Surface Drip Research Articles

Effect of Irrigation Systems, Bio-Fertilizers and Polymers on some Growth Characteristics and Potato Production in Desert Soils, Karbala Governorate

Two field experiments were conducted during the spring season 2020 in Karbala governorate to study the effect of irrigation systems, irrigation intervals, biofertilizers and polymers on some characteristics of vegetative growth and potato production. The results showed that there were significant differences in the values of the average plant height due to the effect of the double interference between the irrigation system and the improvers, The height of potato plant under any irrigation system was superior when adding conditioners compared to the control treatment, as it reached 48.56, 58.00 and 64.33cm when adding polymer, biofertilizer, and polymers+ biofertilizers, respectively compared with the control treatment of 44.64cm in the surface drip irrigation system. While it was 51.74, 58.19 and 64.67cm in the treatments of adding polymer, biofertilizers and polymers+ biofertilizers, respectively, compared with the control treatment 41.51cm under the sprinkler irrigation system, Also, there were significant differences in the values of average root lengths as a result of the effect of the double interference between the irrigation system and the improvers, as the potato root lengths under any irrigation system excelled when adding the improvers compared to the control treatment, It reached 36.29, 41.94 and 49.37cm when adding polymer, biofertilizers and polymers+ biofertilizers, respectively, compared with the control treatment 31.28cm at surface drip irrigation system. While it was 35.94, 40.69 and 48.14cm when adding polymer, biofertilizer, and polymers + biofertilizer, respectively, compared with the control treatment of 30.33cm at the sprinkler irrigation system, There were significant differences in the values of the total yield as a result of the effect of the double interference between the irrigation system and the conditioners, as the total yield of potato tubers under the two irrigation systems exceeded when adding the improvers compared to the control treatment, It reached 25.31, 28.86 and 36.90 μg ha-1 when adding polymer, biofertilizers and polymers + biofertilizers, respectively, compared with the control treatment 17.21 μg ha-1 at the surface drip irrigation system.

Productivity and profitability of drip fertigated wheat (Triticum aestivum) – mungbean (Vigna radiata) – maize (Zea mays) cropping system

An experiment was conducted at the research farm of ICAR-Indian Agricultural Research Institute, New Delhiduring 2019–20 and 2020–21 to study the productivity and economic viability of wheat (Triticum aestivum L.)–mungbean (Vigna radiata (L.) R. Wilczek)–maize (Zea mays L.) fertigated with 0, 60, 80, 100% recommended dosesof NPK and irrigated at 0.6 and 0.8 crop evapotranspiration (ETc) through subsurface (SSDI) and surface drip irrigation (SDI). The results were compared with the conventional practice of surface irrigation and soil application of 100% recommended doses of NPK. Grain yields of wheat, mungbean, maize and system wheat equivalent yield (SWEY) improved by 22.9, 7.2, 21.9 and 19.4%, respectively with increase in NPK fertigation doses from 60 to 100% and by 15.6, 9.2, 4.9 and 9.7% with the increase in irrigation frequency from 0.6 to 0.8 ETc. However, SDI and SSDI had equal system productivity (12.48 and 12.85 Mg/ha). The SWEY at 0.8ETc fertigated either with NPK80 or NPK100was statistically at par (14.2–15.9 Mg/ha) with the conventional practice (14.3–15.2 Mg/ha). The cash inflow, netincome and benefit cost ratio (BCR) of the cropping system also increased successively with increase in fertigationdoses and irrigation frequency. The net income and BCR followed the order maize>wheat>mungbean. The net income under SSDI at 0.8 ETc with NPK80 or NPK100 in wheat, mungbean, maize and system was 11–13, 88–105, 1-9 and 8–14% higher than the conventional practice. At 0.8 ETc and NPK100, BCR in SSDI (1.86) was higher than in SDI(1.71) and conventional system (1.67).

