Furrow Irrigation Research Articles

Irrigation alters biogeochemical processes to increase both inorganic and organic carbon in arid-calcic cropland soils

Irrigation in arid croplands is necessary to sustain crop growth, but with increasing water scarcity and population growth in drylands, irrigation systems may need to shift from flooding to dripping techniques to cope with increased water demand. Therefore, it is important to understand how irrigation drives organic and inorganic carbon dynamics in arid-calcic soils. This study on arid-calcic cropland soils assessed the influence of flood and subsurface drip irrigation on soil organic carbon (SOC) and soil inorganic carbon (SIC) formation as influenced by soil chemical properties and bacterial and fungal biomass. As well, these dynamics were assessed in an unmanaged/unirrigated desert soil. Under drip irrigation, SOC was significantly greater than under flood irrigation, but flood stored more SIC than drip irrigation and no irrigation. The observed SOC–SIC patterns were likely driven by calcium binding. Flood irrigation adds significantly more calcium and bicarbonate to the system, while leaching dissolved organic carbon (DOC). Under flood, calcium is likely more preferentially bound as calcium carbonate. Under drip irrigation, less water was added, calcium and SOC were maintained in the rooting zone where SOC may be stabilized via cation-mediated bridging. Despite higher SOC under drip, more total, and bacterial biomass were detected under flood than drip irrigation, which promoted fungal biomass. Bacterial biomass under flood irrigation may be contributing to microbial carbonate precipitation, supported by the greater presence of common bacterial groups known to contribute to this process, and significant positive relationships with calcium. This research emphasizes the importance of examining SOC and SIC dynamics from abiotic and biotic and particularly microbial perspectives; to optimize soil carbon storage in arid croplands.

The Influence of Organic and Inorganic Fertilizer Applications on Nitrogen Transformation and Yield in Greenhouse Tomato Cultivation with Surface and Drip Irrigation Techniques

Facility agriculture in China is facing the challenge of the excessive use of chemical fertilizers (nitrogen fertilizers), which hinder the development of sustainable and environmentally friendly agriculture. Optimizing nitrogen fertilizer allocation is essential to balance agricultural production and environmental concerns. The aim of this study was to determine the optimal organic fertilizer strategy for tomato cultivation under different irrigation methods. An experiment was conducted in a greenhouse, and two irrigation methods, surface irrigation (SI) and drip irrigation (SDI), were used during tomato growth. The fertilization treatments included urea alone (CK); 30%, 40%, and 50% chicken manure mixed with urea (FC1, FC2, FC3); and 50% cow manure and sheep manure mixed with urea (FB3, FS3). The results showed that the irrigation techniques and fertilization had significant effects on ammonia volatilization accumulation, soil mineral nitrogen content, and tomato yield and quality. Compared with the surface irrigation technique with the same amount of fertilizer application, the drip irrigation technique reduced the ammonia volatilization accumulation by a maximum of 76.40%. The SDIFC3 and SDIFB3 ammonia volatilization accumulation was as low as 5.24 (kg·hm−2) and 7.61 (kg·hm−2); the soil nitrate nitrogen content was reduced, and the tomato yield increased significantly by 17.11%. The SDIFC3 treatment achieved a maximum yield of 13,414 (kg·hm−2), increased the tomato vitamin C and soluble sugar contents by 19.13% and 8.97%, and lowered the titratable acid content by as much as 30.51%. Under drip irrigation fertilization conditions, the SDIFC3 treatment showed lower ammonia volatilization accumulation and the highest tomato yield and quality compared to CK and the same proportion of organic fertilizer substitutes with cow and sheep manure. The increase in the proportion of organic fertilizers replacing chemical fertilizers resulted in a gradual decrease in ammonia volatilization accumulation and a gradual increase in the tomato yield and various qualities. The soil mineral N content, on the other hand, was significantly affected by irrigation, fertilizer application, and water–fertilizer interaction effects, with a tendency for the content to increase and then decrease after each fertilizer application. The mineral N content was lower with drip irrigation compared to surface irrigation, especially in the 10–20 cm soil layer than in the 0–10 cm layer. Increasing drip irrigation and organic fertilizer substitution significantly increased the vitamin C and soluble sugar contents in the tomatoes, while decreasing the titratable acid content.

