Effect Of Irrigation Strategies Research Articles

Yield prediction of wheat at different sowing dates and irrigation regimes using the AquaCrop model

Water efficiency models are playing an increasingly important role in helping agricultural activities adapt to climate change. AquaCrop is one of the models that can accurately correlate water-plant-climate parameters. In this study, the effects of irrigation strategies (I1; rainfed, I2; irrigation at Germination (G)+Tillering (T)+Heading (H) stages, I3; irrigation at G+H stages, I4; irrigation at G+T stages) and sowing dates (SD1; normal sowing date, SD2; late sowing date) on winter wheat yield and soil water conditions were investigated in semi-arid climate conditions. Biomass, grain yield, soil water content and crop canopy cover values observed in field conditions and simulated by AquaCrop. According to results SD1 did not have a negative effect on grain yield and biomass however SD2 would significantly reduce grain yield and biomass amount. Considering the biomass and grain yields in terms of irrigation, the highest yield was obtained in the irrigation water applied during the I2SD1 treatment. The yield reduction was 39% in rainfed treatments, 22% when irrigated in G+T periods, and 5% when irrigated in G+H stages. The model predicted 2-year grain yield and biomass values more accurately in SD1 than in SD2. The model predicted yield, biomass, soil moisture content and canopy cover values with an acceptable accuracy.

Effects of Irrigation Strategy and Plastic Film Mulching on Soil N2O Emissions and Fruit Yields of Greenhouse Tomato

Agriculture is a major source of global greenhouse gas emissions. Approximately 1/3 of vegetables in China are produced in greenhouses. However, the effects of different irrigation strategies and plastic film (PF) mulching combinations on N2O emissions and tomato fruit yields in greenhouses are unclear. The aims of this study were to explore the effects of micro-sprinkler irrigation under plastic film (MSPF), drip irrigation under plastic film (DIPF) and micro-sprinkler irrigation (MSI) on the soil nutrients, enzyme activity, nirS-type denitrifying bacterial community, N2O emissions and fruit yields of tomato. The results showed that MSPF could improve the uniformity of soil water distribution and surface (0–40 cm) soil water content. Film mulching could increase soil temperature at depths of 5–25 cm. Both MSPF and DIPF increased microbial nitrogen, promoted the activity of rhizosphere soil urease and leucine aminopeptidase, changed the community of denitrifying bacteria, accelerated the turnover of soil nutrients and improved yield and water use efficiency. PF mulching had a greater impact on the nirS-type denitrifying bacterial community when compared to irrigation strategy. We conclude that MSPF can be used to configure commercially available installation and operation. The comprehensive benefit of MSPF treatment is that it is more profitable than that of DIPF.

Effects of irrigation strategies and soil properties on the characteristics of deep percolation and crop water requirements for a variable rate irrigation system

Reducing deep percolation (DP) across the field is one of the main objectives of a variable rate irrigation (VRI) system under a semi-humid climate. A study was conducted in the North China Plain during the 2016 and 2017 maize growing seasons in a 1.64-ha one-quadrant plot irrigated by a VRI centre pivot irrigation system. The study was designed to quantify and compare the DP dynamics of three irrigation strategies, including soil water balance (SWB), measured soil water content (SWC), and a combination of SWB and rain forecasting for the next three days (RF). The area irrigated by the VRI system was delineated into three management zones (zones 1, 2, and 3) based on the available soil water holding capacity (AWC). Based on the seasonal cumulative DP, the zone-specific crop coefficient (Kc) for each zone was quantified to enhance the accuracy of the SWB method. The results indicated that high daily DP rates occurred during the initial and end growing seasons as well as following rainfall and irrigation events during the mid-season. The delay of DP after an intermittent large rainfall was observed in both seasons. The cumulative DP in zone 2 with a medium AWC and a uniform soil profile was 36% less than the mean values of DP for zones 1 and 3. Compared to the SWC and SWB methods, the cumulative DP for the RF treatment was reduced by 10% and 36%, respectively. During both seasons, the maximum DP values were observed in zones 2 and 3 under the SWB methods. The SWC method tended to increase the risk of DP for a coarse profile, whereas a lower sandy content soil tended to increase the risk for the SWB method. The mean Kc values derived based on DP for the initial, mid-season, and end of the late season stages were 0.86, 0.73, and 0.91 for zones 1, 2, and 3, respectively, with a 7% reduction compared to the Kc without considering DP. The seasonal crop water requirement determined by zone-specific Kc was reduced by 31 mm compared with the uniform Kc in different management zones. Our results suggested that the RF method exhibited promise for reducing DP, and the zone-specific Kc values were helpful to enhance the water savings of the SWB method for a VRI system.

