Consumptive Use Research Articles

Developing a Crop Water Production Function for Alfalfa under Deficit Irrigation: A Case Study in Eastern Colorado

Recent Colorado, USA water law provisions allow a portion of irrigation water to be leased between agricultural and other users. Reducing consumptive use (CU) through deficit irrigation while maintaining some crop production could allow farmers to earn revenue from leasing water rights. This observational study aimed to determine if deficit irrigation of alfalfa (Medicago sativa L.) can be used to reduce CU, provide parameters for an alfalfa crop water production function (WPF), and evaluate the potential for improved farm income by leasing water. Soil water balance, evapotranspiration (ET), and dry matter yield from eight commercial fields (1.70 to 2.14 ha zones), growing subsurface drip-irrigated alfalfa, were monitored for five seasons (2018–2022) at Kersey, Colorado. Four irrigation treatments [Standard Irrigation (SI) = irrigate when soil water deficit (D) exceeds management allowed depletion (MAD); Moderate Deficit Irrigation (MDI) = 70% of SI; Severe Deficit Irrigation (SDI) = 50% of SI; and Over Irrigation (OI) = 120% of SI] were applied, with two zones per treatment. Reductions in CU ranged from 205 to 260 mm per season. The shape of the alfalfa WPF (dry biomass yield vs. ET) was concave, indicating that water use efficiency (WUE) could be optimized through deficit irrigation. The average WUE was 0.17 Mg ha−1 cm−1 and tended to increase with greater deficits. Deficit irrigation also increased the relative feed value. If conserved CU from deficit irrigation can be leased into a transfer water market, farmers could profit when the water lease revenue exceeds the forgone profit from alfalfa production. We found incremental profit from deficit irrigation and water leasing to be positive, assuming 2020 prices for hay ($230 bale−1) and water prices above $0.50 m−3.

Production maximization of rainy season rice (Oryza sativa) through effective use of water and solar radiation under modified system of rice intensification in Assam

A field experiment was conducted in a farmers’ field at Nepalikhuti, Golaghat, Assam during the rainy (kharif) season of 2016 and 2017, to find out the effect of different transplanting dates and hill densities of rice (Oryza sativa L.) under system of rice intensification (SRI) which was compared with conventional rice cultivation (CRC). The experiment was designed in factorial split-plot with 2 crop-establishment methods (SRI and CRC) and 3 transplanting dates (26 June, 10 and 25 July) in the main plot; and 4 different hill densities (20 cm × 10 cm, 20 cm × 20 cm, 25 cm × 20 cm and 25 cm × 25 cm) in the subplots and replicated thrice. With an increased grain yield of 5.71 t/ha, SRI-establishment showed a significant yield advantage of 0.83 t/ha coupled with 2.64% more consumptively used water and 1.29 kg/ha-mm more water-use efficiency over CRC. Results showed strong positive correlation (0.95**) between water-use efficiency (WUE) and yield attributes primarily the effective tillers/m2. Regression analysis revealed that irrespective of establishment methods, the consumptive use (CU) of water, accumulated incident photosynthetically active radiation (AIPAR), radiation-use efficiency (RUE) and heat-use efficiency (HUE) greatly influenced the grain yield. However, in SRI, WUE appeared to be an additional key determinant of grain yield. Between 2 establishment methods, SRI was found to be more competent in utilizing water and solar radiation owing to its ideal canopy environment.

Riparian Plant Evapotranspiration and Consumptive Use for Selected Areas of the Little Colorado River Watershed on the Navajo Nation

Estimates of riparian vegetation water use are important for hydromorphological assessment, partitioning within human and natural environments, and informing environmental policy decisions. The objectives of this study were to calculate the actual evapotranspiration (ETa) (mm/day and mm/year) and derive riparian vegetation annual consumptive use (CU) in acre-feet (AF) for select riparian areas of the Little Colorado River watershed within the Navajo Nation, in northeastern Arizona, USA. This was accomplished by first estimating the riparian land cover area for trees and shrubs using a 2019 summer scene from National Agricultural Imagery Program (NAIP) (1 m resolution), and then fusing the riparian delineation with Landsat-8 OLI (30-m) to estimate ETa for 2014–2020. We used indirect remote sensing methods based on gridded weather data, Daymet (1 km) and PRISM (4 km), and Landsat measurements of vegetation activity using the two-band Enhanced Vegetation Index (EVI2). Estimates of potential ET were calculated using Blaney-Criddle. Riparian ETa was quantified using the Nagler ET(EVI2) approach. Using both vector and raster estimates of tree, shrub, and total riparian area, we produced the first CU measurements for this region. Our best estimate of annual CU is 36,983 AF with a range between 31,648–41,585 AF and refines earlier projections of 25,387–46,397 AF.

