Volume 10, Issue 3

Coffee Response to Liming in the Acid Soils of Tanzania: Pilot Study in Three Agro-ecological Zones
Original Research
A pilot study was undertaken to establish the response of Arabica and Robusta coffee to liming in the acid coffee soils of Tanzania, and its applicability to smallholder coffee farmers. It involved three field trials at Lyamungu (Hai) and Mbimba (Mbozi) for Arabica coffee, and Maruku (Bukoba) for Robusta. In each site, two side-by-side trials were laid out under Randomized Complete Block Design (RCBD), six treatments replicated three times. Random soil samples were taken and pH-water measured at 1:2.5 soil-water ratio. Lime requirement was determined using the barium chloride-triethanolamine titration method and regressed against the pH values. The ensuing linear trendline equations were used to calculate the standard lime requirements (LR), and treatments were assigned in the order 0.0LR, 0.25LR, 0.5LR, 0.75LR, 1.0LR and 1.5LR. Methods were top-dressing and incorporation to at least 10cm depth. Change in soil pH, growth characteristics and 3-year yield data were collected, rearranged to fit a split-plot design where methods were considered as sub-factors, and exposed to ANOVA and mean separation by Tukey’s HSD method using CoStat software. The change in pH reflected the dosage of lime used. Dosages were highly significant in Mbimba, and very highly significant in Lyamungu and Maruku, showing an added advantage of liming. Mean yields increased in the order Robusta new (313-426 kg ha-1) < Arabica new (988-1347 kg ha-1) < Arabica superimposed (1252-1815 kg ha-1). This study has unveiled the hitherto unrealized hurdles of lime application among smallholders; including complexities in lime requirement determination, availability and quality of liming materials, methods and uniformity of application. While research is underway to determine a simple but accurate LR determination method and explore the interaction between lime and phosphorus, mulch and manure/compost, smallholder coffee farmers should adopt a CAN/MRP regime rather than direct liming.
World Journal of Agricultural Research. 2022, 10(3), 94-101. DOI: 10.12691/wjar-10-3-5
Pub. Date: November 08, 2022
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Morphological Characterization of Baobab Fruit (Adansonia Digitata L.) in Makueni, Taita Taveta, Kilifi and Kwale Counties in Kenya
Original Research
Baobab (Adansonia digitata L.) is a multipurpose tree with a long lifespan which grows throughout sub-Saharan Africa in the semi-arid and humid regions. The Fruit pulp, which is an important part, is used by locals as a food additive and at times the pulp is consumed directly by children and adults. In Kenya, the fruit pulp is consumed directly in some parts of the country while other parts of the country, mostly coastal regions add value to it and sell to earn an income. Baobab’s natural habitat is under threat yet both the morphological and genetic diversity is not well documented. The aim of this study was to determine morphological characteristics of baobab fruit in Makueni, Taita Taveta, Kilifi and Kwale counties. Sixty-four trees (one tree per farm) were randomly selected, and 10 fruits were picked that were used for morphological characterization using 29 qualitative and 15 quantitative descriptors modified from those given for mango by the International Plant Genetic Resources Institute (IPGRI). The results indicated ellipsoid fruit shape was dominant (2.0-3.6) with acute apex (2.8-6.4) and slightly-oblique (4.0-8.4). Baobab fruit had perceptible fruit beak (ranging 4.4-10.0). The results also showed hierarchical clustergram in terms of hair, color, surface, shell hairness and shell surface texture whereby Kilifi and Kwale were clustered together and differed from Makueni and Taita Taveta. In terms of shell hardness to crack, most of the baobab was hard (6.0-8.0) with intermediate adherence of fibre to fruit (6.0-8.0) and intermediate amount of fibre in fruit (2.4-6.0). The seed shape was very reinformed (2.0-9.6), coarse seed testa texture and hard seed testa. The results indicated that fruit length ranged from 12.18-25.06cm, fruit diameter from 7.10-9.08cm. Fruit weight ranged 101.74-319.16g, fibre weight (1.86-5.17G0 and shell weight (46.30-159.68g).