Assessing the Effects of Treated Wastewater Irrigation on Soil Physico-Chemical Properties

For assessing the effects of wastewater on soil physical and chemical properties, manual irrigation (MI) and surface drip irrigation (SDI) systems were investigated. The experiment was conducted over 12 months. Before and after the experiment, soil samples were collected from three depths (0–20 cm, 20–40 cm and 40–60 cm) for analysis. The obtained results indicated that wastewater application probably preserves soil quality by maintaining its pH-water values whatever the irrigation system used. This study suggested that nutrient input from wastewater promotes soil microbial activity and organic matter (OM) mineralization. In fact, at the soil depths of 0–20 cm and 20–40 cm, MI using treated wastewater (TWW) leads to decrease OM content. P input may justify treated wastewater fertilizing effect in the topsoil. Moreover, TWW fertilizing effect was demonstrated by increased potassium (K) amount in the two upper soil layers (0–20 cm and 20–40 cm) following SDI system. This last system may block metals (iron (Fe), copper (Cu), cobalt (Co) and selenium (Se)) translocation to plants and their accumulation in soil. In contrast, metal translocation was maintained by the MI system. The present data is encouraging to reuse TWW for agricultural purposes, especially for orchard irrigation.

Interactive effect of nitrogen and irrigation on evapotranspiration, growth, yield and water productivity of subsurface drip‐irrigated spring maize: Field and simulation studies

AbstractIn northwest India, spring maize water productivity can be increased with subsurface drip irrigation. Therefore, a field experiment was conducted in a split‐plot design for 2 years to assess the effect of three nitrogen levels (125 [N1], 100 [N2] and 75 [N3] kg N ha−1) in the main plots and seven irrigation regimes (six subsurface and one surface drip) in the subplots on water productivity of spring maize. Subsurface drip irrigation was applied at 100%, 80% and 60% cumulative pan evaporation on alternate days (I1, I3 and I5) and at 2‐day intervals (I2, I4 and I6) along with surface drip irrigation at 80% pan evaporation on alternate days (I7). The evapotranspiration (ET), transpiration (T), dry matter accumulation (DMA), leaf area index (LAI), root mass density (RMD), N uptake and grain yield were at par in N1 and N2 but significantly higher than in N3. T, DMA, LAI, RMD, grain N uptake and grain yield were at par in I1, I2, I3 and I7 but significantly higher than in I4, I5 and I6. The real water productivity was at par in N1I1, N1I3 and N2I3 but significantly higher than other interactive combinations. The CERES‐Maize model satisfactorily simulated crop biomass, grain yield, LAI, ET and transpiration.

Assessment of Various Uniformity Aspects under Surface Drip Irrigation System in Tomato

Background: Water in any form is the prime constitute of plant growth and development. Right amount of water applied at right time and in right quantity to any crop will helpful to get maximum yield potential of that crop. This is possible with surface drip irrigation method. Uniform application of water through emitters is the necessary aspect to avail benefits like higher water use efficiency of surface drip irrigation. Uniformity of surface drip irrigation system can be measured by various uniformity aspects viz., coefficient of variation (CV), distribution uniformity (DU), statistical uniformity (SU) and coefficient of uniformity (CU). Factors like land levelling, maintenance of drip lines, pressure management etc. plays a vital role in conserving the uniformity of outflow of emitters.
 Methodology: In this trial, all these uniformity aspects were measured using catch cane method at initial stage of drip irrigation system installation and on the basis of these dataset several improvements were made for better uniformity of emitter outflow at later planting stage.
 Results: Coefficient of uniformity (CU) of surface drip irrigation system was recorded 96.89% at initial stage and later on it was improved to 97.02% during the first experimental year whereas in second year it was noted 95.58% at initial stage and was improved to 96.80% at later stage.

EVALUATION OF THE AQUACROP MODEL PERFORMANCE AND THE IMPACT OF FUTURE CLIMATE CHANGES ON POTATO PRODUCTION UNDER DIFFERENT SOIL MANAGEMENT SYSTEMS