More risk, more money: When are payments for water savings from limited irrigation profitable for farmers?

As farmers in semiarid climates seek new ways of adding value to their operations, those with irrigation water rights are increasingly receptive to payments, or credits, for water sharing. Yet, past research on the economic feasibility of limited irrigation strategies for consumptive use (CU) savings seldom considers production risk. Using stochastic dominance, we compare the effect of three limited irrigation practices—deficit irrigation, root zone drying, and early crop maturity—on the returns to corn production for sprinkler and subsurface technology. Field-level simulations show that the practices reduce returns and increase risk, but credits for CU savings could make them economically viable for farmers. Larger credits (more money) incentivize limited irrigation at greater levels (less yield and more risk), but fully compensating farmers for risk-bearing will be costly. With sprinkler technology, root zone drying becomes risk-efficient at lower credit values than deficit irrigation. Deficit irrigation along with root zone drying become risk-efficient at the lowest credit values for subsurface technology. Thus, risk aversion could explain why some farmers choose not to share water even when credits are large enough, on average, to compensate for differences in expected returns. Improved knowledge about the profitability and risk of limited irrigation practices can increase the joint sustainability of irrigated agriculture and other societal water uses.

Effect of Deficit Irrigation and Weed Control Treatments on Grain Yield and Water Productivity for Three Bread Wheat Genotypes

A field experiment was conducted during two winter seasons 2018/2019 and 2019/2020 at Sakha Agricultural Research Station, Kafr El-Sheikh Governorate, Egypt to study the effect of deficit irrigation and weed control treatments on grain yield and water productivity of three bread wheat genotypes. The experimental design was stripe split-plot, with three replicates. Irrigation treatments were in the vertical plots which include I1 irrigation at all stages (full irrigation), while I2, I3 and I4 were deficit irrigation through withholding one irrigation at elongation, booting, and anthesis stages, respectively. Four weed control treatments were allocated in horizontal plots that include, W1 (Gerostar + Action), W2 (Atlants), W3 (hand weeding twice), and W4 control (untreated), Sub-Subplots were three wheat genotypes G1 (Giza 171), G2 (Sakha 95) and G3 (promising Line). The results revealed that the highest values of plant height, number of spikes m2, number of kernels spikes-1, 1000-kernel weight, biological yield, grain yield and straw yield were recorded under I1 compared to all the studied irrigation treatments, as well as under W1 compared to other weed control treatments and G2 compared to others genotypes in the two seasons. The highest values of water consumptive use (CU), and applied water (AW) were recorded under I1 to be 37.67, and 48.26 cm respectively, the values of AW under I2, I3 and I4 were reduced by 18.5%, 17.6%, and 22.3% respectively compared to I1 as mean of the two seasons. The values of productivity of irrigation water (PIW), and water productivity (WP) were taken the descending order W1> W2 > W3 > W4 and G2 > G1 > G3 for weed, and genotypes respectively. It could be recommended the I2 × W1 × G2 interaction which recorded the highest grain yield, PIW and WP, moreover saved a reasonable amount of irrigation water.

