High Irrigation Rates Research Articles

Methane pulse spray and irrigation promote seed germination and seedling growth of common vetch

BackgroundGrazing livestock emits methane through rumen intestinal activity, however, its impact on plant growth in grassland while grazing still has not been explored in detail. Therefore, the study examined the effects of methane pulse spray (MPS), according to grazing intensity, at four grazing intensities (0, 3.6, 5.0, and 6.5 sheep·hm− 2 yr− 1) on seed germination and seedling growth of common vetch (Vicia sativa), while two irrigation rates (35 and 53 ml d− 1) were employed to simulate the precipitation.ResultsThe study revealed significant interactions between MPS and irrigation rate on seed germination and seedling growth parameters. Under moderate MPS intensities (0.74 and 1.04 mol m− 2), seed germination rate, potential, index, and vigor index improved, especially at higher irrigation rates (53 ml d− 1). Conversely, excessive MPS (1.33 mol m− 2) inhibited particularly at the germination rate and growth,. The seedling growth dynamics fitted a logistic model, with MPS advancing the rapid growth phase and increasing maximum growth rates.ConclusionsThis study demonstrates that low to moderate levels of MPS from ruminants can promote seed germination and seedling growth of common vetch, while excessive MPS inhibits these processes. Irrigation enhances plant sensitivity to MPS, with wetter conditions (620 mm yr− 1) facilitating a more pronounced response. The findings introduce a new model elucidating plant responses to external perturbations, which can inform grazing management strategies in diverse ecosystems. In wetter regions, moderate grazing intensities may leverage MPS benefits, while arid regions require careful grazing regulation to maintain grassland-livestock balance.

Remote detection of water stress in cotton using a center pivot irrigation system-mounted sensor package.

Much research has been invested in infrared temperature (IRT)-based methods for cotton (Gossypium hirsutism L.) water stress detection using in-field sensors, but adoption of these is low, perhaps due to logistical challenges. Alternatively, the Water Deficit Index (WDI) was developed for crop water stress assessment using remote sensors not embedded in the canopy. The objective of this research was to evaluate the performance of a sensor package-including modern IRT and normalized difference vegetation index (NDVI) sensors facing downward at 45˚, and a mini weather station-attached unintrusively to a center pivot irrigation system for detecting cotton water stress using WDI. Sensor packages were evaluated in a two-year field study that included four irrigation treatments (0, 30, 60, and 90% ET replacement) and in two production cotton fields. Overall, the tested system was effective at distinguishing crop water stress among irrigation rates. Comparison of the results to a ground-based station and simulations indicated that WDI overestimated water stress at the highest irrigation rate, but performed well otherwise. Accuracy of the system could be improved by measuring canopy coverage (Fc) from the same vantage point as the IRT and NDVI sensors (from the pivot, downward at a 45˚ angle).

Irrigation termination has the potential to improve cotton yield and quality on different soil types

AbstractIrrigation termination timing is challenging for cotton producers in humid regions, especially for fields with varying soil types. A field experiment was conducted in Jackson, TN, to investigate the best cotton irrigation termination on different soil types. The water management treatments consisted of rainfed conditions (RF) and terminating irrigation 2 weeks before the first crack boll (ITBC1 and ITBC2), at the first crack boll (ITC1 and ITC2), and 2 weeks after the first cracked boll (ITAC1 and ITAC2). The irrigation rates consisted of normal irrigation (2) and increased irrigation (1) during the 2 weeks prior to irrigation termination. Irrigation treatments were implemented on three soils: a low, an intermediate, and a high available water‐holding capacity (AWHC) soil. In sandy soil, seed yield increased by 127% in 2015 with the ITAC1 treatment and by 313% in 2016 with the ITC1 treatment, compared to the control (RF). These treatments were also found to be optimal for lint yield and irrigation water productivity in their respective years. The high AWHC soil did not require any irrigation in either growing season to optimize yield. In fact, irrigating at a high rate at every termination date caused yield loss in 2015. These results indicate that cotton can benefit from later termination and higher irrigation rates when soil water and rainfall are low at the end of the growing season or be harmed when the opposite is true.

