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V.P. PRAMOD, B. BAPUJI RAO, S.S.V.S. RAMAKRISHNA, V.M. SANDEEP, N. R. PATEL, M.A. SARATH CHANDRAN, V.U.M. RAO, P. SANTHIBHUSHAN CHOWDARY e P. VIJAYA KUMAR. "Trends in water requirements of wheat crop under projected climates in India". Journal of Agrometeorology 20, n. 2 (1 giugno 2018): 110–16. http://dx.doi.org/10.54386/jam.v20i2.520.
Testo completoAbstract (sommario):
Various global circulation models predict a change in net irrigation requirements worldwide due to the impacts of climate change and in India, depending upon the region, irrigation requirements are likely to change by different magnitudes. The spatial distribution of trend in crop and irrigation water requirements of wheat projected for two climatic periods (2021-50 and 2051-80) across major wheatgrowing districts of the country were analyzed, making use of climate change projection data from NorESM1-M model of the CMIP5 in combination with RCP 4.5. Decreasing trends in water requirements were projected over 90 per cent of wheat growing districts in 2021-50, whereas increasing trends in crop and irrigation water requirement are expected over 95.4 per cent and 62.4 per cent areas, respectively in 2051-80 climatic periods. Results showed that decreasing/increasing trends projected in water requirements of wheat crop is due to change in crop growing period, which is projected to decrease across entire wheat growing area in 2021-50, whereas it is likely to increase over 78.2 per cent in 2051-80 climatic periods.
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Jia, Kun, Wei Zhang, Bingyan Xie, Xitong Xue, Feng Zhang e Dongrui Han. "Does Climate Change Increase Crop Water Requirements of Winter Wheat and Summer Maize in the Lower Reaches of the Yellow River Basin?" International Journal of Environmental Research and Public Health 19, n. 24 (11 dicembre 2022): 16640. http://dx.doi.org/10.3390/ijerph192416640.
Testo completoAbstract (sommario):
With increasing water resources stress under climate change, it is of great importance to deeply understand the spatio-temporal variation of crop water requirements and their response to climate change for achieving better water resources management and grain production. However, the quantitative evaluation of climate change impacts on crop water requirements and the identification of determining factors should be further explored to reveal the influencing mechanism and actual effects thoroughly. In this study, the water requirements of winter wheat and summer maize from 1981 to 2019 in the lower reaches of the Yellow River Basin were estimated based on the Penman–Monteith model and crop coefficient method using daily meteorological data. Combined with trends test, sensitivity and contribution analysis, the impacts of different meteorological factors on crop water requirement variation were explored, and the dominant factors were then identified. The results indicated that the temperature increased significantly (a significance level of 0.05 was considered), whereas the sunshine duration, relative humidity and wind speed decreased significantly from 1981 to 2019 in the study area. The total water requirements of winter wheat and summer maize presented a significant decreasing trend (−1.36 mm/a) from 1981 to 2019 with a multi-year average value of 936.7 mm. The crop water requirements of winter wheat was higher than that of summer maize, with multi-year average values of 546.6 mm and 390.1 mm, respectively. In terms of spatial distribution patterns, the crop water requirement in the north was generally higher than that in the south. The water requirements of winter wheat and summer maize were most sensitive to wind speed, and were less sensitive to the minimum temperature and relative humidity. Wind speed was the leading factor of crop water requirement variation with the highest contribution rate of 116.26% among the considered meteorological factors. The results of this study will provide important support for strengthening the capacity to cope with climate change and realizing sustainable utilization of agricultural water resources in the lower reaches of the Yellow River Basin.
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MEHRAJ U DIN DAR, RAJAN AGGARWAL e SAMANPREET KAUR. "Effect of climate change scenarios on yield and water balance components in ricewheat cropping system in Central Punjab, India". Journal of Agrometeorology 19, n. 3 (1 settembre 2017): 226–29. http://dx.doi.org/10.54386/jam.v19i3.631.
Testo completoAbstract (sommario):
The study focuses on simulating the effect of climate change under RCP4.5 scenario on irrigation requirements,crop yield, crop duration, and water -use efficiency of rice–wheat cropping system with DSSAT v 4.6.1 model at Ludhiana. Model simulations predict reduction in irrigation requirements for rice crop and increase in irrigation requirements for wheat crop under RCP 4.5 scenarios. Also reductions in crop yields in future associated with shortening of growth period due to increased temperature were predicted by the model. Increased rainfall in future would decrease irrigation water requirement of crops but would not offset the adverse effect of increased temperature. Although evapotranspiration would decrease towards end of the century, yet relatively more decrease in yield would lower water use efficiency.
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Sheet, Eman H., e Entesar M. Ghazal. "Effect of Ground Water Table on Irrigation Scheduling Model". Tikrit Journal of Engineering Sciences 12, n. 3 (31 agosto 2005): 20–35. http://dx.doi.org/10.25130/tjes.12.3.08.
Testo completoAbstract (sommario):
An irrigation scheduling model was developed based on daily soil water balance which takes into account the effect of water table on irrigation water requirement for wheat crop at Mosul area for eleven years. Capillary rise of water table was estimated with Darcy’s equation .Crop evapotranspiration was estimated by pan evaporation method. The model inputs are daily climatological data for eleven years at Mosul Station, soil data (total available water, field capacity, permanent wilting point, allowable percent depletion, saturated hydraulic conductivity),and crop data(root depth for wheat crop, crop coefficient).The model estimates daily and seasonal actual evapotranspiration, effective rainfall, irrigation requirement and upward capillary rise from water table. Using the model for wheat, the seasonal irrigation requirements were reduced by 40% for silt loam soil and 90% for loam soil ,avoiding crop water stress or excessive irrigation.
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Zhang, Peng, Wandi Ma, Lei Hou, Fusheng Liu e Qian Zhang. "Study on the Spatial and Temporal Distribution of Irrigation Water Requirements for Major Crops in Shandong Province". Water 14, n. 7 (27 marzo 2022): 1051. http://dx.doi.org/10.3390/w14071051.
Testo completoAbstract (sommario):
Understanding the spatial and temporal distribution of irrigation water requirements is significant to realize the rational allocation of water resources and also serves as the basis for analyzing agricultural water-saving potential. This study refers to the standard irrigation regions in southwestern, northern, central, southern, and eastern Shandong province. The irrigation water requirements at 20 weather stations in Shandong Province from 1968 to 2016 were calculated, and the spatial and temporal distribution characteristics were analyzed. The results indicated the following: (a) The trend of the annual irrigation water requirements for summer maize and winter wheat showed an insignificant increase in the eastern Shandong irrigation region, a significant decline in northern and southwestern Shandong irrigation regions, and an insignificant decrease in the other irrigation regions. (b) The multi-year average irrigation water requirement for summer maize generally presents a spatial distribution characteristic which is less in the southwest, more in the northeast, less in the south, and more in the north, while the spatial distribution characteristic for winter wheat is less in the southeast, more in the northwest, less in the south, and more in the north. (c) The main meteorological factors affecting the irrigation water requirements for summer maize are precipitation and sunshine duration, while relative humidity is the main factor affecting winter wheat in Shandong Province.
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Sheet, Eman H., e Entesar M. Ghazal. "EFFECT OF GROUND WATERTABLE ONIRRIGATION SCHEDULING MODEL". Tikrit Journal of Engineering Sciences 12, n. 1 (31 marzo 2005): 20–35. http://dx.doi.org/10.25130/tjes.12.1.03.
Testo completoAbstract (sommario):
An irrigation scheduling model was developed based on daily soil water balance which takes into account the effect of water table on irrigation water requirement for wheat crop at Mosul area for eleven years. Capillary rise of water table was estimated with Darcy's equation .Crop evapotranspiration was estimated by pan evaporation method. The model inputs are daily climatological data for eleven years at Mosul Station, soil data (total available water, field capacity, permanent wilting point, allowable percent depletion, saturated hydraulic conductivity),and crop data(root depth for wheat crop, crop coefficient).The model estimates daily and seasonal actual evapotranspiration, effective rainfall, irrigation requirement and upward capillary rise from water table. Using the model for wheat, the seasonal irrigation requirements were reduced by 40% for silt loam soil and 90% for loam soil ,avoiding crop water stress or excessive irrigation.
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Wang, Xin Hua, Mei Hua Guo e Hui Mei Liu. "Research Dry Crop and Irrigation Water Requirement in Environment Engineering". Applied Mechanics and Materials 340 (luglio 2013): 961–65. http://dx.doi.org/10.4028/www.scientific.net/amm.340.961.