Effect of Irrigation Scheduling and Intercropping Pattern on Growth, Yield, Quality of Green Onion, Lettuce and some Water Relations in North Nile Delta Region

Two field trials were performed at Sakha Agricultural Research Station Farm, Kafr El- Sheikh Governorate, during the two winter seasons 2017/18 and 2018/19 to study the influence of irrigation scheduling; traditional watering (I1), irrigation at 1.2(I2), 1.0(I3) and 0.8(I4) of accumulative pan evaporation(APE) and four systems of sole and intercropping pattern; sole green onion cv. Giza 6(P1), sole lettuce cv. Balady(P2), 2green onion : 1 lettuce(P3) and 1 green onion : 2 lettuce(P4) in a split plot design with four replications. Data indicated that the highest values for seasonal applied water (AW) and water consumptive use (CU) were registered under irrigation treatment(I2). For water consumptive use efficiency (Ecu%), the highest values were recorded under treatment (I1). productivity of irrigation water (PIW) and water productivity (WP) were clearly impacted by irrigation treatments, intercropping patterns in addition crop type where the highest values also recorded I2 besides P4. The results also revealed that yield, yield component and quality parameters for green onion; plant height, fresh weight of leaves, plant weight, leaf area/ plant, chlorophyll content and total yield as well as lettuce; plant height, leaf area/ plant, chlorophyll content, plant weight, head weight, diameter and total yield increased with increasing irrigation applied water. On contrary, for crop pattern the highest values for yield component recorded under sole crop but the total yield recorded under 1:2green onion- lettuce planting pattern. For gross return and increasing income was attained I2 besides P4. Land equivalent ratio (LER) exhibited higher values with I1 besides P4.

Growth-stage-specific crop coefficient and consumptive use of Capsicum chinense using hydraulic weighing lysimeter

This research was conducted to determine growth stage-specific crop coefficient (Kc) and Consumptive Use (CU), for Capsicum chinense (Ata rodo) grown under irrigation in Omu-Aran, North central Nigeria. Daily CU and growth stage-specific crop coefficient Kc for Capsicum chinense was measured using a developed and calibrated hydraulic weighing lysimeter over 2 consecutive dry seasons (2015/16 and 2016/17). The values of CU and growth stage-specific Kc obtained were compared to that estimated using CROPWAT 8.0 and with existing Food and Agricultural Organization (FAO) Kc values for bell pepper. The Kc values determined over the growing seasons varied from 0.32 to 0.7, 1.02 to 1.45 and 0.76 to 0.9 representing Kc initial, Kc mid-season and Kc late season (Kcini, Kcmid and Kcend), respectively. These Kc varied significantly (P < 0.05) from FAO established Kc values. The observed Kc was validated using relevant statistical methods. The seasonal CU of Capsicum chinense was 580.01 ± 54 mm, while the reference evapotranspiration increased from 3.26 mm day−1 in October to 4.19 mm day−1 in February. The crop factor increased from 0.7 in October to attain its peak of 1.45 in January, but decreased to 0.9 during crop senescence in February. Likewise, the daily crop water need was 2.28 mm day−1 in October but reached its peak of 5.82 mm day−1 in January and thereafter decreased to 3.77 mm day−1 in February. Mean monthly water need of Capsicum chinense pepper was 68.36 mm month−1 in October. The water need of crop rose to its peak of 166.32 mm month−1 in December, and thereafter declined to 113.13 mm month−1 in February It is inferred that the application of growth stage-specific Kc will assist in irrigation management and would serve as useful guide for precise water applications for areas around Omu-Aran as it differs from region to region.

Water productivity for Egyptian clover as affected by different irrigation regimes and cultivation methods in the North Middle Nile Delta Region

A FIELD experiment was conducted in the two successive winter seasons ( 2016-17 and 2017-18) to investigate the impact of cultivation method; dry cultivation ( dry seed on dry soil) and traditional one (wet seed on wet soil) and irrigation regime; five different irrigation regimes as follows, irrigation till 5 cm above soil surface, (traditional, I1), using soil moisture depletion (I2), irrigation with 0.8 from pan evaporation (I3), irrigation with Hargreaves equation, 1981 (I4) and irrigation till 2.5 cm above soil surface (I5).The obtained results showed that decreasing amount of irrigation water from traditional method (I1) to 2.5 cm above soil surface (I5) reduced fresh yield by 5.49 and 6.75 ton fed.-1 with water saving ≈14.5% (≈ 336.0 m3fed.-1,) for dry seeds cultivation method, and the corresponding values 4.87 and 7.34 ton fed.-1 with water saving 10.75% (≈ 280.0 m3fed.-1,) for wet cultivation one in the overall seasons. Meaningfully, an average of ≈ 700-840 million m3 water could be saved at the national level (≈2.5 million fed.). Moreover, mean reduction in dry yield by 24.62 kg fed.-1, (6.35 %) and 13.00 kg fed-1 (3.51 %) could be resulted from dry cultivation method, and by 36.45 kg fed-1 (8.68 %) and 10.91 kg fed-1 (2.60 %) could be resulted from wet cultivation method in the first and second seasons respectively.The highest overall mean values of water consumptive use (CU) and consumptive use efficiency (Ecu, %) were recorded irrigation without any stress during the growing season (I1). Productivity of irrigation water (PIW kgm-3) and water productivity (WP kgm-3) for fresh yield was the highest values recorded under I5 (the lowest water consumed) for dry and wet cultivation methods.

