June 30, 1969.Submitted to Office of Water Resources Research, U.S. Department of Interior.Bibliography: page 5.OWRR Project A-002-COLO; grant nos. 14-01-0001-553, 726, 900, 1074, 1625

Danielson, Robert E.

Kemper, William Doral, 1928-

English

June 30, 1969.Submitted to Office of Water Resources Research, U.S. Department of Interior.OWRR Project A-002-COLO; grant nos. 14-01-0001-553, 726, 900, 1074, 1625

Kemper, William Doral, 1928-, author

Danielson, Robert E., author

Natural Resources Center, Colorado State University, publisher

Mountain Scholar (Digital Collections of Colorado and Wyoming)

     IMPROVING EFFICIENCY IN AGRICULTURAL WATER USE  by  W. D. Kemper and R. E. Danielson      Completion Report No. 8      ~~1~r8~~. St8te ~niversity, ?ort~~llins. N~turpl ~PS8UrCoS~omDletian ?eport series. no. SIMPROVING EFFICIENCY INAGRICULTURAL WATER USEPartial Completion ReportOWRR Project A-002-COLOTitle: SURFACE WATERJune 30, 1969byw. D. Kemper and R. E. DanielsonDepartment of AgronomyColorado State Universitysubmitted toOffice of Water Resources ResearchU. S. Department of InteriorWashington, D. C.Covering research under Agreements14-01-0001-553, 726, 900, 1074, 1625authorized by P.L. 88-379, Title I, Sec. 100During FY 1965 through FY 1969NATURAL RESOURCES CENTERColorado State UniversityFort Collins, ColoradoNorman A. Evans, DirectorABSTRACTIMPROVING EFFICIENCY IN AGRICULTURAL WATER USEManagement of runoff under dry land cropping was attempted by collectingprecipitation from sealed surfaces 4' to lot wide on untreated crop strips IS"wide. In the dry years of 1966 and 1968, when only six and eight inches ofwater were available, respectively, (soil storage plus ~ainfal1) yields frommicrowatersheds were five times yields on untreated check areas. Crops grownincluded corn, sugar beets, and sweet corn. During the four-year study period,1965-1969, with an average of 8.5" of moisture available, corn on the treatedplots yielded 68 bushels per acre compared to 32 bushels per acre from the un-treated area. In 1968 when 8" of moisture was available, sweet corn on micro-watersheds yielded 924 ears per acre compared to 165 ears per acre from thecheck. Sugar beets yielded 9 tons per acre compared to 3 tons per acre on thecheck. In 1967 with 11" of moisture available, beets on the microwatershedsyielded 12 tons per acre compared to 11 tons per acre on the check.An evaluation of several possible water proofing or infiltration reducingcovers for the microwatersheds were made. The cost of concrete was $3,000per acre. Other materials tested included polyethelyene plastic, hydrophobicchemicals, and sodium salts, none of which proved fully acceptable due toshort life.Plant growth and moisture use under controlled water stress conditionswere studied. Controlling water stress by irrigation scheduling reducedevaporation 61 percent while yields were reduced only 36 percent comparedto maximum yields under ideal moisture stress conditions. Other plantresponses to moisture stress include leaf turgidity, stomata opening, andleaf sugar content.Kemper, W. Doral and R. E. DanielsonIMPROVING EFFICTENCY IN AGRICULTURAL WATER U8B.Partial completion report to Office of Water Resources ResearchU.S. Department of Interior, June 30, 1969, 5 p.KEYWORDS --/~water conservation/ water management/ *microwatershed//evapotranspiration/ crop response/ growth rates//*irrigation effects/ *moisture stress/ moisture uptake//*runoff management/ water yield.Completion ReportOWRR Annual Allotment FundsSurface Water - A-002 Colo.Agronomy Sub-ProjectJune 1969I. Sub-project Title: Management of Water on Dry and Irrigated Lands forMore Efficient Use.II. Principal Investigators: W. D. Kemper and R. E. Danielson, Department ofAgronomy.III. Cooperators: H. R. Gardner and M. Fairbourn, USDA, SWCRD.tv. Research Findings:A system involving the use of elevated strips of the land surface tocontribute water to adjacent cropped strips was tested and shall be calledthe mtc rowa t er shcd sys tern in succeeding discussion. The "wa tershed" areasinvolved strips from 4' to 10' wide which were interspersed with croppedstrips 18" wide which contained two rows of plants (corn, sugar beets, orsweet corn) spaced 12" apart. Since effective and durable soil sealantswere not yet available, the potential of this microwatershed system wastested by covering the sheds with about 2" of concrete which, when painted,shed essentially 100% of the precipitation to adjacent cropped strips.The best microwatershcd treatments yielded an average of 68 bu. ofcorn/acre and used an average of 8.5" of water per year during 1965-1969inclusive. Check treatments (rows spaced 3' apart yielded an average of32 bu/acre using essentially the same amount of water. The yield differ-ences were greatest in the dry years of 1966 and 1968 when only 6" and 8"of water (stored plus rainfall) were available to the crops. In theseyears the yields on microwatershcd systems were more than 5 times theyields on the check treatments.Yields of salable swee t; corn wcre 9,240 e:.rJ;:u:-re on micro\vatershedsystems in 1968 and 165 ears/acre on the check plots.-2-In 1967 check plots of sugar beets yielded 11 tons per acre andmicrowatersheds yielded 12, using about 11 inches of water. During 1968when only an of water was available to the beets, microwatersheds yielded9 tons of sugar beets and check plots yielded only 3 tons/acre.All yields are calculated on the basis of the total areas in theplots, including microwatershed areas.The general conclusions are: If an economical waterproofing agentcan be found for microwatersheds, yields of corn could be doubled andsugar beets could be grown in many of the dryland areas of the Great Plains.Such a cropping system would be particularly beneficial during periods ofprolonged drought, since it could produce about 45 bushels of corn/acre·on only 6" of water.While the present cost (about $3000/acre) of waterproofing micro-watersheds with concrete is not economical for field crops, even thissystem provides insurance for a highly industrialized nation which, iffaced with droughts of the