Impact of irrigation management on crop water footprint reduction using RZWQM2 in Baghdad, Iraq

Water scarcity becomes a serious global challenge in several world regions and particularly in the Middle East. Appropriate irrigation practice is critical for improving crop yield and alleviating crop water footprint (WF). To alleviate water scarcity, the possibility of reducing wheat and barley water footprint has been examined through alternative surface irrigation practices. The WF was compared under farmers’ irrigation practice and experimental irrigation practice to discover the impact of irrigation practices on the reduction of WF in the west of Baghdad. Weather data and crop management information were collected from 2016 to 2020 for the farmer’s fields in the study area as well as for the experimental field. The Root Zone Water Quality Model (RZWQM2) was used for estimating wheat and barley evapotranspiration. The study results showed that the crop WF was well estimated using the RZWQM2 due to the model capability and accuracy for estimating the impact of field management on crop evapotranspiration and crop water use. Experimental irrigation practice could improve crop yield, water use efficiency, and water profitability by up to 28%, 35%, and 35%, respectively; while the WF was reduced by 35%, compared to the farmers’ irrigation practice. The WF of the wheat crop was lower than the barley WF due to the low barley production.

The effect of alternate partial root-zone drying and deficit irrigation on the yield, quality, and physiochemical parameters of milled rice

While paddy fields produce a high yield, they also require a large amount of water and produce a significant amount of methane. Therefore, the adoption of water-saving irrigation techniques for rice cultivation is critical. Furrowed rice farming may be a viable alternative to paddy rice cultivation. The objective of the present study was to evaluate the impact of alternate partial root-zone drying irrigation on rice yield, milled rice quality, and cooking quality under furrow rice cultivation. A two-year field trial was conducted on a local rice cultivar, Tarom Hashemi, in 2015 and 2016. Seven water regimes, including three levels of regulated deficit irrigation (RDI), three levels of alternate partial root-zone drying irrigation (APRDI), and conventional flooding irrigation (CFI), were used in this study. In RDI and APRDI treatments, plots were irrigated when soil matric potential had reached −0.1 (RDI1 and APRDI1), −0.3 (RDI3 and APRDI3), and −0.6 bar (RDI6 and APRDI6). RDI1 and APRDI1 treatments produced milled rice yield similar to the CFI, while irrigation water productivity (IWP) was significantly higher by 22.9% and 45.7%, respectively. Regardless of the soil water potential, the IWP in APRDI treatments was 16% higher than that of RDI treatments. Severe water stress (RDI6 and APRDI6) caused a marked increase in amylose content and alkali spreading value of milled rice resulting in improved cooking quality. Nitrogen uptake in APRDI treatments was 2% higher than that of RDI treatments. On average, methane emission per milled grain yield declined by 77.9% and 78.7% in RDI and APRDI treatments, respectively. Our data indicate that the expensive and laborious practice of puddling can be avoided to increase water productivity and improve rice quality without sacrificing yield. The results also show that furrow rice cultivation could significantly reduce the methane emission contribution of rice production.

Assessing the Productivity and Economic Sustainability of Banana Cultivation under Diverse Colored Plastic Mulches in Western Maharashtra Region of India

