Mm Of Irrigation Research Articles

Enhancing wheat protein through low-water-fertility under climate change without yield penalty

Efforts to enhance wheat quality without compromising yield are imperative in the context of climate change. However, the quantification of management measures that simultaneously elevate wheat protein concentration, especially its components, while maintaining yield has been scarcely addressed due to its inherent complexity. In this study, we investigated the impact of various combinations of sowing dates, nitrogen fertilizer, and irrigation on improving the protein concentration of strong gluten winter wheat (Jimai 20) using a validated wheat grain protein component simulation model in Tai'an, Shandong. Our results indicate that climate change between 2031 and 2060 is anticipated to cause a significant decrease in wheat yield and an increase in wheat protein concentration compared to the period from 1981 to 2010. Albumin and globulin are projected to decrease, while gliadin and glutenin are expected to increase, respectively. The average glutenin-to-gliadin ratio in the baseline is 1.096, whereas in scenarios SSP2–4.5 and SSP5–8.5, it is 1.093 and 1.102, respectively. Adapted measures can effectively synergize to enhance both wheat protein quality and yield under climate change. Specifically, delaying sowing and reducing nitrogen application to 210–240 kg·ha−1 with 200–240 mm of irrigation contribute to maintaining yields at the current conventional treatment level. Furthermore, these practices result in a 3.89 % and 0.13 % increase in grain protein concentration, and a 1.19 % and 6.02 % enhancement in the glutenin-to-gliadin ratio under scenarios SSP2–4.5 and SSP5–8.5, respectively, compared to conventional treatments. This comprehensive analysis provides valuable insights into practical strategies for synergistically improving wheat yield and protein quality in the face of climate change.

Assessment of crop water requirement and irrigation scheduling for selected crops in the Kohima district, Nagaland, India

Abstract This study was done to examine agricultural water and irrigation schedules for key crops grown in Kohima area of Nagaland, India, which has a humid subtropical climate. Climatic data over 16 years (2006–2021) were used to estimate crop water requirements using CROPWAT 8.0 model. Rice, maize, soybean, potato, cabbage, dry bean, ginger, and naga chili are the most common crops. ET0 was calculated using the FAO Penman–Monteith method and ranged from 1.41 to 3.65 mm/day. The USDA SCS approach calculated effective rainfall. The average annual ETC for rice, maize, ginger, soybean, bean (dry), potato, cabbage, and naga chili were 537.1, 305.7, 342.7, 292.2, 288.1, 364.3, 190.6, and 141 mm, respectively. Rice, maize, ginger, soybean, bean (dry), potato, cabbage, and naga chili require an average of 251.7, 54.9, 26, 73.1, 21.3, 21.9, 121.9, and 14.5 mm of irrigation each year, respectively. The crop irrigation schedules were created with 70% efficiency. The study emphasizes that irrigation must be adjusted to each crop's individual needs, whether through strategic scheduling or modifying net and gross irrigation volumes, to enhance water management and maximize crop production in the region.

The potential of growing soybean in Saskatchewan and its irrigation water needs under climate change scenarios—a modelling study

The soybean industry in Canada is seeking opportunities to expand cultivation due to economic and environmental benefits of growing soybean. Climate projections indicate that soybean expansion into Saskatchewan would be possible with the increases in the available crop heat units under a future warmer climate; however, crop water availability could limit yields. Using a crop growth model, we simulated soybean yields within the Canadian Regional Agricultural Model regions in Saskatchewan for the near-term (2030s), mid-term (2050s), and distant future (2070s) periods under different climate scenarios. Soybean yields were simulated without water stress (potential yield), with water stress (rainfed yield), and under full and partial irrigation scenarios. Irrigation water needs were estimated under the irrigation scenarios and irrigation water availability was discussed. Our results suggest that reasonable and likely more profitable yields (∼2000–2500 kg ha−1) can be achieved under rainfed conditions in the Black soil zone neighbouring Manitoba but soybean production would be less favourable in the Dark Brown soil zone and least favourable in the Brown soil zone. Northeastern regions in the Black soil zone were found to be suitable for growing soybean cultivars in the maturity group (MG) 0 in the distant future and MG 00 in the mid-term under the medium–high greenhouse gas emission scenarios. Soybean would still not be suitable in the northwestern region. Our results indicate that regions in central Saskatchewan requiring 120–170 mm of irrigation are more likely to benefit from the proposed Lake Diefenbaker Irrigation Projects in the future.

