Low Irrigation Research Articles

Pyrite-lined shells as indicators of inefficient bioirrigation in the Holocene–Anthropocene stratigraphic record

Abstract. Although the depth of bioturbation can be estimated on the basis of ichnofabric, the timescale of sediment mixing (reworking) and irrigation (ventilation) by burrowers that affects carbonate preservation and biogeochemical cycles is difficult to estimate in the stratigraphic record. However, pyrite linings on the interior of shells can be a signature of slow and shallow irrigation. They indicate that shells of molluscs initially inhabiting oxic sediment pockets were immediately and permanently sequestered in reduced, iron-rich microenvironments within the mixed layer. Molluscan biomass-stimulated sulfate reduction and pyrite precipitation was confined to the location of decay under such conditions. A high abundance of pyrite-lined shells in the stratigraphic record can thus be diagnostic of limited exposure of organic tissues to O2 even when the seafloor is inhabited by abundant infauna disrupting and age-homogenizing sedimentary fabric as in the present-day northern Adriatic Sea. Here, we reconstruct this sequestration pathway characterized by slow irrigation (1) by assessing preservation and postmortem ages of pyrite-lined shells of the shallow-infaunal and hypoxia-tolerant bivalve Varicorbula gibba in sediment cores and (2) by evaluating whether an independently documented decline in the depth of mixing, driven by high frequency of seasonal hypoxia during the 20th century, affected the frequency of pyrite-lined shells in the stratigraphic record of the northern Adriatic Sea. First, at prodelta sites with a high sedimentation rate, linings of pyrite framboids form rapidly in the upper 5–10 cm as they already appear in the interiors of shells younger than 10 years and occur preferentially in well-preserved and articulated shells with periostracum. Second, increments deposited in the early 20th century contain < 20 % of shells lined with pyrite at the Po prodelta and 30 %–40 % at the Isonzo prodelta, whereas the late 20th century increments possess 50 %–80 % of shells lined with pyrite at both locations. At sites with slow sedimentation rate, the frequency of pyrite linings is low (< 10 %–20 %). Surface sediments remained well mixed by deposit and detritus feeders even in the late 20th century, thus maintaining the suboxic zone with dissolved iron. The upcore increase in the frequency of pyrite-lined shells thus indicates that the oxycline depth was reduced and bioirrigation rates declined during the 20th century. We hypothesize that the permanent preservation of pyrite linings within the shells of V. gibba in the subsurface stratigraphic record was enabled by slow recovery of infaunal communities from seasonal hypoxic events, leading to the dominance of surficial sediment modifiers with low irrigation potential. The presence of very young and well-preserved pyrite-lined valves in the uppermost zones of the mixed layer indicates that rapid obrution by episodic sediment deposition is not needed for preservation of pyrite linings when sediment irrigation is transient and background sedimentation rates are not low (here, exceeding ∼ 0.1 cm yr−1) and infaunal organisms die at their living position within the sediment. Abundance of well-preserved shells lined by pyrite exceeding ∼ 10 % per assemblage in apparently well-mixed sediments in the deep-time stratigraphic record can be an indicator of inefficient bioirrigation. Fine-grained prodelta sediments in the northern Adriatic Sea deposited since the mid-20th century, with high preservation potential of reduced microenvironments formed within a mixed layer, can represent taphonomic and early diagenetic analogues of deep-time skeletal assemblages with pyrite linings.

Systematic Characterization of High-Power Short-Duration Ablation: Insight From an Advanced Virtual Model

Background: High-power short-duration (HPSD) recently emerged as a new approach to radiofrequency (RF) catheter ablation. However, basic and clinical data supporting its effectiveness and safety is still scarce.Objective: We aim to characterize HPSD with an advanced virtual model, able to assess lesion dimensions and complications in multiple conditions and compare it to standard protocols.Methods: We evaluate, on both atrium and ventricle, three HPSD protocols (70 W/8 s, 80 W/6 s, and 90 W/4 s) through a realistic 3D computational model of power-controlled RF ablation, varying catheter tip design (spherical/cylindrical), contact force (CF), blood flow, and saline irrigation. Lesions are defined by the 50°C isotherm contour. Ablations are deemed safe or complicated by pop (tissue temperature >97°C) or charring (blood temperature >80°C). We compared HPSD with standards protocols (30–40 W/30 s). We analyzed the effect of a second HPSD application.Results: We simulated 432 applications. Most (79%) associated a complication, especially in the atrium. The three HPSD protocols performed similarly in the atrium, while 90 W/4 s appeared the safest in the ventricle. Low irrigation rate led frequently to charring (72%). High-power short-duration lesions were 40–60% shallower and smaller in volume compared to standards, although featuring similar width. A second HPSD application increased lesions to a size comparable to standards.Conclusion: High-power short-duration lesions are smaller in volume and more superficial than standards but comparable in width, which can be advantageous in the atrium. A second application can produce lesions similar to standards in a shorter time. Despite its narrow safety margin, HPSD seems a valuable new clinical approach.