Aims: Banana is a heavy feeder of the nutrients. It is therefore, essential to study the crop with respect to color plastic mulches and irrigation scheduling. In this study, the effect of various colored plastic mulches on the growth and quality parameters of banana crop along with its economic feasibility was assessed.
 Study Design: This experiment followed a Complete Randomized Block Design (CRBD) with nine treatments (T1 to T9), each with three replications.
 Place and Duration of Study: This study was carried out at Mahatma Phule Krishi Vidyapeeth, Rahuri, Maharashtra for the period of one year (crop cycle of banana).
 Methodology: Different color plastic mulches in combination with varying irrigation schedule were evaluated for growth and yield of banana crop. Various growth parameters of banana crop, yield, micrometeorological parameters, water use efficiency and cost economics of banana production were evaluated for the different treatments.
 Results: The highest banana yield recorded was 84.45 tons per hectare, and this was achieved using silver-black plastic mulch in conjunction with daily drip irrigation set at 48% of the Pan Evaporation (Ep) rate, referred to as treatment T3. Treatment T3 led to 37% increase in banana yield compared to surface irrigation with 1.00 Irrigation Water to Cumulative Pan Evaporation (IW/CPE) ratio (treatment T9). The seasonal water requirement for banana cultivation with treatment T3 amounted to 1015 mm, resulting in an impressive water use efficiency of 83.18 kg ha-1 mm-1. Normalized Difference Vegetation Index (NDVI) values exhibited a range from 0.3895 during the initial growth stage of the banana to 0.8918 at the peak growth stage.
 Conclusion: From an economic perspective, the utilization of silver-black plastic mulch emerged as the best choice among all treatments, boasting the highest benefit to cost ratio of 2.34 and yielding the maximum net income of ₹ 3, 86,286 per hectare.

Enhancing Broccoli (Brassica oleracea var. italica) Growth, Yield and Water Productivity through Irrigation and Mulching Techniques in Local Climate

Introduction: Broccoli's efficient irrigation management is critical with changing climatic patterns and increasing water scarcity. The study aimed to assess the impacts of various irrigation methods and mulching techniques on broccoli cultivation.
 Methodology: A randomized complete block design with three replications was used, considering two factors: irrigation methods (drip and surface) and mulching materials (black polythene, white polythene, grass straw, and no mulching).
 Results: Drip irrigation, combined with black polythene mulching (I1MBP), consistently demonstrated its superiority that significantly improved multiple aspects of plant growth, yield and water productivity. In particular, I1MBP resulted in the highest plant heights at different growth stages, with the tallest plants at harvest (43.87 cm). However, surface irrigation with the same mulching (I2MBP) also showed higher plant heights but slightly shorter than drip irrigation. A similar trend was observed for the number of leaves per plant, with the I1MBP treatment having the most leaves. In curd development, the treatment (I1MBP) produced curds with larger diameters and lengths at harvest. In contrast, surface irrigation with the same mulching (I2MBP) also showed a larger curd size but, again, slightly lower than drip irrigation. In terms of curd initiation time, the I1MBP treatment had a longer duration, while the I1MN treatment had a shorter duration. Surface irrigation treatments followed a similar trend. With respect to yield, the I1MBP consistently had the highest unit weight of curd (423.14 g plant-1), yield per plot (25.39 Kg plot-1), and total yield (16.93 t ha-1), regardless of the mulching condition. However, surface irrigation with the same mulching (I2MBP) also showed higher yields (15.93 t ha-1) but slightly less than drip irrigation. On the other hand, the I1MBP demonstrated superior water use efficiencies (74.68 kg/ha-mm) and productivity (7.47 Kg m-3) compared to other treatments. Still, surface irrigation with the same mulching (I2MBP) also exhibited better water use efficiency (64.98 kg/ha-mm) and productivity (6.50 Kg m-3) than treatments with no mulch. Environmental factors, including temperature, humidity, wind speed, sunshine hours, and evaporation, were found to correlate with broccoli growth stages, emphasizing their influence on crop development.
 Conclusion: Finally, drip irrigation and black polythene mulching are pivotal for improved growth, yield, and water management, contributing to sustainable agriculture practices.