This study was aimed to investigate the effect of surface sprinkler and drip irrigation systems using a model AquaCrop, irrigation intervals, bio-organic fertilizers and polymers in desert soils. Two field experiments were conducted during the spring season 2020 at Karbala governorate. The experiment included three factors: 1-Irrigation system surface drip T1 and sprinkler T2, 2- The Irrigation interval: every 2 days I1, 4 days I2 and 6 days I3, 3- Addition of soil conditioners: control without any addition C, bio-organic fertilizers (seek) B, polymer (zeba) P, and polymer+ bio-organic fertilizers P+B. The experiment was designed according to the nested design with three replicates results of regional climate models and AquaCrop model. The results showed that there was an increase in the amount of annual precipitation and seasonal during the periods (2016-2035) and (2046-2065) under RCP4.5 scenario, compared to the base period (1985-2005). With an increase in the amount of annual precipitation and seasonal during the period at scenario RCP8.5 with a slight decrease during the period (2046-2065) compared to the base period. Moreover, an increase in the maximum and minimum temperatures according to scenario RCP4.5 and RCP8.5 scenario during the period (2016-2035) and (2046-2065) compared to the base period. The expected productivity using the AquaCrop, as R2 was 0.85 and 0.81 for twelve years, under surface drip irrigation systems and sprinkler, respectively. The correlation coefficient (r) was 0.95 and 0.90, the root means square error (RMSE) 2.43 and 2.19, and the efficiency coefficient 0.66 and 0.42 for the surface drip and sprinkler systems, respectively. Finally, the increase in water productivity and productivity in the scenario RCP4.5 and RCP8.5 for the treatment of BP and the irrigation interval I1and treatment C and the irrigation interval I3 when comparing the base period with the periods (2016-2035) and (2046-2065) For surface drip irrigation systems and sprinkler.

Assessing the availability of potassium and its quantity-intensity relations under long term conservation agriculture based cereal systems in North-West India

Potassium fertilization is often neglected and /or ignored leading to imbalanced fertilization under intensive cultivation especially in the Indo Gangetic Plains (IGP) in North-West India. Recently conservation agriculture (CA) with crop residue retention has become quite popular among the farmers and land practitioners in India and globally. Crop residues are generally rich in potassium (K) content and its continuous addition under CA may impact K dynamics and supply to crops to some extent. Keeping this in view, a field experiment was conducted to assess the effect of long-term cereal-based CA on K supplying capacity in soil of North-West India. Both routine method (neutral normal ammonium acetate extractable) and quantity-intensity (Q/I) approach were adopted to predict K supply under CA vis-à-vis conventional agriculture. Available K and Q/I parameters were analyzed after 11 years of an experimental setup consisting of six scenarios i.e. Scenario 1 (Sc1): conventional till rice-wheat cropping system; Scenario 2 (Sc2): partial CA based rice-wheat-mungbean system; Scenario 3 (Sc3): full CA based rice-wheat-mungbean system; Scenario 4 (Sc4): full CA based maize-wheat-mungbean system; Scenario 5 (Sc5) and 6 (Sc6): same as Sc3 and Sc4 but with sub surface drip irrigation system. Results revealed that full CA based scenarios maintained significantly higher (p < 0.05) available K (145 mg kg−1) than Sc1 (86 mg kg−1). However, it was observed that Q/I approach helped in better understanding of K supply under long term CA soils than routine method. Regarding K availability, Sc6 was the best scenario with high values of planar K (0.147 cmol kg−1), labile K (0.325 cmol kg−1) and potential buffering capacity (PBCK) while Sc1 (without K fertilization or residue addition) presented lowest values of Q/I parameters. Partial CA (Sc2) maintained higher labile K (0.368 cmol kg−1) and equilibrium concentration ratio (CRe0K) (1.93(mol L−1) 1/2 × 10−3) but very low PBCK (36.4 cmol kg−1 (mol L−1) −1/2) suggesting that K intensity shall not be sustained for long period of time and lead to soil K depletion over time. However, on an average, all full CA based scenarios maintained higher Q/I parameters over the conventional practice (Sc1), representing better ability to supply K both immediately and over a long period of time to meet crop requirement. The impact of maize-wheat-mungbean cropping system was prominently observed with respect to CRe0Kover rice-wheat-mungbean system; whereas the effect of irrigation method was not significantly distinguishable. The study thus highlights the potential of long term crop residue retention under CA for improving and maintaining K supply to crops.