Modeling evapotranspiration and evaporation in corn/tomato intercropping ecosystem using a modified ERIN model considering plastic film mulching

Intercropping planting pattern under plastic film mulching (PFM) has been widely adopted in the arid regions to reduce soil evaporation (E), improve land-use efficiency, and increase crop yield. However, water competition between intercropping components in the soil-plant-atmosphere continuum remains largely unexplored. The evaporation and radiation interception using the neighboring species model (ERIN) can effectively estimate evapotranspiration (ET) in a different intercropping ecosystem. However, the effects of soil surface resistance in the mulching area on ET are not considered in the ERIN model. Thus, the existing ET models do not accurately estimate ET in the intercropping ecosystem with PFM. In this study, we proposed a modified ERIN model (MERIN). In the MERIN model, soil surface resistance in the mulching area was taken into account, and its performance was compared to ERIN and Penman-Monteith (PM) models. These models were validated against observed ET and E using the water balance method and micro-lysimeters in a corn intercropped tomato experiment under high (HI: 30 mm for corn and 22.5 mm for tomato, a locally recommended irrigation depth), medium (MI: 22.5 mm for corn and 16.9 mm for tomato, 25% of HI), and low irrigation depth (LI: 15 mm for corn and 11.25 mm for tomato, 50% of HI) during 2018-2019, respectively. The outcomes of this study showed that the MERIN model could accurately estimate ET and E variation for a corn-tomato intercropping ecosystem under PFM during the entire crop growth season compared to the other examined models. The most intense water competition between corn and tomato was observed in stage II (the elongation and tasseling stages for corn; the flowering and fruiting stages for tomato). T of corn generally was higher than tomato, but an opposite result was also observed in stage II. Additionally, the variation of water competition under different irrigation levels was similar in the intercropping ecosystem. When irrigation depth decreased to 22.5 and 15 mm from 30 mm, average T for corn decreased by 10.7% and 16.3%, respectively, and by 12.9% and 22.4% for tomato, respectively, in both years.

Improved water productivity in summer squash under water deficit with PGPR and synthetic methyl amine applications

Insufficient freshwater resources require the improvement of deficit irrigation with approaches that induced high yields by increasing the adaptation of plants to physiological and photosynthetic responses to water scarcity in the soil. The aim of this study is to evaluate water productivity applying combinations of three different plant growth promoting rhizobacteria-PGPR (Bacillus megaterium TV91C, Bacillus megaterium TV6D, Bacillus subtilis RK1900) with a synthetic methylamine molecule for summer squash (Cucurbita pepo L.) at four irrigation levels (full irrigation, and 15, 30 and 45% deficit irrigation), comparing with control (without PGPR and MA). For that, the results of the small plot field experiment carried out in squash growing season of 2017 and 2018 in a semi-arid region were evaluated. PGPR + MA applications decreased the harmful effects on photosynthetic traits (Pn, gs, Ci and Tr), chlorophyll content, electrolyte leakage and leaf relative water content by water deficit and significantly improved also. Although the negative correlations between yield and physiological and photosynthetic traits, PGPR + MA applications provided higher marketable yield as much as the plants full irrigated even at low irrigation levels with a potential root growth from physiological and photosynthetic improving. Higher yield in PGPR + MA applications resulted in higher water productivity for water consumption and decreased irrigation quantities also increased water productivity for irrigation quantity applied. The most striking result was that all PGPR + MA applications resulted in significantly higher water consumption and water productivity for irrigation quantity applied values at all irrigation levels compared to the fully irrigated control treatment. Therefore, it would be possible to optimize water productivity, with water saving and squash yield increases from PGPR + MA applications in terms irrigation water management.