Influence of Irrigation Intervals under Different Sowing Dates on Water Relations, Yield and Quality Nutrition of Guar Forage Crop

TWO FIELD experiments were conducted at Giza Agriculture Research Station during the two growing seasons of 2015 and 2016. The investigation was carried out to study the effect of different irrigation intervals, i.e., two weeks and three weeks in combination with different sowing dates, i.e., 1st April ,15th April , 1st May and 15th May on Guar forage crop (Cyamopsis tetragonoloba L.,var. Shandaweel 1 ) crop - water relations, yield and yield components under middle Egypt conditions. The main results could be summarized as follows:-The number of applied irrigations and seasonal water consumptive use (CU) were increased with decreasing irrigation interval days which the shortage irrigation interval (irrigation every 15 days) recorded the maximum CU under all sowing date with an overall average being 442 and 453 mm for first and second season, respectively. The same trend was found with sowing date, with plant sown in 1st April consumed more water than the other sowing dates. The lowest water use efficiency (WUE) was recorded under longer irrigation interval (irrigation every 21days) comparable to (irrigation every 15 days) and values of WUE differed due to sowing date, which the S4 (sowing at 15th May) gave the lowest WUE while, S1( sowing at 1st April) obtained the highest value. The crop coefficient (Kc) values started small and increased to reach their maximum values in mid season under all sowing dates, then decline again until the crop maturity under all sowing dates.All yield and yield component traits were markedly affected by sowing date and irrigation interval. Most of the studied traits except leaves/stem ratio as well as fiber %, decreased by delaying sowing date from 1st April to 15th May. Decreasing irrigation interval days from 21 to 15 days significantly increased plant height, number of branches/plant, fresh and dry yield ton fad-1, while leaves/stem ratio and crud fiber% which increased by increasing irrigation intervals from 15 to 21 days.

Water Productivity of Wheat Crop as Affected by Different Sowing Dates and Deficit Irrigation Treatments

Climate change scenarios require reconsidering different agricultural practices including sowing dates and irrigation intervals. For this purpose, a field experiment was carried out at the Agricultural Research Farm of Sakha Agricultural Research Station, Kafr-Elsheikh Governorate during the successive winter seasons 2013/2014 and 2014/2015 to investigate the impact of deficit water irrigation and sowing dates on wheat crop productivity(Triticum aestivum L.). The experimental site located at latitude of 30˚: 37 N, longitude of 31 ˚ - 57 E, and altitude of +6 meters above the sea level. The experimental design was split – plot with three replicates. The main plot was assigned to sowing dates of 15th November (S1) , 30th November (S2) and 15th December (S3), while the sub plot was assigned to irrigation treatments i.e. I1 (given four irrigations plus the sowing irrigation, I2 (given three irrigations following the sowing irrigation) and I3 (given two irrigations after the sowing irrigation). The highest mean values of water applied (Wa) and consumptive use (CU) were 613.6 and 485.6 mm under treatment S1I1 , respectively. While the corresponding lowest mean values were 363.3 and 310.4 mm under treatment S3I3 . The highest contribution percentages of rainfall to water applied (Wa) were 46.6% and 38.4 % for treatments S3I3 under third sowing date in the first season. While, in the second season were 43.4% and 35.7% for treatments S2I3 under the two sowing date, respectively. The lowest contribution percentages were 27.3%, 31.7 % and 27.8% , 32.4% for treatment S1I1 under first sowing date in two seasons. Moreover, the highest mean values of grain water productively (WPg), straw water productively (WPs) were recorded under S1 and I3 in the first season with values of 1.47, 1.48, 2.27 and 2.19 kg m-3, respectively. While in the second season the highest values were recorded under S2 and I3 with values 1.7, 1.59, 2.31 and 2.41 kg m-3, respectively. The highest mean values of productivity of water applied for grain and straw (PWag , PWas ) were recorded under S2, I3, in two growing seasons with values of 1.17, 2.23, 1.39, 1.33,1.82, 1.89, 1.97 and 1.92 kg m-3, respectively. In addition, biological yield, grain yield, straw yield, plant height and 1000-grain weight given the highest values under S1I1 , S2I1 in the two seasons.