Application of silicon foliar spray to increase growth and yield of shallot (Allium ascalonicum L.) under sprinkler and furrow irrigation system

Silicon foliar application can help mitigate the negative effects of drought stress and is an important component of climate-smart agriculture. This study aimed to assess the effect of various concentrations of silicon foliar spray (SFS) on shallot growth and yield under two irrigation systems. On-farm experiment was arranged in the randomized block with split-plot design in dryland of East Lombok District of Nusa Tenggara Barat (NTB) Province during dry season of 2018. The main plot was furrow and sprinkler irrigation system, and the sub-plot was four concentrations of SFS (0, 15, 30, and 45 ml) with five replications. In general, plant height, leaf number, bulb number, and fresh biomass of shallot were increased following the increase of SFS concentration, with the optimal dosage being 15 ml/lt for the experiment site. Shallot fresh yield was significantly higher under sprinkler irrigation (3.72 kg/m2) compared to furrow irrigation (2.70 kg/m2). The significant interaction effects were found on plant height (20 and 40 days after planting) and weight loss (after sun-dried and after 90 days of storage to produce bulb seeds). All in all, the sun-dried shallot yield was significantly higher from 14.76% (30 ml) to 28.40% (15 ml) compared to the control.

Identification and mapping of surface irrigation potential in the data-scarce Jewuha watershed, Middle Awash River Basin, Ethiopia

Abstract This study was conducted to identify and map the surface irrigation potential in the data-scarce Jewuha watershed of the Awash Basin, Ethiopia. The suitability of the land, based on the soil characteristics and slope, was first assessed by the parametric evaluation technique. The overall suitability of the land was then evaluated considering additional factors including land use land cover, proximity to a water source and road using weighted overlay analysis through the analytic hierarchical process (AHP). Water diversion sites as the source of water supply points were selected based on theoretical site selection criteria with the help of a geographic information system (GIS) and physical observation. The surface water available at the diversion sites was estimated using the Soil and Water Assessment Tool (SWAT) model combined with the spatial proximity regionalization technique. The land suitability analysis revealed that 16.7% (11,359 ha) of the study area is suitable for surface irrigation. Five diversion sites were identified as sources of water supply and the total flows at these sites were 12.92 Mm3. It was found that only 27.3% (3,098 ha) of the suitable land, 5% of the total area of the watershed, can be effectively developed by surface irrigation.

Impact of wood fiber substrate additions on water capture through surface and subsurface irrigation

Impact of wood fiber substrate additions on water capture through surface and subsurface irrigation

Automação de irrigação de lavouras de arroz usando controlador fuzzy e previsão meteorológica

ABSTRACT This paper presents a new irrigation controller based on fuzzy logic that uses weather forecast data and crop characteristics to evaluate the real-time need for irrigation of rice crops and to increase the efficiency of irrigation systems. Tests were performed with real data obtained from three different crop fields in Rio Grande do Sul State, Brazil, and on four meteorologically different days of the 2021/2022 harvest to demonstrate the ability to reduce power consumption for irrigation; the power consumption on days of heavy precipitation was above 80% under all simulated conditions. Depending on the size of the crop and the tested meteorological conditions, the minimum reductions in energy consumption were between 33-66% on dry days with no precipitation forecast. More than 15% reduction in the flow of the water catchment was also observed, even in the most adverse farming scenarios. This study reveals the necessity for technological advances in rice-crop irrigation systems to increase the efficiency of flood irrigation in large areas for reducing electricity consumption, increasing the profitability of rural producers, and ensuring the preservation and availability of water resources.

Water Use, Growth, and Yield of Ratooned Guayule under Subsurface Drip and Furrow Irrigation in the US Southwest Desert

