Kanemasu, E. T.

Kansas State University

Kansas Agricultural Experiment Station Research Reports Volume 0 Issue 12 Keeping up with Research Article 40 1979 Evapotranspiration from Corn, Sorghum, Soybean, and Winter Wheat E. T. Kanemasu This report is brought to you for free and open access by New Prairie Press. It has been accepted for inclusion in Kansas Agricultural Experiment Station Research Reports by an authorized administrator of New Prairie Press. Copyright 1979 Kansas State University Agricultural Experiment Station and Cooperative Extension Service. Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. Brand names appearing in this publication are for product identification purposes only. No endorsement is intended, nor is criticism implied of similar products not mentioned. K-State Research and Extension is an equal opportunity provider and employer. Follow this and additional works at: https://newprairiepress.org/kaesrr Recommended Citation Kanemasu, E. T. (1979) "Evapotranspiration from Corn, Sorghum, Soybean, and Winter Wheat," Kansas Agricultural Experiment Station Research Reports: Vol. 0: Iss. 12. https://doi.org/10.4148/2378-5977.7277 Evapotranspiration from Corn, Sorghum, Soybean, and Winter Wheat Keywords Keeping up with research; 43 (April 1979); Kansas Agricultural Experiment Station contribution; no. 79-204-S; Evapotranspiration; Corn; Sorghum; Soybean; Winter wheat Creative Commons License This work is licensed under a Creative Commons Attribution 4.0 License. This research report is available in Kansas Agricultural Experiment Station Research Reports: https://newprairiepress.org/kaesrr/vol0/iss12/40 APRIL 1977 Evapotranspiration from Corn, Sorghum, Soybean, and Winter Wheat 1 E. T. Kanemasu Research Microclimatologist Information on evapotranspiration (ET) rates is important to many agricultural and water-related problems. The ET rates are regulated largely by potential evapotranspiration (Keep-ing Up With Hesearch 30), soil texture, crop cover, and water stress. Therefore, both total seasonal ET and seasonal trends in ET vary with climate, crop species and variety, disease, fertility, and other management practices. Figs. 1-3 show the trends in actual evapotran-spiration (ET) and potential evapotranspiration (PET) throughout the 1976 growing season for corn, sorghum, and soybeans at Manhattan, Kansas. Because the fields were not irrigated and droughty conditions existed, the seasonal ET values are slightly lower than normal. Wa-Contribution no. 1643-s, Agronomy Department AGRICULTURAL EXPERIMENT STATION This publication from Kansas State University Agricultural Experiment Station and Cooperative Extension Service has been archived. Current information: http://www.ksre.ksu.edu.ter stress at the end of the season (late in August) hastened maturitv; therefore, the leaves dried earlier and ET less than PET. PET and ET were from July through mid-August for all three crops. ET can exceed PET (Fig. 2 soybeans) because of soybeans' ability to take heat from hot air. Periods of highest water use by crops are during their reproductive stages-half bloom for sorghum, tassel-silk for corn, and full bloom for soybeans. Because spring rains are our common 10 20 30 10 20 30 JUNE Jl.\.Y 1976 CORN-Manhattan 10 20 30 AUGUST Fig. I.-Seasonal trends in evapotranspiration (ET) and llotential evapotranspiration (PE T) of corn at Manhat-tan, Kansas, 1976. ( 10 20 30 10 zo 30 .NNE JVLY 10 2.0 30 AUGUST t976 Fig. 2.-Seasonal trends in evapotranspiration (ET) and pot· evnpotranspir:•'i"" ... rainfall pattern a t ::-.ranhattan, the period of highest water use (mid to late July) is about when the soil-water rese1Toir (root zone) is de-pleted enough to cause water stress. Our silt loam soil holds about 10 inches of available wa·-tcr·. Adding ET lues in F igs. 1-3 from plant-ing to the reproductive stages of each of the SORGHUM - Manhottm 10 20 30 10 20 30 10 20 30 10 20 J UNE J.J<..Y AUGUST SEPTEMB€R 1976 Fig. 3.-Scasonal trends in evapotranspiration (ET) and potential cvupotranspiralion (PET) of sorghum at l'I.Jan-hattan, Kansas, l!:l76. 9.0 8 .0 z 6.0 a: 2.0 1.0 0 MANHATTAN ELLSWORTH GAROEN CITY ET PET - = -.. :::: WINTER WHEAT ET = 19.0 inches __ PLANTING EMERGENCE JOINTING HEADING EMERGENCE JOINTING HEADING SOFT DOUGH Fig. 4.-Evapotranspin:ition (ET) and potential cvapo· transpit·ation (PE Tl of winter wheat at .. stages j . This publication from Kansas State University Agricultural Experiment Station and Cooperative Extension Service has been archived. Current information: http://www.ksre.ksu.edu.crops shows that ahout 7 to 9 inches of water has been lost. If no significant rains h:l\'e fallen, the yield from the crops can be reduced wa-.er stress unless irrigation is a\·ailahle. During '-'iuly, the crops usc about 0.25 inch per day; thus, a l-inch rain is used up in 4 days. Fig. 4 shows the ET and PET pattern for winter wheat at Kansas locations: l\'lanhattan, El1sworth, and Garden Cih·. l\fanhattan had the highest ET and Garden City the lowest ET. Because of the difference in seeding rates across the state, crop cover is greater in the east than in the west. Only at :\Ianhattan during the joint-heading growth stage does the ET equal the PET. In western Kansas, the wheat requires about 6 inches of water after jointing (after mid-April); therefore, rains during :\ larch and April are critical to wheat Yields. Irrigation during "off-season" (late fall 'and early can the effect of a dry spring. Publications and public meetings by the Kansas Agri-cultural Experiment Station are available and open to the public regarr1 1 • This publication from Kansas State University Agricultural Experiment Station and Cooperative Extension Service has been archived. Current information: http://www.ksre.ksu.edu.

Evapotranspiration from Corn, Sorghum, Soybean, and Winter Wheat (1977)

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Evapotranspiration from Corn, Sorghum, Soybean, and Winter Wheat (1979)

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