Evaluation of Induced Microclimate Modification via Changing Planting Dates and/or Irrigation Methods on Maize Water Productivity in Two Locations in Egypt

A field experiment was executed in2015 summer season, at Gemmeiza (Middle Nile Delta, Lat. 30.47, Long. 31.00) at El-Gharbia Governorate and Mallawi (Middle Egypt, Lat. 28.05 Long. 30.44) at El-Minia Governorate to find out the extent to which grain yield, water use and water productivity for SC10 maize hybrid were influenced by irrigation schemes and planting dates and itinteraction. Irrigation schemes (furrow and bed irrigation schemes) were combined with three planting dates (May, 15; May, 30 and June, 14), and assessed in Randomized Complete Block Design andarranged in split plot design. Irrigation schemes were tested in main plots, while the split plots were assigned to planting dates, and each treatment was replicated three times. The important findings could be summarized as follows: * Maize grain yield at Gemmeiza location insignificantly increased thatatMallawi location. The adopted irrigation schemes significantly influenced the grain yield, and furrow irrigation surpassed bed furrow irrigation by 9.15%. Maize grain yield was significantly influencedby planting dates, whereplanting on May, 15 was superior, and the grain yield was increased by 3.77 and 7.42%, comparable with May, 30 and June, 14 planting dates, respectively. * The highest consumptive use (CU) value (600.5 mm) was recorded under Mallawi conditions, which exceeded that under Gemmeiza by 17.86%. Such findings are mainly attributable to prevailing weather conditions during the growing season, which encourages higher crop water use under Mallawi conditions. Water use value under furrow irrigation scheme was higher by 22.24% more than that with bed irrigation. The lowest CU value (542.3 mm) was found for May, 15 planting date, and increased by 2.34 and 4.79%,respectively, comparable withMay, 30 and June, 14 planting dates. *Water productivity (WP) value proved that maize plants, under Gemmeiza conditions, used the irrigation water efficiently by 10.74%, higher than that recorded under Mallawi conditions. Bed irrigation scheme exhibited higher WP value than that recorded with furrow irrigation scheme by 5.15%. The highest WP value (7.74 kgfad-1mm-1) resulted from May, 15 planting date, and delaying the planting date to May, 30 or June, 14 caused reductions in WP values being13.05 and 17.05%, respectively, lower than that with May, 15 planting date. Based on the obtained results, maize production at Gemmeiza (Middle Nile Delta, Lat. 30.47 Long. 31.00), compared with Mallawi (Middle Egypt, Lat. 28.05 Long. 30.44) is preferred due to lower water use and higher water productivity as well.

Water budget analysis for the Middle Mohlapitsi wetland in the Oliphants River Basin, Limpopo province, South Africa

The objective of the study was to design a workable water balance of the wetland to develop a comprehensive water-resources plan for the basin. The study area water budget describes inputs to the watershed (precipitation and imported water), outputs of water from the watershed (streamflow, exported water, leakage, consumed water, and evapotranspiration), and changes in ground-water and surface-water storage. Hydrological and meteorological data was obtained from Department of Water and Sanitation (DWS) and South African Weather Service (SAWS) respectively. The study area water-budget equation was calculated for evapotranspiration (ET). No water was imported to the study area, and no GW was exported to the surrounding catchments. The average precipitation (R), streamflow (SF), change in groundwater storage (ΔGWs), change in surface water storage (ΔSWs), consumptive use (CoU) and evapotranspiration (ET) and errors were 20.93, 14.93, &minus;4.68, &minus;4.04, 9.43 and 5.29 cm respectively.