Irrigation and Greenhouse Gas Emissions: A Review of Field-Based Studies

Irrigation practices can greatly influence greenhouse gas (GHG) emissions because of their control on soil microbial activity and substrate supply. However, the effects of different irrigation management practices, such as flood irrigations versus reduced volume methods, including drip and sprinkler irrigation, on GHG emissions are still poorly understood. Therefore, this review was performed to investigate the effects of different irrigation management strategies on the emission of nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) by synthesizing existing research that either directly or indirectly examined the effects of at least two irrigation rates on GHG emissions within a single field-based study. Out of thirty-two articles selected for review, reduced irrigation was found to be effective in lowering the rate of CH4 emissions, while flood irrigation had the highest CH4 emission. The rate of CO2 emission increased mostly under low irrigation, and the effect of irrigation strategies on N2O emissions were inconsistent, though a majority of studies reported low N2O emissions in continuously flooded field treatments. The global warming potential (GWP) demonstrated that reduced or water-saving irrigation strategies have the potential to decrease the effect of GHG emissions. In general, GWP was higher for the field that was continuously flooded. The major finding from this review is that optimizing irrigation may help to reduce CH4 emissions and net GWP. However, more field research assessing the effect of varying rates of irrigation on the emission of GHGs from the agricultural field is warranted.

Effect of Irrigation Strategies on Yield of Drip Irrigated Sunflower Oil and Fatty Acid Composition and its Economic Returns

A field trial was conducted to observe the effects of different irrigation strategies on the yield and the water use, oil content and marginal return of sunflower which was irrigated by means of a drip system during 2010 and 2011 under Cukurova condition of Turkey. The irrigation strategies include three irrigation intervals (A1: 25 mm; A2: 50 mm; A3: 75 mm of cumulative pan evaporation) and six water levels (WL) based upon the percentages of cumulative pan evaporation (WL1= 0.50, WL2= 0.75, WL3= 1.00 and WL4= 1.25). In addition, WL5= PRD50 and WL6= PRD75 treatments were evaluated. They obtained water from alternative laterals 50% and 75% of the WL3 treatment. Additionally, a nonirrigated treatment (NI) was included as control plot in the experiment. In each of the experimental years, the largest and the smallest average yields were acquired from the A2WL4 and NI treatments, respectively. The oil content and fatty acid composition were significantly affected by irrigation strategies. The oil content increased with the increasing amount of irrigation. Among all irrigation intervals, PRD-50 (WL5) treatment provided the largest water use efficiency (WUE) and irrigation water use efficiency (IWUE) values in both growing seasons. In order to attain higher yields and a generated the marginal return, A2WL4 irrigation regime is suggested for sunflower production in the Mediterranean region. A2WL3 water strategy is proposed for an acceptable marginal return in case of water shortage.

Effectiveness of irrigation strategies on the removal of the smear layer from root canal dentin.