Soybean yield response to managed depletion irrigation regimes in a Mid-South silt loam soil

Soybean irrigation experiments were conducted for five years (2013–2017) on silt loam soil in Jackson, TN, a sub-humid region with high and variable precipitation. The purpose of the experiment was to investigate managed depletion irrigation (MDI) regimes in soybean to obtain the highest yield with minimal water applied on high water-holding capacity soil. Another goal was to find the best use of soil matric potential sensors and water balances to achieve MDI goals. Irrigation supplemented rainfall at a rate of 1.27, 2.54, and 3.81 cm wk−1 starting from first bloom (R1), first pod (R3), and first seed (R5) stages and these treatments were compared against a rainfed control. The results lead to the recommendation that delaying irrigation to R5 in most years and R3 in dry years produced yields at the highest significance level. The connection between irrigation rate and yield fluctuates yearly, but generally, higher rates result in greater crop yields, necessitating a high irrigation rate and rainfall for managed depletion after initiation. The water balance method best emulated optimum MDI results when irrigation was delayed until the soil moisture depletion reached the management allowable depletion (MAD) and then was followed by irrigation that maintained soil water at the MAD level. The irrigation trigger points were initially lowered for matric potential sensors to avoid excess watering in early growth, transitioning to higher levels for optimal yield later in the R3 stage. These results may be applicable in other regions with high water holding capacity soil and moderate to high rainfall rates during the growing season.

The impact of urban tree shade on residential irrigation demand in a semi-arid Western U.S. City

This research examines how shade offsets residential landscape irrigation demand in a semi-arid city in the western United States. Using over 40,000 customer records from Denver Water, the relationship between residential irrigation and quantities of turf, tree canopy, and shade was studied, controlling for other factors related to the vegetation, parcel, and residence. LiDAR and imagery were used to model turf and tree canopy area and daily hours of shade falling on turf. Simultaneous Autoregression determined that each additional hour of daily building and tree shade falling on turf was associated with 18,672 and 11,683 fewer liters of irrigation per growing season, respectively, for the average parcel (turf area = 476 m2), equating to reductions of 39.2 and 24.5 liters per m2 per growing season for a single hour of shade. These numbers, incorporating spatial spillovers, suggest that for landscapes with both trees and turf—the dominant pattern in many Western US cities— mature trees could potentially be arranged to produce enough shade to reduce water demand of underlying turf by an amount equal to, or even greater than, the trees' irrigation demand. This benefit was not found for shorter and younger trees, which have higher irrigation rates per unit area.

Change in renal blood flow in response to intrarenal pressure alterations induced by ureteroscopy in an in-vivo porcine model.

High irrigation rates are commonly used during ureteroscopy and can increase intrarenal pressure (IRP) substantially. Concerns have been raised that elevated IRP may diminish renal blood flow (RBF) and perfusion of the kidney. Our objective was to investigate the real-time changes in RBF while increasing IRP during Ureteroscopy (URS) in an in-vivo porcine model. Four renal units in two porcine subjects were used in this study, three experimental units and one control. For the experimental units, RBF was measured by placing an ultrasonic flow cuff around the renal artery, while performing ureteroscopy in the same kidney using a prototype ureteroscope with a pressure sensor at its tip. Irrigation was cycled between two rates to achieve targeted IRPs of 30mmHg and 100mmHg. A control data set was obtained by placing the ultrasonic flow cuff on the contralateral renal artery while performing ipsilateral URS. At high IRP, RBF was reduced in all three experimental trials by 10-20% but not in the control trial. The percentage change in RBF due to alteration in IRP was internally consistent in each porcine renal unit and independent of slower systemic variation in RBF encountered in both the experimental and control units. RBF decreased 10-20% when IRP was increased from 30 to 100mmHg during ureteroscopy in an in-vivo porcine model. While this reduction in RBF is unlikely to have an appreciable effect on tissue oxygenation, it may impact heat-sink capacity in vulnerable regions of the kidney.