Water budget analysis for the Middle Mohlapitsi wetland in the Oliphants River Basin, Limpopo province, South Africa

The objective of the study was to design a workable water balance of the wetland to develop a comprehensive water-resources plan for the basin. The study area water budget describes inputs to the watershed (precipitation and imported water), outputs of water from the watershed (streamflow, exported water, leakage, consumed water, and evapotranspiration), and changes in ground-water and surface-water storage. Hydrological and meteorological data was obtained from Department of Water and Sanitation (DWS) and South African Weather Service (SAWS) respectively. The study area water-budget equation was calculated for evapotranspiration (ET). No water was imported to the study area, and no GW was exported to the surrounding catchments. The average precipitation (R), streamflow (SF), change in groundwater storage (ΔGWs), change in surface water storage (ΔSWs), consumptive use (CoU) and evapotranspiration (ET) and errors were 20.93, 14.93, −4.68, −4.04, 9.43 and 5.29 cm respectively.

EFFECT OF IRRIGATION SCHEDULING AND SOWING DATE ON WATER RELATION, YIELD AND YIELD COMPONENTS FOR WHEAT CROP GROWN IN MIDDLE EGYPT (GIZA REGION)

A field experiment was executed during the two successive seasons of 2010/2011 and 2011/2012 at Giza Agriculture. Research. Station to identify the most effective coefficient of daily pan evaporation accumulation selected from (1.25,1.00 and 0.75) evaporation pan coefficient (EPC) in scheduling irrigation for wheat cultivar Sakha 93 under three sowing date at 20th November (S1) , 10th December (S2) and 30th December (S3) in order to evaluate best sowing date to maximize crop and water productivity. The number of applied irrigations and water consumptive use (CU) were increased as the value of EPC increased and, CU differed significantly due to sowing date , with plant sown in10thDecember consumed more water than the other sowing date. The lowest Water Use Efficiency (WUE) was recorded under 1.25 EPC comparable to the other tested EPC values and values of WUE differed due to sowing date, which the S1 gave the lowest WUE while S3 obtained the highest value. The plant height, grain weight spike-1, grain weight m-2 and 1000-grain weight were significantly affected due to the adopted irrigation regimes and generally, tended to increase as EPC increased. Grain and straw yields tended to increase with increasing EPC. The highest grain yield was obtained with 1.25 EPC and was lower with the other EPC treatments particularly with straw yield. All of agronomic yields and yield components were increased when wheat crop planted in 10th December and decreased with delaying sowing date . The maximum values of yields and their components were given by planted wheat cultivar Sakha 93 in10th December and irrigating when pan evaporation accumulation rech1.25 EPC.

Productivity and water use efficiency of wheat(Triticum aestivum)under different resource conservation techniques and irrigation regimes

In India wheat is conventionally planted on flat-bed and irrigation is applied by flooding, which results in low water-use efficiency. Efficient use of irrigation water is a major researchable issue in most command areas for improving crop productivity. Resource conservation technologies aimed at improving productivity and water-use efficiency such as raised-bed planting have been found useful in wide row crops like maize, cotton, sunflower, sugarcane, etc. However, such information is not available for a relatively narrow row crop like wheat. A field experiment was conducted during 2002–04 at New Delhi on a sandy loam soil to evaluate the performance of wheat crop under resource conservation techniques (RCTs), viz. furrow-irrigated raised-bed (FIRB), broad-bed and furrow (BBF), raised-bed and sunken-bed (RBSB) and conventional flat-bed (FB) in main plots, and 4 irrigation regimes, viz. irrigation only at crown root initiation (CRI); irrigation at 0.9 and 1.2 IW/CPE (irrigation water/cumulative pan evaporation) ratio and irrigations at six critical physiological growth stages in subplots. Wheat performed equally well under all the RCTs with respect to grain yield. The maximum grain yield was recorded under 1.2 IW/CPE ratio, which was at par with 6 irrigations at critical growth stages, but significantly higher than 0.9 IW/CPE and one irrigation at CRI. Bed planting techniques involving FIRB and BBF recorded significantly lower consumptive use (CU) of water than RBSB and FB. There was saving of 18.2 to 19.5% irrigation water by adopting FIRB compared to FB with flood irrigation. Water-use efficiency under FIRB and BBF was 8.3–22.8 and 4.9–24.8% higher respectively over the FB with flooding.