The aim of this study was to evaluate the removal of the smear layer by some commonly used (needle-and-syringe irrigation, sonic activation, ultrasonically activated irrigation) and new root canal irrigation strategies (negative pressure irrigation and polymer rotary file) using a novel approach by comparing pre- and post-experimental images. Prepared root canals (n = 50) were subjected to a split tooth model and divided into 5 groups (n = 10): (1) needle-and-syringe irrigation (control); (2) sonic activation (SA); (3) negative pressure irrigation with continuous warm activated irrigation and evacuation (CWA); (4) polymer finishing file (FF); (5) ultrasonically activated irrigation (UAI). Smear layer scores and percentage of open dentinal tubules (%ODT) were evaluated by 2 examiners before and after irrigation procedures, from the middle and apical thirds of the root canal, on scanning electron microscopic images. Data were analysed using Kruskal-Wallis and post hoc tests at P = 0.05. Needle-and-syringe irrigation (control) showed no significant difference (both smear score and %ODT) compared to the pre-experimental value (P > 0.05). All other groups showed lower smear scores and higher %ODT, compared to the control (P < 0.05). The lowest smear score and highest %ODT were observed in the CWA group, which was significantly different from all other groups (P < 0.05). SA group showed significantly higher smear scores and lower %ODT than FF or UAI (P < 0.05). CWA showed superior removal of smear layer in the middle and apical thirds of the root canal compared to the other irrigation strategies.

Effects of irrigation strategies, planting methods and nitrogen fertilization on yield, water and nitrogen efficiencies of safflower

Safflower (Carthamus tinctorius L.) is a multipurpose crop that is used as food dyeing spice, edible oil, livestock feed, biofuels and medicinal applications in many areas of the world. Drought and scarce resource of irrigation water are serious concerns in agricultural production and global food security that have occurred in Iran and other arid and semi-arid regions. The objective of this study is to investigate the effects of partial root drying (PRD) irrigation, planting method and different nitrogen application rates on yield, water and nitrogen use efficiencies of safflower. The experiment was designed as split-split plot that arranged in randomized complete blocks with irrigation strategy as the main plot, planting method as the subplot and nitrogen levels as the sub-subplot in three replications. The irrigation strategies consisted of ordinary furrow irrigation (OFI) and variable alternate furrow irrigation (VAFI) as a PRD technique. The planting methods included of on-ridge planting (ORP) and in-furrow planting (IFP) methods. The fertilizer levels were 0 (N0), 100 (N1) and 200 (N2) kgha−1 of urea as 0, 46 and 92kgNha−1. In present study, VAFI technique dominantly saved applied irrigation water by 30.2% against only a 13% reduction in safflower seed yield that was not statistically significant among treatments. The coefficient of crop response to water (Ky) obtained as 0.83 which shows that safflower is a tolerant crop to VAFI strategy which is recommended in areas with limited water resources. Furthermore, in-furrow planting method resulted in 13.5% enhancement in safflower seed yield due to the better soil conditions (temperature and moisture) that is provided by this technique. Therefore, this method is considered as an appropriate alternative for safflower planting due to its favourable influence on water use efficiency (WUE) and other safflower traits, especially in semi-arid and arid regions. Most of safflower traits were definitely enhanced by application of 46kgNha−1 such as yield production, WUE and nitrogen use efficiencies; whereas higher rate of nitrogen showed negligible effect on safflower traits compared with 46kgNha−1.

Effects of irrigation strategies and soils on field grown potatoes: Root distribution

Abstract Root distribution of field grown potatoes (cv. Folva) was studied in 4.32 m 2 lysimeters and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies. Drip irrigation was applied for all irrigations. Irrigations were run in three different soils: coarse sand, loamy sand, and sandy loam. Irrigation treatments started after tuber bulking and lasted until final harvest with PRD and DI receiving 65% of FI. Potatoes irrigated with water-saving irrigation techniques (PRD and DI) did not show statistically different dry root mass and root length density (RLD, cm root per cm 3 soil) compared with root development in fully irrigated (FI) potatoes. Highest RLD existed in the top 30–40 cm of the ridge below which it decreased sharply. The RLD was distributed homogenously along the ridge and furrow but heterogeneously across the ridge and furrow with highest root density in the furrow. Most roots accumulated in the surface layers of coarse sand as compared to the other soil types. In the deep soil profile (30–70 cm) a higher root density was found in loamy sand compared with the sandy loam and coarse sand. Approximately twice the amounts of roots were found below the furrows compared with the corresponding layers below the ridges. The RLD values in the soil profile of the ridges and the furrows followed the Gerwitz and Page model: RLD = α × exp(− β × z ). The highest value of surface root density ( α ) and rate of change in density ( β ) was found in coarse sand while the lowest values of α and β were found in the sandy loam and loamy sand. The model estimated the effective rooting depth in coarse sand and sandy loam quite well but did slightly overestimate it in the loamy sand. Statistical analysis showed that one α and β value can be used for each soil irrespective of the irrigation treatment. Thus, the effective rooting depths corresponding to root length densities of 0.1 and 0.25 cm cm −3 for sandy loam, loamy sand, and coarse sand soils were 99, 141, and 94 cm, and 80, 115, and 78 cm, respectively, calculated from top of the ridge. The findings of this study can be used in practice for efficient use of water and nutrients in the field.

