Effect of N-enriched co-compost on transpiration efficiency and water-use efficiency of maize (Zea mays L.) under controlled irrigation

Population growth, urban expansion and economic development are increasing competition for water use between agriculture and other users. In addition, the high rate of soil degradation and declining soil moisture in the Sub-Saharan African Region have called for several crop production management and irrigation options to improve soil fertility, reduce water use by crops and produce 'more crops per drop of water'. Notwithstanding this, considerable variations exist in the literature on water-use efficiency, WUEcwu (economic yield per water used) for maize (Zea mays L.) across climates and soil management practices. Different views have been expressed on the effect of different rates of nitrogen (N) application on transpiration efficiency, TE (biomass produced per unit ofwater transpired). The objectives of the study were to assess the effect of different rates of N-enriched municipal waste co-compost and its derivatives on TE, WUEcwu and yield of maize (Z. mays L.) in comparison to inorganic fertiliser. The greenhouse pot experiment was conducted in Accra, Ghana on a sandy loam soil (Ferric Lixisol) using a split plot design. The main plot treatmentswere soil (S), dewatered faecal sludge(DFS), municipal solidwaste compost (C),co-compost from municipal solid waste and dewatered faecal sludge (Co), compost enriched with (NH4)2SO4 (EC), co-compost enriched with (NH4)2SO4 (ECO), (NH4)2SO4 and NPK15-15-15 + (NH4)2SO4. The sub-plot treatments were different rates of application of nitrogen fertiliser applied at the rate of 91, 150 and 210 kg N ha1 respectively. Maize cv. Abelehii was grown in a poly bag filledwith 15 kg soil. Eight plants per treatment were selected randomly and used for the collection of data on growth parameters forth-nightly. At physiological maturity two plants per treatment were also selected randomly from each treatment plot for yield data. The results showed that TE of maize (Z. mays) varied for the different treatments and these are 6.9 Pa in soil (S) alone to 8.6 Pa in ECO. Increase in N application rate increased TE at the vegetative phase for fast nutrient releasing fertilisers (DFS, ECO, EC, NPK + (NH4)2SO4, (NH4)2SO4) and at the reproductive phase for slow nutrient releasing fertilisers (C and CO). Water-use efficiency increased significantly as rate of N application increased. Treatment ECO improved crop WUEcwu and was 11% and 4 times higher than that forNPK + (NH4)2SO4 or soil alone; and 18-36% higher than those for DFS and CO. Treatment ECO used less amount of water to produce drymatter yield (DMY) and grain yield (GY) that was 5.2%and 12.6%, respectively, higher thanNPK + (NH4)2SO4. Similarly, the DMY and GY for ECO was 8.9-18.5% and 23.4-34.7%, respectively, higher than DFS and CO. High nutrient (N and K) uptake, TE, and low leaf senescence accounts for 83% of the variations in DMY whereas WUEcwu accounts for 99% of the variations in GY. Thus, the study concluded that different sources of fertiliser increased TE and WUEcwu of maize differently as N application rate increases

Production and storage of N-enriched co-compost

Recovery of the organic fraction of municipal waste for peri-urban agriculture could contribute to the improvement of environmental sanitation and increase agricultural productivity in Sub-Saharan Africa. However, municipal waste co-compost (Co) has low nitrogen (N) content. Therefore, this study investigated the type and form of inorganic N fertiliser that is capable of improving the nitrogen content of Co and monitored the changes in the properties of this N-enriched product under storage. To attain 30,000 mg kg1 (3%) N content, different amounts of urea or ammonium sulphate were applied in various forms (dry, paste and liquid) to enrich Co. The product termed comlizer was stored and its moisture, pH, total nitrogen, NH2?4 -N, NO3 -N, and C/N ratio were monitored under ambient conditions for two years. In the first four months of storage, total N content of 50 kg Co + 3.26 kg urea (CoUD) increased from 31,333 to 54,000 mg kg1, and 50 kg Co + 7.14 kg (NH4)2SO4 (CoASD) from 35,333 to 52,000 mg kg1. At the end of two years of storage, the initial N content of CoUD and CoASD decreased by 47% and 24%, respectively. Based on these results, it is recommended that dry (NH4)2SO4 should be used in N enrichment of Co, and that the comlizer should be stored in sealed bags but not more than four months

Effects of co-composting of faecal sludge and agricultural wastes on tomato transplant and growth

Purpose: Faecal sludge (FS) has been co-composted with many organic solid wastes globally. Agricultural wastes, such as oil palm empty fruit bunches (EFB) and cocoa pod husks (CPH), have received very little research attention as far as combining with FS is concerned. This study aimed at co-composting these wastes at different ratios to produce safe compost for use as soilless medium for raising tomato transplants. Methods: Dewatered FS (DFS) was mixed with shredded EFB and CPH at five different ratios: 1DFS:1EFB, 1DFS:1CPH, and DFS:EFB:CPH in ratios of 1:1:1, 2:1:1, and 2:2:1 and composted for 3 months. Select physicochemical parameters and pathogens were monitored every fortnightly and 3 weeks, respectively. Results: Maximum temperatures obtained ranged 46.8–54.5 °C. Though these temperatures were lower than sanitizing temperatures prescribed by USEPA, no E. coli was found in any of the piles at the end of composting. The ratio 2DFS:2EFB:1CPH was found to be the safest formulation and hence was used to grow tomato under greenhouse conditions. Tomato seeds were sown in three different growing media: 100% FS-based compost, 100% rice husk biochar, and 50% FS-based compost–50% rice husk biochar mix. Conclusion: Results showed that FS-based compost was a suitable growing medium for tomato. Further studies into the optimal rate and frequency of application of compost teas on tomato are recommended