Coupling effects of water and nitrogen on photosynthetic characteristics, nitrogen uptake, and yield of sunflower under drip irrigation in an oasis

An experiment was conducted in an oasis area in northwest China to assess the coupling effects of water and nitrogen supply through drip irrigation on photosynthetic characteristics, nitrogen uptake, and yield of sunflower (Helianthus annuus L.), as well as the nitrate distribution in the root-zone soil. The experiment included three irrigation levels (210 [W1], 300 [W2], and 390 [W3] mm), three nitrogen levels (162 [N1], 232 [N2], and 302 [N3] kg/hm2), and control treatment (no fertilization during whole growth period and only irrigated at the budding stage). A nitrogen content over-accumulation in the soil was observed under the low irrigation amount with high fertilizer supply, which cannot enhance the sunflowers’ absorption of nitrogen. Excessive irrigation caused leach of the soil nitrogen, reduced nitrogen content in the root-zone soil (0-40 cm) and limited nitrogen uptake by the crop. Although low irrigation amount with high fertilizer supply can increase the nitrogen content in the soil, it cannot enhance the sunflowers’ absorption of nitrogen. At the vegetative stage of sunflower growth, the accumulation of nitrogen in the organs was mainly concentrated in the leaves, while it was transferred to the flower disk at the reproductive growth stage. Reasonable coupling of water and nitrogen improved the transport of nitrogen from leaves and stems to the flower disk aromoted the formation of yield components. Six regression equations were established with irrigation and fertilization amount as independent variables, and seed rate, seed weight per flowerdisk, 1000 grain weight, yield, water use efficiency and nitrogen partial factor productivity as dependent variables, respectively. Multiple regression and spatial analysis suggested that the irrigation amount of 241.62- 253.35 mm and the fertilization application of 202.02-209.40 N kg/hm2 was a good irrigation strategy, under which all six factors exceed 75% of their maxima, and the yield of sunflower reached 3 229.3 kg/hm2. Keywords: fertilization, Helianthus annuus L., irrigation management, nitrogen transformation, nutrient uptake, Xinjiang DOI: 10.25165/j.ijabe.20211405.6399 Citation: Wang T Y, Wang Z H, Wu Q, Zhang J Z, Quan L S, Fan B H, et al. Coupling effects of water and nitrogen on photosynthetic characteristics, nitrogen uptake, and yield of sunflower under drip irrigation in an oasis. Int J Agric & Biol Eng, 2021; 14(5): 130–141.

Photosynthetic Physiological Characteristics of Water and Nitrogen Coupling for Enhanced High-Density Tolerance and Increased Yield of Maize in Arid Irrigation Regions.

To some extent, the photosynthetic traits of developing leaves of maize are regulated systemically by water and nitrogen. However, it remains unclear whether photosynthesis is systematically regulated via water and nitrogen when maize crops are grown under close (high density) planting conditions. To address this, a field experiment that had a split-split plot arrangement of treatments was designed. Two irrigation levels on local traditional irrigation level (high, I2, 4,050 m3 ha−1) and reduced by 20% (low, I1, 3,240 m3 ha−1) formed the main plots; two levels of nitrogen fertilizer at a local traditional nitrogen level (high, N2, 360 kg ha−1) and reduced by 25% (low, N1, 270 kg ha−1) formed the split plots; three planting densities of low (D1, 7.5 plants m−2), medium (D2, 9.75 plants m−2), and high (D3, 12 plants m−2) formed the split-split plots. The grain yield, gas exchange, and chlorophyll a fluorescence of the closely planted maize crops were assessed. The results showed that water–nitrogen coupling regulated their net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), quantum yield of non-regulated non-photochemical energy loss [Y(NO)], actual photochemical efficiency of PSII [Y(II)], and quantum yield of regulated non-photochemical energy loss [Y(NPQ)]. When maize plants were grown at low irrigation with traditional nitrogen and at a medium density (i.e., I1N2D2), they had Pn, Gs, and Tr higher than those of grown under traditional treatment conditions (i.e., I2N2D1). Moreover, the increased photosynthesis in the leaves of maize in the I1N2D2 treatment was mainly caused by decreased Y(NO), and increased Y(II) and Y(NPQ). The coupling of 20%-reduced irrigation with the traditional nitrogen application boosted the grain yield of medium density-planted maize, whose Pn, Gs, Tr, Y(II), and Y(NPQ) were enhanced, and its Y(NO) was reduced. Redundancy analysis revealed that both Y(II) and SPAD were the most important physiological factors affecting maize yield performance, followed by Y(NPQ) and NPQ. Using the 20% reduction in irrigation and traditional nitrogen application at a medium density of planting (I1N2D2) could thus be considered as feasible management practices, which could provide technical guidance for further exploring high yields of closely planted maize plants in arid irrigation regions.