Estimating Crop Water Use via Remote Sensing Techniques vs. Conventional Methods in the South Platte River Basin, Colorado

AbstractWe compared two methods of estimating crop water consumption to assess whether remote sensing techniques provide consumptive use (CU) estimates commensurate with conventional methods. Using available historical satellite and meteorological data, we applied Mapping EvapoTranspiration at high Resolution using Internalized Calibration (METRIC) to 317,455 ha in the South Platte basin, in northeastern Colorado, for the 2001 irrigation season. We then compared these derived CU estimates with values calculated by using the Colorado Water Conservation Board's South Platte Decision Support System StateCU model. Evaluating the data by irrigation ditch service area, we disaggregated the output to allow for comparison by service area size, crop type, irrigation method, water supply source, and water availability. We concluded that METRIC is a suitable alternative to StateCU in the South Platte basin and could help to identify areas with inhibited crop growth or deficit irrigation practices. In addition, METRIC could be used as a complement to StateCU to refine StateCU model parameters, allowing for more accurate estimates of crop water shortages and groundwater recharge associated with irrigation delivery and application.

Effect of nutrient-and moisture-management practices on crop productivity, water-use efficiency and energy dynamics in rainfed maize (Zea mays) + soybean (Glycine max) intercropping system

A field experiment was conducted during the rainy season of 2012 at New Delhi, to study the effect of cropping systems, nutrient-and moisture-management practices on productivity and water-use efficiency (WUE) of maize (Zea mays L.) + soybean [Glycine max (L.) Merr.] intercropping system under rainfed conditions. Treatment com- prised 2 cropping systems (maize sole and paired row planting maize + soybean) and 2 moisture-management practices (control and Kaolin 6% + organic mulch) in main plots, and 4 nutrient levels, viz. control, 50% recom- mended dose of fertilizer (RDF) + 50% recommended dose of nitrogen (RDN) through FYM, 50% RDF + 50% RDN through vermicompost and 100% RDF in subplots of splitplot design. However, maize-equivalent yield (3.47 t/ha) was the highest under paired row planting maize + soybean. The 100% RDF registered significantly higher grain yield (2.99 t/ha) of maize over control (2.03 t/ha) and 50% RDF+ 50% RDN through FYM (2.74 t/ha), 50% RDF+ 50% RDN through vermicompost (2.85 t/ha). Paired-row planted maize + soybean also registered more consumptive use (CU) of water (331.7 mm) than sole maize (324.6 mm). Moisture-conservation practices showed considerable variation in CU. Maximum water-use efficiency (WUE) was recorded with Kaolin 6% + or- ganic mulch. Fertility levels also influenced the CU with highest value with100% RDF (330 mm) followed by 50% RDF + 50% RDN through vermicompost (329.1 mm). Significantly higher WUE was observed under paired row planted maize + soybean (10.9 kg/hamm). Cropping systems altered the soil-moisture extraction pattern in all the 3 layers (015, 1530 and 3045 cm). Energy output, energy input and energy-use efficiency was higher in paired-row planted maize + soybean, Kaolin 6% + organic mulch and 100% RDF than their respective counter- parts.

Productivity and economics of soybean (Glycine m a ~ ) - based cropping sequences under irrigated conditions

