demonstrated that brackish water salinity, irrigation uniformity and crop tolerance are relevant factors that affect the optimal combination decisions. This work may encourage farmers to accept desalinated water.

Mapping and management of aquifers suffering from over-exploitation of groundwater resources in Baswa-Bandikui watershed, Rajasthan, India

Dwindling of groundwater resources in northern India for the past few decades is one of the serious concerns. Groundwater resources in the Baswa-Bandikui watershed located in the state of Rajasthan in northwest India are ‘overexploited,’ and the groundwater level in the area is gradually depleting. In order to find a solution to this serious problem, micro-level aquifer mapping was carried out in the area. The study involved the application of advanced geophysical techniques like airborne electromagnetic, electrical resistivity tomography, vertical electrical sounding and VES coupled with conventional hydrogeological investigations such as water well drilling, aquifer performance tests, etc. The area is characterized by alluvium underlain by hard rock aquifer. Both aquifer types are in hydraulic continuity at places. Numerical modeling studies reveal that, within the next 10 years, a considerable portion of the productive upper alluvium aquifer will go dry if groundwater extraction continues at the present rate. Mathematical simulation studies were further extended to test the efficacy of the hypothetical groundwater management plans proposed for the study area. The studies indicate that the situation is so critical that it would require simultaneous implementation of four management interventions, viz., regulation of groundwater extraction, artificial recharge to groundwater, on-farm irrigation management practices and water conservation practices such as recycle and reuse of water to control further depletion of the water table.

Adaptation of pressurized irrigation networks to new strategies of irrigation management: Energy implications of low discharge and pulsed irrigation

This paper analyzes the consequences of adopting new on-farm irrigation management strategies (low discharge rates, long irrigation times and high frequencies) in an existing on-demand and sectorized pressurized irrigation system in eastern Spain. The sectorized behavior of the network was analyzed using two criteria: (i) the operating sectors obtained in a first stage by arranging the hydrants depending on their altitude respecting the pumping station and (ii) the operating sectors obtained by means of an optimization process. The Simulated Annealing combinatorial metaheuristic optimization technique was employed to find the best solution. Random on-demand patterns were generated using a Montecarlo simulation. The hydraulic requirements of the network were analyzed in every scenario by the Epanet 2.0 engine. The effect on energy consumption, power requirements and energy costs was assessed taking into account the electricity tariff billing structure. It was found that reductions in emitter discharge (qe) and Energy consumption (E)-Energy Cost (EC) savings are not inherently related to each other. Certain amounts of E and EC could be saved when the number of sectors and operating time parameters were properly selected. Pulsed irrigation in the current scenario showed an energy saving potential of 10.67, 6.43 and 6.99% for power capacity, E and EC, respectively.

Adaptation of Soil Spectral Reflectance Technique for Monitoring and Managing of Center-Pivot Irrigation Water

Center pivot irrigation system has the potentiality for economically net –return of various crop patterns, although it’s higher fixed costs inputs. Therefore, water management under the specified center pivot irrigation system can play a crucial role in maximizing water unit productivity and enhancing physical-agricultural resources sustainability. Hereby, the aim of this research was to evaluate the optional of a general reflectance model based solely on soil moisture distribution pattern as a key for on-farm irrigation management under center pivot irrigation system. Data revealed that the relative reflectance was strongly correlated with soil moisture contents. However, the best correlation was found act high soil moisture level between the reflectance values of 700 nm (Red-NIR) wave length and the volumetric water content (R² = 0.9). Moreover, the observed data could help to quality the strong in influence of soil moisture on spectral reflectance and absorption features and should aid in the development operational and management algorithms of on-farm irrigation systems.

Evapotranspiration mapping for agricultural water management: An overview

Evapotranspiration (ET) is an essential component of the water balance. Any attempt to improve water use efficiency must be based on reliable estimates of ET, which includes water evaporation from land and water surfaces and transpiration by vegetation. ET varies regionally and seasonally according to weather and wind conditions. Remote sensing based agro-meteorological models are presently most suited for estimating crop water use at both field and regional scales. Numerous ET algorithms have been developed to make use of remote sensing data acquired by sensors on airborne and satellite platforms. The use of remote sensing to estimate ET is presently being developed along two approaches: (a) land surface energy balance (EB) method and (b) Reflectance based crop coefficient and reference ET approach. The reported estimation accuracy varied from 67 to 97% for daily ET and above 94% for seasonal ET indicating that they have the potential to estimate regional ET accurately. Automated contours are not confined to specific pre-determined geographic areas (as in MLRA), require less time and cost. The spatial and temporal remote sensing data from the existing set of earth observing satellite platforms are not sufficient enough to be used in the estimation of spatially distributed ET for on-farm irrigation management purposes, especially at a field scale level (~10 to 200 ha). However, research opportunities exist to improve the spatial and temporal resolution of ET by developing algorithms to increase the spatial resolution of reflectance and surface temperature data derived from K1VHRR/Landsat/ASTER/MODIS images using same/other-sensor high resolution multi-spectral images.