Alternate drip irrigation regulates the soil fungal community structure and metabolic function based on root–fungus interactions

AbstractFungal communities play an essential role in soil nutrient cycling, but the mechanism of their response to soil dry–wet cycles under alternate drip irrigation (ADI) is uncertain, which limits the improvements in crop yield that can be achieved through fungal community management in controlled environmental agriculture. In this study, surface drip irrigation was used as the control (CK) to study the effects of ADI with different thresholds of irrigation (designated A50, A60, and A70) on the soil fungal community and root–fungus interactions and to analyze the contribution of root–fungus interactions to tomato yield. Compared with CK, ADI increased the tomato fine root length and specific root fork number but decreased fungal community richness while shaping fungal communities with different compositions and functional metabolisms. For example, the relative abundance of Basidiomycota in A70 was 8.73, 3.25, and 2.81 times those of CK, A50, and A60 respectively. Among the well‐defined fungal functional guilds, the fungal community of A50 was dominated by pathotroph‐saprotroph‐symbiotroph; however, that of A60 was dominated by pathotroph‐saprotroph‐symbiotroph and pathotroph‐symbiotroph, and that of A70 was dominated by pathotroph‐symbiotroph. The root–fungus interaction model showed significant one‐way direct positive effects between adjacent pairs of variables among the four variables (from tomato specific root fork number and fine root length to Basidiomycota, total nitrogen in roots and then tomato yield). These results provide insights into the possibility of regulating the fungal community by optimizing drip irrigation techniques to improve water use efficiency and tomato yield.

Polymer fertilizer and the fertigation of grape tomatoes in protected cultivation

Efficient fertilization alternatives are needed in protected environments that do not cause soil salinization, as with fertigation. Thus, it is important to advance knowledge with new technologies to meet these lacks. Hence, the objective was to compare the use efficiency of polymer fertilizer to fertigation for a tomato cultivar, the Milla cultivar (grape tomato type). The experiment was conducted in a protected environment, with seedlings transplanted to areas along surface drip lines, with a randomized block experimental design consisting of two treatments with six replications. The evaluated treatments were controlled-release polymers (POL) and nutrient fertigation (FERT). Quantitative and qualitative parameters were evaluated, as well as the production of fresh and dry plant masses in each treatment. Monitoring the electrical conductivity in the soil ensured that the POL treatment maintained crop nutrition throughout the experiment by an average of 0.68 dS m − 1. In addition, Tukey's test at 5% showed any significant difference in the quantitative and qualitative analysis of the fruits between the types of fertilization. Thus, we concluded the polymer fertilizer met the nutritional demand of the grape tomato plants and can replace fertigation in a protected environment without compromising productivity.

Sweet corn crop yield response to aerated drip irrigation under various irrigation water management strategies

In the era of decreasing irrigation water availabilities, the focus must be on decreasing crop production water footprints. The various irrigation water management like deficit irrigation, fertigation, and mulching along with MIS can help reduce water footprints. However, the effects of aerated drip irrigation on sweet corn performance under various options of irrigation water management are not yet examined elsewhere. So, it was assessed through field experiments for 2 years during the winter season of the year 2020-21 and 2021-22 at the research farm of the Junagadh Agricultural University campus at Junagadh having a soil texture of clay loam. Two air injection rates i.e. 0 and 12 % by volume of irrigation flow rate was imposed on 16 different treatment combinations of 2 irrigation levels (deficit irrigation-0.7 ETc and full irrigation-1.0 ETc {Crop Evapotranspiration}), 2 fertigation levels (deficit fertigation-0.7 RDF and full fertigation-1.0 RDF {Recommended Dose of Fertilizer}), 2 drip system type (surface drip and subsurface drip) and 2 mulch levels (mulch and no mulch). The aerated irrigation effects on the production of fresh cob yield were found different under various options of irrigation water management. Overall, on average, sweet corn cob yield increased by 8.94% due to aerated irrigation as compared to non-aerated and the results were found significant. The adoption of aerated subsurface drip irrigation under mulch with irrigation/fertigation scheduling at 1.0 ETc/1.0 RDF would result in higher yield if adopted by farmers, in other words, the yield increase of fresh cob would be almost twice as compared to traditional practices with benefit cost ratio (B/C) as 3.01 for aerated treatment and 2.78 for non-aerated treatment for subsurface drip irrigation under mulch with irrigation/fertigation scheduling at 1.0 ETc/1.0 RDF.