Testo completoAbstract (sommario):
According to Kunming 1980-2010 monthly weather data and CROPWAT software and the corresponding crop data, crop water requirements and irrigation water use are calculated. By frequency analysis, irrigation water requirement was get for different guaranteed rate. The results show that: corn, potatoes, tobacco, and soybeans average crop water requirements were 390.7mm, 447.9mm, 361.8mm and 328.4mm, crop water dispersion coefficient is small, period effective rainfall during crop growth in most of the year can meet the crop water requirements, so irrigation water demand is small. While the multi-year average crop water requirements were 400.8mm, 353.5mm, 394.3mm for small spring crops of wheat, beans, rape. Because the effective rainfall for these crops during growth period is relative less, crop irrigation water requirements for small spring crop is much. Vegetables and flowers are plant around the year, so the crop water and irrigation water requirements are the largest.
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Najm, Abu Baker A., Isam M. Abdulhameed e Sadeq O. Sulaiman. "Water Requirements of Crops under Various Kc Coefficient Approaches by Using Water Evaluation and Planning (WEAP)". International Journal of Design & Nature and Ecodynamics 15, n. 5 (10 novembre 2020): 739–48. http://dx.doi.org/10.18280/ijdne.150516.
Testo completoAbstract (sommario):
In this study, the Dual-Kc approach within FAO-56 paper was applied by water evaluation and planning (WEAP) to get the Kc parameters (Kcb and Ke) and to calculate the water requirement for various soil textures. The results compared with the outputs of Single-Kc approach for summer and winter crops in addition to trees. The results showed when applying Dual-Kc approach, the water requirements was more compared with the Single-Kc approach, except the tomato, eggplant, and Broad bean crop, which decreased by 5%, 4%, and 17% respectively. Also, there was a different in values of coefficient when compare two approaches, it was increased in Dual-Kc approach for wheat by 62% with 20% during initial and end-stage while ranged between 26-58% for trees during all season with more different for other winter and summer crops. The water requirement of crops was different according to soil texture. The net water requirement of wheat was 429 mm and 433 mm for sandy loam and clay loam respectively, with different in irrigation intervals 11 and 12 respectively, while the silt loam was recording water requirement 417 mm with 8 irrigation intervals.
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Wheeler, R. M., C. L. Mackowiak, W. L. Berry, G. W. Stutte e J. C. Sager. "242 WATER, NUTRIENT, AND ACID REQUIREMENTS FOR CROPS GROWN HYDROPONICALLY IN A CELSS". HortScience 29, n. 5 (maggio 1994): 464c—464. http://dx.doi.org/10.21273/hortsci.29.5.464c.
Testo completoAbstract (sommario):
Requirements for water, nutrient replenishment and acid (for pH control) were monitored for stands of wheat, soybean, potato, and lettuce grown in a recirculating hydroponic culture using a modified 1/2 Hoagland solution with NO3-N. Water use at full canopy cover for all crops ranged from 4 to 5 L m-2 day-1. When averaged over the entire crop cycle, nutrient stock solution (∼0.9 S m-1) use varied from 0.2 L m-2 day-1 (lettuce: to 0.75 L m-2 day-1 (wheat), while acid use varied from 6 mmol m-2 day-1 (lettuce and soybeans) to over 40 mmol m-2 day-1 (wheat). Water-per unit biomass was highest for soybean and lettuce (0.3 to 0.4 L g DW), and least for wheat and potato (0.15 L g DW). Nutrient replenishment per unit biomass was highest for lettuce, 34 mL g-1 DW, with other crops ranging from 21-26 mL g-1 DW. Acid requirements were highest for wheat, 1.2 mmol g-1 DW, and lowest for potato, 0.7 mmol g-1 DW. On a PAR basis, acid needs were highest for wheat, 0.6 mmol mol-1 photons, with all other crops near 0.4 mmol mol-1. Acid data suggest that wheat nutrient uptake favors anions more strongly than the other species, or that more nitrate loss (e.g., denitrification) may occur during wheat growth.
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A. S. RAO e SURENDRA POONIA. "Climate change impact on crop water requirements in arid Rajasthan". Journal of Agrometeorology 13, n. 1 (1 giugno 2011): 17–24. http://dx.doi.org/10.54386/jam.v13i1.1328.
Testo completoAbstract (sommario):
The impact of projected climate change by 21st century on water requirements of rainfed monsoon and irrigated winter crops of arid Rajasthan has been studied. Crop water requirements were estimated from daily potential evapotranspiration at ambient and projected air temperature by 2020, 2050, 2080 and 2100 using modified Penman-Monteith equation and then by multiplying with crop coefficients. Crop water requirements in the region varied from 308 to 411 mm for pearl millet, 244 to 332 mm for clusterbean, 217 to 296 mm for green gram, 189 to 260 mm for moth bean, 173 to 288 mm for wheat and 209 to 343 mm for mustard. Further, due to global warming, if the projected temperatures rises by 40C, by the end of 21st century, water requirement in arid Rajasthan increases from the current level, by 12.9% for pearl millet and clusterbean, 12.8% for green gram, 13.2% for moth bean, 17.1% for wheat and 19.9% for mustard. The increased crop water requirements in the region, resulted in reduction in crop growing period by 5 days for long duration crops, but the crop acreage where rainfall satisfies crop water requirements, reduced by 23.3% in pearl millet, 15.2% in clusterbean, 6.7% in green gram, 13% in moth bean. The study reveals that the impact will be more severe on rabi crops than kharif crops, the rabi crops being dependent on depleting ground water resources in the region.
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Kassab, M., E. Moursi e M. Ibrahim. "WATER REQUIREMENTS FOR SOME WHEAT CULTIVARS IN NORTH NILE DELTA". Journal of Plant Production 1, n. 6 (1 giugno 2010): 805–18. http://dx.doi.org/10.21608/jpp.2010.86409.
Testo completo
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Moursy, Ahmed A., e MM Ismail. "Effects of Different Nitrogen Fertilizers and Humic Acid On Wheat Crop Irrigated With Different Water Regime Using 15N". Bangladesh Journal of Botany 50, n. 2 (18 giugno 2021): 261–67. http://dx.doi.org/10.3329/bjb.v50i2.54081.
Testo completoAbstract (sommario):
A field experiment was conducted to observe effects of water requirements and different fertilizers on wheat crop’s yield, production and N uptake. Data showed that dry matter yield of wheat grain was higher with Hu + AS (5.82 mt/ha) compared with applied water 100% ETC. Concerning the rate of water regime, the best significant grain yield of wheat was obtained with 100% ETc (4.23 mt/ha). Nitrogen derived from fertilizer Ndff% with 50% ETC of water was 28.41 and 27.28% for grain and straw, respectively. At 100% ETC of water the Ndff% was 30.16 and 27.75% for grain and straw, respectively. Nitrogen utilized by grains and straw was more efficient under treatment Hu + AS combined with 50% Etc, 100% Etc recording 15.6 and 32.23%, respectively. At 50% ETC of water requirements for wheat crop, higher N remained in 0 - 15, 15 - 30 and 30 - 45 cm soil depth were nearly closed to each other compared with the treatment made at 100% ETC of water requirements.
Bangladesh J. Bot. 50(2): 261-267, 2021 (June)
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Shrestha, S., B. Gyawali e U. Bhattarai. "Impacts of climate change on irrigation water requirements for rice–wheat cultivation in Bagmati River Basin, Nepal". Journal of Water and Climate Change 4, n. 4 (22 maggio 2013): 422–39. http://dx.doi.org/10.2166/wcc.2013.050.
Testo completoAbstract (sommario):
This study highlights the spatial and temporal impacts of climate change on rice–wheat cropping systems, focusing on irrigation water requirement (IWR) in the Bagmati River Basin of Nepal. The outputs from a general circulation model (HadCM3) for two selected scenarios (A2 and B2) of IPCC and for three time periods (2020s, 2050s, and 2080s) have been downscaled and compared to a baseline climatology. CROPWAT 8.0 model is used to estimate the water requirements. IWRs show different trends in different physiographic regions and different growth stages of rice and wheat. A decreasing trend of IWRs in the Mid Hills and the High Hills indicates that farmer-based small irrigation schemes are sufficient to meet the requirements. However, in the Terai region, where there is an increasing trend in IWRs, the deficit volume of water needs to be supplied from potential large-scale irrigation schemes.
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El-Metwally, Ibrahim M., Ramadan E. Abdelraouf, Mohamed A. Ahmed, Oussama Mounzer, Juan José Alarcón e Magdi T. Abdelhamid. "Response Of Wheat (Triticum aestivum L.) Crop And Broad-Leaved Weeds To Different Water Requirements And Weed Management In Sandy Soils". Agriculture (Polnohospodárstvo) 61, n. 1 (1 marzo 2015): 22–32. http://dx.doi.org/10.1515/agri-2015-0007.
