Fertility enhancement with biochar application is well documented for tropical acidic soils; however, benefits of biochar coapplied with synthetic fertilizers (SFs) on soil fertility are not well documented, particularly for alkaline chernozems. We examined the short-term interactive effects of woodchip biochar amendment with fertilizers on selected soil properties, available phosphorus (P), and P fractions of two alkaline Chernozems from Manitoba. Treatments were (1) urea and monoammonium phosphate fertilizers, (2) biochar at 10 g kg−1, (3) biochar at 20 g kg−1, (4) biochar at 10 g kg−1 with fertilizers, (5) biochar at 20 g kg−1 with fertilizers, and (6) a control. Treated soils were analysed for pH, electrical conductivity (EC), and Olsen P concentration biweekly, and for P fractions, cation exchange capacity (CEC), organic carbon (OC), and wet aggregate stability after 70 d of incubation. Biochar amendment without fertilizers significantly increased soil pH and CEC but had no effect on EC, while coapplication with fertilizers significantly increased Olsen P and labile P concentrations. When coapplied with fertilizers, biochar did not significantly increase soil pH relative to the control. Results suggest that biochar improved soil properties and available P in alkaline Chernozems, and the beneficial effects were enhanced when coapplied with SFs.

Antibiotic residues and bacteria resistant to antimicrobial have been found in poultry litter, which is popular low cost manure in agriculture. A study was conducted to investigate a pre-treatment method to reduce antibiotic resistant bacteria in poultry litter. Poultry litter was collected from eleven medium-scale broiler farms in Kandy. Total and antibiotic resistant (tetracycline and/or enrofloxacin) culturable bacteria were isolated using Tryptic Soy Agar supplemented with 0 or 100 ppm of each antibiotic. A fresh and a cured broiler litter sample were collected from one farm and treated with different temperatures ( 25o C, 40 o C, 60 o C and 80 o C for 24 hours), neem seed extract (10 and 1000 ppm for 4 day) and neem dry leaves (10% w/w for 4 days) in triplicates. Total and antibiotic resistant bacteria in treated litter were assessed. Broiler litter from all farms contained tetracycline resistant bacteria. Heating at 80 o C reduced tetracycline resistant bacteria by 96-100% compared to 25 o C. Neem seed extract at 10 ppm reduced tetracycline resistant bacteria by 75-96%. Treating broiler litter with high temperature (>60 o C) and neem seed extract (10 ppm) could minimize spread of antibiotic resistant bacteria to the environment.

Compost is a widely accepted organic fertiliser throughout the world. It is being produced using a wide variety of source materials at household to commercial scale. With the increased population and changes in food consumption pattern tending towards a vegetable- and meat-rich diet, the amount of organic waste generated in urban and peri-urban settings has increased. Many governments promote composting as a process that helps them to reduce the volume of organic waste and recycle nutrients back to croplands. Some examples of organic waste accumulated in large scale include household waste from urban and peri-urban settings, sewage, animal farm waste, agricultural waste from large-scale markets, food debris, and kitchen waste from hotels. The composition of compost varies in a wide range depending on the nature of materials used to produce it. The safety concerns related to compost also vary along the same line. The quality of compost has become a subjective term that means different aspects to different bodies due to a lack of commonly agreed standards to regulate the composting process and the final product itself. Recent research findings indicate that compost can serve as a carrier of potentially toxic trace elements, organic pollutants, and determinants of antimicrobial resistance to the environment and along the food chain. Producing good-quality compost safe to human health and the environment at large has become a challenge that should be addressed at various levels: from production to policymaking. This chapter discusses some of the major challenges faced in Sri Lanka with compost making. To prepare the background for this discussion, information on the policies and current practices of nutrient management in Sri Lanka is also presented. The context may be applicable to many other developing countries in the tropics.

Beneficial management practices can be used to improve the crop productivity of tropical Alfisols. This study evaluated beneficial management practices to overcome the soil physical and chemical limitations for growing maize (Zea mays). The experiment was conducted in the Low Country Dry Zone (DL1b) on Reddish Brown Earth soil (Typic Rhodustalf). Four treatments; un-amended control (C), site specific fertilizer (SSF), biochar applied at 1 t/ha with SFF (BC+SSF) and rock powder applied at 10 t/ha with SSF (RP+SSF) were tested using maize as the test crop initially in the greenhouse and later in the field at DL1b for two growing seasons (2013 Yala and 2013/2014 Maha) for their effects on crop growth and soil fertility. Soil was neutral, non-saline, sandy clay loam in texture with comparatively high clay content (27%) and low in organic matter content (1.5%) and deficient in N, P, S, Ca, Zn, and Cu, initially. In the greenhouse, plant dry weight increased significantly with the addition of amendments i.e., fertilizers alone (SSF), or BC+SSF or RP+SSF. In the field study, no significant differences were observed for soil pH with the addition of amendments but biochar application significantly increased cation exchange capacity, organic matter, potentially mineralizable nitrogen and carbon management index. Rock powder+SSF and BC+SSF significantly increased the grain yield over the control in both seasons. Both labile and recalcitrant C were significantly higher in BC+SSF treatment than the others. Further, application of BC and RP had no significant impact on soil textural fractions and bulk density, yet in both seasons, BC+SSF application increased the aggregate stability greater than other treatments. The results of the field experiment suggest that biochar and rock powder with adequate nutrients effectively improved soil fertility and productivity.

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