| Abstrakt: |
Virtually no direct measurements have been made to determine if wind barriers, in fact, do affect evaporation from bare soils. Our objective, therefore, was to quantify the effect of a tall wheatgrass (Agropyron elongatum) wind barrier system on soil drying from fallow soil compared with open‐field fallow. The experiment was done on a Williams loam soil (fine‐loamy, mixed, frigid family of Typic Argiborolls) near Sidney, Mont. We applied a 3.8‐cm irrigation and sampled for soil water content at half‐hour intervals and small depth increments to 10 cm. Ancillary data collected included wind in the barrier interval and in the open, plus global radiation, air temperature, and humidity in the open. The north‐south oriented system consisted of 8 double‐row tall wheatgrass barriers 1.2 m tall, 183 m long, with seven 15 m wide cropping intervals. For the study, we selected three locations in the third interval from the east, along with a location on an unprotected (check) area outside the influence of the barriers. The surface 4 cm of soil inside the barrier system remained wetter for about 3 days after the irrigation as compared with the check area. The drying rate remained constant at all four locations until approximately noon the day after irrigation. Thereafter, drying rate was influenced by exposure to wind. There are many periods of small, intermittent precipitation events during April and May when tall wheatgrass barriers could benefit a crop by creating a suitable soil water environment for seed germination, plant emergence and establishment, and soil resistance to wind erosion. |
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