Gender in Irrigated Farming

The division of Central Asia into several independent states, and the transition from the centrally planned economy to a market economy in the majority of those states, affected all sectors and all social levels in the region. One such example is irrigation. Centrally planned and financed from Moscow, on-farm irrigation systems were managed by collective farms. The process of decentralization through the dismantling of collective farms led to a restructuring of services and infrastructure throughout Central Asia. Water users associations (WUAs) have been established to transfer on-farm irrigation management to farmers throughout the region, including Uzbekistan. Many women in Uzbekistan actively participate in farming activities, so their role in the on-farm irrigation restructuring process is important. Yet, the findings from this study suggest that participation of women is very limited in WUAs as very few women are registered as land owners. Because of high levels of migration by men to other countries, farm activities are mostly carried out by women. Despite this, women’s decision-making power within their farms is limited.

Leaching irrigated saline sandy to sandy loam apedal soils with water of a constant salinity

With the optimization of irrigation, more salts accumulate in the root zone of soils, due to less over-irrigation. On-farm irrigation management requires a certain amount of leaching to ensure sustainability. The objective is to quantify the pore volume of water required to efficiently leach excess salts from two saline soils, widely irrigated in central South Africa. A total of 30 lysimeters, 15 per soil type arranged in two parallel rows under a moveable rain shelter, were used. Five different salinity profiles per soil type, replicated three times, were leached using irrigation water with a 75 mS m−1 electrical conductivity. During irrigation the residual more saline pore water was displaced from the top downward through the root zone. The mean salinity of the soil profiles approached an equilibrium concentration equal to that of the irrigation water after 0.9 pore volume of soil was displaced by drainage water. For the sandy soil 0.2 and for the sandy loam soil 0.3 pore volumes were required to efficiently remove 70% of the excess salts. The remainder of the water was needed to leach the remaining 20% of the excess salts. This, however, was not efficient in terms of the amount of water required.

ET mapping for agricultural water management: present status and challenges

Evapotranspiration (ET) is an essential component of the water balance. Remote sensing based agrometeorological models are presently most suited for estimating crop water use at both field and regional scales. Numerous ET algorithms have been developed to make use of remote sensing data acquired by sensors on airborne and satellite platforms. In this paper, a literature review was done to evaluate numerous commonly used remote sensing based algorithms for their ability to estimate regional ET accurately. The reported estimation accuracy varied from 67 to 97% for daily ET and above 94% for seasonal ET indicating that they have the potential to estimate regional ET accurately. However, there are opportunities to further improving these models for accurately estimating all energy balance components. The spatial and temporal remote sensing data from the existing set of earth observing satellite platforms are not sufficient enough to be used in the estimation of spatially distributed ET for on-farm irrigation management purposes, especially at a field scale level (∼10 to 200 ha). This will be constrained further if the thermal sensors on future Landsat satellites are abandoned. However, research opportunities exist to improve the spatial and temporal resolution of ET by developing algorithms to increase the spatial resolution of reflectance and surface temperature data derived from Landsat/ASTER/MODIS images using same/other-sensor high resolution multi-spectral images.

Farmers' Practices in On-Farm Irrigation Management in the Gezira Scheme, Central Sudan

Farmers' Practices in On-Farm Irrigation Management in the Gezira Scheme, Central Sudan

Effects of waterlogging and soil salinity on irrigated agriculture in the Murray Valley: a review

A physical model was used to assess the effects of surface waterlogging and soil salinity on the productivity of winter cereals and irrigated dairy pastures on irrigation farms in the Berriquin and Wakool Irrigation Districts of the Murray Valley region of New South Wales. Parameters describing the physical properties of major soil types were combined with statistically derived estimates of rainfall excess over evapotranspiration to establish the incidence of waterlogging. Soils predisposed to waterlogging occupy 150000 ha of Berriquin District (45% of District) and 24 800 ha of Wakool District (73%). Estimates of yield losses from waterlogging ranged from 12.5% in annual subterranean clover-based pastures, 20% in winter cereals, to 25% for perennial ryegrass-white clover pastures. The relationships between yield and soil salinity were determined for barley, wheat, white clover, subterranean clover, and irrigated annual and perennial pastures growing under existing management practices in shallow watertable areas of the 2 Districts. Response functions were applied to soil salinity frequency distributions to derive production loss coefficients. Surveys showed that average soil salinities were lower in Berriquin than in Wakool. In 1984, 43% the soils in shallow watertable areas of Berriquin could be classed as saline, whereas, in 1982 the corresponding figure for Wakool was 72%. A further survey taken in 1984, 2 years after the inception of a deep drainage scheme, showed that saline soils in Wakool had decreased to 46% of the total area.We assessed economic losses associated with soil salinity and waterlogging by applying the derived loss coefficients to achievable yields for known production areas. Total annual losses for the 2 Districts exceeded $A13 million, or 16% of the 1984 value of the District's agricultural production. This figure underestimates real losses because we excluded livestock enterprises other than dairying, as well as summer cropping, from the study. Losses due to waterlogging ($A10 million overall) were more serious than those due to soil salinity (nearly $A4 million), particularly in Berriquin where shallow watertables were less extensive. In Wakool, 2 years' operation of the deep drainage scheme reduced losses due to soil salinity by $A750 000.Thus surface waterlogging and soil salinity cause serious economic losses in the irrigated areas of southern New South Wales. Research into appropriate techniques for on-farm irrigation management may reduce these losses, and delay further development of shallow watertables and soil salinisation, with sub of stantial economic and environmental benefits.