ОПРЕДЕЛЕНИЕ ПОЛИВНОЙ НОРМЫ ДЛЯ ФОРМИРОВАНИЯ ПЕРВИЧНОГО ЛОКАЛЬНОГО КОНТУРА КАПЕЛЬНО-УВЛАЖНЕННОЙ ПОЧВЫ

Purpose: development of methodology for determining the irrigation rate value, which ensures the formation of a primary local contour of moistened soil in the soil space under drip irrigation with one emitter. Materials and methods. The methodological and factual basis of the development were materials and empirical dependencies obtained from the data of author's field studies of local moisture contours formed under various soil conditions with above-surface and surface drip irrigation. Results and discussion. The analysis and evaluation of known approaches to the calculation of irrigation rates for drip irrigation of plants is carried out, the direction of the development of the methodology is determined. Based on materials of field and office studies, 11 contour profiles of drip-moistened soil formed under various soil and technological conditions of drip irrigation were obtained. Soil conditions are characterized by a wide range of changes in their parameters: the content of physical clay is from 20.8 to 74.6 % of the dry soil mass (DSM), the lowest moisture capacity is from 16.9 to 32.2 % of DSM, the level of additional irrigation moisture is from 60 to 70 % of the lowest moisture capacity. Moisture contours were formed with an average soil moisture content of 90 % of the lowest moisture capacity. Empirical dependencies for determining the maximum and average radius (diameter) of moisture contours at given depths of the moistened soil layer, which make it possible to predict the volumes of moisture contours are obtained. The dependence and a method for calculating the irrigation rate value, which ensures the formation of a moisture contour of a given depth and a given level of soil moisture, are obtained for a wide range of granulometric and water-physical characteristics of soils. Conclusion. A method for calculating the irrigation rate required for the formation of a local moisture contour in soil space with specified dimensional and moisture parameters during irrigation water delivery by one drip micro emitter is proposed.

Effect of Treated Wastewater from Anaerobic Digester Coupled with Anaerobic Baffled Reactor as Fertigation on Soil Nutrient Residues, Growth and Yield of Maize Plants

Water scarcity, wastewater management and growing food demand associated with global population increase, are among the drivers cited for water reuse in agriculture. The current study intends to contribute on the influence of treated wastewater from the anaerobic digester coupled with anaerobic baffled reactor (ABR) as a fertigation on soil nutrient residues, growth and yield attributes of maize plants by using surface drip irrigation system to apply the treated wastewater. The experiment consisted of experimental plots irrigated with treated wastewater and control plots irrigated with tap water; all with three replications. The treated wastewater was lightly alkaline with pH of 7.8±0.2 and high concentration of nutrients than tap water, but were within the acceptable levels. Fertigation with treated wastewater improved soil fertility evidenced by significant improvement (P≤0.05) in plant height, leaf area Index (LAI) and maize yield. Plant height was 1.5 times taller and LAI was about 2.5 times more in treatment than in control plots. Yield attributes in experimental plots including number of grains per cob, (97±11.3); weight of grains per cob, (80.7±7.9 g); mass of 100 grains, (35.0±3.5 g), and grain yield, (745.8±62.9 Kg/ha) were significantly higher (P≤0.05) compared to their counterpart control plots. The grain yield in experimental plots was about 37% higher than the yield in control plots. Therefore, fertigation with treated wastewater from the anaerobic digester coupled with ABR improves maize yield and is advisable in areas with water scarcity.

INFLUENCE OF IRRIGATION SYSTEMS AND COVER CROP ON WATER PRODUCTIVITY, AND MAIZE GROWTH

A field experiment was carried out to assess the effect of different irrigation systems, which included surface drip irrigation, sub-surface drip irrigation, surface irrigation in basins and cover crop on water productivity, growth and yield of maize in a silty clay loam soil in the Nile sub-district of Babil Governorate, in the fall season 2020. The experiment was designed using the split plot arrangement according to a complete randomized block design (RCBD) with three replications. The experiment treatments included two factors: cover crop (C) includes cover crop (C1) and without the cover crop (C0), and irrigation systems (I): includes surface drip irrigation (I1) subsurface drip irrigation (I2) and surface irrigation in basins (I3). Scheduling Irrigation was applied after 50% depletion of the plant available water. The water balance equation was used to determine the water consumption of maize. The results showed that C1I3 treatment was highest mean of plant height 235 cm, grain yield 11236 kg ha-1, leaf area 6076 cm2 plant-1, and leaf area index 4.05. Whereas, C0I1 was the lowest values for the previous traits, 183 cm, 5200 kg ha-1, 3997 cm2 plants-1, and 2.67 respectively. Treatment C1I2 was superior in the value of field water use efficiency and crop water use efficiency, which reached 3.49 kg m-3 and 3.05 kg m-3, respectively. Whereas, treatment C0I1 gave the lowest value for field and crop water use efficiency, which was 1.11 kg m-3 and 1.05 kg m-3, respectively. The highest water consumption of maize was 709 mm season-1 was for treatment C0I3, and the lowest water consumption was 362 mm season-1 for the treatment C1I2. It is clear that surface drip irrigation in the presence of cover crop contributed to saving irrigation water by reducing water consumption of maize.

