Impact of Soil Amendments on Soil Heat and Moisture Content in Calcareous soil
A field experiment was carried out to study the impact of soil amendments on soil heat content and soil moisture content in calcareous soil. Experimental field, located in the Desert Research Centerʾs station in Ras Sudr, South Sinai. Three rates of sheep dung were used (0, 5 and 10 ton/ fed), sheep wool (0.5 and 1 ton/fed) and their combination (5 ton/fed sheep dung and each of 1 and 0.5 ton/fed sheep wool). Two rates 100% and 75% of available water were applied using drip irrigation system. Sorghum (Sorghum bicolor L. Monech) was planted in 1st June, 2016. The soil temperature was recorded and moisture content was determined at the same times after each plants cutting every an hour, from 9.00 am until 6.00 pm in July, August and September months for 0 – 5, 5– 10 and 10 –15 cm soil depths. Heat content was calculated in Calories for each soil depth.
The obtained results reveal that, the maximum soil heat content increased in the following order : 10 ton/fed sheep dung > 5 ton/fed sheep dung > combination (5 ton/fed sheep dung with 1 ton /fed sheep wool > combination (5 ton / fed sheep dung + 0.5 ton /fed sheep wool) > 1 ton /fed sheep wool > 0.5 ton /fed sheep wool > control (un treated).
The following equation: was applied to calculate the total area under curve of the heat content ( Heat Index HI), In July month, the 0-5 cm soil depth, results showed increase for Heat Index, of 10 ton /fed and 5 ton/fed sheep dung amendments with (100 and 75 % water applied) compare to control. The rates of increasing were 13.32, 10.49 %, 13.78 and 12.03 % for up above treatments respectively. While, the increase rate of the integrated heat content of 1 ton /fed and 0.5 Ton/ fed sheep wool with (100 and 75 % water applied) was < 1 %. In the soil depth 5-10 cm, the results showed the rates of increasing were 14.63, 12.18, 10.07 and 11.68% for sheep dung amendments, 1.18 and 1.55 % of 1 ton /fed and 0.5 ton/ fed sheep wool, respectively. The increase of (Heat Index, HT) was slightly in 10-15 cm soil depth. The same trend was found in August and September months. But HI in August month was higher than the total heat content under area in July and September.
The results were highly significant in HI as 100 & 75% of irrigation water applied for 0-5 and 5-10 cm soil depths. There was no significant of sheep wool treatment. There was no significant for 10-15 cm soil depth each of soil amendments and water applied in July and August month, but it had significant differences in September month. The results showed a significant increment in HI in the depth 10-15 cm at the end of the experiment, due to the influence of root growth.
Keywords: heat capacity, soil heat content, soil temperature, soil amendments and soil moisture retention.