World Journal of Agricultural Research. 2022, 10(3), 82-93. DOI: 10.12691/wjar-10-3-4
Pub. Date: November 02, 2022
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The Nitrogen and Phosphorus Release Potential of Selected Organic Materials Applied to Three Contrasting Soils of Kilimanjaro Region
Original Research
The nutrient release potential of selected types of organic materials available in a coffee farming system was studied with three contrasting soils of Kilimanjaro Region, to broaden the ISFM options. An incubation experiment was conducted at TaCRI Lyamungu screenhouse between June and November 2019. The design was split plot RCD, three soil types Humi-Umbric Nitisols from Lyamungo, Eutric Cambisols from Kilacha and Humi-Rhodic Luvisols from Kikafu Chini as main factors, and different organic additives (cattle manure and leaves of Tithonia diversifolia, Tephrosia vogelii, Vernonia subligera and Adhatoda engleriana) as sub-factors. The organics were dried, crushed, sieved in a 6 mm sieve, mixed with the soils at 2% organic to soil ratio, moistened to field capacity and incubated in 10 litre plastic containers at room temperature. Duplicate soil samples were taken at day 0, 3, 8, 15, 26, 45, 74, 112 and 180 and analyzed for NH4-N, NO3-N, and available P. The total amounts of nutrients released during the incubation period were subjected to Analysis of Variance using COSTAT Statistical Software, with means separated by Tukey’s HSD at p ≤ 0.05. The nutrient release trends were more or less the same in all the three soil types. In terms of NH4-N, NO3-N and P, soil types, additives and their interactions were very highly significant (p < 0.001). In all the soil types, the four organics are fairly comparable to manure and can be used as its substitute. It was noted that soils differ in their responsiveness to organic treatments. Also unveiled was the potential of the wild plants such as Adhatoda, available in the wilderness around Mt. Kilimanjaro and Usambaras, which could be domesticated and planted at hedgerows for ISFM purposes. It also encourages the use of the semi-domesticated hedgerow plants like Tithonia and Vernonia; and Tephrosia as temporary shade plants.
World Journal of Agricultural Research. 2022, 10(3), 76-81. DOI: 10.12691/wjar-10-3-3
Pub. Date: October 24, 2022
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Biomass Production of Brachiaria ruzizienzis and Crotalaria retusa in Different Cropping Systems on an Andic Ferralsol in Western Highlands of Cameroon
Original Research
Benefits associated with cover crops in direct seeding mulch-based cropping systems (DMC) often depend on the establishment of a highly productive cover crop community. The objective of this study was to assess biomass production for the implementation of DMC and its efficiency based on Land Equivalent Ratios (LER) of Brachiaria ruziziensis and Crotalaria retusa grown in different cropping systems on an Andosol in the Western Highlands of Cameroon. The six treatments were pure stands and combinations of one or two lines of each cover crop. These were assigned to experimental units in a randomized complete bloc design with four replications. Biomass production, ability to start DMC and Land Equivalent Ratios (LER) were used to compare treatments. B. ruziziensis produced 10.51 t DM ha-1 in pure stands and 2.9 to 5.37 t DM ha-1 in intercropping. C. retusa produced 5.03 t DM ha-1 in pure stands and 2.88 to 5.28 t DM ha-1 in intercropping. There were highly significant differences (p < 0.01) among treatments for total biomass production. Biomass production was significantly higher when two lines of B. ruziziensis were associated with a single line of C. retusa. Intercropping one line of B. ruziziensis and one line of C. retusa was the only combination that could not allow the implementation of DMC the following season. LER larger than 1 for the other intercropping indicated their superiority compared to pure stands. Growing B. ruziziensis and C. retusa during the first season with one line of one species and two lines of the other species, or two lines of each crop species were considered appropriate for the implementation of DMC. Results provided a basis for DMC implementation using intercropping of B. ruziziensis and C. retusa as cover crops during the first cropping season. Further studies are necessary to evaluate the residual effects of the biomass produced.
World Journal of Agricultural Research. 2022, 10(3), 70-75. DOI: 10.12691/wjar-10-3-2
Pub. Date: October 22, 2022
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Prevalence and Genetic Determinism of Viviparity in the Bottle Gourd Lagenaria siceraria (Molina) Standley (Cucurbitaceae)
Original Research
Viviparity or early germination of seeds in fruits still attached to the parent plant is a factor in yield reduction and economic loss in agriculture. Lagenaria siceraria (Molina) Standl. is a plant of nutritional, medicinal and agronomic importance facing a decrease in production due to viviparity. The objective of this work was to study the genetic determinism of viviparity in L. siceraria. Eight accessions (4 viviparous and 4 non-viviparous) resulting from a screening of 100 accessions of two cultivars (Calabash and Egussi) of L. siceraria were used in direct and reciprocal crosses. Self-fertilisation of F1 progeny resulted in F2 progeny. Four field experiments in six cycles yielded the different individuals of each generation used in this study. Results indicated that accessions of the gourd cultivar were non-viviparous. The majority (96.67%) of accessions of the cultivar Egussi were viviparous and were present in all agro-ecological collection areas. F1 plants from direct and reciprocal crosses were all non-viviparous. Self-fertilization of F1 plants led to F2 progeny in 3:1 segregation (3 for non-viviparous and 1 for viviparous). The non-viviparous phenotype appeared dominant over the viviparous phenotype. Seed viviparity is controlled by a gene, with an allele pair (V/v). Plants with non-viviparous fruits can be, VV or Vv. Plants with viviparous fruits are vv.
World Journal of Agricultural Research. 2022, 10(3), 64-69. DOI: 10.12691/wjar-10-3-1
Pub. Date: October 22, 2022