A field experiment was conducted during 1995-97 at Rahuri, to study the productivity and economics of soybean [Glycine max (L.) Merr.1-based cropping sequences under irrigated conditions. The total grain equivalent of soybean- chickpea (Cicer arietinum L.) (65.92 qlha) was significantly higher than the rest of sequences. Next in order was soybean-wheat (Triticum aestivum L. emend. Fiori &amp; Paol.) (50.60 qlha) and lowest was in groundnut (Arachis hypogaea L.)- wheat (41.61 qlha). Optimum level of irrigation (at all critical growth stages) recorded the maximum grain-equivalent yield than suboptimum (elimination of 1 irrigation from recommended CGS). The total consumptive use (CU) was maximum in soybean-wheat (55 cm), while water-use efficiency (WUE) was higher in soybean-chickpea (153 kglha-cm). The total CU and WUE were 24% higher and 20% lower respectively in optimum as compared to suboptimum irrigation. The soybean-chickpea sequence gave significantly higher gross (Rs 59,274lha) and net retums (Rs 46,530lha) than rest of sequences, followed by soybean-wheat sequence. The per day productivity (Rs 270ldaylha) and retums per unit of water used (Rs 1,398lha-cm) were maximum in soybean-chickpea (4.65) than other sequences studied. The optimum irrigation recorded significantly higher gross and net retums than suboptimum irrigation. The returns per unit of water used were 15% lower ip optimum irrigation than suboptimum irrigation (Rs 1,049lha-cm).

Productivity of maize (Zea mays) wheat (Triticum aestivum) system under dif- ferent tillage and crop establishment practices

The experiment with eight treatments: Flat conventional tillage (CT) in kharif followed by CT in rabi (CT/CT)], Flat CT/no tillage (NT) (CT/NT), NT/NT, NT + wheat straw mulch @ 5 t/ha(S)/NT (NT+S/NT), Fresh beds (FB)/flat CT (FB/CT), CT/FB, permanent beds (PB)/permanent beds (PB/PB) and PB+S/PB was conducted at PAU, Ludhiana during kharif and rabi seasons of 2003-04 and 2004-2005 in RBD with four replications. Straw mulching in PB+S/PB or NT+S/NT reduced the soil temperature and improved photosynthetically active radiation intercep- tion that however failed to increase yield of maize and wheat markedly. NT+S/NT and PB+S/PB in maize recorded 10.37 and 3.40% less consumptive use (CU) of water than CT/CT and FB/CT treatments, respectively during 2004. PB+S/PB treatment in wheat recorded significantly lower CU and higher water use efficiency (WUE) than all CT and NT treatments. Soil bulk density recorded in NT/NT (1.50 g/cm3) was significantly higher than CT/CT, FB/ CT, CT/FB, PB/PB and PB+S/PB treatments. On an average, the highest net returns (Rs 43,536/ha) were ob- served in NT/NT treatment. The minimum input energy and energy output/input ratio (13.82) was seen in PB/PB treatment while energy output (3,92,035 MJ/ha/year) was highest in NT+S/NT.

Influence of irrigation and tillage management on growth, yield and water-use efficiency of wheat (Triticum aestivum) in Gangetic plains in West Bengal

A field experiment was carried out during the winter seasons of 201617 and 201718 at Gayeshpur, Nadia (West Bengal) in the Gangetic alluvial soil, to assess the impact of irrigation and tillage-management practices on growth attributes, yield components, yield and water-use efficiency of wheat (Triticum aestivum L.) cv. UP 262 Results revealed that increase in irrigation frequency from irrigation water : cumulative pan evaporation (IW : CPE) 0.4 to 1.0 significantly promoted growth parameters, and 6 irrigations at 1617 days interval (IW : CPE ratio of 1.0) was found to be superior. Growth parameters were significantly higher under conventional tillage over minimum tillage. The plants receiving 6 irrigations (IW : CPE 1.0) recorded the highest consumptive use (CU), while the highest consumptive-use efficiency (CUE) was obtained with the plants receiving 5 irrigations. The maximum num- ber of spikes/m2, spike length and number of filled grains/spike were found in plants irrigated 6 times (IW : CPE 1.0) at an interval of 1617 days. Maximum wheat grain and straw yield were obtained with 6 irrigations, closely followed by those obtained with 5 irrigations (IW : CPE 0.8). Tillage practices showed significant variation in the number of spikes/m2 and it was maximum with crops grown under conventional tillage. Both grain and straw yields were significantly higher for plants grown under conventional tillage than those obtained under the minimum till- age. The gross returns, net returns and benefit: cost ratio were maximum when the crop received 6 irrigations un- der conventional tillage management. Hence, 6 irrigations under conventional tillage could be more effective in augmenting wheat yield, CUE and economics in the Gangetic plains of West Bengal.