The Influence of Aerated Irrigation on the Evolution of Dissolved Organic Matter Based on Three-Dimensional Fluorescence Spectrum

In order to unravel the effect of aerated irrigation on soil dissolved organic matter (DOM) fluorescence characteristics, and humification degree, a randomized block experiment was conducted with three factors and a two-level design, i.e., two irrigation rates (0.6 and 1.0 times of crop evaporation pan coefficient, W1 and W2), two nitrogen application rates (225 and 300 kg hm−2, N1 and N2), and two aeration rates (15% and 0% in control treatment, A1 and A0). Fluorescence regional integration (FRI) and correlation analysis methods were used to investigate the evolution characteristics of the soil DOM fluorescence spectrum. Under aerated and conventional subsurface irrigation, soil DOM components were dominated by humic acid-like substances, fulvic acid-like substances, tryptophan-like proteins, and supplemented by tyrosine-like proteins and dissolved microbial metabolites. Soil aeration could promote the consumption of soil DOM components under low irrigation rates and accelerate the consumption of soil DOM components under high irrigation rates. The humification index of AI treatments varied from 8.47 to 9.94 during the maturity growth stage of pepper, averagely increased by 31.59% compared with the non-aeration treatment. To sum up, aerated irrigation can promote the depletion of small molecular proteins and accelerate nutrient turnover and the accumulation of big molecular proteins.

Evaluating the Combined Effects of Water and Fertilizer Coupling Schemes on Pear Vegetative Growth and Quality in North China

Unreasonable fertilizer and irrigation applications and dosages in orchards in northern China result in poor vegetative growth and fruit quality. To reveal the combined effect of water and fertilizer coupling on vegetative growth and fruit quality, this study used pear as a field experiment material, considering: (1) irrigation lower limits (55%, 65%, 75%θf, θf is field capacity) and (2) nitrogen fertilizer application (162, 324, 486 kg·ha−1). Nine coupling schemes and a control treatment (C) were set up in the orthogonal combination. The results showed that, under the higher irrigation rate and nitrogen dose, the spring shoot length, base diameter, and leaves relative chlorophyll content values were increased by 36.77%, 31.86% and 12.91%, respectively. The response of each coupling scheme was different. However, selected water and nitrogen coupling schemes improved the fruit quality. The evaluation results indicated that medium irrigation and high fertilizer scheme were optimal. In conclusion, integrating the vegetative growth and fruit quality, it is recommended that the water and fertilizer coupling scheme for pear in the northern China is as follows: a lower irrigation limit of 65%θf and a nitrogen fertilizer amount of 486.00 kg·ha−1.

Effects of Meteorological Conditions and Irrigation Levels during Different Growth Stages on Maize Yield in the Jing-Jin-Ji Region

Maize is a major crop that is particularly sensitive to climate change. In addition, the extreme shortage of water resources threatens crop production. Thus, improving the effective utilization rate of water is an important problem to discuss. In this regard, we quantified the combined effects of meteorological conditions and irrigation levels during different growth stages on city-level maize yields in the Jing-Jin-Ji region from 1993 to 2019. The results show that the sowing period was affected by the minimum temperature, while the other growth stages were affected by the maximum temperature. At the ear stage of summer maize, when the effective irrigation rate reached the average level (52%), the inflection point of the total precipitation was 401.42 mm in the Jing-Jin-Ji region. When the total precipitation was higher than 401.42 mm, the summer maize yield decreased with the increasing total precipitation. Furthermore, the summer maize growth was significantly affected by drought at the seedling stage. At high effective irrigation rates and over long dry spells, as the mean daily temperature during dry spells increased, the maize yield easily increased. The increase in the effective irrigation rate can reverse the decrease in the summer maize yield. Moreover, the effective irrigation rate increased the maize yield with the increase rise in the temperature during longer dry spells, but the maize yield decreased with warmer temperatures during shorter dry spells. As such, our evaluation results will be useful for assessing food security and moving gradually toward achieving a water–energy–food nexus.

Technical and technological Solutions for environmentally safe Irrigation with wide-reach Sprinklers

It is known that sprinkling can cause surface runoff of irrigation water and water erosion of soils, which leads to deterioration of water-physical and agrochemical properties of soils, its fertility decreases. The purpose of the research was to ensure environmentally safe irrigation with wide-reach sprinklers by improving the designs of sprinklers and their placement along the pipeline. The developed sprinklers were equipped with sprinklers “Frigate” DMU-B463-90. Studies have shown that the volume of surface runoff of irrigation water during the irrigation season when watering with sprinklers with developed sprinklers was less, and as a percentage of the irrigation norm was: in 2020, when watering DM with sprinklers having a rotating deflector – 6.3%, when watering with a machine with sprinklers having a double deflector – 3.9%; in 2021 respectively – 6.6 and 4.1%, in 2022 – 6.0 and 3.9%. The conducted studies allowed us to recommend installing sprinklers with a rotating deflector or cascade versions at high irrigation rates in the end part of the machine.