Interactive Effects of Nitrogen Application and Irrigation on Water Use, Growth and Tuber Yield of Potato under Subsurface Drip Irrigation

Potatoes are a high-value crop with a shallow root system and high fertilizer requirements. The primary emphasis in potato production is minimizing nitrogen-leaching losses from the shallow root zone through fertigation. Therefore, a field experiment was conducted for two consecutive years, 2018–2019 2019–2020 to assess the effect of nitrogen and irrigation amount and frequency on tuber yield, water balance components and water productivity of potatoes under surface and subsurface drip irrigation. The experiment was laid out in a split-plot design with three nitrogen levels (187.5 kg N ha−1 (N1), 150 kg N ha−1 (N2) and 112.5 kg N ha−1 (N3)) in main plots and six irrigation levels in the subsurface (drip lines were laid at 20 cm depth) and one surface drip in subplots. Irrigation scheduling was based on 100% of cumulative pan evaporation at an alternate (I1) and two-day interval (I2), 80% of cumulative pan evaporation at an alternate (I3) and two-day interval (I4), 60% of cumulative pan evaporation at an alternate (I5) and two-day interval (I6) and 80% of cumulative pan evaporation at alternate days with surface drip (I7). Our results showed that potato transpiration was higher in N1 and N2 compared to N3, while soil evaporation was higher in N3 over N1 and N2. Irrigation regimes I5 and I6 had lower transpiration than I1, I2, I3 and I7, while I7 had more soil evaporation than I1, I2 and I3. Leaf area index (LAI), dry matter accumulation (DMA), root mass density (RMD) and tuber yield in N1 and N2 were at par but significantly higher than N3. The LAI and DMA were statistically at par in I1, I2 and I3 but significantly higher than recommended irrigation (I7). Tuber yield was statistically at par in I1, I2, I3 and I7 but I3 and I7 saved 20% irrigation water compared to I1 and I2. On the other hand, real water productivity (WPET) under N1 and N2 were comparable in I3 and I4 but significantly higher than recommended practice (I7) as pooled evapotranspiration (ET) and soil evaporation (E) in I7 were 19.5 and 20.6 mm higher, respectively, than in I3. Among interactive treatment combinations, N1I1, N1I2, N1I3, N1I7, N2I1, N2I2 and N2I3 recorded the highest tuber yields without any significant differences among them. Treatment N2I3 saved 20% nitrogen and irrigation water compared to all other combinations. Water productivity in N1 and N2 was comparable in I3 and I4 but significantly higher than recommended practice (I7).

Soil water dynamics and yield response of broccoli (Brassica oleracea) under drip irrigation with different irrigation frequency

Semi-arid region can benefit greatly from surface and subsurface drip irrigation techniques in overcoming the problem of water scarcity. Therefore, a field study was carried out at the research farm of CCS Haryana Agricultural University, Hisar, Haryana during winter (rabi) season 2019–20 and 2020–21 to investigate the effectiveness of surface and subsurface drip irrigation on growth and yield of broccoli (Brassica oleracia L.). Subsurface drip irrigation shows higher moisture content than surface drip irrigation at vertical as well as radial distance. The growth parameters were found highest in the treatment irrigation after one day under subsurface drip irrigation. The average highest (14610 kg/ha in 2019–20 and 14740 kg/ha in 2020–21) and lowest (12920 kg/ha in 2019–20 and 13030 kg/ha in 2020–21) total yield was recorded under irrigation after one day in subsurface drip irrigation and irrigation after three days in surface drip irrigation treatments, respectively. It is concluded that alternate days irrigation with subsurface drip irrigation gives better performance to obtain the maximum yield of broccoli grown in the semi-arid region of India.

