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| movement in layered soils during evaporation under perforated plastic mulch |
| LI Yi, REN Xin, SI Bing-Cheng |
| (1.College of Water Resources and Architecture Engineering, Northwest A ＆ F University, Yangling, Shaanxi 712100, China; 2.Institute of Water Saving Agriculture in Arid Areas of China, Northwest A ＆ F University, Yangling, Shaanxi 712100, China; 3.Accounts Bureau of Nanyang, Nanyang, Henan 473000; 4.Department of Soil Science, University of Saskatchewan, Saskatoon SKS7N 5A8, Canada) |
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Abstract In order to reveal the evaporation characteristics of different textures of layered soils, two types of layered soils such as Lou soil and sandy soil, were selected to do column evaporation experiment in laboratory at three layer positions under the perforated plastic mulch conditions of 6 percentages of open area (0-100%). During the experiment the soil moisture and temperature distributions were measured, the evaporation was recorded against time as well. The results showed that soil temperature distribution is dependent of openholeratio and layer position; the temperatures on the soil surface under the condition with mulch fully covered at three positions are higher than the bare soil by 3.6, 66 and 21.8℃, respectively. The deeper the layer position, the more the difference of soil temperature between the soil surface and the deepest layer position. Such a difference is reduced for a larger openholeratio of mulch. A larger openholeratio results to a higher evaporation and the deeper the layer position, the higher the curve of cumulative evaporation against time. Power and logarithmic function can better describe the relationship between cumulative evaporation and time for both sparse and sandy soils. Generally, both openholeratio of mulch and layer position affect water and heat movement in soil.
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Received: 31 May 2012
Published: 30 November 2012
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