Effect of Irrigation Regime on the Cultivation of Five Wild Colocynth[Citrullus colocynthsis (L.) Schrad.] Ecotypes in Terms of Their Growth, Seed Yield and Oil content

The objective of this research was to evaluate the response of five wild colocynth (an important medicinal plant) ecotypes toirrigation regime as a basic input of cultural practices. The research was laid out in a split plot design with three replications. Treatments were two irrigation regimes (Q1= 100 % Etc and Q2= 50 % Etc) and five wild colocynth ecotypes (G, SF, SD, GD and NK). The experiment was run for two seasons (2014 and 2015). Parameters measured were days to 50 % flowering, number of fruits per plant, number of seeds per fruit weight of 1000 seeds, seed yield and oil content of seeds. Days to 50 %flowering were not significantly affected by watering regimes for the two seasons; however, ecotypes were significantly effective in the first season only. Number of fruits per plant was not significantly affected by watering regimes in both seasons; yet, ecotypes were significantly affected in the first season only. The highest number of fruits/plant wasproduced by ecotype G in the first season and by NK in the second season. The lowest number was produced by ecotype SD in both seasons. Number of seeds per fruit was not significantly different between the watering regimes in both seasons; it was, however, significantly different among ecotypes in both seasons. There was no significant difference in seed yields between watering regimes in both seasons. Ecotype GD produced the highest seed yield in both seasons.The two watering regimes and ecotypes were significantly different regarding weight of 1000 seeds in the first but not in the second season.Mean oil percent of seeds resulting from irrigated ecotypes (15.2%) was higher than that of seeds collected from the wild (12.1%).Moreover, mean oil percent from seeds produced by high and low irrigation was individually higher than that of seeds from the wild habitat. In the wild habitat, SD produced the highest (16.0%) oil percent and NK the lowest (6.4%). When irrigated, ecotypes showed differential positive response. In conclusion, wild colocynth ectypes responded positively to irrigation regarding oil content of seeds, which is the most important product, indicating possibility of inclusion of colocynth in the existing cropping system thereby ensuring its conservation and economic use. More research, however, is needed todetermine, precisely, the irrigation water requirement for colocynth seed production.

Evaluation of Some Transpiration Regulators in Sunflower for Saving Irrigation Water in Relation to Productivity

An experimental field trial was conducted in seasons of 2015 and 2016 at Giza Experimental Station of Agricultural Research Centre (ARC), Egypt to evaluate the foliar spray effect with transpiration regulators (Potassium, Kaolin and Ascorbic acid) and three levels of irrigations (100%, 80% and 60% of Et0) on yield, its attributes, and water productivity of two sunflower cultivars (Giza 102 and Solala 120). The factorial treatments were arranged in split- split plot design with three replications. The irrigation levels (100%, 80% and 60% of Et0) were devoted for main plots, while subplots contained the three spraying treatments of transpiration regulators. (Potassium at 1%, Kaolin at 3% and Ascorbic acid at 100 ppm), in addition to control treatment (water spray). Sub-sub plots were occupied by the two sunflower cultivars (Giza 102 and Solala 120). Obtained results proved that, increasing irrigation levels up to (80- 100%) caused significant increase in all growth characteristics, photosynthetic pigments (total chlorophyll), relative water content (RWC %) and seed oil %. Also, yield parameters being head diameter, 1000-seed weight and seed yield) show significant reduction under water deficit. Foliar spray with (Potassium at 1%, Kaolin at 3% and Ascorbic acid at 100 ppm), positively affected all the growth and physiological criteria of the tested plants compared with control. Generally, under low irrigation levels, application of transpiration regulators effectively reduced the detrimental impact of drought stress on growth, yield and its components of the two used cultivars in the two seasons. While, foliar spraying of potassium under 100% of Et0 gave the best treatment in this respect. Concerning cultivars, WUE (water use efficiency) for Solala 120 was significantly higher than for Giza 102 in the two seasons. All interactions among factors under study due to WUE were not significant in 2015 and 2016 seasons.

