Browsing by Author "Maghembe, J. A"
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Item Dry-season sesbania fallows and their influence on nitrogen availability and maize yields in Malawi(Kluwer Academic Publishers., 2001) Ikerra, S. T; Maghembe, J. A; Smithson, P. C; Buresh, R. JNitrogen deficiency is widespread in southern Africa, but inorganic fertilizers are often unaffordable for smallholder farmers. Short-duration leguminous fallows are one possible means of soil fertility restora- tion. We monitored preseason topsoil (0 to 20 cm) ammonium and nitrate, fallow biomass production and grain yields for three years in a relay cropping trial with sesbania [Sesbania sesban (L.) Merr.] and maize (Zea mays L.). Sesbania seedlings were interplanted with maize during maize sowing at 0, 7400 or 14,800 trees ha –1 , in factorial combination with inorganic N fertilizer at 0 or 48 kg N ha –1 (half the recommended rate). After maize harvest, fallows were allowed to grow during the seven-month dry season, and were cleared before sowing the next maize crop. Both sesbania fallows and inorganic N fertilizer resulted in significantly greater (P < 0.01 to 0.05) preseason topsoil nitrate-N than following unfertilized sole maize. In plots receiving no fertilizer N, preseason topsoil inorganic N correlated with maize yield over all three seasons (r 2 = 0.62, P < 0.001). Sesbania fallows gave significantly higher maize yields than unfertilized sole maize in two of three years (P < 0.01 to 0.05). Sesbania biomass yields were extremely variable, were not significantly related to sesbania planting density, and were inconsistently related to soil N fractions and maize yields. Short-duration fallows may offer modest yield increases under conditions where longer duration fallows are not possible. This gain must be considered against the loss of pigeonpea (Cajanus cajan L. Millsp) harvest in the similarly structured maize-pigeonpea intercrop common in the region.Item Effect of hot water and chemical treatments on the germination of Albizia schimperana seed(Elsevier Science Publishers B.V, 1986-03) Msanga, H. P; Maghembe, J. AThe effect of water temperature at soaking and various chemical applications following soaking on the germination of Albizia schimperana seed was studied. The aim was to increase the overall germination percentage and to hasten the rate at which germination occurs. The water soaking treatments included: (1) no soaking; (2) soaking at 50°C; (3) soaking at 75°C; and (4) soaking at 99°C. The chemical treatments included; (1) no chemical applied; (2) immersion in KNO3; (3) immersion in H2O2; and (4) combined in a factorial arrangement replicated 4 times. Germination percentages were generally low, ranging from 10.0 to 33.5% at 36 days after sowing. The highest germination percentage (33.5%) was attained by seeds which were soaked in water at 75°C followed by immersion in hydrogen peroxide. Seeds which were soaked in water at this temperature but not treated with chemicals showed a germination of 32.0%. It is preliminary recommended that seeds of A. schimperana be immersed in water at the initial temperature of 75°C and allowed to soak until the water cools to room temperature.Item Growth and ectomycorrhizal development of pinus caribaea seedlings inoculated with basidiospores of scleroderma dictyosporum in fertilized nursery soil in Tanzania(Elsevier, 1984-01) Maghembe, J. A; Redhead, J. FSeeds of Pinus caribaea were sown in plastic pots containing nursery soil with or without a basidiospore inoculum of Scleroderma dictyosporum. After seedling establishment, five fertilizer treatments involving 0, 250, 500, 750 and 1000 g NPK per m3 of nursery soil were administered. The ratio of N:P:K in NPK was 3:3:1.Basidiospores of S. dictyosporum were an effective inoculum for P. caribaea seedlings. Inoculated seedlings showed superior growth in height, root collar area, length of stem with needles and dry matter production. Inoculation also increased the concentration of P in the plant tissues but had no effect on other nutrients studied.Fertilizer response was evident, but there were generally no benefits of using fertilizer levels above 250 g NPK per m3 soil. In fact, mycorrhizal development was progressively reduced with each increase in the level of NPK fertilizer. Tissue Mg concentrations were also deficient, a reflection of nutrient uptake imbalance due to high concentrations of ammonium sulphate and potassium chloride in the soil. Basidiospores of S. dictyosporum can therefore be used for routine inoculation of P. caribaea seedlings in nursery soils at low levels of NPK. Coincidentally such a reduction in the amount of NPK applied in nursery soil will have both biological as well as economic benefitsItem Insects feeding on Sesbania species in natural stands and agroforestry systems in southern Malawi(Kluwer Academic, 2012-04) Sileshi, G.; Maghembe, J. A; Rao, M. R; Ogol, C. K. P. O; Sithanantham, S.Pest