Crop coefficients of major crops in South India
TL;DR: In this article, the modified Penman method was used to estimate crop coefficients for cotton, sorghum and millet for tropical South India based on lysimeter measured actual evapotranspiration (ET) and reference crop ET computed by the modified penman method.
About: This article is published in Agricultural Water Management.The article was published on 1994-09-01. It has received 34 citations till now. The article focuses on the topics: Crop coefficient.
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TL;DR: In this paper, the daily, weekly, and seasonal evapotranspiration of wheat and sorghum from sensitive weighing-type lysimeters was measured from a set of 2 × 2 m in surface area and 2-m deep LBSs.
Abstract: Wheat and sorghum are important cereal crops next only to rice in India and several other Asian countries. Improved water management requires accurate scheduling of irrigation, which in turn requires an accurate measurement of daily crop evapotranspiration ETc. Thus, the first objective of this study was to measure daily, weekly, and seasonal crop ETc of wheat and sorghum directly from sensitive weighing-type lysimeters. Experiments were conducted in a set of two electronic weighing-type lysimeters, 2 × 2 m in surface area and 2-m deep, to measure the hourly evapotranspiration of wheat and sorghum from 1991 to 1995 at Karnal, India. The average daily ETc of wheat varied from 4 mm/d at milking stage. The peak ETc of wheat was 4.6 mm/d and it occurred 16 weeks after sowing at the reproductive growth stage when leaf area index was 3.5. The measured seasonal ETc of wheat was 336 mm. In the case of sorghum, ETc was 3 mm/d at the initial stage, achieved a peak value of 6 ...
76 citations
TL;DR: In this article, the authors measured daily, weekly and seasonal ETc of maize and berseem directly from weighing type lysimeters and developed crop coefficients (Kc) from ETc measurements and weather data.
Abstract: Maize and berseem are among the most important crops in India and several other countries in the world. Irrigation is provided to these crops to get higher production; hence, determining the water requirements of these crops is important for irrigation planning. Improved water management of these crops requires accurate scheduling of irrigation, which in turn requires accurate measurement of crop evapotranspiration (ETc). Thus, the first objective of this study was to measure daily, weekly and seasonal ETc of maize and berseem directly from weighing type lysimeters. Experiments were conducted in a set of two electronic weighing-type lysimeters of 7.82 m3 to measure the hourly ETc of maize and berseem from June 1996 to April 1998 at Karnal, India. The average daily ETc of maize varied from 4 mm day–1 at development and reproductive stages. The peak daily ETc of maize was 7.7 mm day–1 and this occurred 9 weeks after sowing (WAS) at the silking stage of maize when leaf area index (LAI) was 5.5. The measured seasonal ETc of maize was 354 mm. In the case of berseem, the average daily ETc was 0.9 mm day–1 at the initial stage, achieved a peak value of 6.9 mm day–1 between 25 and 26 WAS during the fifth cut. The measured seasonal ETc of berseem was 480 mm. Precise information on the crop coefficient, which is required for regional-scale irrigation planning, is lacking for semi-arid climates such as those found in north India. Therefore, the second objective of this study was to develop crop coefficients (K
c) for maize and berseem from ETc measurements and weather data. The estimated values of K
c for maize by the Penman–Monteith method at the four crop growth stages; namely, initial, crop development, mid-season and maturity, were 0.55, 1.00, 1.23 and 0.64, respectively, and the corresponding values for berseem were 0.76, 0.82, 1.11 and 1.24, respectively. In the case of these two crops, actual K
c values determined from this study are different from those suggested by the FAO (Allen et al. 1998), indicating the need for generating these values at the local/ regional level.
69 citations
Cites background from "Crop coefficients of major crops in..."
...Mohan and Arumugam (1994) conducted experiments in lysimeters at Bangalore in southern India and observed that the ratio of ETc of maize and ET0 from PMon method became unity after 7 WAS and increased to a maximum value of 1.3 in the 10th WAS....
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TL;DR: In this paper, the Bowen ratio energy balance (BREB) technique was used to determine ETc and the Kc curve values using the Bowen Ratio Energy Balance (BE) technique.
44 citations
TL;DR: In this article, the authors used meteorological and lysimetric data for a period of nine years to develop crop coefficients for rice grown under lowland conditions in a sub-humid tropical climate in India.