Adoption of irrigation scheduling in the South African sugarcane industry: the use of a demonstration trial to bring about change

In the South African sugarcane industry, as in many countries, poor adoption of irrigation scheduling is common, leading to ineffective use of irrigation water and loss in yield and income. The reasons for the lack of adoption include economic constraints, difficulty with implementation and human perceptions. To demonstrate the benefits of effective irrigation scheduling under local conditions, a demonstration trial was conducted over 5 years at Pongola, South Africa. Here, a fixed irrigation schedule (control) was compared with three scheduling treatments: (1) the MyCanesim® computer model with data from an automatic weather station; (2) soil-water data from a capacitance probe; and (3) a combination treatment, where MyCanesim® was integrated with a capacitance probe. The number of stress days from either under- or over-irrigation, along with the RV (recoverable value) yield, irrigation applied, irrigation water productivity (IWP) and financial benefits was used to assess each treatment. The adoption of irrigation scheduling was also evaluated through farmer surveys before and after the trial. When compared to the fixed-cycle control, the use of irrigation-scheduling techniques resulted in an increase of up to 13% in RV yield, a reduction of up to 58% in irrigation water applied, improved IWP of up to 23.9 t cane/100 mm of irrigation and financial benefits of up to ZAR10,487/(ha · a) (USD698/(ha · a)). The combination treatment incurred the least water-stress days, 79% lower than the control. Farmer surveys showed an increase of 45% in the adoption of irrigation scheduling, from 11% (n = 111) in 2014 to 56% (n = 100) in 2020. Although site-specific, the trial results show substantial benefits that can be realised by scheduling irrigation. The trial results compare well to other similar studies, showing that the results can be used in other areas to promote the adoption of irrigation scheduling.

The Effect of Drainage and Subirrigation From a Small Drainage Water Recycling Reservoir on Corn and Soybean Yields in Eastern North Carolina

Highlights The Drainage Water Recycling (DWR) reservoir stored enough water to meet irrigation demand in three of four growing seasons. Subirrigation raised the groundwater table by an average of 15 cm. On average, DWR increased corn and soybean yields by 0.52 Mg ha-1 (8%) and 0.45 Mg ha-1 (17%), respectively. Subirrigation from the small size DWR reservoir did not protect corn from extended dry conditions during the growing season. Nutrients recycled back to the field via supplemental irrigation were not large enough to reduce fertilizer application rate. Abstract. Drainage water recycling (DWR) has been proposed as a source of supplemental irrigation to increase crop production resilience to extended and more frequent dry periods during the crop growing season; however, the system’s potential benefits have not been adequately quantified. The main objective of this study was to assess the performance of a DWR system for providing water for supplemental irrigation to corn and soybean at a research site in eastern North Carolina and quantify corn and soybean yield responses during 4 growing seasons (2018-2021) with varying weather conditions. Two treatments were implemented at the study site: DWR and the control (CT) treatment. The CT treatment was a 11.23 ha non-irrigated field that was primarily drained by a surface drainage system. The DWR treatment (11.48 ha) had a subsurface drainage system that provided drainage during the wet periods and subirrigation during the dry periods of the growing season. A small size reservoir (5,458 m3) was used to collect surface runoff and subsurface drainage and subirrigate the DWR treatment. Results showed that the DWR reservoir stored enough water to meet irrigation requirements in 3 of the four growing seasons and provided 5 to 73 mm of irrigation to the DWR treatment. Subirrigation raised the groundwater table by an average of 15 cm, which helped increase the upward movement of soil water to the root zone and meet crop evapotranspiration demand. DWR increased corn yields by 0.13 and 0.91 Mg ha-1 (1% and 79%) and soybean yields by 0.31 and 0.59 Mg ha-1 (9% and 30%). Subirrigation, which is generally less efficient than overhead irrigation methods, did not optimize the use of the limited water stored in the small reservoir and could not provide enough protection to corn against prolonged dry conditions in the 2019 growing season. The amount of nutrients recycled back to the field through subirrigation was not large enough to help reduce fertilizer application rate. Overall, the results demonstrated that DWR is a promising practice for increasing the resilience of crop production in the southeastern U.S. to the uncertainty in precipitation, which is expected to intensify by climate change. Monitoring the performance of DWR for longer periods with varying factors of weather, soil, and system design and management would help guide the design and management of the system to optimize the performance and minimize the implementation cost. Keywords: Drainage water management, Drainage water reuse, Irrigation reservoir, On-farm water storage, Subsurface drainage, Supplemental irrigation.