Effects of irrigation strategies and soils on field grown potatoes: Yield and water productivity

Yield and water productivity of potatoes grown in 4.32 m2 lysimeters were measured in coarse sand, loamy sand, and sandy loam and imposed to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies. PRD and DI as water-saving irrigation treatments received 65% of FI after tuber bulking and lasted for 6 weeks until final harvest. Analysis across the soil textures showed that fresh yields were not significant between the irrigation treatments. However, the same analysis across the irrigation treatments revealed that the effect of soil texture was significant on the fresh yield and loamy sand produced significantly higher fresh yield than the other two soils, probably because of higher leaf area index, higher photosynthesis rates, and “stay-green” effect late in the growing season. More analysis showed that there was a significant interaction between the irrigation treatments and soil textures that the highest fresh yield was obtained under FI in loamy sand. Furthermore, analysis across the soil textures showed that water productivities, WP (kg ha−1 fresh tuber yield mm−1 ET) were not significantly different between the irrigation treatments. However, across the irrigation treatments, the soil textures were significantly different. This showed that the interaction between irrigation treatments and soil textures was significant that the highest significant WP was obtained under DI in sandy loam. While PRD and DI treatments increased WP by, respectively, 11 and 5% in coarse sand and 28 and 36% in sandy loam relative to FI, they decreased WP in loamy sand by 15 and 13%. The reduced WP in loamy sand was due to nearly 28% fresh tuber yield loss in PRD and DI relative to FI even though ET was reduced by 9 and 11% in these irrigation treatments. This study showed that different soils will affect water-saving irrigation strategies that are worth knowing for suitable agricultural water management. So, under non-limited water resources conditions, loamy sand produces the highest yield under full irrigation but water-saving irrigations (PRD and DI) are not recommended due to considerable loss (28%) in yield. However, under restricted water resources, it is recommended to apply water-saving irrigations in sandy loam and coarse sand to achieve the highest water productivity.

Effects of irrigation strategies and soils on field-grown potatoes: Gas exchange and xylem [ABA

Gas exchange was measured in potatoes (cv. Folva) grown in lysimeters (4.32 m 2 ) in coarse sand, loamy sand , and sandy loam and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies . PRD and DI as water-saving irrigation treatments received 65% of FI and started after tuber bulking and lasted for six weeks until final harvest. Midday photosynthesis rate ( A n ) and stomatal conductance ( g s ) of fully irrigated (FI) plants were lowest in coarse sand and mean A n of diurnal measurements in FI, PRD and DI tended to be lower in this soil as compared with the loamy sand and sandy loam. The results revealed that diurnal values of A n and g s in PRD and DI were consistently lower than FI without reaching significant differences in accordance with findings that xylem [ABA] in PRD was significantly higher than FI, and tended to be higher than in DI. Diurnal measurements showed that A n reached peak values during mid-morning and midday, while g s were highest during the morning. Intrinsic water use efficiency ( A n / g s ) correlated linearly well with the leaf to air vapor pressure deficit (VPD) and the slope of the line revealed the rate of A n / g s increase per each kPa increase in VPD, i.e. approximately 10 μmol mol −1 . Transpiration efficiency ( A n / T ) of PRD was higher than DI, which shows slightly better efficient water use than DI. The slope of the linear relationship between transpiration efficiency and VPD decreased from −2.03 to −1.04 during the time course of the growing season, indicating the negative effect of leaf ageing on photosynthesis and thus on plant water use efficiency. This fact shows the possibility to save water during last growth stages through applying water-saving irrigations without much effect on transpiration efficiency.

