Investigation of the effect of sunflower mulch the soil Least Limiting Water Range (LLWR)

It is important to detect the range of soil moisture at which plant growth is associated with the water potential, soil resistance and least limiting water range (LLWR). The present study was conducted to investigate the effect of sunflower mulch at different levels on the subsurface resistance (Q) and on the LLWR in a completely randomized factorial design. Experiments were performed to improve the condition of soil moisture range at three levels of sunflower mulch and five levels of moisture with three replications. Q was measured by a laboratory automatic microprocessor by adjusting the depth and velocity of the device cone in the soil. The moisture content in Q critical for control treatment (without mulch) and treatment with sunflower mulch (10 and 20 tons per hectare) occurred in 28.4%, 22% and 19.1% by volume, respectively. The critical moisture content (Q) of 10 and 20 tons of mulch per hectare treatment decreased by 6.4 and 9.3%, respectively, compared to the control treatment. This decreasing trend means an improvement in the moisture content at critical Q (2 MPa). The moisture content in the Q critical of the 20-tons mulch per ha treatment has decreased by 2.9% compared to the 10-ton mulch treatment per hectare. This means that better results are obtained by increasing the amount of mulch per hectare. The LLWR for control treatment and 10 and 20 tons mulch per hectare was calculated to be 5.11, 9.09 and 9.17% by volume, respectively. This increasing of moisture content in LLWR indicates the positive performance of sunflower mulch.