Transcriptomic and metabolomic analysis of changes in grain weight potential induced by water stress in wheat

The sink strength of developing ovaries in wheat determines the grain weight potential. The period from booting to the grain setting stage is critical for ovary growth and development and potential sink capacity determination. However, the underlying regulatory mechanism during this period by which the wheat plant balances and coordinates the floret number and ovary/grain weight under water stress has not been clarified. Therefore, we designed two irrigation treatments of W0 (no seasonal irrigation) and W1 (additional 75 mm of irrigation at the jointing stage) and analyzed the responses of the ovary/grain weight to water stress at the phenotypic, metabolomic, and transcriptomic levels. The results showed that the W0 irrigation treatment reduced the soil water content, plant height, and green area of the flag leaf, thus reducing grain number, especially for the inferior grains. However, it improved the grain weight of the superior and inferior grains as well as average grain weight at maturity, while the average ovary/grain weight and volume during –3 to 10 days after anthesis (DAA) also increased. Transcriptomic analysis indicated that the genes involved in both sucrose metabolism and phytohormone signal transduction were prominently accelerated by the W0 treatment, accompanied by greater enzymatic activities of soluble acid invertase (SAI) and sucrose synthase (Sus) and elevated abscisic acid (ABA) and indole-3-acetic acid (IAA) levels. Thus, the sucrose content decreased, while the glucose and fructose contents increased. In addition, several TaTPP genes (especially TaTPP-6) were down-regulated and the IAA biosynthesis genes TaTAR1 and TaTAR2 were up-regulated under the W0 treatment before anthesis, which further increased the IAA level. Collectively, water stress reduced the growth of vegetative organs and eliminated most of the inferior grains, but increased the ABA and IAA levels of the surviving ovaries/grains, promoting the enzymatic activity of Sus and degrading sucrose into glucose and fructose. As a result, the strong sucrose utilization ability, the enhanced enzymatic activity of SAI and the ABA- and IAA-mediated signaling jointly increased the weight and volume of the surviving ovaries/grains, and ultimately achieved the trade-off between ovary/grain weight and number in wheat under water stress.

Enhancing Wheat Gluten Content and Processing Quality: An Analysis of Drip Irrigation Nitrogen Frequency

Drip irrigation is a water-saving and fertilizer-saving application technology used in recent years, with which the frequency of drip irrigation nitrogen application has not yet been determined. In order to investigate the effects of different drip irrigation nitrogen application frequencies on the processing quality of medium-gluten wheat (Jimai22) and strong-gluten wheat (Jimai20 and Shiluan02-1), a two-year field experiment was carried out. Two frequencies of water and N application were set under the same conditions of total N application (210 kg·ha−1) and total irrigation (120 mm): DIF4, consisting of four equal applications of water and N (each of 30 kg·ha−1 of N application and 30 mm of irrigation) and DIF2, consisting of two equal applications of water and N (each of 60 kg·ha−1 of N application and 60 mm of irrigation). The results showed that IF4 significantly increased protein content by 2–8.6%, wet gluten content by 4.5–22.1%, and hardness value (p > 0.05), and PC2 was considered as a protein factor; the sedimentation value was highly significantly correlated with most of the parameters of the flour stretch (p < 0.01). DIF4 improved the stretching quality, and the flour quality of Jima22 was decreased, the flour quality of strong-gluten wheats Jimai20 and Shiluan02-1 was improved, and PC1 was considered to be the dough factor. In conclusion, although the frequency of nitrogen application by drip irrigation increased the protein factor and improved the tensile quality, the flour quality was not necessarily enhanced.

Irrigation scheduling for potatoes (Solanum tuberosum L.) under drip irrigation in an arid region using AquaCrop model.

