Liming effects of poultry litter derived biochar on soil acidity amelioration and maize growth.

Crop production in acid soils is facing enormous challenges due to low soil quality associated with an increase in the acidification rate and aluminum toxicity. Despite comprehensive prior work with biochar application on nutrient availability and crop productivity in acid soils, little information is available about the recommendation or standardization of biochar application rates that are more suitable for soil fertility improvement under different soil environments (physico-chemical properties) for maximizing the benefits of biochar applications and minimizing the potential environmental risk. Thus, the objective of this study was to investigate the effectiveness of poultry litter (PL) and poultry litter biochar (PLB) in ameliorating the fertility of acid soils through incubation and pot experiments. The soil was amended with different materials as follows; lime (1 g kg-1), PL (5, 10 and 15 g kg-1) and PLB (5, 10 and 15 g kg-1) along with control (non-amended). A pot experiment was also conducted using similar treatments to observe the responses of maize crop to the different amendments. The results indicated an increase in the pH and a decrease in exchangeable acidity in lime, PL and PLB amended soils. Lower soil pH, base cations and soil available phosphorus (P), and higher exchangeable acidity were found in control than the amended soils. Compared to PL and lime, PLB achieved greater increase rate in soil pH and reduction rate in soil exchangeable acidity with increased soil exchangeable base cations. An increase in soil available calcium (Ca) was observed in the lime treatment, while in PL and PLB treatments, there was an increase in soil available Ca, magnesium (Mg), potassium (K) and P. Application of the amendments increased availability of nitrogen (N), P, K, Ca and Mg relative to the control for maize in the pot experiment. When PL and PLB amendments were compared, it was found that the PLB was the best choice for the amelioration of acid soils as well as nutrient uptake by maize plants. It is suggested that application of PLB at the rate of 15 g kg-1 is suitable for maize growth in acid soils.

Amelioration of an Ultisol profile acidity using crop straws combined with alkaline slag.

The acidity of Ultisols (pH <5) is detrimental to crop production. Technologies should be explored to promote base saturation and liming effect for amelioration of Ultisol pH. Column leaching experiments were conducted to investigate the amelioration effects of canola straw (CS) and peanut straw (PS) in single treatment and in combination whether with alkaline slag (AS) or with lime on Ultisol profile acidity. The treatment without liming materials was set as control, and the AS and lime in single treatment are set for comparison. Results indicated that all the liming materials increase soil profile pH and soil exchangeable base cations at the 0-40-cm depth, except that the lime had amelioration effect just on 0 to 15-cm profile. The amelioration effect of the liming materials on surface soil acidity was mainly dependent on the ash alkalinity in organic materials or acid neutralization capacity of inorganic materials. Specific adsorption of sulfate (SO4(2-)) or organic anions, decarboxylation of organic acids/anions, and the association of H(+) with organic anions induced a "liming effect" of crop residues and AS on subsoil acidity. Moreover, SO4(2-) and chloride (Cl(-)) in PS, CS, and AS primarily induced base cations to move downward to subsoil and exchange with exchangeable aluminum (Al(3+)) and protons (H(+)). These anions also promoted the exchangeable Al to leach out of the soil profile. The CS was more effective than PS in decreasing soil acidity in the subsoil, which mainly resulted from higher sulfur (S) and Cl content in CS compared to PS. The CS combined with AS was the better amendment choice in practical agricultural systems.

Antinociceptive activity of Derris uliginosa.

The ethanol extract of leaves of Derris uliginosa given by oral route at dose of 250 and 500 mg/kg produced a significant inhibition on acetic acid-induced writhing in mice.