Optimizing crop water productivity and altering root distribution of Chardonnay grapevine (Vitis vinifera L.) in a silt loam soil through direct root-zone deficit irrigation

The potential for sustaining grape production and improving crop water productivity in semi-arid areas through direct root-zone irrigation (DRZ) has been demonstrated in recent studies; however, it has only been tested for red wine grapes in sandy soils. To expand its application, a field study was conducted to investigate the influences of DRZ with reduced irrigation rate on yield, berry quality, root growth, plant water status and crop water productivity of white wine grape Vitis vinifera L. cv. Chardonnay grown in a silt loam soil within a semi-arid region of Washington state, USA. Compared with the surface drip irrigation which has been applied for decades in the study area, DRZ could improve the crop water productivity by 23 – 34 % and reduce the irrigation amount by 16 – 23 % without yield loss under variable weather conditions, indicating the efficacy of the DRZ as a novel subsurface irrigation strategy. Concurrently, DRZ restricted root distribution within 0 – 60 cm soil layers, and significantly reduced root number and root length density were observed in 20 – 40 cm soil depth. Moreover, grapevines under moderate water stress induced by DRZ accumulated more soluble sugar (8.8 % increase in °Brix on average) and yeast assimilable nitrogen (24.4 % increase on average) in berries. We conclude that proper deficit irrigation applied through DRZ would be applicable to optimize the water use for production and efficiently alter the root distribution pattern of Chardonnay grapevine cultivated in moderately permeable soils with improved berry quality.

Sub-surface drip fertigation improves seed cotton yield and monetary returns.

Surface flood (SF) method is used to irrigate cotton in India, which results in huge wastage of water besides leaching of nutrients. This necessitates the adoption of efficient management strategies to save scarce water without compromising the yield. Therefore, a 2-year field investigation was conducted under two climatic regimes (Faridkot and Abohar) to study the effect of sub-surface drip fertigation (SSDF) on seed cotton yield (SCY), water productivity, nitrogen use efficiency (NUE), and economic parameters in comparison with SF and surface drip fertigation (SDF). The field experiment had a total of eight treatments arranged in a randomized complete block design. Three levels of sub-surface drip irrigation [(SSDI); i.e., 60%, 80%, and 100% of crop evapotranspiration (ETc)] and two N fertigation levels [100% recommended dose of nitrogen (RDN; i.e., 112.5kg N ha-1) and 75% RDN] made up six treatments, while SF (Control 1) and SDF at 80% ETc (Control 2), both with 100% of RDN, served as the controls. Among irrigation regimes, the SSDI levels of 80% ETc and 100% ETc recorded 18.7% (3,240 kg ha-1) and 21.1% (3,305 kg ha-1) higher SCY compared with SF (2,728 kg ha-1). Water use efficiency under SF (57.0%) was reduced by 34.2%, 40.8%, and 38.2% compared with SSDI's 60 (76.5%), 80 (80.3%), and 100% ETc (78.8%), respectively. Among fertigation levels, NUE was higher by 19.2% under 75% (34.1kg SCY kg-1 N) over 100% RDN (28.6kg SCY kg-1 N), but later it also registered 11.9% higher SCY, indicating such to be optimum for better productivity. SSDF at 80% ETc along with 112.5kg N ha-1 recorded 26.6% better SCY (3455kg ha-1) and 18.5% higher NUE (30.7kg SCY kg-1 N) over SF. These findings demonstrate that the application of SSDF could save irrigation water, enhance SCY, and improve the farmers' returns compared with SF. Therefore, in northwestern India, SSDF at 80% ETc along with 112.5kg N ha-1 could be a novel water-savvy concept which would be immensely helpful in enhancing cotton productivity.