Potato is one of the key food crops and China is the largest potato producer in the world. However water scarcity is the major constraint to increase the productivity of potato in the arid regions such as Ningxia in northwest China where this crop is extensively cultivated. The overall objective of this study was to optimize the irrigation for potato cultivated under the drip irrigation. To do this, the AquaCrop model was calibrated and validated using the data obtained from two years of field experiment. Then, the calibrated crop model was used to simulate growth and tuber yield of potato in response to 30 different irrigation schemes under two different irrigation scenarios. The crop model evaluation parameters namely, the root mean square error (RMSE), the index of agreement (d), the normalized root mean square error (NRMSE) and the coefficient of determination (R2) showed that the AquaCrop model could simulate the growth and yield of potato under the drip irrigation with different irrigation treatments with reasonable accuracy. Furthermore, yield of potato has increased with increasing amount of total irrigation under drip irrigation; however, yield begins to decline when the amount of total irrigation exceeds 2500 m3 ha-1. The study also found that the optimum irrigation schedule for potato was 20mm of irrigation quota at 7 days of irrigation cycle (i.e., 1800 m3 ha-1 or 180mm of total irrigation). The above irrigation scheduling has achieved 46.77t ha-1 of tuber yield with 15.74kg m-3 of water use efficiency. These findings may be evaluated in potato cultivation across different climate and soil conditions for wide applicability at different arid regions of the world.

Utilizing the CROPGRO Simulation Model to Optimize Management Practices for Achieving High Soybean Yields

A study was conducted during the kharif (June–September) season of 2018 at G.B.P.U.A.&T., Pantnagar, Uttarakhand, India to calibrate and validate the CROPGRO-soybean model for Terai region and determine the optimal management practices for soybean variety PS1347. The experiment followed a Two Factorial Randomized Block Design, involving two fertilizer treatments with three sowing dates replicated thrice. The CROPGRO model was calibrated and validated using the field data of 2018 and 2017, respectively. The RMSE% between the observed and simulated values of different crop stages and yield indicators were between 3.24% and 14.22%. Subsequently, the crop yield for different management practices was also simulated. The model encompassed yield simulations for various management practices viz., six tillage methods, five fertilizer treatments, nine sowing dates, and six irrigation levels. To achieve error minimization, soybean yield was simulated for four consecutive years (2015–2018) under various management practices, and the data was averaged. The simulation results indicated that the optimal management practices for achieving the highest soybean yield include sowing the seeds on the 20th June after implementing a tillage regimen involving three ploughings and two harrowing operations and further nourishing the crop with fertilizer dose of N:P:K:S::25:60:40:20 and applying 90 mm of irrigation. These findings will aid in optimizing management practices and developing sustainable and efficient approaches to achieve higher soybean yields with minimal inputs.

Growth and Performance of Guar (Cyamopsis tetragonoloba (L.) Taub.) Genotypes under Various Irrigation Regimes with and without Biogenic Silica Amendment in Arid Southwest US.

Guar is a potential crop that can be grown as a forage or as a seed crop in arid to semi-arid regions due to its low water requirements and tolerance to heat. Optimizing irrigation water use is important for making alternative crops such as guar a sustainable option. Amendments such as biogenic silica, a sedimentary rock from a biogenic source such as fossils, may help plants tolerate water stress due to reduced irrigation. The objective of the current study was to evaluate seed yield and attribute components and agronomic and physiological parameters for four guar genotypes (Matador, Kinman, Lewis, and NMSU 15-G1) under five drip irrigation regimes (I1-normal irrigation, I2-no irrigation at 75% pod formation, I3-no irrigation at 50% and 75% pod formation, I4-terminate irrigation at flowering, and I5-terminate irrigation at flowering + biogenic silica amendment) at Las Cruces in southern New Mexico, USA, from 2016 to 2018. On average, the I1 irrigation regime produced the highest guar seed yield (2715 kg ha-1) followed by I5 (2469 kg ha-1) from 2016 to 2018. As compared to the I1 regime, the I2 and I3 regimes resulted in a 20.8% and 23.4% decline in guar seed yield, respectively, on average from 2016 to 2018. The results suggest that the addition of biogenic silica might help to improve guar seed yield under reduced irrigation conditions and can produce comparable yields with an average of 300 mm of irrigation during the growing season in the southern New Mexico region of the Southwest US.