Does the Novel Thulium Fiber Laser Have a Higher Risk of Urothelial Thermal Injury than the Conventional Holmium Laser in an In Vitro Study?

Introduction and Objective: The novel thulium fiber laser (TFL) has been shown to break stones more rapidly than the holmium:YAG laser (HL). However, some evidence suggests that the TFL generates more heat. The purpose of this study is to compare ureteral temperatures generated by these lasers during ureteroscopic laser lithotripsy in a benchtop model. Methods: A 1-cm BegoStone was manually impacted in the proximal ureter of a three-dimensional printed kidney-ureter model and submerged in 35.5°C saline. Lithotripsy was performed using a 7.6F flexible ureteroscope and a 200 μm laser fiber without a ureteral access sheath. The Dornier 30 W HL, Olympus 100 W HL, and Olympus 60 W TFL were compared. A needle thermocouple to measure temperature was inserted 2 mm from the laser tip. Irrigation was maintained at 35 cc/minute at room temperature using the Thermedx FluidSmart System. Intraluminal temperature was continuously recorded for 60 seconds of laser activation. Five trials were performed for each of four different power settings: 3.6, 10, 20, and 30 W. Analysis of variance and Mann-Whitney U tests were performed with p < 0.05 considered significant. Results: Intraureteral fluid temperature increased as laser power settings increased for all lasers (p < 0.05). The TFL generated higher average ureteral fluid temperatures than the Dornier and Empower HL at all power settings tested (p < 0.001). The maximum temperature for the TFL was higher than the Dornier and Empower HL at all power settings tested (p < 0.001), except at 20 W with the Empower HL. At 30 W, the TFL exceeded 43°C, the threshold for tissue damage. Conclusions: The TFL generated more heat at all settings tested. Supraphysiologic ureteral temperatures may be generated with extended use at high energy settings and low irrigation rates. Understanding the heat generation properties of both lasers could help improve the safety of ureteroscopic laser lithotripsy.

Influence of the Irrigation Regime on the Soybeans (Glycine Max) Root System

The efficiency of crop irrigation depends largely on the extent of the root system and the corresponding depth at which the soil is moistened by irrigation. The incorrect determination of irrigation rates can cause water stress or unnecessary irrigation costs, and in both cases the efficiency of irrigation decreases. The aim of this work is to study the root system of soybean plants irrigated with full and reduced irrigation rates. The research work was been carried out on alluvial meadow soil from Bulgaria. The variety “Biser” is used. Treatments of the experiment: 1) without irrigation; 2) full irrigation (100%m), 3) irrigation with 70% of the full irrigation application rate (70%m), 4) 50%m, 5) 30%m. Water applications in treatment 2 were realized at 80% of FC (field capacity) pre-irrigation soil moisture in the 0-60 cm soil layer. Irrigation water was applied in short closed furrows. The weight of the roots and their distribution in soil layers were established. For this purpose, soil monoliths with dimensions of 10x35x10 cm at a depth of up to 100 cm have been cut. The irrigation regime had a significant impact on the soybean root weight. The small irrigation rates can increase their dry weight by almost a quarter. The higher irrigation rates can increase the root weight between 64 and 73%. The main part of the soybean roots (37-44%), regardless of the irrigation regime, is located in the surface soil layer 0-20 cm. Most of it is in the 10-20 cm soil layer. In the critical soil layer (20-40 cm), 23% of the roots of non-irrigated plants and 27% of the roots of those irrigated with low irrigation rates (30%) are formed. When applying irrigation rates in the range of 50-100%, the relative share is the same (30-31%). If irrigation rate is calculated to moisten the layer 0-40 cm, it can provide water to 67-70% of the entire root system. If it is calculated for 0-60 cm, it covers 86-89% of the root system. The conclusion is that the criterion for irrigation should be provides the optimal soil moisture in the layer 0-40 cm, and irrigation rates should be moisten the soil layer up to 0-60 cm.