Thermal effects of thulium: YAG laser treatment of the prostate\u2014an in vitro study

PurposeTo objectively determine whether there is potential thermal tissue damage during Tm:YAG laser-based LUTS treatment.MethodsOur experimental model was comprised of a prostatic resection trainer placed in a 37 °C water bath. In a hollowed-out central area simulating the urethral lumen, we placed a RigiFib 800 fibre, irrigation inflow regulated with a digital pump, and a type K thermocouple. A second thermocouple was inserted 0.5/1 cm adjacently and protected with an aluminum barrier to prevent it from urethral fluid. We investigated continuous and intermittent 120 W and 80 W laser application with various irrigation rates in eight measurement sessions lasting up to 14 min. Thermal measurements were recorded continuously and in real-time using MatLab. All experiments were repeated five times to balance out variations.ResultsContinuous laser application at 120 W and 125 ml/min caused a urethral ∆T of ~ 15 K and a parenchymal temperature increase of up to 7 K. With 50 ml/min irrigation, a urethral and parenchymal ∆T of 30 K and 15 K were reached, respectively. Subsequently and in absence of laser application, prostatic parenchyma needed over 16 min to reach baseline body temperature. At 80 W lower temperature increases were reached compared to similar irrigation but higher power.ConclusionsWe showed that potentially harming temperatures can be reached, especially during high laser power and low irrigation. The heat generation can also be conveyed to the prostate parenchyma and deeper structures, potentially affecting the neurovascular bundles. Further clinical studies with intracorporal temperature measurement are necessary to further investigate this potentially harming surgical adverse effect.

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 ...

Melilot of the Caspian region and prospects of their conveyor use

The data of daily conveyor production of melilot hay, harvested mainly in early highly nutritious phases of development, branching and budding, are presented. Melilot, possessing a number of important advantages over other feed crops, nevertheless, are not popular among agricultural practitioners because of their coarse stems, low feed intake and high content of coumarin in plants. Undoubted advantages of melilot include: high yield of hay, haylage and green mass, seeds; salt tolerance and possibility of reclaiming saline lands without drainage and soil leaching; sun resistance; drought resistance; winter hardiness; low irrigation rate; high nutritional value and digestibility of feed; high protein content in plants; low cost cultivation; possibility of obtaining high yields without introduction of nitrogen fertilizers, unpretentiousness to soil fertility; excellent phytomeliorant and soil orderly; soil fertility restorer and excellent precursor for many crops. The varieties of melilot created for cultivation on saline lands of the Caspian Sea region provide an extension of conveyor period of pasture use and harvesting of their raw materials up to 188 days per season.

Targeting Irrigation Expansion to Address Sustainable Development Objectives: A Regional Farm Typology Approach

Sustainable water management is a core sustainable development goal (SDG) that also contributes to other SDGs, including food and water security, ecosystem health, and climate adaptation. To achieve these synergies, policies must target efforts to regions that best correspond with development objectives. This study designs a targeting strategy for irrigation expansion in southern Mexico—a region long considered to have strong potential for sustainable irrigation development. We use an integrated farm typology and decision tree approach to identify priority municipalities for irrigation expansion. We use multivariate statistics to examine the relationships among farm characteristics in 933 municipalities, classifying each according to four farm types: lowland, midland, midland-irrigated, and highland. We then partition municipalities into 11 farm-type subgroups, each ranked by priority level for receiving irrigation interventions following Mexico’s National Water Program guidelines. Results identify a ‘highest-priority’ subgroup of 73 municipalities comprised mostly of midland and highland farm types. These types are characterized by low irrigation use, small farmland areas, high vulnerability to climate, high marginalization (poverty), strong representation from indigenous communities, low maize yield, and high rates of subsistence production. Findings provide a crucial first approximation of where irrigation expansion would best address water policy priorities and sustainable development objectives in southern Mexico. This study also provides a useful framework for scaling organizations tasked with targeting development efforts across large spatial scales.

