The Effect of Soil Temperature and Moisture Content on the Thermal Properties of Ismailia Sandy Soil Under Alfalfa Cover

Abstract

ABESTRACTFifty one registers (one every week) of soil temperatures in 51 weeks through twelve months from January to December were recorded for every depth. They were recorded for three soil depths (0.05, 0.15, and 0.30m) in sandy soil that covered with alfalfa plants in Ismailia Agriculture Research Station of Ismailia governorate. The total soil temperature registers recorded were (51 observations x 3 depths) 153 readings. One hundred and fifty three soil samples in the same 51 weeks were collected from the same locations of the three depths. The volumetric heat capacity, thermal conductivity and thermal diffusivity were calculated. The obtained results were summarized as follows:Soil volumetric heat capacity increased with increasing moisture content at the nearest soil surface depth (0.05m) or the deepest one (0.30m). They ranged from 1.345479 to 1.803934, 1.286049 to 1.678707 and from 1.281804 to 1.757947 MJm -3 c -1 for the three depths 0.05, 0.15 and 0.30m respectively.Soil thermal conductivity increased with increasing soil moisture content. The values ranged from 1.2603 to 2.2489, 1.23222 to 2.15026 and 1.03913 to 2.18332Jm -1 s -1 c -1 , at moisture content ranged from 0.024 to 0.133, 0.010 to 0.103 and 0.009 to 0.122m 3 m -3 for the abovementioned depths, respectively. However, soil temperature showed a small effect on increasing the thermal conductivity.Soil thermal diffusivity was affected by soil temperature and soil volumetric moisture content. They ranged from 9.