Abstract: Meteorological and lysimetric data for a period of nine years were used to develop crop coefficients for rice grown under lowland conditions in a sub-humid tropical climate in India. The estimated crop coefficients were found to be higher than those values recommended by FAO. A crop coefficient model with basal coefficient, moisture availability coefficient and surface wetness coefficient terms has been proposed and found suitable. On most counts, the moisture availability coefficient was found to be near unity and the wetness coefficient was found to be significant. The basal crop coefficients for lowland rice have also been presented for practical use with the proposed models.
28 citations
TL;DR: In this article, the effects of future expansion/intensification of irrigated agriculture on groundwater and surface water levels and availability in a semi-arid watershed were evaluated using an integrated hydrologic model in conjunction with biophysical measurements.
24 citations
Cites background from "Crop coefficients of major crops in..."
...…Leaf Area Index (LAI), Root Depth (RD) (mm) and Crop coefficient Kc Cotton (Maximum) LAI - 3.5 Literature ( Allen et al., 1998; Al–Khafaf et al., 1978; Bland, 1993; Mohan and Arumugam, 1994 ) RD - 900 mm K c - 1.05 Vegetable (Maximum) LAI - 2.5 RD - 500 K c - 1 .1 Manning’s number for…...
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References
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TL;DR: In this paper, an equation is presented that estimates ETo from measured values of daily or mean values of maximum and minimum temperature. But this equation is compared with various other methods for estimating ETo.
Abstract: MEASURED lysimeter evapotranspiration of Alta fescue grass (a cool season grass) is taken as an index of reference crop evapotranspiration (ETo). An equation is presented that estimates ETo from measured values of daily or mean values of maximum and minimum temperature. This equation is compared with various other methods for estimating ETo. The equation was developed using eight years of daily lysimeter data from Davis, California and used to estimate values of ETo for other locations. Comparisons with other methods with measured cool season grass evapotranspiration at Aspendale, Australia; Lompoc, California; and Seabrook, New Jersey; with lysimeter data from Damin, Haiti; and with the modified Penman for various locations in Bangladesh indicated that the method usually does not require local calibration and that the estimated values are probably as reliable and useable as those from the other estimating methods used for comparison. Considering the scarcity of complete and reliable climatic data for estimating crop water requirements in developing countries, this proposed method can do much to improve irrigation planning design and scheduling in the developing countries.
3,252 citations
01 Jan 1977
TL;DR: Guidelines for predicting crop water requirements as mentioned in this paper, which are based on guidelines for predicting water requirements, are used to predict water requirements in the field of crop water forecasting, and they can be found in Table 1.
Abstract: Guidelines for predicting crop water requirements , Guidelines for predicting crop water requirements , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
2,098 citations
Book•
01 Jan 1977
TL;DR: Guidelines for predicting crop water requirements as discussed by the authors, which are based on guidelines for predicting water requirements, are used to predict water requirements in the field of crop water forecasting, and they can be found in Table 1.
Abstract: Guidelines for predicting crop water requirements , Guidelines for predicting crop water requirements , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
1,780 citations
TL;DR: In this article, improved crop coefficients for various Pacific Northwest irrigated crops were developed for estimating crop evapotranspiration (ET) from estimates or measurements of reference ET, based on that for well watered, actively growing alfalfa with sufficient growth for near maximum ET in arid, irrigated regions.
Abstract: Improved crop coefficients for various Pacific Northwest irrigated crops were developed for estimating crop evapotranspiration (ET) from estimates or measurements of reference ET. Reference ET was based on that for well watered, actively growing alfalfa with sufficient growth for near maximum ET in arid, irrigated regions. ET for the alfalfa reference crop and other crops was measured with sensitive weighing lysimeters at the field site near Kimberly, Idaho. The new crop coefficients are basal or minimal coefficients for conditions when soil evaporation is minimal but root-zone soil moisture is adequate. When combined with improved estimates of evaporation from wet soils, they should permit more accurate estimates of daily crop ET, more accurate irrigation scheduling, and more reliable estimates of crop water requirements. Curves were developed for alfalfa, potatoes, snap beans, sugarbeets, peas, sweet and field corn and winter and spring cereals.
614 citations
01 Mar 1978
353 citations