Impact of crop management and environment on the spatio-temporal variance of potato yield at regional scale

• We determine and quantify the main drivers of potato yield variability under irrigated conditions. • We used correlation analysis, decomposition of variability sources and maps to assess potato yield variability. • Using APSIM, three planting dates × four irrigation strategies were simulated. • Crop management factors explained the greatest potato yield variability when compared to environmental factors. • We identified a need to discriminate the drivers of potato yield variability regionally. The uncertainties associated with crop model inputs can affect the spatio-temporal variance of simulated yields, particularly under suboptimal irrigation. The aim of this study was to determine and quantify the main drivers of irrigated potato yield variance; as influenced by crop management practices as well as climate and soil factors. Using a locally calibrated crop model (APSIM), three planting dates × three irrigation strategies (plus a non-water limited treatment) were simulated using 30 years of historical weather data across potato production areas in Tasmania, Australia. We used (i) correlation analysis, (ii) variance decomposition and (iii) maps to visualise the spatial decomposition of variance of potato yield. Our results showed that the implementation of potential irrigation compensated for the impact of planting date on climate drivers of simulated yield and changed the most important yield driving factors from irrigation and planting date to global solar radiation (r = 0.69−0.81). Under early-planting, we found positive correlations of simulated yield vs. global solar radiation (r up to 0.75 under high and medium irrigation) and between the simulated yield and rainfall (r up to 0.55 under low irrigation). In general, a mix of negative and positive correlations were found for minimum and maximum temperature depending on soil type. Using variance decomposition analysis, we found that crop management factors explained the greatest yield variance depending on soil type related to plant available water capacity (PAWC). For soils with high PAWC (>200 mm), most variance was explained by global solar radiation (56–62 %) followed by planting date (43–47 %). However, when PAWC values decreased from 242 mm to 94 mm, the contribution of global solar radiation and planting date were reduced from 62 % to 5.8 % and from 47 % to 4.4 %, respectively, and the contribution of irrigation strategy increased from 0.4%–32.5%. We identified a need to quantify and differentiate the variance contribution of environmental and crop management factors on crop yield and within these factors, discriminate the key drivers of yield variance at regional scale.

Pollinators and plant nurseries: how irrigation and pesticide treatment of native ornamental plants impact solitary bees.

A key conservation goal in agroecosystems is to understand how management practices may affect beneficial species, such as pollinators. Currently, broad gaps exist in our knowledge as to how horticultural management practices, such as irrigation level, might influence bee reproduction, particularly for solitary bees. Despite the extensive use of ornamental plants by bees, especially little is known about how irrigation level may interact with insecticides, like water-soluble neonicotinoids, to influence floral rewards and bee reproduction. We designed a two-factor field cage experiment in which we reared Megachile rotundata (Fabricius) (Hymenoptera: Megachilidae) on containerized ornamental plants grown under two different irrigation levels and imidacloprid treatments (30% label rate dosage of a nursery formulation or an untreated control). Lower irrigation was associated with modest decreases in nectar volume and floral abundance in untreated plants, whereas irrigation did not affect plants treated with imidacloprid. Furthermore, higher irrigation decreased the amount of imidacloprid entering nectar. Imidacloprid application strongly reduced bee foraging activity and reproduction, and higher irrigation did not offset any negative effects on bees. Our study emphasizes the impact of a nursery neonicotinoid formulation on solitary bee foraging and reproduction, while highlighting interactions between irrigation level and neonicotinoid application in containerized plants themselves.

The climatic effects of irrigation over the middle and lower reaches of the Yangtze River, China