Guayule (Parthenium argentatum, A. Gray) is a perennial desert shrub with ratoon-cropping potential for multiple harvests of its natural rubber, resin, and bagasse byproducts. However, yield expectations, water use requirements, and irrigation scheduling information for ratooned guayule are extremely limited. The objectives of this study were to evaluate dry biomass (DB), contents of rubber (R) and resin (Re) and yields of rubber (RY) and resin (ReY) responses to irrigation treatments, and develop irrigation management criteria for ratooned guayule. The water productivity (WP) of the yield components were also evaluated. Guayule plants that were direct-seeded in April 2018 were ratooned and regrown starting in April 2020, after an initial 2-year harvest at two locations in Arizona: Maricopa and Eloy on sandy loam and clay soils, respectively. Plots were irrigated with subsurface drip irrigation (SDI) at 50, 75, and 100% replacement of crop evapotranspiration (ETc), respectively, and furrow irrigation at 100% ETc replacement, as determined by soil water balance measurements. The Eloy location did not include the 100% irrigation treatment under SDI due to unsuccessful regrowth for this specific treatment. The irrigation treatments at the locations were replicated three times in a randomized complete block design. After 21–22 months of regrowth, the guayule plants were harvested in plots. The results showed that DB increased with the amount of total water applied (TWA, irrigation plus precipitation), while R and Re were reduced at the highest TWA received at both locations. Ultimately, the SDI treatments with 75% ETc replacement resulted in the best irrigation management in terms of maximizing RY and ReY, and WP for both locations and soil types. Compared to the initial 2-year direct-seeded guayule crop, ratooned guayule required less TWA and attained higher DB, RY, and ReY, as well as higher WP, with average increases of 25% in dry biomass, 33% in rubber yield, and 32% in resin yield. A grower’s costs for planting the initial direct-seeded guayule crop would be offset by the additional yield revenue of the ratooned crop, which would have comparatively small startup costs.

Mitigating ammonia volatilization in rice cultivation: The impact of partial organic fertilizer substitution

Optimizing water and nitrogen management to minimize NH3 volatilization from paddy fields has been extensively studied. However, there is limited research on the combined effect of different rates of organic fertilizer substitution (OFS) and irrigation methods in rice cultivation, exploring an effective water and nitrogen combination is beneficial to mitigate NH3 volatilization. To address this gap, we conducted a two-year field experiment to investigate NH3 volatilization under different OFS rates (0%, 25%, and 50%) combined with continuous flooding irrigation (CF) and alternate wet and dry irrigation (AWD). Our findings revealed that NH3 fluxes exhibited similar emission patterns after each fertilization event and significantly decreased with increasing rates of OFS during the basal stage. Compared to no substitution (ON0), the low (ON25) and high (ON50) rates of OFS reduced cumulative NH3 emissions by 18.9% and 16.6%, and lowed NH3 emission factors (EFs) by 26.7% and 23.3%, respectively. Although OFS resulted in a slight reduction in rice yield, yield-scaled NH3 emissions were significantly reduced by 11.9% and 6.5% under the low and high substitution rates, respectively. This reduction was mainly attributed to the slight yield reduction observed at the low substitution rate. Furthermore, when combined with ON0, AWD irrigation had the potential to increase NH3 volatilization. However, this increase was not observed when combined with ON25 and ON50. During each fertilization stage, floodwater + concentration emerged as the prominent environmental factor influencing NH3 volatilization, showing a stronger and more positive correlation compared to other factors such as floodwater pH, soil pH, and NH4+ concentration. Based on our findings, we recommend implementing effective water and nitrogen management strategies to minimize NH3 volatilization in rice cultivation. This involves applying a lower rate of organic fertilizer substitution during the basal stage, maintaining high water levels during fertilization, and implementing mild AWD irrigation during non-fertilization periods.

SIRMOD and WinSRFR model simulation comparisons for furrow irrigation in a sugarcane field at Kasinthula Cane Growers Scheme, Malawi

Models play a key role towards understanding real-life processes in various fields including surface irrigation. A better understanding of the performance of a particular model in simulating the processes in question is of prime importance. Against this background, simulation capabilities of the surface irrigation simulation, evaluation and design (SIRMOD) and WinSRFR models were compared through field studies conducted at Kasinthula Cane Growers Scheme (KCGS) in Malawi. The objectives of the study were to assess performance of each model in simulating water application and distribution efficiencies, and conduct a comparison in the resulting efficiencies and user-friendliness of each model. The study was conducted in sugarcane field furrows using volume balance method. Each of the two models estimated irrigation application efficiency, distribution efficiency, and deep percolation values that were very close to 51%, 79% and 49%, respectively, implying that the two were representative of each other. Both models showed the need for improving the current operation variables at KCGS to achieve optimal performance. It was further established that the simulation procedure in SIRMOD was more tedious than the one employed in WinSRFR. Furthermore, WinSRFR had a platform for conducting sensitivity analyses while SIRMOD did not. However, SIRMOD simulations had lower RMSE values for advance and recession than WinSRFR implying that SIRMOD model more accurately simulated these parameters than WinSRFR. The study also established that WinSRFR was a more appropriate model for practical application by irrigation frontline staff and/or farmers because it is more user-friendly than SIRMOD. The study concluded that SIRMOD's simulation accuracy presented it as a better research model than WINSRFR hence it would be ideal for calibrating and validating other surface irrigation models.