Effect of Autumn Irrigation on Salt Leaching under Subsurface Drainage in an Arid Irrigation District

Non-growing season irrigation and farmland subsurface drainage play a crucial role in salt leaching and salinization control in arid irrigation areas. This study aimed to investigate the reduction of autumn irrigation quotas and drainage discharge while maintaining soil moisture retention and reducing soil salinization. Field experiments were conducted with different autumn irrigation quotas (160 mm for SD1, 180 mm for SD2, and 200 mm for SD3) combined with subsurface drainage (1.5 m drain depth and 45 m spacing). A control treatment (referred to as CK) without subsurface drainage received 200 mm of irrigation. The results showed that, after 31 days of autumn irrigation, the groundwater depth in all three subsurface drainage plots stabilized to 1.5 m, with the CK being 0.2–0.3 m shallower compared to the SD plots. The mean soil water content in the 0–150 cm soil layer of the SD1, SD2, SD3, and CK after autumn irrigation was 0.36, 0.39, 0.41, and 0.42 cm3cm−3, respectively. The combination of autumn irrigation and subsurface drainage significantly reduced the soil salt content. The mean desalination rates in the root zone (0–60 cm) soil layer were 57.5%, 53.7%, 51.9%, and 45.1% for the SD3, SD2, CK, and SD1, respectively. The mean desalination rate of 60–150 cm was not significantly different between the SD2 and SD3 (p > 0.05), and both were significantly higher than that of the SD1 and CK (p < 0.05). The drainage discharge was 31, 36, and 40 mm in the SD1, SD2 and SD3, respectively. The amount of salt discharge through the drain pipe increased with increasing irrigation quota, which was 1.22 t/ha, 1.41 t/ha, and 1.50 t/ha for the SD1, SD2, and SD3, respectively. Subsurface drainage is an effective way to prevent salt accumulation in the soil, and an autumn irrigation quota of 180 mm is recommended for leaching of salinity in the Hetao Irrigation District. These findings provide valuable insights into optimizing irrigation practices and managing soil salinization in arid regions.

Targeted irrigation expands scope for winter cereal production in water-limited areas of California's San Joaquin Valley

CONTEXTEfforts to achieve groundwater sustainability in California's San Joaquin Valley will entail substantial pumping reductions, and much irrigated cropland may become newly fallowed. Winter crops grown under water-limited conditions could offer an alternative to fallowing, but their viability may be limited by variable rainfall and high crop failure rates. OBJECTIVEThe first objective of this study was to evaluate how small (100–200 mm), targeted irrigation events impact crop establishment, forage and grain yields, and the resulting economic and agronomic water productivity of winter wheat at 4 sites in the San Joaquin Valley. Additionally, we assessed the probability of producing economically viable forage yields across the region based on historical precipitation totals combined with 0, 100, or 200 mm of supplemental irrigation. METHODSWe used APSIM to run 20-yr simulations of winter wheat establishment and productivity under historical weather conditions at four groundwater dependent sites in California's San Joaquin Valley. For each site, we simulated wheat productivity (biomass and grain) under three irrigation scenarios (no irrigation, 100 mm, or 200 mm) and three sowing dates (mid-October, mid-November, and mid-December). We applied model outputs to calculations of economic and agronomic water productivity, and used the modeled relationship between soft dough biomass yield and total water input (precipitation plus irrigation) to determine the likelihood of a successful wheat crop in any given year across the region. RESULTS AND CONCLUSIONSWe found that two 100 mm applications of irrigation applied at times of critical soil water depletion decreased crop failure rates from 45% of years to 0% of years at the driest site. Economic water productivity was highest when wheat was harvested for forage at the soft dough stage, and agronomic water productivity of soft dough forage was highest with supplemental irrigation and early planting. Given the precipitation requirements to achieve economically viable soft dough-stage forage yields, the addition of 100 mm of irrigation in a single event expanded the potential cropping area to 11% (126,356 ha) of groundwater dependent cropland in the region, while 200 mm of irrigation expanded the potential cropping area to 100% (1,109,888 ha) of cropland. SIGNIFICANCEThese results suggest that small, targeted supplemental irrigation events could greatly expand the scope for water-limited winter forage production in the San Joaquin Valley. Such an approach could serve as an alternative to land fallowing in areas transitioning away from irrigated summer crops where appropriate technological and policy mechanisms are in place.