Salt and irrigation management of soil-grown Mediterranean greenhouse tomato crops drip-irrigated with moderately saline water

Five integrated experiments, irrigated with water of moderate salinity (about 1.6 dS m−1), were conducted in an Spanish Mediterranean greenhouse to provide a better insight into soil salt accumulation processes in tomato crops and how to leach away these salts by irrigation both during and outside the cropping period. Salts (mostly chloride and sodium coming from the irrigation water) accumulated in the soil wet bulb leading to soil solution electrical conductivities (ECSS) of about 6 dS m−1 or higher during the second half of the crop cycles. During the first phases of these tomato crops it appears to be advisable to apply the crop evapotranspiration (ETc) requirements or slightly higher rates (1.1 ETc). Subsequently, before salts accumulated reach hazardous levels, it is necessary to over-irrigate with a leaching fraction to avoid further salinity increments. Moreover, crop water requirements must be applied with a single daily irrigation, rather than several shorter ones. After the cropping period, the application of 60–70 mm of irrigation water leached away most of the accumulated salts and led to ECSS slightly below 3 dS m−1, considered appropriate for planting a new crop. This amount of water, which has to be adapted to the soil salinity content and characteristics, supplied with daily irrigation rates of about 3–10 mm d−1, led to lower ECSS values, compared with higher irrigation rates. Moreover, the application of crop water requirements with water (11–33% of the irrigation rate) and nutrient solution, instead of nutrient solution over the whole event, substantially reduced the total fertiliser supplied and the concentration of the main nutrients in the wet bulb, but did not negatively affect the biomass, productivity or fruit quality of tomato crop. However, this fertigation strategy requires low-cost, fast monitoring systems of water and nutrients in the soil and/or the plant

Effects of irrigation rates on cotton yield as affected by soil physical properties and topography in the southern high plains.

Lack of precipitation and groundwater for irrigation limits crop production in semi-arid regions, such as the Southern High Plains (SHP). Advanced technologies, such as variable rate irrigation (VRI), can conserve water and improve water use efficiency for sustainable agriculture. However, the adoption of VRI is hindered by the lack of on-farm research focusing on the feasibility of VRI. The objective of this study was to assess the effect of irrigation rates on cotton yield as affected by soil physical properties and topography in the Southern High Plains. This study was conducted in two fields within a 194-ha commercially managed farm in Hale County, Texas, in 2017. An irrigation treatment with three rates was implemented in a randomized complete block design with two replications as separate blocks in each field. A total of 230 composite soil samples were collected from the farm in spring 2017 and analyzed for texture. Information on apparent soil electrical conductivity (ECa), elevation, and final yield were collected from the fields. A statistical model showed that the effect of irrigation rates on cotton yield depended on its interaction with soil physical properties and topography. For example, areas with slope >2% and sand content >50% had no significant response to higher irrigation rates. This model suggests that applying irrigation amounts based on the yield response can be a basis for VRI. This study provides valuable information for site-specific irrigation to optimize crop production in fields with significant variability in soil physical properties and topography.

MP65-03 DOES THE NOVEL THULIUM LASER GENERATE MORE HEAT THAN THE CONVENTIONAL HOLMIUM LASER?