Characterizing climatic effects of agricultural irrigation is of great importance and challenging to understand the full influence of water management on the Earth's environment and hydroclimatic cycle. The investigation of the local and remote climatic responses to irrigation in the middle and lower reaches of the Yangtze River (MLRYR), a typical humid region, was previously unidentified. A novel combined subgrid-scale irrigation scheme for wheat (dynamic irrigation) and rice (fixed irrigation) was developed and incorporated into the Weather Research and Forecasting (WRF) modeling framework. The comprehensive climatic effects on energy balance, temperature, precipitation and the planetary boundary layer, were assessed by numerical experiments with irrigation off/on for ten crop growth seasons from 2007 to 2016. Both the simulated irrigation amounts of wheat and rice were generally in agreement with actual values. Surface energy and water budgets have been substantially altered by irrigation, and the magnitudes were dependent on the irrigation amounts. Irrigation increased latent heat flux and reduced sensible heat flux, especially during summer. The warm bias in the simulation without consideration of irrigation was reduced by the cooling effects of irrigation. The mean surface air temperature decreased significantly by 0.12–0.24 °C and 0.4–0.8 °C for spring and summer, respectively. Meanwhile, irrigation presented stronger cooling effects on daytime temperature than nighttime temperature, resulting in the reductions of diurnal temperature range in irrigated area. Moreover, the irrigation-induced increase of geopotential height and anomalous anticyclones led to the decreases in precipitation over the MLRYR. The changes of precipitation in remote areas were generally related to the irrigation induced large-scale circulation change. Furthermore, although the climatic effects of irrigation in grid scale were not relatively high due to the relatively low irrigation fraction, they exhibited apparently stronger in the subgrid scale, which can be used to investigate the impacts of climatic effects of irrigation on crop growth.

Improving wheat grain yield via promotion of water and nitrogen utilization in arid areas

Crop yield is limited by water and nitrogen (N) availability. However, in Hexi Corridor of northwestern China, water scarcity and excessive fertilizer N in wheat (Triticum aestivum L.) production causes serious conflicts between water and N supply and crop demand. A field experiment was conducted from 2016 to 2018 to evaluate whether reducing of irrigation and fertilizer N will reduce grain yield of wheat. There were two irrigation quotas (192 and 240 mm) and three fertilizer N rates (135, 180, and 225 kg N ha−1). The results showed that reducing irrigation to 192 mm and N rate to 180 kg N ha−1 reduced water uptake, water uptake efficiency, and N uptake of spring wheat as compared to local practice (i.e., 240 mm irrigation and 225 kg N ha−1 fertilizer). Whereas, it improved water and N utilization efficiency, and water and N productivity. Consequently, the irrigation and N rate reduced treatment achieved the same quantity of grain yield as local practice. The path analysis showed that interaction effect between irrigation and N fertilization may attributable to the improvement of grain yield with lower irrigation and N rate. The enhanced water and N utilization allows us to conclude that irrigation quota at 192 mm coupled with fertilizer N rate at 180 kg N ha−1 can be used as an efficient practice for wheat production in arid irrigation areas.

Jujube is at a competitiveness disadvantage to cotton in intercropped system

AbstractIntercropping is a key methodology used by farmers to improve economic benefits. However, in certain areas such as Xinjiang, China, limitations in available irrigation water make intercropping difficult to implement. Farmers are therefore challenged to improve economic benefits in water‐limited conditions. We evaluated the effectiveness of intercropped common jujube (Zizyphus jujuba Mill.) and cotton (Gossypium hirsutum L.) under different irrigation regimes. Using a factorial design, crops were planted individually and together (i.e., intercropping) under five different irrigation systems. We measured growth parameters and evaluated the temporal distribution of root system growth and fruit yield. Intercropped cotton displayed higher fitness metrics and outperformed the single‐cropped cotton in crop yield. Intercropping, however, had the opposite effect on jujube plants: the overall fitness and yield of jujube were significantly curtailed under the interspecific competition induced by this planting technique. Under low irrigation levels, cotton plants tended to invade the jujube niches that reduced jujube growth and development. Our findings suggest that in a jujube/cotton intercropping system, cotton is the dominant competitor, whose ability to inhibit the development of the less competitive jujube is exacerbated under water deficit situations. Although intercropping system affected jujube development, overall cotton yield, and therefore benefit to farmers was considerably higher using this system. However, the competitive ability of jujube gradually increases as the plant aged which could reduce the economic advantages of the intercropping system.

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.