Water and nitrogen management influence on oil and protein concentration in maize

AbstractThe effects of water and nitrogen management on the oil and protein concentration of maize (Zea mays L.) grown in semiarid conditions are not well documented, although it is rather important for local consumers. The objectives of this study were, therefore, to determine the interaction between different nitrogen fertilizer rates and irrigation regimes on nitrogen uptake, and oil and protein content of maize grain. The importance of this study is to understand how the interaction of nitrogen and irrigation management affects the growth of maize and, thus, identify the best management practices to attain an optimal yield. A field experiment was conducted for 2 consecutive years in 2009 and 2010 using 5 nitrogen fertilizer rates, ranging from 100 to 300 kg N ha−1, and 3 levels of irrigation management, ranging from 375 to 525 mm ha−1, for a total of 15 treatments. The results showed that nitrogen accumulation in the maize plant linearly increased in applications up to 300 kg N ha−1 even under deficit irrigation (375 mm ha−1). For the application of 300 kg N ha−1 under optimum irrigation (525 mm ha−1), nitrogen accumulation in the plant's aboveground canopy was significantly increased (e.g., 145.7 and 144.3 kg ha−1 during 2009 and 2010, respectively) as compared to smaller N application rates. The combined nitrogen and irrigation regimes of 300 kg N ha−1 with 525 mm of irrigation resulted in the numerically maximum grain oil concentration, that is, 62 and 65 g kg−1 during 2009 and 2010, respectively, and protein concentration in grains, that is, 116 and 120 g kg−1 during 2009 and 2010, respectively. The regression analyses showed that the protein and oil concentrations of the grain are significantly and positively correlated with total nitrogen uptake. The nitrogen concentration in maize is driven by irrigation water and nitrogen fertilizer rates. Therefore, irrigation water and nitrogen fertilizers are the major inputs for not only improving maize grain yield but also maize grain quality.

Investigation of Irrigation Water Requirement and Evapotranspiration for Water Resource Management in Southern Punjab, Pakistan

Water scarcity and water quality degradation are exacerbated by climate change in all countries, including Pakistan. The use of water in agriculture is one of the most predominant resources, so reducing consumption and improving resource management is of utmost importance. In the past few decades, excessive irrigation has led to severe water scarcity and reduced water quality. This study determined the irrigation requirements for cotton, rice, and wheat, using the CROPWAT model in Southern Punjab (Multan District). In the study area, evapotranspiration ranged from 1.8 to 10.24 mm/day, while effective rainfall ranged from 2 to 31.3 mm. Rice, cotton, and wheat each required 996.4, 623.3, and 209.5 mm of irrigation, respectively. Among rice, cotton, and wheat, the total net irrigation was 72.4, 67.8, and 44.1 mm, respectively, while the total gross irrigation was 103.5, 99.8, and 63 mm. The CROPWAT model showed a moderately useful result for identifying irrigation needs in Southern Punjab. The study emphasizes the need for groundwater harvesting and water management technologies to implement a water management system that reduces water shortages.

TIMELY IRRIGATION ENHANCES THE YIELD AND WATER PRODUCTIVITY OF CHICKPEAS IN BANGLADESH

Groundwater level declination is a significant issue in various regions of Bangladesh, primarily due to intensive irrigation in agriculture. To address this growing problem, a potential solution is to shift from cultivating water-intensive crops to less water-demanding crops like chickpeas in water-scarce areas, which could prove to be an effective strategy. With this view, a 3-year long (from 2015 to 2018) experience was done in two different locations (Gazipur and Rajshahi) to investigate the response of irrigation to the growth, yield, and water use of chickpeas. There were four treatments (each has three replications), namely, T1 = rainfed, T2 = one irrigation at post-sowing (20-22 days after sowing (DAS)), T3 = one irrigation at pod development (80-85 DAS) stage, and T4 = two irrigations each at post-sowing and pod development stages. The results showed that relying solely on rainfall was insufficient for satisfactory chickpea yield in Gazipur, emphasizing the need for irrigation. Conversely, if Rajshahi receives ample rainfall, there might not be a requirement for irrigation. Applying irrigation twice (at the post-sowing and pod-filling stage) in Gazipur and once (at the pod-filling stage) in Rajshahi, along with approximately 82.45 mm of irrigation in Gazipur and 75.94 mm in Rajshahi, resulted in enhanced growth and yield of chickpeas. The study findings indicate that chickpeas can be effectively cultivated with no or minimum irrigation, thereby reducing the risks of water-table mining in drier parts of the country.