Testo completoAbstract (sommario):
Abstract Water scarcity is a major cause of crops yield reduction in many parts of the world. So, a more rational use of irrigation water should be adapted and deficit irrigation principles should be accepted with a certain level of reduction in yield level. To study the efficiency of four water requirements (100% whole season, 75% whole season, 50% whole season and 100% whole season while 50% at grain-filling stage) and five weed-control treatments (three postemergence herbicides i.e., metosulam, tribenuron-methyl, and bromoxynil), hand weeding and unweeded check, and their interactive effects, two field experiments on wheat crop were conducted in two successive seasons at the agricultural experimental station of the National Research Centre, Nubaria, Egypt. Bromoxynil, tribenuron-methyl came in the first order for controlling total broad-leaved weeds. Application of 100% water requirement recorded the highest values compared to all other irrigation water treatments in term of flag-leaf area, chlorophyll content, plant height, number of spike/m2, spike weight, grains number/spike, weight of 1,000 grains, yield and yield attributes of wheat. Metosulam followed by bromoxynil, tribenuron-methyl and hand-weeding treatments gave higher values of grain yield/ha. The highest grain yield, protein and carbohydrates percentages of wheat grains were obtained from addition of 100% water requirement with metosulam treatment was used followed by 75% of water requirement combined with metosulam treatment without significant difference among these treatments.
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Bouregaa, Tarek. "Impact of climate change on yield and water requirement of rainfed crops in the Setif region". Management of Environmental Quality: An International Journal 30, n. 4 (10 giugno 2019): 851–63. http://dx.doi.org/10.1108/meq-06-2018-0110.
Testo completoAbstract (sommario):
Purpose The purpose of this paper is to show the impact of climate change on yield and water requirement of three rainfed crops in Setif region. Design/methodology/approach This study investigates likely changes in annual temperature and precipitation over Setif high plains region (North East of Algeria) among three future periods: 2025, 2050 and 2075. The projections are based on the SRES A2 and B2 scenarios. MAGICC-SCENGEN 5.3 v.2 was used as a tool for downscaling the four selected general circulation models (GCMs) output data. The expected impact of climate change on yield and water requirement of winter wheat, barley and olive was evaluated using the CROPWAT model. Findings The projection of the four GCMs showed that average temperature will increase by 0.73 to 3.42°C, and the precipitation will decrease by 1 to 52.7 percent, across the three future periods under the two SRES scenarios. Winter wheat and olive yields are expected to decrease under the three types of soils (heavy, medium and light). However, barley yield is expected to reduce under light soil only. Crop water requirements and irrigation water requirements are expected to increase under the two scenarios and across the three future periods. Originality/value This research is one of the first to study the impact of future climate change on water requirement and yield of rainfed crops over Setif region.
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Li, Yinbo, Hongwei Wang, Yun Chen, Mingjiang Deng, Qian Li, Adiliai Wufu, Dan Wang e Ligang Ma. "Estimation of regional irrigation water requirements and water balance in Xinjiang, China during 1995–2017". PeerJ 8 (3 gennaio 2020): e8243. http://dx.doi.org/10.7717/peerj.8243.
Testo completoAbstract (sommario):
Estimating water requirements and water balance for irrigated agricultural areas are important and will facilitate the efficient allocation of water resources for agriculture while minimizing the impact on natural ecosystems in arid regions. Based on the Penman-Monteith formula and GIS technology, the irrigation water requirements (IWR) of three main crops (cotton, corn and wheat) during the growing season were estimated and their spatio-temporal changes over the past 23 years (1995–2017) were analyzed in Xinjiang province, China. Our results indicated a dramatic increase in IWR from 14.12 billion m3 in 1995 to 38.99 billion m3 in 2017 due to the rapid cropland expansion of approximately 2.58 × 104 km2 in this period. Monthly IWR usually peaked in summer from May to July and varied in different basins. From the perspective of crops, cotton was identified to have consumed the largest amount of water, reaching 26.39 billion m3 in 2017, accounting for 67.68% of total water consumption. Spatially, the fastest increasing rate of IWR was Tarim Basin, which was attributable to the increase in water requirement of cotton. By comparing IWR and actual irrigation of Xinjiang in 2014, the amount of water scarcity had reached −15.01 billion m3 (−9.80 billion m3 in Tarim Basin and −6.58 billion m3 in Junggar Basin). The planting areas of three main crops (wheat, corn and cotton) were more sensitive to IWR than rising temperature indicated by our model. This study is of great significance for the scientific allocation of water resources in the irrigated areas of the different prefectures of Xinjiang.
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Ahmad, Mirza Junaid, e Kyung-Sook Choi. "Climate-Induced Perspective Variations in Irrigation Schedules and Design Water Requirements for the Rice–Wheat System". Agronomy 11, n. 10 (3 ottobre 2021): 2006. http://dx.doi.org/10.3390/agronomy11102006.
Testo completoAbstract (sommario):
Conceptualizing the implications of climate change for crop evapotranspiration (ETc) and subsequent net irrigation water requirement (NIWR) is critical to sustaining Pakistan’s agriculture and food security. In this article, future ETc, NIWR, and design water requirements (DWR) were projected for the rice–wheat system of Punjab, Pakistan. Consistently increasing temperatures signify an impending hotter transition in the future thermal regime, accompanied by a substantial increase in monsoon rainfall. Future climate warming accelerated ETc and NIWR, which were compensated by 2–5 and 1–2 additional irrigations during the rice and wheat seasons, respectively. Future rice and wheat required 13–18 and 2–5 irrigations per season, respectively. Effective rainfall increments did not compensate for the warming-driven higher ETc and NIWR because of uneven and erratic rainfall distribution. Rainfall occurrence and the duration of peak irrigation demand were mismatched, resulting in surplus rainwater availability during the future rice season. The results suggest that DWR for 5- and 10-year return period droughts during the baseline period (965 and 1000 mm, respectively) should be revised to accommodate the additional 100–200 mm of irrigation water per season; otherwise, the study area will face an acute water shortage in the future.
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Hussain, Sajjad, Muhammad Mubeen, Wajid Nasim, Shah Fahad, Musaddiq Ali, Muhammad Azhar Ehsan e Ali Raza. "Investigation of Irrigation Water Requirement and Evapotranspiration for Water Resource Management in Southern Punjab, Pakistan". Sustainability 15, n. 3 (17 gennaio 2023): 1768. http://dx.doi.org/10.3390/su15031768.
Testo completoAbstract (sommario):
Water scarcity and water quality degradation are exacerbated by climate change in all countries, including Pakistan. The use of water in agriculture is one of the most predominant resources, so reducing consumption and improving resource management is of utmost importance. In the past few decades, excessive irrigation has led to severe water scarcity and reduced water quality. This study determined the irrigation requirements for cotton, rice, and wheat, using the CROPWAT model in Southern Punjab (Multan District). In the study area, evapotranspiration ranged from 1.8 to 10.24 mm/day, while effective rainfall ranged from 2 to 31.3 mm. Rice, cotton, and wheat each required 996.4, 623.3, and 209.5 mm of irrigation, respectively. Among rice, cotton, and wheat, the total net irrigation was 72.4, 67.8, and 44.1 mm, respectively, while the total gross irrigation was 103.5, 99.8, and 63 mm. The CROPWAT model showed a moderately useful result for identifying irrigation needs in Southern Punjab. The study emphasizes the need for groundwater harvesting and water management technologies to implement a water management system that reduces water shortages.
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Huang, H., Y. Han, J. Song, Z. Zhang e H. Xiao. "Impacts of climate change on water requirements of winter wheat over 59 years in the Huang-Huai-Hai Plain". Soil and Water Research 11, No. 1 (2 giugno 2016): 11–19. http://dx.doi.org/10.17221/164/2014-swr.
Testo completo
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Jia, Kun, Yanzhao Yang, Guanglong Dong, Chao Zhang e Tingting Lang. "Variation and determining factor of winter wheat water requirements under climate change". Agricultural Water Management 254 (agosto 2021): 106967. http://dx.doi.org/10.1016/j.agwat.2021.106967.
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Mustafa, M. A., K. A. Akabawi e M. F. Zoghet. "Irrigation water requirements of wheat in the life zones of Saudi Arabia". Journal of Arid Environments 17, n. 3 (novembre 1989): 349–54. http://dx.doi.org/10.1016/s0140-1963(18)30888-7.