severity encountered ·in the major droughts ofthe Great Plains in the 18th and 19th centuries, could turn its industrialcapability to the production of microwatersheds on the Great Plains andprevent starvation of its people.The search for and evaluation of other waterproofing materials wasnot very productive. In general, hydrophobic agents were expensive andwhen applied only in thin layers on soil surfaces, were subject to mechani-cal breakdo~m by raindrop impact.Polyethylene sheeting was effective, but the necessity of replacingit yearly mak~s its long-term cost about the· same as that of concrete.Sodium salts are fairly effective in breaking down the aggregatestructure of soil surfaces and increasing runoff. while sodium phosphate-3-and carbonate gave the best initial runoff, sodium chloride had a more last-ing effect. A treatment of 400 lbs/acre increased runoff from 2"/year ona check treatment (bare soil surface) to 4"/year on Na-treated plots. Re-treatment with the salt about every two years appears to be. necessary tomaintain the increased runoff. Long-term treatment (e.g. 40 years) of thistype would result in soil with high runoff, but it would be difficult toconfine the treatment to the watershed area. Eventually the cropped areawould become salinized with the consequent negative influence on cropgrowth. However, the success of the runoff plots at Avdat, Israel, wherefruit trees are being grown on about 4" of precipitation per year, is un-doubtedly due to the fact that the soils are slightly saline with Na salts.Their dikes hold the water on the cultivated area long enough to ensureinfiltration and occasional leaching of the cultivated area keeps the saltcontent of the root zone to reasonable levels. Development of such agri-cultural systems is much more likely to be accepted by the public if it isapplied to low value lands in arid zcnes which are already saline.Investigat~ons directed toward the management of surface water onirrigated crop land have involved laboratory and ~reenhouse studies aswell as field trials. Controlled laboratory studies were designed toevaluate the influence of water stress levels in plants on transpirationand growth rates in order to evaluate photosynthetic efficiency in terms ofwater use. Techniques for developing and maintaining plant water stressby artificial means were evaluated. Plant physiological responses andtranspiration were measured under the artificial stress conditions andcompared to results from plants gro,vn in soils.Water use and relative growth rates of bean plants were both reducedby plant water stress conditions as would be expected) but water use was-4-reduced to the greatest extent. Thus, water use efficiency by stressedplants was significantly increased when water availability to the roots wasmaintained at levels below that required for potential transpiration undera specified foliar environment. Comparable results were obtained when soilcultures were used under greenhouse conditions by limiting irrigation fre-quency so as to develop periodic stress. The findings provide knowledgeusable where irrigation water supplies are insufficient to adequatelyirrigate all the land available or where water is sufficiently costly tomake water use efficiency of greater concern than maximum production.Field plot data has been obtained to substantiate the laboratory results.In 1968 controlled development of plant water stress through irrigationscheduling reduced consumptive use of water during the crop season by61 percent, while yield was only reduced 36 percent as compared withirrigation systems where maximum production resulted.The atudies have provided an opportunity to measure various plantresponses other than growth in relation to water stress levels. Leafrelative turgidity measurements were found to be relatively insensitive towater stress levels through the range where transpiration is significantlyreduced. Measurements of stomatal aperature, however, are closely associatedwith transpiration and thus are related in a meaningful way to interval leafwater stress. Leaf sugar concentrations were found to increase somewhatas plant water stress increased, but the consistency of the data was notsufficiently good to recommend such an analysis as a means of measuringwater stress.Details of the experimental results are provi.ded in publications andmanuscripts prepared for publication.-5-v. Publications:Muturi, S. N. 1966. Influence of soil moisture tension On the internalwater balance of beans. Master of Science Thesis, Colorado StateUniversity.Unger, P. W. and R. E. Danielson. 1967. Water relations and growth ofbeans (Phaseolus vulgaris L.) as influenced by nutrient solutiontemperatures. Agron. Journ. 59:143-146.Aase, J. K. 1967. Water use and yields as affected by microwatershedsand ground color. Ph.D. Dissertation, Colorado State University.Aase, J. K., W. D. Kemper, and R. E. Danielson. 1968. Response of cornto white and black ground covers. Agron. Journ. 60:234-236.Aase, J. K. and W. D. Kemper. 1968. Effect of ground color and micro-watersheds on corn growth. J. Soil and Water Conservation 23:60-62.Kemper, W. D. and L. Noonan. 1969. Runoff as affected by salt treatmentsand texture. (Manuscript accepted for publication in Soil Sci. Soc.Amer. Proc.)Conway, J. T. 1~69. Irrigation of sodium ions in a soil profile. Masterof Science Thesis, Colorado State University.Conway, J. T., W. D. Kemper, and N. Lahav. Successive Na profiles andtheir effect on runoff. (Manuscript in preparation for submissionto Soil Sci. .soc, Ame r , Proc ,Fairbourn, M. L. and W. D. Kemper. Production of sugar beets as affectedby microwatersheds and ground color. (Manuscript in preparation forsubmission to Agron. Jour.VI. Student Training:Six graduate students have been involved in the research conducted underthe project. These have included three Master of Science and three Ph.D.candidates.

Improving efficiency in agricultural water use

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Improving efficiency in agricultural water use

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