and disease interactions in agroforestry systemsis a little studied area.Surveys were conducted in the Mangochi and Zomba districts of southern Malawi between December 1997 and February 1998 to identify insects feeding on Sesbania species in natural stands and in agroforestry systems at the research station and on farms, and the host range of the insects. Out of a total of 30 insect species recorded in natural stands, Brachyplatys testudonigro, Mesoplatys ochroptera, Exosoma sp. and Ootheca sp. were the most commonly found insects feeding on S. sesban. Afrius figuratus, Glypsus conspicuus, Macrorhaphis acuta, Mecosoma mensor, Rhinocoris segmentarius and Cyaneodinodes faciger were recorded for the first time as natural enemies of Mesoplatys ochroptera in Malawi. The defoliating beetles, M. ochroptera, Exosoma sp. and Ootheca sp., were the most frequently found insects infesting S. sesban on farms. M. ochroptera attacked only Sesbania species, and usually higher populations of this beetle were recorded on annual Sesbania species (S. tetraptera, S. bispinosa, S. leptocarpa and S. sericea) than on perennial types. Although the sap-sucking bug, B. testudonigro, was relatively less common on sesbania on farms, it has been found to infest a number of other legumes of the genera Aeschynomene, Crotalaria, Desmodium, Indigofera, Mucuna, Phaseolus, Tephrosia and Vigna. Given the wide variety of plant species it attacks, B. testudonigro may become a potential pest of many agroforestry tree species. The insects Anoplocnemis curvipes, Aphis fabae, Hilda patruelis, Megaleurothrips sjostedti, Mylabris dicincta, Nezara viridula and Ootheca sp. also have the potential to become pests of agroforestry systems, as they can damage many agroforestry trees, including Sesbania, and crops. There is a need to study the biology and ecology of potential insect pests of S. sesban to plan for their integrated management in agroforestry.Item Intercropping, weeding and spacing effects on growth and nutrient content in Leucaena leucocephala at Morogoro, Tanzania(Elsevier, 1986-03) Maghembe, J. A; Kaoneka, A. R. S; Lulandala, L. L. LThe study was conducted to evaluate the suitability of Leucaena leucocephala for fuelwood and pole production using agroforestry in a semiarid environment. The trial site, planted in February 1980 at Mafiga, Morogoro, was a split plot design with four main plots: (1) Leucaena intercropped with maize; (2) Leucaena intercropped with beans; (3) Leucaena monoculture and clean weeded; and (4) Leucaena monoculture and spot weeded. Each main plot included three tree-spacing sub- plots, 3 X 3 m, 4 X 4 m and 5 × 5 m, and replicated four times. Each of the subplots comprised at least 25 trees. Twenty-four trees representing all the diameter classes in the trial were harvested in March 1984 and used to determine mean plot height, volume and biomass by regression analysis. Nutrient content was determined using routine laboratory methods. Mean subplot height varied from 7.0 to 7.8 m, whereas diameter at the stem base varied from 10.2 to 14.9 cm. The volume varied from 10.3 to 32.8 m 3 ha -~ and total biomass values from 13.5 to 31.1 metric t ha -1. Trees under spot weeding showed the poorest growth, whereas those under clean weeding showed the best. Spacing influenced both diameter and height growth, with the widest spacing producing the largest trees. Because of a higher tree population, however, the lowest spacing showed the highest volume and biomass production. Intercropping with maize and beans showed significantly higher volume and biomass production as compared to spot weeding. However, there was no significant difference between trees under clean weeded treatments and those under intercropping. Nutrient concentra- tions were high and comparable to other pasture legumes. The total nutrient accumulation in the aerial biomass in kg ha- 1 was 201, 25.1,267, 106, 34 and 18 for nitrogen, phosphorus, potassium, calcium, magnesium and sodium, respectively.Item Plant species in the Kilimanjaro agroforestry system(Martinus Nijhoff/Dr W. Junk, 1984) O'kting'ati, A; Maghembe, J. A; Fernandes, E. C. M; Weaver, G. HAn inventory of plant species was conducted on farms, farm boundaries and homesteads in the Kilimanjaro agroforestry system. The survey covered 30 farms in 6 villages in Hal District on the slopes of Mount Kilimanjaro, Tanzania. Over 100 plant species spread over 40 families were identified and their uses obtained through inter- views with farmers. The species identified include 53 tree species, 29 food crop species, 21 non-woody plants of economic value and 8 weed species. The food crops, trees and other economically useful plants are carefully chosen by the local farmers and intimately intercropped on the same unit of land. In most cases, the plants had two or more uses of which food, fuelwood, medicine, poles, timber and fodder were the most important.