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, WUE_cwu (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 of water 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, WUE_cwu 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 treatments were soil (S), dewatered faecal sludge (DFS), municipal solid waste 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 ha⁻¹ respectively. Maize cv. Abelehii was grown in a poly bag filled with 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 WUE_cwu and was 11% and 4 times higher than that for NPK + (NH₄)₂SO₄ or soil alone; and 18-36% higher than those for DFS and CO. Treatment ECO used less amount of water to produce dry matter yield (DMY) and grain yield (GY) that was 5.2% and 12.6%, respectively, higher than NPK + (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 WUE_cwu accounts for 99% of the variations in GY. Thus, the study concluded that different sources of fertiliser increased TE and WUE_cwu of maize differently as N application rate increases.     

Effects of Algae and Shell Pigment Extract‐supplemented Diets on Shell Pigmentation and Growth Performance of Pacific Abalone,Haliotis discus hannai

To improve shell pigmentation and growth performance of Pacific abalone, five extruded diets were prepared by supplementing a formulated control diet with 3% each of three species of algae (Pacific dulse, Porphyra yezoensis, Spirulina) and a pigment extract from the abalone shells (0.02%). Each of the five diets and a commercial feed were randomly assigned to three containers each stocked with 1000 juvenile Pacific abalone (2 g per individual) in a flow‐through seawater system for a 5‐mo feeding trial. Test results showed: (1) all the supplements significantly (P < 0.05) increased percentages of dark‐brown shelled abalone in the test treatments, relative to the control treatment; (2) the abalone fed the experimental diets achieved significantly (P < 0.05) greater final weight, shell‐length growth rates, and higher meat protein contents than those fed the commercial feed (P < 0.05); and (3) the abalone fed the Spirulina‐supplemented diet achieved the best overall growth, pigmentation performances, and feed conversion ratio; and the Pacific dulse supplement generated the highest protein content in abalone meat product (P < 0.05) among the tested diets. These results demonstrate the potential of locally made feed, which can generate desirable characteristics in abalone under aquaculture conditions.     

Comparison of tiletamine-zolazepam-ketamine and tiletamine-zolazepam-ketamine-xylazine anaesthesia in sheep

Summary The anaesthetic effects of intravenous tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg (TK) and tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg-xylazine 0.11 mg/kg (TKX) were evaluated in six wethers. Heart rate, respiration rate, arterial blood pressure, and the electrocardiogram were monitored during anaesthesia. Analgesia was tested by electrical stimulation in the left flank. Atropine (0.03 mg/kg) was given intramuscularly before induction, but after recording of baseline heart rate and respiratory rate. The duration of analgesia was 28.7 ± 6.9 min with TK and 82.8 ± 26.6 min with TKX. Heart rate increased significantly within 5 min after TK or TKX administration. Respiratory rate remained unchanged after TK administration, but increased significantly from 5 to 45 min after TKX administration. Arterial blood pressure decreased significantly at 15 min with TK and 30 min with TKX. Sheep remained recumbent for 201 min with TK and 166 min with TKX. All recovered uneventfully. We conclude that either TK or TKX may be used for anaesthetising sheep.     

Adonis microcarpa (pheasant''s eye) toxicity in pigs fed field pea screenings

Seed of Adonis microcarpa (pheasant's eye) fed at 5.6 g/kg of the diet induced virtually total feed refusal within 3 d in growing and finishing pigs. It also caused vomiting, rapid and shallow breathing and death in a minority. These effects were probably caused by cardiac glycosides whose structure and effects closely resemble those of digoxin. Feed intake and growth recovered within 2 weeks of removal of the seed.