Effects of different management practices of barely straw and alfalfa residue on soil moisture content and aeration behavior under field conditions

Iran as an arid and semiarid country has been faced with low precipitation and water shortage. In this regard, the application of suitable management practices using plant residues is one of the most important strategies resulting in the improvement of organic matter content as well as water retention of soils. Therefore, in many soils of arid and semiarid regions, organic matter is as the best amendment to increase water content and improve physical properties of the soil (23, 40). Plant residue can increase soil moisture content through the improvement of soil organic carbon content and the reduction of runoff and evaporation (9, 25). Application of plant residue is one of the common methods for improving soil properties. However in some areas, plant residues are removed from the filed or burned by the farmers. This study was performed to investigate the effect of different types of plant residues and their management on soil moisture content as well as aeration properties under field conditions.
The experiment was conducted under field conditions as factorial statistical design based on RCBD consisting three replicates. The first factor was residue type including barely straw and alfalfa residue and the second factor was different managements of the residues including 1) incorporating one percent of the plant residues with the soil, 2) incorporating 0.5 percent of the plant residues with the soil, 3) surface retention of plant residues, 4) burning of plant residues and 5) control. After nine months, the final soil moisture content at seven suctions including 0, 30, 50, 100, 500, 1000 and 1500 kPa was measured. In addition, the available water content and aeration porosity were calculated.
The result showed that among the experimental treatments, the incorporation and also surface retention of plant residues increased soil moisture compared to control, whereas, burning the plant residues reduced the moisture content. In comparison to the control, the incorporation of one percent barely straw to the soil led to the highest increases in the moisture content at PWP (70%) and the available water (12.5%). Reversely, burning of barely straw showed the highest reduction in the moisture content at PWP (34.5%) compared to control. In addition, the surface retention of plant residues resulted in the highest increase (48%) in aeration porosity compared to control.
The findings of this study showed the favorite efficiency of incorporating and surface application of organic sources in improving soil moisture and aeration porosity.