Evapotranspiration of irrigated and rainfed maize–soybean cropping systems

Abstract We have been making year-round measurements of mass and energy exchange in three cropping systems: (a) irrigated continuous maize, (b) irrigated maize–soybean rotation, and (c) rainfed maize–soybean rotation in eastern Nebraska since 2001. In this paper, we present results on evapotranspiration (ET) of these crops for the first 5 years of our study. Growing season ET in the irrigated and rainfed maize averaged 548 and 482 mm, respectively. In irrigated and rainfed soybean, the average growing season ET was 452 and 431 mm, respectively. On average, the maize ET was higher than the soybean ET by 18% for irrigated crops and by 11% for rainfed crops. The mid-season crop coefficient Kc (=ET/ET0 and ET0 is the reference ET) for irrigated maize was 1.03 ± 0.07. For rainfed maize, significant dry-down conditions prevailed and mid-season Kc was 0.84 ± 0.20. For irrigated soybean, the mid-season Kc was 0.98 ± 0.02. The mid-season dry down in rainfed soybean years was not severe and the Kc (0.90 ± 0.13) was only slightly lower than the values for the irrigated fields. Non-growing season evaporation ranged from 100 to 172 mm and contributed about 16–28% of the annual ET in irrigated/rainfed maize and 24–26% in irrigated/rainfed soybean. The amount of surface mulch biomass explained 71% of the variability in non-growing season evaporation totals. Water use efficiency (or biomass transpiration efficiency), defined as the ratio of total plant biomass (YDM) to growing season transpiration (T) was 5.20 ± 0.34 and 5.22 ± 0.36 g kg−1, respectively for irrigated and rainfed maize crops. Similarly, the biomass transpiration efficiency for irrigated and rainfed soybean crops was 3.21 ± 0.35 and 2.96 ± 0.30 g kg−1. Thus, the respective biomass transpiration efficiency of these crops was nearly constant regardless of rainfall and irrigation.

[1]  T. Meyers,et al.  Measuring Biosphere‐Atmosphere Exchanges of Biologically Related Gases with Micrometeorological Methods , 1988 .

[2]  C. Tucker,et al.  Northern hemisphere photosynthetic trends 1982–99 , 2003 .

[3]  S. Verma,et al.  Eddy correlation measurement of CO2 flux using a closed-path sensor: Theory and field tests against an open-path sensor , 1993 .

[4]  C. Kucharik,et al.  Residue, respiration, and residuals: Evaluation of a dynamic agroecosystem model using eddy flux measurements and biometric data , 2007 .

[5]  Derrel L. Martin,et al.  Crop rotations with full and limited irrigation and dryland management , 1991 .

[6]  W. J. Shuttleworth,et al.  Evapotranspiration: Progress in Measurement and Modeling in Agriculture , 2007 .

[7]  R. Neilson,et al.  Potential consequences of climate variability and change for the forests of the United States , 2001 .

[8]  L. S. Pereira,et al.  Crop evapotranspiration : guidelines for computing crop water requirements , 1998 .

[9]  Loyd R. Stone,et al.  Comparative Water Use Characteristics of Six Row Crops , 1988 .

[10]  G. Stanford,et al.  Nitrogen Requirements of Winter Wheat (Triticum aestivum, L.) Varieties ‘Blueboy’ and ‘Redcoat’ 1 , 1973 .

[11]  Howard M. Taylor,et al.  Water Use in Agriculture. (Book Reviews: Limitations to Efficient Water Use in Crop Production) , 1984 .

[12]  Robert D. Perlack,et al.  Current and potential U.S. corn stover supplies. , 2007 .

[13]  J. Bowman,et al.  Impacts of Irrigation and Drought on Illinois Ground-Water Resources , 1987 .

[14]  P. Unger,et al.  Soil Water Accumulation under Different Precipitation, Potential Evaporation, and Straw Mulch Conditions , 2001 .

[15]  D. Paslier,et al.  Net Exchange of CO2 in a Mid-Latitude Forest , 1993, Science.

[16]  K. Steffey.  Handbook of corn insects. , 1999 .

[17]  N. J. Rosenberg,et al.  Microclimate: The Biological Environment. , 1976 .

[18]  D. Baldocchi,et al.  Seasonal variation of carbon dioxide exchange rates above and below a boreal jack pine forest , 1997 .

[19]  C. Norwood.  Water use and yield of dryland row crops as affected by tillage , 1999 .

[20]  J. Shroyer,et al.  The impact of reduced tillage on soilborne plant pathogens. , 1998, Annual review of phytopathology.

[21]  C. B. Tanner,et al.  Estimating Evaporation and Transpiration from a Row Crop during Incomplete Cover1 , 1976 .

[22]  S. Verma,et al.  Carbon dioxide budget in a temperate grassland ecosystem , 1992 .

[23]  S. Verma,et al.  Interannual water vapor and energy exchange in an irrigated maize-based agroecosystem , 2008 .

[24]  R. H. Shaw,et al.  The Effects of Soil Moisture Stress at Different Stages of Growth on the Development and Yield of Corn1 , 1960 .

[25]  Daniel T. Walters,et al.  Maize Root Biomass and Net Rhizodeposited Carbon , 2006 .

[26]  S. Verma,et al.  Interannual variability in net CO2 exchange of a native tallgrass prairie , 2003 .

[27]  J. Shukla,et al.  Influence of Land-Surface Evapotranspiration on the Earth's Climate , 1982, Science.

[28]  J. Boyer.  Plant Productivity and Environment , 1982, Science.

[29]  John H. Prueger,et al.  Managing Soils to Achieve Greater Water Use Efficiency , 2001 .

[30]  T. Arkebauer,et al.  Impacts of management on decomposition and the litter-carbon balance in irrigated and rainfed no-till agricultural systems , 2009 .

[31]  Andrew E. Suyker,et al.  Annual carbon dioxide exchange in irrigated and rainfed maize-based agroecosystems , 2005 .

[32]  T. Meyers,et al.  An assessment of storage terms in the surface energy balance of maize and soybean , 2004 .

[33]  J. Norman,et al.  Surface energy balance of a corn residue-covered field , 1998 .

[34]  Joe T. Ritchie,et al.  Model for predicting evaporation from a row crop with incomplete cover , 1972 .

[35]  William J. Massman,et al.  The attenuation of concentration fluctuations in turbulent flow through a tube , 1991 .

[36]  J. T. Musick,et al.  Irrigated Corn Yield Response to Water , 1980 .

[37]  C. J. Moore.  Frequency response corrections for eddy correlation systems , 1986 .

[38]  Freddie R. Lamm,et al.  Water Requirement of Subsurface Drip-irrigated Corn in Northwest Kansas , 1995 .

[39]  D. R. Linden,et al.  Crop and Soil Productivity Response to Corn Residue Removal: A Literature Review , 2004 .

[40]  E. K. Webb,et al.  Correction of flux measurements for density effects due to heat and water vapour transfer , 1980 .