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Ullah, Rehmat, Shehzada Munawar Mehdi, Khalid Saif Ullah Khan, Aftab Ahmed Sheikh, Sigit Mujiharjo e Muhammad Saud. "Soil Water Release Curves : Indicator to Suit Sustainable Cropping Scheme under Sloppy Rain-Fed Climatic Conditions of Pothowar Plateau of Punjab-Pakistan". AGRITROPICA : Journal of Agricultural Sciences 1, n. 1 (18 giugno 2018): 9–24. http://dx.doi.org/10.31186/agritropica.1.1.9-24.
Testo completoAbstract (sommario):
In arid environment, limitations of crop productivity could be improved by soil management practices like soil conservation measures, tillage and reducing slopes through terracing on different cropping patterns. These patterns include area as Wheat-Maize (WMCP) and Wheat-Fodder (WFCP) in Kahuta (high rainfall climatic area), Wheat-Millet-Fallow (WMFCP) and Wheat- Millet-Lentil (WMLCP) in Khairimurat (medium rainfall climatic area) and Wheat-Fallow (WFCP) and Fallow-Groundnut (FGCP) in Pindi Gheb (low rainfall climatic area). In areas that have more crop water requirements the yield of these crops has been affected when the drought prevails. Our results evidenced that more average soil water content (ASWC) was available in high to medium height terraces in WMCP and low to medium in WFCP of Kahuta area. ASWC remained more in high to medium height terraces under all cropping pattern of Khairimurat during September. ASWC remained more in low to medium height terraces under all cropping pattern of Pindi Gheb during September and December. Equidistantly, soil water release curve also indicated that medium rainfall sites had more plant water availability as compared to high and low rainfall sites. Yield relationship to plant water availability revealed significance for intrusion of modified cropping patterns rather than existing cropping patterns on sustained basis. Finally, our study suggests that cropping patterns of high and low rainfall areas should adjusted by growing low water requirement crops in summer seasons to cope the drought period for the sustainability of agriculture under rainfed climatic conditions. Keywords : cropping patterns, Pothowar Plateau, soil water contents, soil water release curve, sloppy lands
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Ullah, Rehmat, Shehzada Munawar Mehdi, Khalid Saif Ullah Khan, Aftab Ahmed Sheikh, Sigit Mujiharjo e Muhammad Saud. "Soil Water Release Curves : Indicator to Suit Sustainable Cropping Scheme under Sloppy Rain-Fed Climatic Conditions of Pothowar Plateau of Punjab-Pakistan". AGRITROPICA : Journal of Agricultural Sciences 1, n. 1 (18 giugno 2018): 9–24. http://dx.doi.org/10.31186/agt.1.1.9-24.
Testo completoAbstract (sommario):
In arid environment, limitations of crop productivity could be improved by soil management practices like soil conservation measures, tillage and reducing slopes through terracing on different cropping patterns. These patterns include area as Wheat-Maize (WMCP) and Wheat-Fodder (WFCP) in Kahuta (high rainfall climatic area), Wheat-Millet-Fallow (WMFCP) and Wheat- Millet-Lentil (WMLCP) in Khairimurat (medium rainfall climatic area) and Wheat-Fallow (WFCP) and Fallow-Groundnut (FGCP) in Pindi Gheb (low rainfall climatic area). In areas that have more crop water requirements the yield of these crops has been affected when the drought prevails. Our results evidenced that more average soil water content (ASWC) was available in high to medium height terraces in WMCP and low to medium in WFCP of Kahuta area. ASWC remained more in high to medium height terraces under all cropping pattern of Khairimurat during September. ASWC remained more in low to medium height terraces under all cropping pattern of Pindi Gheb during September and December. Equidistantly, soil water release curve also indicated that medium rainfall sites had more plant water availability as compared to high and low rainfall sites. Yield relationship to plant water availability revealed significance for intrusion of modified cropping patterns rather than existing cropping patterns on sustained basis. Finally, our study suggests that cropping patterns of high and low rainfall areas should adjusted by growing low water requirement crops in summer seasons to cope the drought period for the sustainability of agriculture under rainfed climatic conditions. Keywords : cropping patterns, Pothowar Plateau, soil water contents, soil water release curve, sloppy lands
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Ullah, Rehmat, Shehzada Munawar Mehdi, Khalid Saif Ullah Khan, Aftab Ahmed Sheikh, Sigit Mujiharjo e Muhammad Saud. "Soil Water Release Curves : Indicator to Suit Sustainable Cropping Scheme under Sloppy Rain-Fed Climatic Conditions of Pothowar Plateau of Punjab-Pakistan". AGRITROPICA : Journal of Agricultural Sciences 1, n. 1 (18 giugno 2018): 9–24. http://dx.doi.org/10.31186/j.agritropica.1.1.9-24.
Testo completoAbstract (sommario):
In arid environment, limitations of crop productivity could be improved by soil management practices like soil conservation measures, tillage and reducing slopes through terracing on different cropping patterns. These patterns include area as Wheat-Maize (WMCP) and Wheat-Fodder (WFCP) in Kahuta (high rainfall climatic area), Wheat-Millet-Fallow (WMFCP) and Wheat- Millet-Lentil (WMLCP) in Khairimurat (medium rainfall climatic area) and Wheat-Fallow (WFCP) and Fallow-Groundnut (FGCP) in Pindi Gheb (low rainfall climatic area). In areas that have more crop water requirements the yield of these crops has been affected when the drought prevails. Our results evidenced that more average soil water content (ASWC) was available in high to medium height terraces in WMCP and low to medium in WFCP of Kahuta area. ASWC remained more in high to medium height terraces under all cropping pattern of Khairimurat during September. ASWC remained more in low to medium height terraces under all cropping pattern of Pindi Gheb during September and December. Equidistantly, soil water release curve also indicated that medium rainfall sites had more plant water availability as compared to high and low rainfall sites. Yield relationship to plant water availability revealed significance for intrusion of modified cropping patterns rather than existing cropping patterns on sustained basis. Finally, our study suggests that cropping patterns of high and low rainfall areas should adjusted by growing low water requirement crops in summer seasons to cope the drought period for the sustainability of agriculture under rainfed climatic conditions. Keywords : cropping patterns, Pothowar Plateau, soil water contents, soil water release curve, sloppy lands
25
Li, Mengna, Mengxia Shi, Jiaxiao Zhang, Yunjiao Qi e Yongdeng Lei. "Quantifying the Space-Time Variations of Water Demands for Major Crops in Hebei Province, China". Atmosphere 13, n. 9 (31 agosto 2022): 1399. http://dx.doi.org/10.3390/atmos13091399.
Testo completoAbstract (sommario):
Hebei Province is a typical water-scarce agricultural region in North China. Quantifying the water demands of major crops and their variations in this region is crucial for the sustainable use of agricultural water resources. Based on meteorological data and crop growth parameters of 21 national weather stations in Hebei Province from 2007 to 2017, this study analyzed the crop water requirement, irrigation water demand, and water deficit index and their dynamic changes for several grain and vegetable crops including winter wheat, summer maize, soybean, potato, tomato, cucumber, eggplant, cowpea, Chinese cabbage, cabbage, and carrot. In addition, regional total irrigation water demands of these water-intensive crops were estimated. The results indicated that, except for summer maize, the crop water requirements and irrigation water demands of grain crops during the growth periods were mostly higher than those of vegetable crops. Winter wheat and cabbage had the highest water deficits among grain and vegetable crops, respectively, while summer maize had the lowest water deficits. Temporally, the irrigation water demands of winter wheat, summer maize, cabbage, and eggplant have increased for years, along with the increase in planting areas. Spatially, the total irrigation water demand in the southeast of Hebei Province was higher than that in the northwest, and the total irrigation water demand of winter wheat was much higher than that of the other crops. To mitigate water scarcity while ensuring food security, the planting areas of crops with higher yields and lower water consumptions, including summer maize, potato, cabbage, and carrot could be appropriately expanded. In contrast, the scale of water-intensive crops such as winter wheat and tomato should be strictly controlled. Our findings will be of great significance for constructing sustainable water-saving cropping systems in a changing climate.
26
Mojid, Mohammad A., Farhana Y. Shibly e Tapos K. Acharjee. "Trends of Water Requirements of Major Crops and Cropping Patterns in Bogura and Rajshahi Districts of Bangladesh". Agricultural Science 2, n. 1 (11 maggio 2020): p170. http://dx.doi.org/10.30560/as.v2n1p170.