Hydraulic and chemical signalling in the regulation of stomatal conductance and plant water use in field grapevines growing under deficit irrigation.

Effects of irrigation strategies on stomata and plant water use were studied in field-grown grapevines (Vitis vinifera L.). We assessed the importance of root-derived chemical signals vs. hydraulic signalling in stomatal regulation. The experiment included two treatments with the same water added to the soil (50% ETc) applied either to the whole root system (DI) or to half of the roots, alternating irrigation side every 15 days (PRD). Well-watered plants (FI) (100% ETc) and non-irrigated grapevines (NI) were also studied. Partial stomata closure occurred in both PRD and DI plants. [ABA] of xylem sap remained constant during the day and was maintained throughout the season, with higher values in NI plants. Xylem sap pH was not affected by soil water availability. A positive correlation between ψpd and maximum g s was found, indicating that grapevine stomata strongly respond to plant water status. In contrast, ABA did not explain stomatal control at veraison. At mid-ripening g s was significantly correlated with ABA, apparently interacting with the rise in xylem sap pH. Therefore, our data suggest that hydraulic feedback and feed-forward root-to-shoot chemical signalling mechanisms might be involved in the control of stomata in response to decreased soil water availability, hydraulic signals playing the dominant role.

Irrigation and nitrogen fertiliser effects on dry matter yield, water use efficiency and nutritive characteristics of summer forage crops in south-west Victoria

Summer forage crops form an integral component of feed rations to meet the dietary requirements of dairy cows in south-west Victoria. Irrigation of such crops has the potential to increase the availability of feed of high nutritive value. The effect of irrigation strategies and nitrogen (N) fertiliser on forage crop accumulation rates, dry matter yield, water use efficiency and nutritive characteristics was determined at each harvest over 2 summers. The crops used were Hunter (Brassica campestris L. × Brassica napus L.), Graza (a complex hybrid of Raphanus sativus L. with introgression from Raphanus maritimus L. and Brassica oleracea L.) and Shirohie millet (Echinochloa utilis Ohwi &amp; Yabuno). Irrigation treatments were dryland control, weekly irrigation to 100% of estimated requirements, weekly irrigation to 50% of estimated requirements and 25% of estimated requirements every second week. Following sowing and after each harvest, N was applied at either 50 or 100 kg N/ha (brassica crops, 3 applications; millet, 2 applications). In both years, fully irrigated crops produced higher dry matter yields than the dryland crops for all species. For Hunter and Graza, full irrigation also resulted in higher dry matter yields than irrigating every second week. Nitrogen at the higher application rate led to higher dry matter yields for Graza in both years and for millet in year 1. Irrigation had inconsistent effects on the nutritive characteristics of all species. Metabolisable energy content ranged from 10.1 to 13.6, 9.8 to 13.3 and 8.2 to 11.3 MJ/kg dry matter for Hunter, Graza and millet, respectively. Nitrogen application at 100 kg N/ha resulted in higher crude protein content for Hunter and Graza at the second and third harvests and for millet at the second harvest at 50 kg N/ha in both years. Water use efficiencies (irrigation plus effective rainfall) varied according to species with all dryland crops having higher water use efficiencies than the irrigated crops. Total water use efficiencies ranged from 21 to 55, 17 to 39 and 28 to 86 kg dry matter/ha.mm for Hunter, Graza and millet, respectively. In contrast, water use efficiencies from applied irrigation water ranged from 0 to 18 kg dry matter/ha.mm for Hunter, 5 to 18 kg dry matter/ha.mm for Graza and 3 to 33 kg dry matter/ha.mm for millet. Economic assessments indicated average costs for dryland Hunter, Graza and millet to be AU$94, $124 and $76/t dry matter and average costs for fully irrigated crops to be $57, $67 and $51/t dry matter, respectively. This study indicates there is potential to economically irrigate these species to provide additional dry matter of medium to high nutritional value to feed lactating dairy cows through late spring and summer. The data also indicate that for the irrigation of summer forage crops in this environment, the most efficient use of limited water supplies is likely to be a weekly application of water at 50% of the estimated perennial pasture requirements.