Response of NPK Fertilization and Irrigation in Nutrient and Soil Moisture Distribution Under High-Density Apple Plantation in the NW Himalayan Region

ABSTRACT Drip fertigation provides enormous opportunities for the effective utilization and distribution of water and nutrients in sustainable management of orchard. Under various drip irrigation and fertigation schedules, the analysis of NO3 −-N and NH4 +-N distribution within the soil has been found to be efficacious to enhance the crop growth. Over the 2-year period of study (2019 and 2020), the response of NPK fertilization and irrigation in nutrient and soil moisture distribution under high-density apple plantation in the NW Himalayan region was investigated. In the present study, under drip irrigation, the wetting front extended up to 45 cm horizontally from the emitter; however, the maximum increase in soil moisture content remained confined near the emitting point. The soil moisture content decreased consistently with the increasing horizontal distance from the emitter. Drip irrigation recorded a higher soil moisture content at the surface soil depth of 0–15 cm compared to conventional surface irrigation, where the sub-surface soil depths of 15–30 cm registered a higher moisture content. The distribution of NO3 −-N and NH4 +-N content under drip fertigation nearly followed the soil moisture distribution pattern. The NO3 −-N and NH4 +-N content was maximum below the emitter and decreased thereafter with the increasing lateral distance from the emitter as nutrient mobility in soil is primarily governed by water movement. The decreasing trend of NO3 −-N and NH4 +-N with the increasing lateral distances is in accordance with the water distribution pattern under drip irrigation. The nutrient mobility is proved to be well pronounced under the drip fertigation system, and nutrients carried along with the water movement get concentrated near the outer periphery of the wetting zone.

The potential of a coordinated system of gates for flood irrigation management in paddy rice farm

Rice is one of the most important staple foods in the world. In Europe, Italy is the main producer of rice, with almost all production concentrated in the northeast of the country. Traditionally, rice is grown in fields that are flooded from before planting until just before harvest. This water management technique requires a great deal of labour for farmers who have to manually adjust the inlet and outlet gates to maintain a constant ponding water level in the fields, especially when there is fluctuation of water supply at the farm inlet, for example as a result of rainfall. In addition, the practice of flood irrigation is very water-intensive. New technologies based on remotely and automatically controlled gates are being studied to increase the efficiency of this irrigation method. The objective of this work is to explore the potential of a coordinated and intelligent system of gates for efficient farm irrigation management and ponding water level maintenance. Based on information and measurements from a real case study consisting of a 40-hectare paddy rice farm located in northern Italy, where automatic gates and water level sensors were placed at strategic points of the farm canals and fields, respectively, a proportional-integral (PI) and a non-linear model predictive control (NMPC) of water levels were implemented and compared through modelling and simulation experiments. The results show that the proportional-integral control reproduces the actions that the farmer uses when faced with situations of surplus of water in the fields or a shortage of water in the farm canal. In particular, the general coordination of the gates is lost, and the individual binomial field-gate prevails as an independent system in the farmer's operation. Conversely, non-linear predictive control coordinates the gate operation to obtain a uniform ponding water level in the fields when there is a shortage of water, or significant water conservation when there is an excess of water as a result of rainfall. In conclusion, a nonlinear predictive control model seems to be a suitable strategy to advance irrigation management in rice farms, allowing rice farmers to continue the tradition of flooding while increasing its performance.