Testo completoAbstract (sommario):
Reliable past trends of water requirements of individual crops and cropping patterns at local level, although crucially important for irrigation forecast and agricultural planning, are yet inadequate for the water-scarce Barind region of Bangladesh. This study, therefore, determined water requirements and their trends of eight major crops (aus, aman, boro, vegetables, mustard, sugarcane, wheat and potato) and six cropping patterns (aus–aman–boro, aus–aman–potato, aman–potato–fallow, vegetables–aman, aman–mustard–fallow and aus–fallow–wheat) of Bogura and Rajshahi districts of the Barind region. Water requirements were determined from crop, soil and weather data for the period 1985–2013 by using Soil-Water Balance via CropWat (SWBcropwat) model. Trends of rainfall, crop evapotranspiration (ETc) and irrigation requirement (IR) were determined with MAKESENS statistical tool. Monthly total rainfall revealed increasing trend in January, August and October but decreasing trend in the other months, with significant (p£0.05) trend in July in Bogura. Monthly total ETc decreased except in July and September, with significant trend in October–April/May. Seasonal ETc for the crops decreased significantly except for aman rice and sugarcane in Bogura and for aman rice in Rajshahi. ETc also decreased for the cropping patterns except for aman–mustard–fallow in Rajshahi. While effective rainfall (ER) for the crops and cropping patterns decreased only minimally, IR decreased significantly for boro, potato and vegetables in Bogura and for mustard and vegetables in Rajshahi. IR decreased for all cropping patterns, with significant trend for aus–aman–potato, aman–potato–fallow and vegetables–aman patterns. In response to changing cropping area, total volume of ETc increased gradually from 1985 to 2005 in Bogura and from 1985 to 2010 in Rajshahi for boro rice, but it decreased until 2005 before increasing for aus rice in both districts. After the year 2000, total volume of ETc decreased for wheat but increased for potato, indicating a shift from wheat to potato cultivation. Due to contrasting trends of ER and ETc and self-motivated shift in crop-choice, continuous adjustment of irrigation-based crop planning is necessary. The results of this study can guide future investigation for all other crops and cropping patterns to help planning agriculture of the study areas by choosing appropriate crops and cropping patterns based on available water resources.
27
Ouda, Samiha, Tahany Noreldin e Khaled Abd El-Latif. "Water requirements for wheat and maize under climate change in North Nile Delta". Spanish Journal of Agricultural Research 13, n. 1 (2 dicembre 2014): e0301. http://dx.doi.org/10.5424/sjar/2015131-6412.
Testo completo
28
Silva, Kayoma K. da, Tirzah M. Siqueira, Katiucia N. Adam, Andréa S. Castro, Luciara B. Corrêa e Diuliana Leandro. "Future irrigation water requirements in the Ijuí River basin, RS". Revista Brasileira de Engenharia Agrícola e Ambiental 22, n. 1 (gennaio 2018): 57–62. http://dx.doi.org/10.1590/1807-1929/agriambi.v22n1p57-62.
Testo completoAbstract (sommario):
ABSTRACT Changes in temperature and precipitation intensity and frequency have influenced the water demand for irrigation. Regions that have agriculture-based economies, as in the Ijuí River basin, are often affected by periods of drought or excessive rainfall, which is harmful for agricultural productivity. This study aimed to evaluate future irrigation water demands of four crops in this basin (bean, corn, wheat and soybean), comparing them with a baseline period. Meteorological data forecasts were obtained from the regional climate model ETA 40 CTRL for the climatic scenario A1B, for the baseline (1961-1990) and future (2011-2100) periods. The one-dimensional SWAP model was used to estimate the water demand for irrigation. The results showed that, in the future, irrigation water requirements will be smaller for all crops. In the short term (2011-2040), water demands were similar to those for the baseline period, but from the middle of the century onwards (2041-2100), greater reductions were observed.
29
Selles, F., R. P. Zentner, D. W. L. Read e C. A. Campbell. "Prediction of fertilizer requirements for spring wheat grown on stubble in southwestern Saskatchewan". Canadian Journal of Soil Science 72, n. 3 (1 agosto 1992): 229–41. http://dx.doi.org/10.4141/cjss92-022.
Testo completoAbstract (sommario):
Results of fertilizer trials conducted throughout southwestern Saskatchewan were used to develop a production function relating grain yield increases of stubble-seeded spring wheat (Triticum aestivum L.) to available water, soil NO3-N content to 60 cm depth, soil PO4-P content to 15 cm depth, and fertilizer N and P applications. The trials were carried out from 1967 to 1971 and from 1978 to 1983 on mid-textured Brown Chernozemic soils. The model accounted for 67% of the variability in yield increases, and identified water availability as the single most limiting production factor, which by itself accounted for 15% of the variability in yield increases. Further, the effects of soil and fertilizer N and P were only significant in their interaction with water. Response to N fertilization was adequately described by a second-degree polynomial. The rates of fertilizer N required for maximum economic yield increases were related to the availability of soil NO3-N and PO4-P and to the rate of fertilizer P application, and inversely proportional to available water and the ratio of N cost to wheat price. The model indicated that soil NO3-N was equally effective as fertilizer N in raising yields, but considered soil PO4-P only one-fifth as effective as seed-placed fertilizer P in modifying the rates of fertilizer N required for maximum return. The effect of fertilizer P in the model was only significant in interactions with fertilizer N and soil PO4-P. Water use efficiency was proportional to the availability of soil and fertilizer nutrients. Key words: Fertilizer N, fertilizer P, soil testing, moisture use, soil N, soil P
30
Soares, Denise C., Edna M. Bonfim-Silva, Tonny J. A. da Silva, Éllen C. A. Anicésio, Thiago F. Duarte e Jakeline R. Oliveira. "Growth and production of wheat cultivars under water tensions in Cerrado soil". Revista Brasileira de Engenharia Agrícola e Ambiental 27, n. 4 (aprile 2023): 279–86. http://dx.doi.org/10.1590/1807-1929/agriambi.v27n4p279-286.
Testo completoAbstract (sommario):
ABSTRACT Brazil is not self-sufficient for the production of wheat (Triticum aestivum L.), and the expansion of cultivation to the Cerrado in the State of Mato Grosso, in an irrigated system, is an alternative solution to increase wheat production. This study aimed to evaluate the effects of soil water tension on the growth and production of wheat cultivars cultivated in the Cerrado Oxisol. The treatments were arranged in a 3 × 5 factorial scheme, with three wheat cultivars (BRS 254, BRS 394, and BRS 264) and five water tensions in soil (5, 15, 25, 35, and 45 kPa), using a randomized block design with four replications. Wheat growth and production exhibited a better response at a tension of 5 kPa. Cultivar BRS 254 showed the lowest production of spikes and grains per spike with increasing soil water tension. Among the cultivars, BRS 264 produced the highest number of grains per spike at tensions of 35 and 45 kPa. The wheat cultivars BRS 254, BRS 394, and BRS 264 have high water requirements. However, BRS 264 presented greater growth and production under conditions of restricted water in the soil, being able to be cultivated with an irrigation system activated less frequently, with less expenditure of water and energy.
31
Ewaid, Abed e Al-Ansari. "Crop Water Requirements and Irrigation Schedules for Some Major Crops in Southern Iraq". Water 11, n. 4 (11 aprile 2019): 756. http://dx.doi.org/10.3390/w11040756.
Testo completoAbstract (sommario):
The climate of Iraq is of the subtropical semi-dry type; however, the country was rich in water resources until a few decades ago. Climate change and the construction of many dams on the Tigris and Euphrates rivers in the neighboring countries have caused water shortages and poor water quality. Now, there is a need to decrease consumption, improve management of water resources, and determine the water requirements of the major crops because agriculture is the first consumer of water in Iraq. The Food and Agriculture Organization (FAO) CROPWAT 8.0 simulation software and the CLIMWAT 2.0 tool attached to it have been used in this research for Dhi-Qar Province in southern Iraq to find the crop water requirements (CWRs) and irrigation schedules for some major crops. The CROPWAT Penman–Monteith method was used to calculate the reference crop evapotranspiration (ET0) and the United States Department of Agriculture (USDA) soil conservation (S.C.) method was used to estimate the effective rainfall. The study results showed that ET0 varied from 2.18 to 10.5 mm/day and the effective rainfall varied from 0.0 to 23.1 mm. The irrigation requirements were 1142, 203.2, 844.8, and 1180 mm/dec for wheat, barley, white corn, and tomatoes, respectively. There is a higher water demand for crops during the dry seasons (summer and autumn) and a lower demand during the wet seasons (winter and spring). The total gross irrigation and the total net irrigation were 343.8 mm and 240.7 mm for wheat, 175.2 mm and 122.6 mm for barley, 343.8 mm and 240.7 mm for white corn, and 203.3 mm and 142.3 mm for tomatoes. This study proved that the CROPWAT model is useful for calculating the crop irrigation needs for the proper management of water resources.