Evapotranspiration of a Hungarian rice variety, ‘SZV Tünde’ in large weighing lysimeter

Aerobic rice production is an alternative growing method to reduce water consumption of rice and thus increase the water productivity of the system without a significant reduction of yield and quality. Evapotranspiration (ETc) of a Hungarian rice variety, ‘SZV Tünde’ under aerobic conditions was measured in large weighing lysimeter during the growing season in 2020. In our experiment, 506.7 g/m2 grain yield and a total above-ground biomass of 1140.4 g/m2 were produced with the application of 315.6 mm of irrigation. Water use-efficiency (WUE) based on the water input and the grain yield was 0.65 g/L. Total ETc for the whole season was measured as 648.3 mm. However, ETc values were ranged 2.04-3.86 mm/day, 3.57-7.90 mm/day and 0.90-4.26 mm/day at the initial, mid and end stages, respectively. Crop coefficients for the different periods of the season were calculated as Kcini=0.82, Kcmid=1.40 and Kcend=0.77. Negative effects of drought can seriously damage rice crop; therefore irrigation scheduling has significant role in successful aerobic rice cultivation. Reliable estimation of evapotranspiration rate in different crop developmental stages can promote this goal.

Use of calcium in bareroot pine nurseries

Bareroot nursery managers may apply dolomite, gypsum, or Ca-nitrate to increase Ca in nursery soils. Although a few managers follow S.A. Wilde’s recommendations and maintain soil at levels of 500 to 1,000 μg g-1 Ca, there is no need to keep Ca levels this high. In contrast, managers at sandy nurseries apply Ca when soil tests drop below 200 μg g-1 Ca. In fact, acceptable pine seedlings have been produced in irrigated soil with <100 μg g-1 available Ca. In plantations, asymptomatic wildlings grow when topsoil contains 17 μg g-1 Ca. In sandy soils, applying too much gypsum can result in a temporary Mg deficiency and too much lime will result in chlorotic needles.
 Managers apply Ca when foliar levels fall below a published “critical value.” The belief that the critical value for Ca varies by stock type is not valid. In fact, numerous “critical” values are invalid since they were not determined using growth response curves. Critical values determined for small seedlings using CaCl2 in sand are apparently not valid for use in bareroot nurseries. 
 At bareroot nurseries, the soil extractable Ca level can decline during a year by 30 μg g-1 or more. Harvesting 1.7 million pine seedlings may remove 20 kg ha-1 of Ca but irrigation can replace this amount or more. When water contains 5 mg l-1 Ca, 600 mm of irrigation will add 30 kg ha-1 Ca. In some areas, 1,000 mm of rainfall will supply 7 kg ha-1 Ca. Even when a Mehlich 1 test shows no exchangeable Ca in the topsoil, pine needles on tall trees may exceed 2,000 μg g-1 Ca due to root growth in subsoil.
 There are few documented cases of deficient pine needles (<300 μg g-1 Ca) in irrigated nurseries in Australia, New Zealand, Scotland and in the Americas. Even when soil fumigation delays the inoculation of ectomycorrhiza, bareroot pines have adequate levels of Ca. Typically, foliage samples from pine nurseries contain at least 1,000 μg g-1 Ca. Samples from 9-month-old seedlings range from 300 to 11,000 μg g-1 Ca. Although the “critical value” for Pinus echinata foliage is not known, 1-0 seedlings with 300 μg g-1 Ca were not stunted and apparently grew well after ouplanting.

Irrigation modulates the effect of increasing temperatures under climate change on cotton production of drip irrigation under plastic film mulching in southern Xinjiang.