Effects of different irrigation methods on regional climate in North China Plain: A modeling study

Agricultural irrigation is important in boosting crop yields in especially water-stressed regions, but little is known about the distinct climatic effects induced by different irrigation methods, particularly in the North China Plain (NCP) where irrigation is applied extensively. Here we examine the climatic effects of flood (FI), sprinkler (SI) and drip irrigation (DI) over NCP during the growing season using dynamic irrigation schemes implemented into a coupled land-atmosphere model. The model generally captures the spatial distribution of surface temperature, relative humidity and precipitation. The changes in regional average surface temperature induced by FI, SI and DI are –0.43, –0.53 and –0.19 °C, respectively. The relatively larger cooling effect for SI than that for FI is associated with enhanced cloud formation. By shifting the surface energy balance, FI and SI cause a wet, cool, cloudy and shallow planetary boundary layer, while DI exhibits the smallest effect and indeed inhibits cloud formation. The increases in convective available potential energy and precipitable water induced by FI and SI enhance convective precipitation over NCP by 0.8–1.2 mm d–1. In contrast, the reduced precipitation due to surface cooling within DI leads to a warmer and drier surface from June to August, which likely increases upper-level geopotential heights and in turn suppresses precipitation in a series of climate feedbacks. The distinct hydrometeorological interactions and feedbacks arising from different irrigation methods are likely related to different irrigation rates, frequencies and approaches of water application. While DI is recognized as the most water-saving method, it also generates the least surface cooling among the three methods and is thus less effective in safeguarding grain yields against rising temperatures. Our study emphasizes the need for more sustainable and adaptive irrigation methods to ensure food security, water conservation and climate stability in the face of climate change.

Revealing the infiltration process and retention mechanisms of surface applied free DNA tracer through soil under flood irrigation

It has been recently demonstrated that free DNA tracers have the potential in tracing water flow and contaminant transport through the vadose zone. However, whether the free DNA tracer can be used in flood irrigation area to track water flow and solute/contaminant transport is still unclear. To reveal the infiltration process and retention mechanisms of surface applied free DNA tracer through soil under flood irrigation, we tested the fate and transport behavior of surface applied free DNA tracers through packed saturated sandy soil columns with a 10 cm water head mimicking flood irrigation. From the experimental breakthrough curves and by fitting a two-site kinetic sorption model (R2 = 0.83–0.91 and NSE = 0.79–0.89), adsorption/desorption rates could be obtained and tracer retention profiles could be simulated. Together these results revealed that 1) the adsorption of free DNA was dominantly to clay particles in the soil, which took up 1.96 % by volume, but took up >97.5 % by surface area and densely cover the surface of sand particles; and 2) at a pore water pH of 8.0, excluding the 4.9 % passing through and 3.1 % degradation amount, the main retention mechanisms in the experimental soil were ligand exchange (42.0 %), Van der Waals interactions (mainly hydrogen bonds), electrostatic forces and straining (together 44.7 %), and cation bridge (5.3 %). To our knowledge, this study is the first to quantify the contribution of each of the main retention mechanisms of free synthetic DNA tracers passing through soil. Our findings could facilitate the application of free DNA tracer to trace vadose zone water flow and solute/contaminant transport under flood irrigation and other infiltration conditions.

Effect of using reclaimed water via furrow and subsurface drip systems under alternate partial root-zone irrigation mechanism on crops growth and soil properties

The growing population in the face of water scarcity inevitably necessitates the quest for alternative sources of irrigation water, which integrates them with irrigation strategies for improved agricultural productivity to meet the Sustainable Development Goals. A three-year field experiment was conducted in 2017, 2018, and 2019 to investigate the effect of water quality (reclaimed water (RW) and clean water (CW)), irrigation techniques (subsurface drip irrigation (SDI) and furrow irrigation (FUI)), irrigation methods (full irrigation (FI) and alternate partial root-zone irrigation (APRI) (70% ETc)), and their interactions on the fresh fruit yield (FY), irrigation water use efficiency (IWUE), and nitrogen use efficiency (NUE) of tomatoes. Further, electrical conductivity (EC), pH, and organic matter (OM) of soil were evaluated. The experiments were undertaken over three growing spring seasons in a greenhouse at the Chinese Academy of Agricultural Sciences in Henan Province, China. Throughout the three years of this study, the yield, the IWUE, and the NUE values of all treatments under RW were higher than those corresponding values under CW. The trend was the same under SDI as it was under FUI. Statistical analyses revealed that there was no significant effect (P > 0.05) of water quality, irrigation technique, and irrigation methods on the soil EC, pH, and OM over the three years. In addition, the interaction between the different experimental factors over the three years of the study was not significant. In conclusion, the application of RW under SDI can result in saving CW and increasing productivity without any negative effect on the investigated soil properties. Furthermore, when RW-SDI is used in conjunction with APRI, it can result in increasing IWUE.