32
Fowler, D. B., e M. I. P. Kovacs. "Influence of protein concentration on farinograph absorption, mixing requirements and mixing tolerance". Canadian Journal of Plant Science 84, n. 3 (1 luglio 2004): 765–72. http://dx.doi.org/10.4141/p03-148.
Testo completoAbstract (sommario):
Accurate and precise measurements of grain quality traits are required throughout the wheat (Triticum aestivum L. Em. Thell.) production and marketing chain to ensure that quality standards are maintained. In the present study, spring and winter wheat genotypes representing a wide range of grain quality types and protein concentration (PC) were grown in dry land and irrigated nitrogen fertilizer trials in western Canada to determine the influence of flour PC and quality on farinograph water absorption, mixing requirements and mixing tolerance. As expected, there was a strong linear relationship between PC and water absorption. In contrast, PC had a large nonlinear influence on mixing requirements and tolerance measurements, which made it difficult to make meaningful comparisons among genotypes when flour PC was less than 12%. Consequently, because cultivar grain yield potential, environment, and fertilizer management decisions have a large and variable influence on PC, it is important that cultivar selection procedures and marketing programs based on farinograph measurements include grain quality comparisons made over a wide range of PC and preferably at similar PC. This allows for a more accurate assessment of cultivar genetic potential that is independent of the normally strong negative relationship between PC and grain yield potential. When combined with the ability to segregate grain on the basis of PC at the time of delivery, it also allows producers a greater opportunity to select cultivars and adopt management practices that maximize returns while maintaining effective quality control in grain handling systems. Key words: Wheat, grain quality, farinograph, protein concentration, N management, cultivar selection and marketing
33
DUBEY, S. K., A. K. SINGH, LAKHAN SINGH, ATAR SINGH, V. K. KANAUJIA e BHUPENDRA KUMAR SINGH. "Crop diversification and small holders: A micro-level evidence from Uttar Pradesh". Indian Journal of Agricultural Sciences 90, n. 1 (2 marzo 2020): 75–79. http://dx.doi.org/10.56093/ijas.v90i1.98536.
Testo completoAbstract (sommario):
Survey was conducted in villages Digsara, Basirpur Mar, Pokhra and Bhavanipur under Jalalabad block of Kannauj districts to analyze the crop diversification systems during 2015–16. The major cropping systems included potato-groundnut/maize; paddy-potato-maize; paddy-wheat-green manuring; groundnut/maize-potato-maize; maizemustard- maize and green manuring-early potato-wheat/seed potato. It was observed that summer groundnut was fast replaced by summer maize despite higher water requirement in summer maize (6–7 irrigation) than groundnut (3–4 irrigation) as farmers were getting higher yield (60–70 q/ha) in summer maize than groundnut (Yield: 37–40 q/ ha).Summer groundnut was perceived more sustainable than summer maize as the underground water level was fast depleting in these area (declining at the rate of 2 ft. every year). Wheat crop was getting marginalized among small land holders. Major cropping systems followed by such farmers were fallow/dhaincha-potato-maize; maize-potatomaize and maize-early potato-wheat (very less area). Diversification with mixed cropping of minor vegetables likes coriander and kharif onion was also analyzed in these districts. Flower cultivation based crop diversification was documented in this study. It was found that flowers like rose, bela (jasmine) and mehndi (henna) were cultivated by the majority of farmers to address the industrial requirements in the district for making edible products of roses as well as perfumes. Potato+rose was the most frequently utilized cropping pattern as the fertilizer requirements of roses were being met from the residual nutrients of potato.The study recommends that the diversity in cropping systems among the small holders ought to be safeguarded and supported with the appropriate development interventions.
34
Campbell, C. A., Y. W. Jamel, A. Jalil e J. Schoenau. "Use of hot KCl-NH4-N to estimate fertilizer N requirements". Canadian Journal of Soil Science 77, n. 2 (1 maggio 1997): 161–66. http://dx.doi.org/10.4141/s96-106.
Testo completoAbstract (sommario):
We need an easy-to-use chemical index for estimating the amount of N that becomes available during the growing season, to improve N use efficiency. This paper discusses how producers may, in future, use crop growth models that incorporate indices of soil N availability, to make more accurate, risk-sensitive estimates of fertilizer N requirements. In a previous study, we developed an equation, using 42 diverse Saskatchewan soils, that related potentially mineralizable N (N0) to NH4N extracted with hot 2 M KCl (X), (i.e., N0 = 37.7 + 7.7X, r2 = 0.78). We also established that the first order rate constant (k) for N mineralization at 35°C is indeed a constant for arable prairie soils (k = 0.067 wk−1). We modified the N submodel of CERES-wheat to include k and N0 (values of N0 were derived from the hot KCl test). With long-term weather data (precipitation and temperature) as input, this model was used to estimate probable N mineralization during a growing season and yield of wheat (grown on fallow or stubble), in response to fertilizer N rates at Swift Current. The model output indicated that the amount of N mineralized in a growing season for wheat on fallow was similar to that for wheat on stubble, as we hypothesized. Further the model indicated that rate of fertilizer N had only minimal effect on N mineralized. We concluded that, despite the importance of knowing the Nmin capability of a soil, it is available water, initial levels of available N and rate of fertilizer N that are the main determinants of yield in this semiarid environment. The theoretical approach we have proposed must be validated under field conditions before it can be adopted for use. Key words: N mineralization, Hot KCl-NH4-N, potentially mineralizable N, CERES-wheat model
35
RASHMI MEHTA e VYAS PANDEY. "Crop water requirement (ETc) of different crops of middle Gujarat". Journal of Agrometeorology 18, n. 1 (1 giugno 2016): 83–87. http://dx.doi.org/10.54386/jam.v18i1.906.
Testo completoAbstract (sommario):
Accurate estimation of crop water requirements (ETc) of any crop is essentially required for irrigation scheduling and water management. The present study was undertaken to estimate the crop water requirement (ETc) of ten major crops (rice, wheat, maize, pearl millet, chickpea, green gram, soybean, groundnut, mustard and cotton) grown in different seasons inmiddle Gujarat region. The daily reference evapotranspiration (ETo) was estimated by FAO Penman-Monteith method using 20 years (1993 to 2013) mean meteorological data of Anand. The growth stage wise crop coefficients (Kc) modified for daily climatic variation was used to estimate the daily ETc for the selected crops.The daily ETo was found to increase continuously from 4.2 mm day-1 in January to its maximum values of 10.1 mm day-1 during 25th-30thMay, thereafter ETo decreased sharply during June and remained low during July and August (H”5.4 mm day-1). With slight increase during September and October, it decreased further and reached to its minimum value (4.0 mm day-1) at the end of year. The seasonal crop water requirement (ETc) estimates showed that, among summer crops, groundnut has higher ETc (849.0 mm) value than pearlmillet (499.2 mm) and green gram (476.5 mm).Among kharif crops,cotton (848.0 mm) and rice(729.3 mm) have the highest crop water requirement whereas pearlmillet (323.6 mm) and green gram (324.6 mm) have the lowest ETc. Amongst winter season crops,wheat has the highest (501.2 mm) ETc and mustard has the lowest (411.7 mm) ETc.These results can be used in efficient management of irrigation water.
36
Tesfamichael, Fekadu, Ramesh Prasad Tripathi e Mehreteab Tesfai. "Irrigation and Nitrogen Requirements of Wheat under Shallow Water Table Conditions of Asmara, Eritrea". Journal of Geoscience and Environment Protection 04, n. 04 (2016): 80–87. http://dx.doi.org/10.4236/gep.2016.44011.
Testo completo
37
Awal, Ripendra, Ali Fares e Haimanote Bayabil. "Assessing Potential Climate Change Impacts on Irrigation Requirements of Major Crops in the Brazos Headwaters Basin, Texas". Water 10, n. 11 (9 novembre 2018): 1610. http://dx.doi.org/10.3390/w10111610.