Warming and drought brought about by climate change seriously harm sustainable agricultural production in southern Xinjiang. It is still unclear how irrigation can improve the ability of crops to cope with climate change. Therefore, in this study, we calibrated and validated the AquaCrop model using data collected in cotton production from 2017 to 2018. The model effectively simulated the growth, biomass, and yield of cotton plants at the experimental site under different warming and irrigation conditions. The meteorological data collected from 1987 to 2016 were used in a simulation to predict cotton production under 3 temperature scenarios (temperature increased by 0°C, 1°C, and 2°C) and 6 levels of irrigation (198, 264, 330, 396, 495, and 594mm) to explain the modulating effect of plastic film mulching-coupled drip irrigation on cotton production in terms of increasing temperatures under climate change in southern Xinjiang. Model prediction showed that an increase in temperature reduced cotton yield under a low irrigation level, while an increase in irrigation mitigated the impact of climate change on cotton yield. An increase of 1°C did not significantly reduce cotton yield at 198-330 mm of irrigation. Under a 2°C increase, 396-594 mm of irrigation was required to ensure plant growth and yield formation. Both aboveground biomass and yield increased with the rise in the irrigation level at the same temperature. High water use efficiency was achieved at 495mm of irrigation without significant yield loss. Therefore, in the low-temperature scenario, it can be preferentially considered to achieve sustainable water use through water management, while in the high-temperature scenario innovative agricultural measures are required to avoid yield loss. Optimizing irrigation strategies can reduce warming-induced damage to crops under climate change.

Response of drought susceptible and resistant Kentucky bluegrass and tall fescue cultivars and mixtures to limited irrigation

AbstractWater consumption and supply for the urban landscape continues to be a concern for many communities throughout the United States. A 2‐yr field study was conducted in the cool‐humid region to determine the irrigation requirements of drought sensitive (DS) and drought resistant (DR) Kentucky bluegrass (Poa pratensis L.; KBG) and tall fescue [Festuca arundinacea Schreb.; syn. Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.; TF] cultivars maintained at two mowing heights (5.1 or 8.9 cm). Additionally, TF:KBG mixtures 90:10 (w/w) containing DS or DR cultivars were also evaluated. Irrigation was determined using a 70% green coverage threshold (GCT70) approach, where turf was imaged twice weekly, and 12.7 mm of irrigation was applied if an individual plot fell below the GCT70. Time to initially fall below the GCT70 ranged from 15.4 to 50.0 d and varied by species and cultivar, with TF and the TF:KBG mixtures taking the longest time to fall below the threshold. Total irrigation ranged from 61.9 to 173.9 mm over the 74‐d drought events. The DR TF and TF:KBG mixtures containing DR TF required the least irrigation. Mowing height generally had no effect on irrigation requirements of the cultivars or mixtures evaluated in this study. These data reinforce the fact that substantial irrigation can be saved by planting DR species and cultivars and employing a limited irrigation strategy based on a minimum green coverage threshold.

Cin mısırının (Zea mays everta Sturt.) bazı kalite özelliklerine sulamanın etkisi

Aims: This study was conducted under Hatay, Turkey ecological conditions in the second crop season and aimed to determine the effect of irrigation numbers and amounts on some quality characteristics of popcorn (Zea mays everta Sturt.)Methods and Results: Antcin 98 popcorn cultivar was cultivated in Hatay Mustafa Kemal University Research Area in the second crop season of 2015 under five irrigation managements as follows: (I1) 12 times (1757 mm), (I2) 8 times (1449 mm), (I3) 6 times (1148 mm), (I4) 5 times (989 mm) and (I5) 4 times (800 mm). After harvest, quality analysis were carried out with 4 repetitions for each irrigation treatment and kernel size, crude protein, crude oil and crude ash ratios were determined. It’s revealed that all the parameters investigated significantly affected by irrigation managements. According to the results; the lowest grain size (89.00 grains 10 g-1) and the highest crude protein ratio (10.59%) were obtained from the I5 treatment, while the highest crude ash (2.04%) and crude oil (5.74%) ratios were obtained from the I4 treatment. It was determined that as the number of irrigation decreased, the crude protein ratio increased, the crude ash and crude oil ratios increased to a certain level and then decreased. With the correlation analysis performed, significant and positive relationships were determined between kernel size and crude protein (r = 0.686) and between crude oil and crude ash (r = 0.852). Conclusions: The results showed that excessive irrigations cannot increase kernel size, which directly affects the popping volume, which is one of the most important quality criteria of popcorn, However, the nutritional values can be changed by applying different irrigation managements. It can be concluded that under similar growing and climatic conditions, popcorn can be produced with 5 irrigations and a total of 989 mm of irrigation water.Significance and Impact of the Study: The study revealed the effects of different irrigation numbers and amounts on some quality characteristics of popcorn grown under second crop season conditions.