You have accessJournal of UrologyStone Disease: Surgical Therapy V (MP65)1 Sep 2021MP65-03 DOES THE NOVEL THULIUM LASER GENERATE MORE HEAT THAN THE CONVENTIONAL HOLMIUM LASER? Joshua D. Belle, Nathaniel Srikureja, Natalie Chen, Mohamed Keheila, Akin S. Amasyali, Jenna Lee, Mohammad Hajiha, and D. Duane Baldwin Joshua D. BelleJoshua D. Belle More articles by this author , Nathaniel SrikurejaNathaniel Srikureja More articles by this author , Natalie ChenNatalie Chen More articles by this author , Mohamed KeheilaMohamed Keheila More articles by this author , Akin S. AmasyaliAkin S. Amasyali More articles by this author , Jenna LeeJenna Lee More articles by this author , Mohammad HajihaMohammad Hajiha More articles by this author , and D. Duane BaldwinD. Duane Baldwin More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002105.03AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The novel thulium fiber laser (TFL) has been shown to break stones more rapidly than the traditional holmium:YAG laser (HL). However, some evidence suggests that the TFL may generate comparatively more heat. The purpose of this study is to compare ureteral temperatures generated by these lasers during flexible ureteroscopic laser lithotripsy in a benchtop model. METHODS: A 1-cm BegoStone (CaOx monohydrate consistency) was manually impacted in the proximal ureter of a 3D printed kidney-ureter model and submerged in 35°C saline. Lithotripsy was performed with a flexible ureteroscope and a 200 μm laser fiber without a ureteral access sheath. Three lasers were compared (Dornier 30W HL, Olympus 100W HL, and Olympus 60W TFL). A needle thermocouple to measure temperature was inserted 2 mm from the laser tip. Irrigation was maintained at 35cc/min at room temperature using the Thermedx FluidSmart System. Intraluminal temperature was continuously recorded for 60 seconds of laser activation. Time was given between each trial for the intraureteral fluid to return to room temperature. 5 trials were performed for each of 4 different power settings: 3.6, 10, 20, and 30 Watts. ANOVA and Mann-Whitney U tests were performed, with p<0.05 considered significant. RESULTS: Intraureteral fluid temperature increased as laser power settings increased for all lasers trialed (p<0.05, table 1). The TFL produced significantly higher temperatures at both 3.6W (26.36°C vs. 24.57°C (Dornier) and 23.23°C (Empower); p<0.05) and 30W (41.76°C vs. 37.28°C (Empower); p<0.05). There was no difference in intraureteral temperature between lasers at the 10W and 20W settings. At 30W, the TFL generated supraphysiologic intraluminal temperature. CONCLUSIONS: The TFL generated significantly more heat at both the 3.6W and 30W settings. Supraphysiologic ureteral temperatures may be generated by the TFL with extended use at high energy settings and low irrigation rates. Understanding the heat generation properties of both the Holmium and Thulium lasers during ureteroscopy could help improve the safety of ureteroscopic laser lithotripsy. Source of Funding: None © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e1119-e1119 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Joshua D. Belle More articles by this author Nathaniel Srikureja More articles by this author Natalie Chen More articles by this author Mohamed Keheila More articles by this author Akin S. Amasyali More articles by this author Jenna Lee More articles by this author Mohammad Hajiha More articles by this author D. Duane Baldwin More articles by this author Expand All Advertisement Loading ...

Substrate Stratification: Layering Unique Substrates within a Container Increases Resource Efficiency without Impacting Growth of Shrub Rose

Nurseries rely on soilless substrates to provide suitable growing media for container grown crops. These soilless substrates have been developed to readily drain water to prevent issues with waterlogging and associated soil-borne disease. A negative consequence of high porosity and subsequent drainage throughout the container profile is the required high or frequent irrigation rates with poor retention of applied nutrients. Substrates with relatively high levels of moisture and nutrient retention placed on top of a coarse and freely draining substrate could further optimize water and nutrient retention, while allowing for needed gas exchange for plant establishment and growth. Containerized Red Drift® rose (Rosa ‘Meigalpio’ PP17877) plants were grown under 16 mm or 12 mm daily irrigation, utilizing a traditional pine bark substrate or stratified substrates with either a conventional bark, bark fines, or a bark–peat mixture on top of a coarse bark within a container. The stratified substrates received 20% less controlled-release fertilizer; however, the fertilizer in the stratified treatments was concentrated in the upper strata only. During the first growing phase or season, plants grown in stratified substrates outperformed those grown in conventional, non-stratified bark substrates under normal irrigation. The stratified substrates did not reduce growth under reduced irrigation regimes. Overall, crop growth was equal or superior for stratified substrates when compared to the non-stratified controls, even with a 20% reduction of fertilizer. This research suggests that stratified substrate systems can be used to reduce fertilizer and irrigation rates while producing crops of similar or superior quality to conventionally grown containerized crops.