Testo completoAbstract (sommario):
In order for the agricultural sector to be sustainable, farming practices and management strategies need to be informed by site-specific information regarding potential climate change impacts on irrigation requirements and water budget components of different crops. Such information would allow managers and producers to select cropping systems that ensure efficient use of water resources and crop productivity. The major challenge in understanding the link between cropping systems and climate change is the uncertainty of how the climate would change in the future and lack of understanding how different crops would respond to those changes. This study analyzed the potential impact of climate change on irrigation requirements of four major crops (cotton, corn, sorghum, and winter wheat) in the Brazos Headwaters Basin, Texas. The irrigation requirement of crops was calculated for the baseline period (1980–2010) and three projected periods: 2020s (2011–2030), 2055s (2046–2065), and 2090s (2080–2099). Daily climate predictions from 15 general circulation models (GCMs) under three greenhouse gas (GHG) emission scenarios (B1, A1B, and A2) were generated for three future periods using the Long Ashton Research Station–Weather Generator (LARS-WG) statistical downscaling model. Grid-based (55 grids at ~38 km resolution) irrigation water requirements (IRRs) and other water budget components of each crop were calculated using the Irrigation Management System (IManSys) model. Future period projection results show that evapotranspiration (ET) and IRR will increase for all crops, while precipitation is projected to decrease compared with the baseline period. On average, precipitation meets only 25–32% of the ET demand, depending on crop type. In general, projections from almost all GCMs show an increase in IRR for all crops for the three future periods under the three GHG emission scenarios. Irrigation requirement prediction uncertainty between GCMs was consistently greater in July and August for corn, cotton, and sorghum regardless of period and emission scenario. However, for winter wheat, greater uncertainties between GCMs were observed during April and May. Irrigation requirements show significant variations across spatial locations. There was no consistent spatial trend in changes of IRR for the four crops. A unit change in precipitation is projected to affect IRR differently depending on the crop type.
38
RIASI, MITRA, SEYED HADI EBRAHIMI e ALI JAVADMANESH. "Virtual water requirement of cow milk production under two different dietary strategies". Indian Journal of Animal Sciences 90, n. 8 (6 gennaio 2021): 1163–67. http://dx.doi.org/10.56093/ijans.v90i8.109302.
Testo completoAbstract (sommario):
Nutritionists have liberty to choose various feeds for formulating a balanced ration depending upon the nutritive value, availability and feed cost. Although final target in an alternative ration is to obtain similar energy, protein and other nutrients, it would be favourable to consider virtual water (VW) requirement which must be spent while making a balanced ration. This paper compared two isonitrogenous and isocaloric balanced dairy cow rations for their VW requirements. VW in the maize silage-based ration was greater than that of alfalfa and wheat straw-based diet (39.73 versus 34.45 m3). It was also found that by-product feeds such as molasses, beet sugar pulp, corn gluten, and soybean meal require a lesser amount of VW, thus, they could be the best candidates to be used as much as conventional main feeds in the ration of dairy cattle for decreasing VW requirement of milk. Using feeds with less water utilization could reduce water requirement for milk production up to 12%.
39
Hervillard, Thomas, Qi Cao e Marie-Pierre G. Laborie. "Improving water resistance of wheat straw-based medium density fiberboards bonded with aminoplastic and phenolic resins". BioResources 2, n. 2 (25 febbraio 2007): 148–56. http://dx.doi.org/10.15376/biores.2.2.148-156.
Testo completoAbstract (sommario):
A long standing problem in the manufacture of wheat-straw based composites with cost-effective formaldehyde-based resins is their poor water resistance as demonstrated by their large water thickness swell. In this study, wheat straw based medium density fiberboards were manufactured using 3 resin/wax systems: a melamine-urea-formalde-hyde resin with either low or high wax content, and a phenol-formal-dehyde resin with low wax content. The flexural properties, internal bond strength, and thickness swell of the resulting composites were evaluated and compared according to ASTM methods. The three MDF compos-ites passed the requirements for MDF in interior application, except for the MDF manufactured with the aminoplastic resin and low wax content that failed to provide acceptable thickness swell. Using the phenolic resin in combination with low wax content resulted in a higher grade MDF composite, grade 120, than with the aminoplastic and high wax content. This study demonstrates that wheat straw based MDF manu-factured with cost-effective aminoplastic and phenolic resins can have flexural properties, internal bond strength and thickness swell perfor-mance above the requirements from the American National Standards Institute.
40
Zhang, Ang. "Effect of wheat flour with different quality in the process of making flour products". International Journal of Metrology and Quality Engineering 11 (2020): 6. http://dx.doi.org/10.1051/ijmqe/2020005.
Testo completoAbstract (sommario):
All kinds of flour products which are made of wheat flour have already become the staple food on people's dining table. With the improvement of living standard, the quality requirements for the flour products have gradually improved. In addition to the production technique, the quality of wheat flour as the raw material is also very important for the quality of flour products. This paper briefly introduced wheat flour and two main components that affected its quality: starch and protein. Then, the related quality of starch and protein and the quality of corresponding flour products were tested for five kinds of wheat flour. The experimental results showed that the quality indexes of five kinds of wheat flour were obviously different and representative. The regression analysis on the quality data of wheat flour and flour products showed that the water absorption of flour decreased with the increase of total starch content, dry gluten content and gluten index, the water solubility of flour decreased with the increase of total starch content and gluten index and increased with the increase of ratio of amylose to amylopectin, and the radial expansion rate of the flour products decreased with the increase of wet gluten content. To sum up, the quality of wheat flour will affect the water absorption, water solubility and radial expansion rate of flour products in the production process.
41
Fenech, Sara, Jerry Knox, Malcolm Borg, Christian Camilleri e Alex Rizzo. "Estimating Impacts of Land Use Change on Evapotranspiration for Three Agricultural Crops in Malta—A Preliminary Assessment". Journal of Agricultural Science 11, n. 3 (15 febbraio 2019): 67. http://dx.doi.org/10.5539/jas.v11n3p67.
Testo completoAbstract (sommario):
Estimating evapotranspiration is crucial for better management of catchment water resources. In this study, the FAO CropWat model was used to estimate reference evapotranspiration (ETo), crop evapotranspiration (ETc), and total gross water requirements for three economically important agricultural crops grown in Malta: potatoes, wheat, and vineyards for three years representative of a typically wet (2003), average (2009), and dry (2013) year. In addition, changes in ETc due to changes in land use were estimated for 2009 and 2013 relative to a 2003 baseline. Across all three years and crops, the average ETo rates were estimated to range between 3.7 mm day -1 (2003) and 4.0 mm day-1 (2013) while average ETc rates were estimated to range between 1.6 mm day-1 and 5.3 mm day-1, respectively. For all three years, the highest total gross water requirement was estimated for wheat, reaching a maximum of 1450 mm in 2013. The results suggest that changes in land use between 2003 and 2013 were the main driver for changes in crop water demand. Differences in water demand compared to 2003 were estimated to range between -38% and 60%. This could have a substantial impact on the future sustainability of Malta’s increasingly constrained water resources.
42
Wang, Nan, Jiujiang Wu, Yuhui Gu, Kongtao Jiang e Xiaoyi Ma. "Factors Influencing the Spatiotemporal Variability in the Irrigation Requirements of Winter Wheat in the North China Plain under Climate Change". Agronomy 12, n. 9 (23 agosto 2022): 1987. http://dx.doi.org/10.3390/agronomy12091987.
Testo completoAbstract (sommario):
The North China Plain is a major grain-producing area, but faces water scarcity, which directly threatens food security. The problem is more severe under climate change and the seasonal impact of climate change on winter wheat is different. Thus, it is of great importance to explore the spatiotemporal characteristics of irrigation requirements (IR) and the factors influencing IR in different growth periods of winter wheat, but it has not received much attention. Therefore, we used relative contribution, partial correlation and path analyses to assess the spatiotemporal characteristics of the IR and primary factors influencing the IR of winter wheat in various growing stages in the North China Plain. The results indicated that wind speed and net solar radiation showed a significant downward trend; no prominent trend was noted in IR (multiyear average, 302.3 mm). Throughout the growing season of winter wheat, IR increased gradually from the southern to northern extent of the North China Plain. The irrigation demand of winter wheat in stage P2 (green-up to heading) was the largest. Furthermore, the dominant drivers of IR in terms of spatial distribution and inter-annual variation were phenological period (Phe), effective precipitation (Pe) and relative humidity (RH); however, the degree of their effects varied across the growth stages and growing regions of winter wheat. Each factor exerted both direct and indirect effects on IR and Phe exhibited the strongest indirect effect on IR. The major factors contributing most to IR were Pe and RH in the P1 stage (sowing to green-up) and Phe, Pe and RH in the P2 and P3 (heading to maturity) stages. Pe and RH limited IR, whereas Phe promoted it. Our findings will help improve agricultural water management in the future.
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Elyadini, Meryem, Abdelkarim Guaadaoui, Souad ElHajjaji, Najoua Labjar, Mustapha Labhilili, Fatima Gaboune e Mohammed Azeqour. "Induced mutagenesis for improving water stress tolerance in durum wheat (Triticumturgidum L. subsp. durum)". E3S Web of Conferences 234 (2021): 00107. http://dx.doi.org/10.1051/e3sconf/202123400107.