Impact of fruit tree hole storage brick treatment on the growth of grape seedlings and water transport in the root zone under root restriction and subsurface drip irrigation

Under the condition of root restriction, the fresh and dry weight of the root absorbed by grapes is reduced, the growth of the main root is hindered, and the upward movement of roots is caused by surface drip irrigation. To solve these problems, this paper designed a fruit tree hole storage brick combining organic fertilizer and polymer material. To investigate the mechanism of how the fruit tree hole storage bricks affect the root and shoot biomass, root distribution, leaf physiological function, and soil water content of grape seedlings, two-year-old ‘Summer Black’ was used as the test material, and three treatments were designed under root restriction conditions: (1) conventional drip irrigation (CK), (2) fruit tree hole storage brick a (T1), and (3) fruit tree hole storage brick b (T2). The results showed that the T1 and T2 treatments significantly increased the total dry matter mass and root-shoot ratio, well maintained the soil water content at a soil depth of 15–30 cm and enhanced the distribution of roots at different soil depths. At a soil depth of 30–45 cm, the total root length, total root surface area and absorbing root length were significantly different among the different treatments, presenting as T2>T1>CK. Under the T1 and T2 treatments, the net photosynthetic rate, transpiration rate and instantaneous water utilization rate of leaves all increased compared with CK. On the 13th day of irrigation, the difference between fluorescence intensity under the T1 and T2 treatments and that under CK increased over time. In conclusion, the fruit tree hole storage bricks made of materials such as organic fertilizer and biochar could well maintain the soil water content and promote the growth of the root system, and the T2 treatment performed the best.

Physiological studies on eggplant (Solanum melongena) grown under drought conditions

Field experiment was conducted during the two growing seasons of 2019 and 2021, at Dokki region, El-Giza Governorate, Egypt, in order to investigate the effect of deficit irrigation (DI) treatments: 100% (control), 70% and 50% of ETo (Reference evapotranspiration) and two irrigation systems: Surface drip irrigation (SDI) and Subsurface irrigation (SSI)porous pipe (20.0cm soil depth) on vegetative growth, chemical constituents, fruit yield and quality of eggplant plants (Cultivars : “Classic” “Swad Eleil”). Results revealed that, DI treatments significantly decreased the vegetative growth, total yield ,marketable yield, leaf relative water content (LRWC) and membrane stability index (MSI) of eggplant plants, compared to control treatment (100% ETₒ). While, water stress treatments improved leaves proline content, alkaloids and irrigation water use efficiency (IWUE). Using SSI (porous pipe) system significantly increased plant height, fresh weight, total yield, marketable fruit yield of eggplant, LRWC and MSI, “Classic” cv had the highest total yield and total marketable yield under the subsurface irrigation system compared to “Swad El-Layl”cv. Regarding, the effect of interaction between DI treatments and irrigation systems, the results illustrated that application of irrigation water with 100% ET0 by SSI system produced the highest significant values of vegetative growth, fruit yield.

Water footprint assessment of surface and subsurface drip fertigated cotton-wheat cropping system – A case study under semi-arid environments of Indian Punjab

The advanced methods of irrigation and nutrient supply may save huge quantity of costly inputs over the prevalent practice of surface flood (SF) irrigation and fertilizer broadcasting in Indian Punjab. Surface drip fertigation (SDF) and subsurface drip fertigation (SSDF) enables the combined application of fertilizer and irrigation for improving the input use efficiency in Cotton-Wheat cropping system (CWCS) over the SF. Though, both SDF and SSDF perform better than SF, but their suitability in reducing the water footprint (WF) of CWCS has been least assessed. Therefore, a 2 yr field study at two distinct agro-climatic zones has been conducted to quantify and compare the WF of SDF and SSDF in comparison to SF for CWCS under semi-arid environments. Results revealed that under SSDF, cotton and wheat crops consumed 32 and 37% lower water than respective SF, indicative of huge water saving over the prevalent practice. Contribution of green, blue and grey components towards total WF under SF was 42, 48 and 10% respectively for cotton, and 24, 59 and 18% for wheat. SSDF application at 80% crop evapotranspiration (ETc) along with 100% recommended dose of nitrogen remarkably reduced the WF without any yield loss for CWCS. Higher total WF for CWCS under SF (5.30 m³ kg⁻1) revealed it to be inferior as compared to SDF (3.71 m³ kg⁻1) and SSDF (3.52 m³ kg⁻1). Cotton alone consumed 65–78% of WFtotal of the CWCS, while the remaining 22–35% was attributed to wheat. A lowered WFtotal for CWCS under SDF and SSDF over that of SF elucidated them to be immensely helpful to conserve limited water resources under semi arid climates. A cropping system based assessment was much reliable option to obtain a clear indicator about the annual WF as compared to single crop based estimation. These results could be utilized to access the performance of alternative irrigation and cultivation systems for developing the WF reduction approach over extended geographical scale.