Effects of irrigation strategies and nitrogen fertiliser on turnip dry matter yield, water use efficiency, nutritive characteristics and mineral content in western Victoria

The effect of different irrigation strategies on turnip forage crop growth rates, dry matter (DM) yield, water use efficiency (WUE), changes in soil volumetric water content, nutritive characteristics and mineral content was determined on different soil types at different sites (site 1 and 2) over 2 years. Treatments were: (A) a dryland control; (B) fully watered to soil field capacity each week; (C) 75% of full watering; (D) 50% of full watering; (E) 25% of full watering; (F) a single watering to soil field capacity or to a maximum of 50 mm between weeks 0–6; (G) a single watering between weeks 6–8; (H) a single watering between weeks 8–10; and (I) a single watering between weeks 10–12 after sowing. In addition, each irrigation treatment received either 0 or 50 kg N/ha applied 5 weeks after sowing. Responses to applied irrigation water were different at each site and also within one year. At site 1, responses to irrigation were adversely affected by insect damage and delayed sowing, particularly in year 1. However, there were significant increases in DM yield to weekly irrigation regimes in both years, with responses greater in year 2, and responses in both years were greater where nitrogen was applied. At site 2, there were significant responses to weekly irrigation regimes in year 1 with DM yields from fully irrigated plots almost double that of the dryland treatment. In year 2, DM yields from all treatments were similar and it is proposed that lower summer temperatures may have contributed to the improved DM yield observed with the dryland treatment. In both years, at site 2, there were generally higher DM yields with nitrogen application irrespective of irrigation regime. Turnip metabolisable energy values were consistently above 11.5 and 13 MJ/kg DM for leaves and roots respectively, with crude protein contents for leaves ranging from 11 to 20% and 13 to 24% and roots from 6 to 14% and 9 to 17% at sites 1 and 2, respectively. Water use efficiencies varied according to irrigation treatment with higher efficiencies observed at site 2 in both years. In year 1 and 2, total WUE at site 1 varied from 5 to 11 kg DM/ha.mm while at site 2 the range was 20–48�kg�DM/ha.mm with higher values being observed in year 2. As with DM yields it is likely that the observed higher WUE in year 2 was due to lower summer temperatures. At site 2, the dryland treatments produced the highest efficiencies in both years. In contrast, WUE from applied irrigation water ranged from 0 to 35 kg DM/ha.mm at site�1 and from 0 to 23 kg DM/ha.mm at site 2. This study suggests that there is potential to economically irrigate turnips to provide additional DM of high nutritional value for lactating dairy cows, however, issues such as sowing dates, soil type, and insect damage will also influence final yields. In particular, summer temperatures influence both dryland growth potential and growth responses to irrigation. Also single irrigations during the growing period will not significantly increase DM yields over a crop grown under dryland conditions.

The effect of irrigation strategies during tuber initiation on marketable yield and development of common scab disease of potato in Russet Burbank in Tasmania

Management of soil moisture deficit during tuber initiation and early development was important for the optimisation of net and marketable tuber yields of cv. Russet Burbank on the typical red ferrosol cropping soils of Northern Tasmania, Australia. An effect of reduced water input during the tuber initiation period on increasing incidence of common scab disease was noted in one trial. In subsequent trials disease inoculum levels were not sufficient to show differences between treatments despite a history of disease at the site. For optimisation of marketable yield and probable assistance in the management of common scab disease it is recommended that irrigation scheduling to known soil moisture deficits be adopted during this period of growth on this soil type.