Testo completoAbstract (sommario):
Over the Water deficit is considered to be one of the most important limiting factors for crop productivity worldwide. Thus, it is important to use water resources more efficiently. One of the ways to conserve water and respond to the climate change is by using appropriate crop species and cultivars, notably which have low requirements for water.Chemical mutagens have contributed immensely to the development of a wide range of genetic variability and the improvement of several crop plants, including durum wheat. This study has the aim of understanding the effect of water stress on some morpho-physiological parameters and identifying tolerant lines to water stress from an EMS-mutated population in durum wheat. The results, under moderate (T1) and severe (T2) conditions of water stress,show the positive effect of mutagenesis on the population resulting in tolerantmutated linesto water deficit. Compared to the non-mutated, 32.15% of lines have a higher specific leaf weight; 57.14% of lines have a better ability to maintain a high water content and 75% of all lines demonstrate a very high intensity of chlorophyll fluorescence .In sum, this study has revealed the improvement of water stress tolerance in some induced durum wheat mutants.
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Makar, Randa S., Sahar A. Shahin, Mostafa El-Nazer, Ali Wheida e Mohamed Abd El-Hady. "Evaluating the Impacts of Climate Change on Irrigation Water Requirements". Sustainability 14, n. 22 (10 novembre 2022): 14833. http://dx.doi.org/10.3390/su142214833.
Testo completoAbstract (sommario):
Climate change and its impact on agriculture and water resources have become a global concern. The implications of extreme weather events on food production and water resource availability are starting to have social and economic effects worldwide. The present research aims at integrating the analysis of the atmospheric parameters with remote sensing, geographic information systems, and CROPWAT 8 model to evaluate the impacts of climate change on the irrigation water requirements estimates in a selected area in El-Beheira governorate, Egypt. Remote sensing and GIS are incorporated to produce land-use/land-cover maps and soil properties maps. On the other hand, the atmospheric parameters were analyzed using python analytical coding. The study utilized the Land-use/Land-cover (LU/LC) map produced from Sentinel-2 data. The agricultural area covered about 89% of the studied area and was occupied by seven crops. Wheat and berseem were the major crops in the area and covered about 67% of the studied area; therefore, their irrigation water requirements were calculated utilizing the CROPWAT 8 model. Furthermore, citrus irrigation water requirements were also included in this research, even though it only covered 10% of the studied area because it had the highest amount of irrigation water requirements. Forecasting the potential climate changes under the best-case scenario for the next thirty years revealed that the studied area will have no rain and a slight decrease in the average temperature. Accordingly, the irrigation water requirements will increase by almost 4% under current practices, and the increase will reach about 13% under no-field loss practices.
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Rawson, HM. "Gas Exchange and Growth in Wheat and Barley Grown in Salt". Functional Plant Biology 13, n. 4 (1986): 475. http://dx.doi.org/10.1071/pp9860475.
Testo completoAbstract (sommario):
By measuring a range of gas exchange and growth variables, attempts were made to select key indicators of response to salinity in a wheat (Q61) and a barley (Beecher). A second wheat (WW15, Anza) was included in the growth measurements. Plants were grown to anthesis in gravel culture flushed with 0, 75 or 150 mol m-3 NaCl, and under the high radiation and evaporative conditions of summer. Salinity increased leaf chloride contents and reduced peak photosynthesis, the initial slope of the light response curves, and dark respiration of young leaves at ligule emergence, but dark respiration of slightly older leaves was increased by salinity as were the CO2 compensation points. Short-duration changes in salinity could modify photosynthesis rates by no more than 15% though dark respiration rates moved quickly towards those of plants held continuously at the new salinity level. While Q61 wheat appeared superior to Beecher barley at moderate salinity using these gas exchange indicators, it died at 150 mol m-3 NaCl; Beecher and WW15 survived. Carbon and water budgets are used to propose that the demise of Q61 could have been partially due to its marginally poorer water-use efficiency and its higher specific leaf weight, i.e. its higher requirement for carbon and water to produce each unit area of leaf. It is suggested that measurements of relative leaf expansion rate, specific leaf weight, and water use efficiency would be basic requirements in a salinity screening program. Measurements of ion contents and gas exchange variables are of little benefit when used alone.
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Houria, Chennafi. "Decadal Evaluation of Durum Wheat Water Requirements to Improve Rainfed Agriculture Under Semi-Arid Conditions". Energy Procedia 18 (2012): 896–904. http://dx.doi.org/10.1016/j.egypro.2012.05.104.
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Multsch, S., J. F. Exbrayat, M. Kirby, N. R. Viney, H. G. Frede e L. Breuer. "Reduction of predictive uncertainty in estimating irrigation water requirement through multi-model ensembles and ensemble averaging". Geoscientific Model Development Discussions 7, n. 6 (10 novembre 2014): 7525–58. http://dx.doi.org/10.5194/gmdd-7-7525-2014.
Testo completoAbstract (sommario):
Abstract. Irrigation agriculture plays an increasingly important role in food supply. Many evapotranspiration models are used today to estimate the water demand for irrigation. They consider different stages of crop growth by empirical crop coefficients to adapt evapotranspiration throughout the vegetation period. We investigate the importance of the model structural vs. model parametric uncertainty for irrigation simulations by considering six evapotranspiration models and five crop coefficient sets to estimate irrigation water requirements for growing wheat in the Murray-Darling Basin, Australia. The study is carried out using the spatial decision support system SPARE:WATER. We find that structural model uncertainty is far more important than model parametric uncertainty to estimate irrigation water requirement. Using the Reliability Ensemble Averaging (REA) technique, we are able to reduce the overall predictive model uncertainty by more than 10%. The exceedance probability curve of irrigation water requirements shows that a certain threshold, e.g. an irrigation water limit due to water right of 400 mm, would be less frequently exceeded in case of the REA ensemble average (45%) in comparison to the equally weighted ensemble average (66%). We conclude that multi-model ensemble predictions and sophisticated model averaging techniques are helpful in predicting irrigation demand and provide relevant information for decision making.
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Xi-Ping, Deng, Shan Lun, Inanaga Shinobu e Keren Rami. "Wheat Yield Improvement in Eroded Semi-Arid Areas of China". Outlook on Agriculture 32, n. 3 (settembre 2003): 155–59. http://dx.doi.org/10.5367/000000003101294415.
Testo completoAbstract (sommario):
The greatest fear from global climate change is drought, and water is the most important factor influencing wheat growth. Soil and water conservation are, therefore, key requirements for sustaining productivity and environmental quality in semi-arid cropping systems. Great attention has been paid to the management of, demand for, and more efficient use of water. The comprehensive technical strategies reviewed in this paper include conserving water to combine both increased agricultural productivity and resource conservation; enquiries into how wheat plants respond to drought through morphological, physiological and metabolic modifications that occur in all plant organs; breeding for drought tolerance where there is a delineated stress environment and genotype × environment interactions are stable; and effective conservation of rainfall and high efficiency of use. Valuable techniques such as conservation tillage, mulch cultivation, limited irrigation, introduction of drought-tolerant varieties and rotation systems can be adjusted to local agricultural practices.
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Aryal, Shreya, Bishwash Dhungel, Khem Raj Subedi, Pawan Lamichhane e Sulav Bhattarai. "RESPONSE OF WHEAT PARAMETERS TO SOWING DATE AND IRRIGATION SUPPLIED IN TERAI REGION OF NEPAL". Tropical Agrobiodiversity 2, n. 1 (3 gennaio 2021): 07–09. http://dx.doi.org/10.26480/trab.01.2021.07.09.
Testo completoAbstract (sommario):
Wheat (Triticum aestivum L.) is one of the most important staple food crops all around the world. It belongs to the family Poaceae. It has high dietary fiber content and is the good source of carbohydrate due to which it has wide cultivation in the entire world. It is the 3 rd most cultivated commercial crop in Nepal. It is most popular among terai region due to suitable climate and irrigation supply. Wheat is generally a winter season crop and its growth and yield highly depends upon various factors where sowing time and irrigation requirements are the major ones. Wheat sown at appropriate time with average water supply and minimum to average temperature contributes to high wheat production. Sowing in time leads the wheat to absorb adequate sunlight and harness it for increasing the production. Similarly ,6-7 irrigation supplied during the growth contributes to higher yield and good grain quality of wheat. With the advancement in technology improved seeds have been introduced in Nepal which are disease resistant. But still water stress resistant wheat varieties have not been introduced and researches are going on. So, sowing on time and providing irrigation is very important for good response of growth parameters and to attain maximum productivity of wheat.
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Ahmed, Bashir Mohammed, Haruya Tanakamaru e Akio Tada. "Application of remote sensing for estimating crop water requirements, yield and water productivity of wheat in the Gezira Scheme". International Journal of Remote Sensing 31, n. 16 (20 agosto 2010): 4281–94. http://dx.doi.org/10.1080/01431160903246733.
Testo completo