Print ISSN: 2077-5822

Online ISSN: 2618-1479

Keywords : thermal properties


Study The Thermal Properties of The Soil Under Systems Irrigation and Mulching Different

Athmar Jameel Kareem Al-Lame; Jamal N. A. Al-Saadoon

Al-Qadisiyah Journal For Agriculture Sciences, 2020, Volume 10, Issue 2, Pages 415-425
DOI: 10.33794/qjas.2020.167503

A field experiment was carried out in the field of the Faculty of Agriculture / University of Wasit located at a longitude 45° 50' 33.5"east and N 29° 36' 49.8" norths for the 2019 growing season, with the aim of studying thermal properties under different irrigation and mulching systems. The study was carried as factorial experiment in RCBD design with three replications, the first factor was mulching (control, wheat straw, palm fronds, and black nylon), and the second factor was irrigation methods (basin, and furrow). Maize crop was planted on 20/7/2019, and harvesting was completed on November 20, 2019. The thermal properties were estimated using equations (thermal conductivity, heat flow, volumetric heat capacity, thermal diffusion), the results showed the following:

It is noticed that superiority of the treatment of mulching with black nylon at the beginning and end of the season by obtaining the highest thermal conductivity of the soil, followed by the treatment of straw and fronds compared to the treatment without mulching, as it reached at the beginning of the season 0.830, 0.769, and 0.752 W∙m−1∙K respectively, and reached at the end of the season 0.772, 0.813, and 0.834 W∙m−1∙K respectively, while the thermal conductivity of the control was 0.665, 0.746 W∙m−1∙K at the beginning and end of the season respectively.
The basin irrigation method outperformed the furrow irrigation method in the thermal conductivity values at the beginning and the end of the season, reaching 0.733 and 0.775 W∙m−1∙K respectively at the beginning of the season and 0.785 and 0.797 W∙m−1∙K respectively at the end of the season.
The black nylon mulch treatment outperformed the rest of the treatments at the beginning of the season, followed by the non-mulched treatment, then the frond mulching and straw mulching treatment by obtaining the highest heat flux rate of 2.96, 3.30, 4.47 and 6.80 W/m2, respectively.
The basin irrigation method outperformed the furrow irrigation method by obtaining the highest heat flux at the beginning of the season, reaching 5.99, and 2.77 W/m2, respectively, but the opposite happened at the end of the season where the furrow irrigation method outperformed the basin irrigation method, reaching 3.99, and 3.85 W/ m2 respectively.
The mulching treatment with black nylon exceeded by obtaining the highest values of volumetric heat capacity, then followed by the treatment of mulching with straw and fronds, and then treatment without mulching at the beginning and end of the growing season, reaching 1.61, 1.53, 1.49, and 1.39 MJ / m3 respectively at the beginning of the season and 1.52, 1.54, 1.54 and 1.63 respectively at the end of the season.
The basin irrigation method outperformed the furrow irrigation method in that it obtained the highest values of volumetric heat capacity which were 1.48 and 1.53 MJ / m3.K respectively at the beginning of the season and 1.57 and 1.54 MJ / m3.K respectively at the end of the season.
The treatment of mulching with black nylon outperformed by obtaining the highest value of thermal diffusivity, followed by the treatment of mulching with fronds and straw, compared to a treatment without mulching at the beginning of the season, which amounted to 5.18x10-7, 5.06x10-7, 5.01x10-7, and 4.79x10-7 m2 / sec respectively.
The basin irrigation method achieved the highest rate of thermal diffusivity compared with the furrow irrigation method at the beginning of the growing season, reaching 5.09 x10-7, and 4.94x10-7 m2 / sec respectively.