A novel water-saving and drought-resistance rice variety promotes phosphorus absorption through root secreting organic acid compounds to stabilize yield under water-saving condition

More than 70% of global rice production depends on irrigation water, which has brought on a progressive reduction in the groundwater table. Further groundwater withdrawal are unsustainable for future rice production. Sustainable rice production calls for the use of resource-saving and environmentally friendly rice varieties. This study investigated the morphological and physiological mechanisms of biomass and tissue phosphorus accumulation in a water-saving and drought-resistance rice variety (Hanyou73) and a normal paddy rice variety (Hyou518) under different water management regimes. The two rice cultivars were grown in pot experiments carried out with factorial combinations of three water regimes, conventional irrigation (high irrigation rate, HR), 60% of conventional irrigation (medium irrigation rate, MR), and 20% of conventional irrigation (low irrigation rate, LR) for four-years. While the grain yield of Hanyou73 was similar as Hyou518 under HR, it was significantly higher than Hyou518 under MR and LR. Under deficit irrigation, the tissue-specific biomass of Hanyou73 was higher than that of Hyou518, and the total P accumulation of Hanyou73 was 70% greater than that of Hyou518. Meanwhile, the root growth, root oxidation activity, and absorption area of Hanyou73 under the MR and LR treatments were significantly higher than those of Hyou518. Analysis of root exudate metabolites revealed an abundance of organic acids produced by the Hanyou73 roots under, which may account for its higher P uptake. Overall, the findings of this study indicate that Hanyou73 promoted P uptake to maintain higher yields under deficit irrigation. The higher P uptake by Hanyou73 may be related to its altered root physiology, which may be the mechanism by which Hanyou73 adapts to water saving irrigation conditions and maintains its yield traits.

Irrigation Recommendation for Water Saving and Salinity Control in Horticulture in the Semi-arid Lower Cheliff Plain (Algeria)

Salinity and water deficit are two major issues for agricultural development in Algeria. The Lower Cheliff plain, northwestern Algeria, is, furthermore, characterised by semi-arid Mediterranean climate, and soils with high clay content. Our study area was a 4 ha farm located in Oued Rhiou and another 1 ha farm located in Ouarizane, both upstream in the Lower Cheliff plain, and irrigated with waters of different salinities: 1.8 and 5.5 dS m-1, respectively. The plots were equipped with drip irrigation and subsurface drainage systems. Farmer’s irrigation management of artichoke and melon were observed during the respective cropping seasons from September 2010 till June 2011, and from April till July 2011. The total irrigation amounts were, respectively, 364 mm and 240 mm, while the precipitations were 367 mm and 67 mm. The soil properties were determined in the entire rooting depths down to 80 cm for artichoke and 60 cm for melon. In addition to these, irrigation water composition, and crop development parameters were used to simulate soil salinity using the SALTIRSOIL_M model. Simulations and observations of soil pH, main ion concentrations and ECe showed reasonable agreements for June 2011. Next, the irrigation schedules that would have met the water needs of both crops, while simultaneously keeping soil salinity below harmful levels were estimated using the model. For the artichoke plot, a lower irrigation rate (290 mm yr-1) could have kept water deficit and soil salinity below their respective harmful thresholds. For the melon plot, on the contrary, a higher irrigation rate (480 mm yr-1) is able to neutralise the water deficit, though not completely the salinity stress would have been adequate. Farmers’ irrigation practices in the context of the climate, water quality and soil properties of the Lower Cheliff plain can be analysed and improved with the aid of soil salinity modelling.

The Effect of Irrigation Rate on the Water Relations of Young Citrus Trees in High-Density Planting