Integrating GIS and remote sensing for land use/land cover mapping and groundwater potential assessment for climate-smart cocoa irrigation in Ghana

Although Ghana is a leading global cocoa producer, its production and yield have experienced declines in recent years due to various factors, including long-term climate change such as increasing temperatures and changing rainfall patterns, as well as drought events. With the increasing exposure of cocoa-producing regions to extreme weather events, the vulnerability of cocoa production is also expected to rise. Supplemental irrigation for cocoa farmers has emerged as a viable adaptation strategy to ensure a consistent water supply and enhance yield. However, understanding the potential for surface and groundwater irrigation in the cocoa-growing belt remains limited. Consequently, this study aims to provide decision-support maps for surface and groundwater irrigation potential to aid planning and investment in climate-smart cocoa irrigation. Utilizing state-of-the-art geospatial and remote sensing tools, data, and methods, alongside in-situ groundwater data, we assess the irrigation potential within Ghana's cocoa-growing areas. Our analysis identified a total area of 22,126 km2 for cocoa plantations and 125.2 km2 for surface water bodies within the cocoa-growing regions. The multi-criteria analysis (MCA) revealed that approximately 80% of the study area exhibits moderate to very high groundwater availability potential. Comparing the MCA output with existing borehole locations demonstrated a reasonable correlation, with about 80% of existing boreholes located in areas with moderate to very high potential. Boreholes in very high potential areas had the highest mean yield of 90.7 l/min, while those in low groundwater availability potential areas registered the lowest mean yield of 58.2 l/min. Our study offers a comprehensive evaluation of water storage components and their implications for cocoa irrigation in Ghana. While groundwater availability shows a generally positive trend, soil moisture and surface water have been declining, particularly in the last decade. These findings underline the need for climate-smart cocoa irrigation strategies that make use of abundant groundwater resources during deficit periods. A balanced conjunctive use of surface and groundwater resources could thus serve as a sustainable solution for maintaining cocoa production in the face of climate change.

On‐farm response of inbred and hybrid rice cultivars to furrow irrigation

AbstractAlternate wetting and drying (AWD) water management reduces irrigation demand compared to a continuous flood in the drill‐seeded, delayed‐flood rice (Oryza sativa L.) production system, but land preparation is time consuming and labor intensive. This research was conducted to determine whether rice grown in a furrow‐irrigated (ROW), raised seedbed system has similar water requirements and profit expectations to AWD. The effects of growing either inbred or hybrid rice under AWD or furrow irrigation management on water applied, grain yield, and net returns were investigated on paired production fields in the Delta region of Mississippi. For both inbred and hybrid rice lines, water applied averaged 587 and 565 mm, respectively, and did not differ between ROW and AWD production (p > 0.05). Compared to AWD, furrow‐irrigating inbred rice cultivars either maintained or decreased yield 16% (p = 0.0207). Conversely, seeding hybrid rice in ROW systems reduced yield 7% regardless of year (p = 0.0083). For both inbred and hybrid rice cultivars, transitioning from AWD to furrow irrigation decreased the average net returns $9.80 and $124.02 ha−1, respectively, and ranged from +$94.48 to −$281.98 ha−1 over 3 years and three rice prices. Transitioning from AWD to an ROW rice will likely have no effect on freshwater demand but will introduce substantial agronomic and economic risk to the production system.