IMPACT OF ADDING BIOGAS LIQUID SLURRY ON SOIL SURFACE ON PENETRATION RESISTANCE

In this study, the impact of adding biogas liquid slurry (BLS) on soil surface on soil penetration resistance (soil cone index) was investigated. The soil penetration resistance was measured using two types of penetrometers: a hand-held type and a hammer type. The BLS application rates were 0, 2, 4 and 6 lit/m². The BLS was spread on the soil surface three days before measurements. The soil penetration resistance was measured up to a 20 cm depth in no-till sandy clay loam soil. The statistical analysis showed that the effects of the BLS application on the soil penetration resistance were significantly different (P 0.05). The highest penetration resistance value was found in the control application (no BLS applied) and the lowest value was obtained in the BLS application of 6 lit/m². The average values of soil penetration resistance measured by the two types of penetrometers within the penetration depth profile of 0–20 cm for the control treatment were 3756 kPa (hand-held type) and 3743 kPa (hammer-type). The lower soil penetration resistances were measured as 2315 kPa (hand-held type) and 2394 kPa (hammer- type) at a BLS application rate of 6 lit/m². The results also showed that the soil penetration resistance was affected by BLS application rate and the penetration depth, and this effect can be predicted using the models generated from the study (within the investigated range of the variables). It could be concluded that adding BLS to the soil surface reduced soil penetration resistance, which may improve root growth and distribution. In addition, the study concluded that the effects of BLS application on soil properties and soil strength over longer periods should be further studied.