The availability and proper irrigation scheduling of water are some of the most significant limitations on citrus production in Florida. The proper volume of citrus water demand is vital in evaluating sustainable irrigation approaches. The current study aims to determine the amount of irrigation required to grow citrus trees at higher planting densities without detrimental impacts on trees’ water relation parameters. The study was conducted between November 2017 and September 2020 on young sweet orange (Citrus sinensis) trees budded on the ‘US-897’ (Cleopatra mandarin x Flying Dragon trifoliate orange) citrus rootstock transplanted in sandy soil at the Southwest Florida Research and Education Center (SWFREC) demonstration grove, near Immokalee, Florida. The experiment contained six planting densities, including 447, 598, and 745 trees per ha replicated four times, and 512, 717, and 897 trees per ha replicated six times. Each density treatment was irrigated at 62% or 100% during the first 15 months between 2017 and 2019 or one of the four irrigation rates (26.5, 40.5, 53, or 81%) based on the calculated crop water supplied (ETc) during the last 17 months of 2019–2020. Tree water relations, including soil moisture, stem water potential, and water supplied, were collected periodically. In addition, soil salinity was determined. During the first year (2018), a higher irrigation rate (100% ETc) represented higher soil water contents; however, the soil water content for the lower irrigation rate (62% ETc) did not represent biological stress. One emitter per tree regardless of planting density supported stem water potential (Ψstem) values between −0.80 and −0.79 MPa for lower and full irrigation rates, respectively. However, when treatments were adjusted from April 2019 through September 2020, the results substantially changed. The higher irrigation rate (81% ETc) represented higher soil water contents during the remainder of the study, the lower irrigation rate (26.5% ETc) represents biological stress as a result of stem water potential (Ψstem) values between −1.05 and −0.91 MPa for lower and higher irrigation rates, respectively. Besides this, increasing the irrigation rate from 26.5% to 81%ETc decreased the soil salinity by 33%. Although increasing the planting density from 717 to 897 trees per hectare reduced the water supplied on average by 37% when one irrigation emitter was used to irrigate two trees instead of one, applying an 81% ETc irrigation rate in citrus is more efficient and could be managed in commercial groves.

Modeling Cotton Growth and Yield Response to Irrigation Practices for Thermally Limited Growing Seasons in Kansas

HighlightsLater planting and greater site elevation or latitude decreased seasonal growing degree days and cotton yield in Kansas.Higher irrigation capacity (rate) usually increased lint yield, which was probably due to increased early boll load.Strategies for splitting land allocations between high irrigation rates and dryland did not increase production.Cotton may reduce irrigation withdrawals from the Ogallala aquifer, but the Kansas growing season limits production.Abstract. Precipitation in the western Great Plains averages about 450 mm, varying little with latitude and providing 40% to 80% of potential crop evapotranspiration (ETc). Supplemental irrigation is required to fully meet crop water demand, but the Ogallala or High Plains aquifer is essentially non-recharging south of Nebraska. Pumping water from this aquifer draws down water tables, leading to reduced water availability and deficit irrigation to produce an alternate crop such as cotton (Gossypium hirsutum L.) with a lower peak water demand than corn (Zea mays L.). Our objective was to compare simulated cotton yield response to emergence date, irrigation capacity, and application period at three western Kansas locations (Colby, Tribune, and Garden City) with varying seasonal energy or cumulative growing degree days (CGDD) and compare split center pivot deficit irrigation strategies with a fixed water supply (i.e., where portions of the center pivot land area are managed with different irrigation strategies). We used actual 1961-2000 location weather records with the GOSSYM simulation model to estimate yields of cotton planted into soil at 50% plant-available water for three emergence dates (DOY 145, 152, and 159) and all combinations of irrigation period (0, 4, 6, 8, and 10 weeks beginning at first square) and capacity (2.5, 3.75, and 5.0 mm d-1). Simulated lint yield and its ratio to ETc, or water use efficiency (WUE), consistently decreased with delayed planting (emergence) as location elevation or latitude increased due to effects on growing season CGDD. Depending on location, simulated cotton lint consistently increased (p = 0.05) for scenarios with increasing irrigation capacity, which promoted greater early season boll load, but not for durations exceeding 4 to 6 weeks, probably because later irrigation and fruiting did not complete maturation during the short growing season. Cotton WUE generally increased, with greater yields resulting from earlier emergence and early high-capacity irrigation. We calculated lower WUE where irrigation promoted vigorous growth with added fruiting forms that delayed maturation and reduced the fraction of open bolls. The irrigation strategy of focusing water at higher capacities on a portion of the center pivot in combination with the dryland balance did not increase net yields significantly at any location because the available seasonal energy limited potential crop growth and yield response to irrigation. However, the overall net lint yield was numerically larger for focused irrigation strategies at the southwest Kansas location (Garden City). Based on lint yields simulated under uniform or split center pivot deficit irrigation, we conclude that cotton is poorly suited as an alternative crop for central western and northwestern Kansas because of limited growing season CGDD. Keywords: Cotton, Crop simulation, Deficit irrigation, Evapotranspiration, Irrigation capacity, Split center pivot irrigation, Water use efficiency, Yield limiting factors.