ارزیابی ردپای آب مجازی محصولات زراعی، دامی و نهاده‌های مصرفی کشاورزی (مطالعه موردی: استان قم)

Introduction: Water resources management in arid and semi-arid regions is very important specially, in agricultural sector. The major share of water use is daily consumption by humans for drinking, washing and cooking. Furthermore, population growth increases agricultural production demand, and this highlights the role of water resources management in the agricultural sector. The 1950’s studies showed 12 countries with a population of 20 million experienced water shortage. Virtual water is the volume of water which is consumed for a production from the beginning stage to the end. Scientists have shown that 96% of water footprints are related to crops, livestock and horticultural productions and only 4% it consumed as domestic water. Water balance data in Qom province shows that 90% of water resources are using in the agricultural sector. Investigation of water footprints in the agricultural sector is highly beneficial to improve water resources management in arid and semi-arid regions such as Qom. Materials and Methods: The research was conducted to find out the production and cultivation water needs in the agricultural sector for 10 years, via calculating the gray, blue and green water footprints using Mekonnen and Hoekstra models. In the livestock sector, water footprint’s information such as the number of livestock and poultry, production of red meat, chicken meat, egg and milk were also determined using the Mekonnen and Hoekstra. The water footprint in fertilizer was calculated using a questionnaire survey. Excel and SAS apps were used to analyze the collected data for all three study sections. Results and Discussion: The results showed that the water footprint in wheat, barley, cotton, onion, tomato, melon, watermelon, alfalfa, and corn were 3018, 2882, 10960, 1463, 1525, 960, 2504, 1683 and 416 m3/ton, respectively. The low irrigation efficiency led to a very high amount of white water footprint in the productions. Green water footprint was very low due to the lack of rainfall. In the livestock sector, the water footprint in red meat and milk were 39 m3/kg and 2.42 m3/lit, respectively which were much more than the global average. In the poultry sector, the water footprint in chicken meat and egg were 7.4 and 4.34 m3/kg, respectively, that were very high compared to the global average. The water footprint in fertilizer for wheat, barley, cotton and alfalfa productions were 2.62, 1.19, 1.07 and 2.54 m3/kg and this amount was higher under nitrogen fertilizer. The average virtual water footprint for chicken meat production in Qom province was 7.4 m3/kg. This amount in the world, USA, India, Russia, Mexico and the Netherlands is equal to 3.92, 2.39, 7.74, 5.76, 5.01 and 2.22 m3/kg respectively. In Netherlands, less water is in use in the agricultural sector than the other countries. In this country, the virtual water footprint in chicken meat is in the best position. India has the highest water consumption in poultry breeding with a consumption of 7.74 m3/kg. The average virtual water footprint in Iran for egg production is 4.34 m3/kg , while the average virtual water footprint for egg production in the world, USA, India, Russia, Mexico and the Netherlands is 3.34, 1.51, 7.53, 4.92, 4.28, and 1.4 m3/kg, respectively. India consumes the most water in the production of eggs such as chicken with a quantity of 7.53 m3/kg and the Netherlands has the least consumption with a value of 1.4 m3/kg . Conclusion: The concept of virtual water footprint in each region reduces the pressure on water resources. For better management in agricultural regions, it is possible to prevent the cultivation of high water demand crops. The most common cause of high water footprint in livestock and poultry is nutrition, so, internationally food import can be a good solution. Industrialization of poultry can also reduce water footprint. The implementation of this research can be a useful clue to the sustainable control and management of water resources and achieving an optimal cultivation pattern in our country and all provinces facing limited water resources.

Organic Farming and Bio-Nanomaterial Conflux: A Way Forward for Sustainable Agriculture.

Increasing population pressure and decreasing cultivable land brought the agricultural sector at an alarming situation of food production particularly in the developing countries. To feed the burgeoning population, the agriculture sector needs to become more productive and diversified while facing the adversity of climate change and limitations of natural resources. During 1960-70, the improved irrigation facilities, the use of fertilizers and pesticides in the cultivation of high yielding varieties of cereals successfully led to the Green revolution in India. In the present scenario, the low irrigation and fertilizer use efficiencies, poor pesticide application and delivery are amongst the important issues in developing countries that need to be addressed for getting higher productivity. Also, fertilizer and pesticide usage also had severe associated environmental consequences like eutrophication, resistance and resurgence in pest, toxicity to non-target organisms, residues in food and feed, accumulation in the environment, etc. In such conditions, organic farming, a traditional practice coupled with the exploration of bio-nanoparticles to achieve a sustainable production system seems to be a better option. This review focuses on current research developments in the areas of bio-nano-enabled crop nutrition, protection, post-harvest management, and the possibility of bio-nanomaterials and organic farming confluence to revolutionize the agricultural sector by ensuring sustainable food security for coming generations.