East African Agricultural and Forestry Journal最新文献

{"title":"Effectiveness of the Wofost Simulation Model to Predict Maize Yield Gaps on the Eastern Slopes of Mt Kenya","authors":"S. Wokabi","doi":"10.4314/eaafj.v69i2.1815","DOIUrl":"https://doi.org/10.4314/eaafj.v69i2.1815","url":null,"abstract":"ABSTRACT The World Food Studies (WOFOST) model was applied to predict 3 production levels of maize on the eastern slopes of Mt Kenya in Embu District. Production level 1 used location, temperature, cloudiness and crop characteristic data to calculate the production potential level of a crop, all other factors remaining optimal. At this production situation only temperature and radiation were limiting factors. This is the crop-time and site-specific maximum obtainable yield under ideal conditions of water and nutrient availability as well as optimum management and input levels. Environment requirements of climate, soil and water for optimum growth and yield vary with crop and crop variety. Production situation 2 analysed the crop production when an additional land quality, the availability of moisture, was limiting. This production situation uses temperature, radiation and moisture as the main limiting factors. Production situation 3 analysed crop production when an additional variable, the nutrient availability is limiting. This situation uses temperature, radiation, water availability and availability of plant nutrients as determining variables. A medium maturity maize (Zea mays L) variety H 511 was used as the test crop during two cropping seasons in 1992–93. Triple superphosphate (TSP) at the rate of 75 kg P/ha and 75 kg N/ha were applied during planting and when the crop was knee high, respectively. Maize yield was also obtained from farmers' fields. Four yield levels were selected for yield gap analysis, namely potential yield, water limited, experimental and farmers' yields. Potential and water-limited grain yield of maize obtained via the application of WOFOST model compared relatively well with the yield obtained from the experimental plots. This means that if soil and climate conditions of a given area are known, the maize production of the area can be determined accurately using WOFOST model.","PeriodicalId":11421,"journal":{"name":"East African Agricultural and Forestry Journal","volume":"40 1","pages":"139 - 147"},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88651709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Emergence of Forage Legume Seedlings as Influenced by Water Potential and Soil Strength","authors":"D. Njarui, L. Bahnisch, B. O'Hagan, B. So","doi":"10.4314/eaafj.v69i1.1803","DOIUrl":"https://doi.org/10.4314/eaafj.v69i1.1803","url":null,"abstract":"ABSTRACT The effects of water potential and soil strength on seedling emergence of 3 forage legume species, desmanthus (Desmanthus virgatus CPI 91146), glycine (Glycine latifolia CQ 3368) and cowpea (Vigna unguiculata cv. Red Caloona) were studied in red-brown earth and black earth under a controlled temperature in a growth chamber. 3 water potentials, -10, -300 and -750 kPa were applied in both soils. To achieve the desired levels of water potential, the soils were placed in columns of dialysis membrane and suspended in polyethylene glycol (PEG) solutions (molecular weight 10,000) of different concentrations until equilibrium was maintained making sure that the soil did not come in contact with PEG. Soil strength increased with decreased water potential and the effect was more rapid in red-brown earth than in black earth. Seedling emergence black earth occurred at water potentials of-10 and—300 kPa (soil strength of 0.64 and 1.98 kg/cm2 respectively) while in the red-brown earth seedling emergence was restricted to—10 kPa (soil strength of 1.75 kg/cm2). However, cowpea showed a greater emergence force by emerging at water potential of -750 kPa (soil strength 2.66 kg/cm2) in the black earth and at -300 kPa (soil strength of 5.27 kg/cm2) in the red-brown earth. Time to emergence increased with decreasing water potential and increased soil strength. Seedling emergence was rapid at both 0.64 and 1.75 kg/cm2 and delayed above this soil strength. It was concluded that low water potential and high soil strength restrict seedling emergence.","PeriodicalId":11421,"journal":{"name":"East African Agricultural and Forestry Journal","volume":"34 1","pages":"29 - 38"},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85051601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic Structure and Population Diversity of Mummy Berry (Monilinia) Collections from the United States of America and Canada","authors":"L. Wasilwa, P. Oudemans, J. S. Lehman","doi":"10.4314/eaafj.v68i3.1786","DOIUrl":"https://doi.org/10.4314/eaafj.v68i3.1786","url":null,"abstract":"Blueberry belongs to the genus Vaccinium of the Ericaceae family (Hancock, 1995). It is one of most recent fruits developed in the Americas and one of a handful of fruit indigenous to this region. The four agriculturally important sections of Vaccinium are blueberries (subgenus Cyanococcus), cranberries (Oxycoccus), lingonberries (Vitisidaea) and billberries (Myrtillus). Wild cranberries, lingonberries and billberries are found in North America and Europe. The four species of cultivated blueberry are highbush (V. cotymbosum), lowbush (V. myrtilloides Michx. and V. angustifolium) and rabbiteye (V. ashie Reade). Highbush blueberry is the most economically important blueberry species (Hancock, 1995).","PeriodicalId":11421,"journal":{"name":"East African Agricultural and Forestry Journal","volume":"48 1","pages":"125 - 134"},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90227791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Soil Fertility Management Strategies on Diversity and Populations Soil Macrofauna in an Agroecosystem","authors":"F. Ayuke, M. Rao, M. Swift, M. Opondo-Mbai","doi":"10.4314/eaafj.v69i2.1814","DOIUrl":"https://doi.org/10.4314/eaafj.v69i2.1814","url":null,"abstract":"ABSTRACT The role of soil invertebrate fauna in decomposition of organic residues and thus nutrient release, soil structure and soil-water relations is well appreciated. The scope, however, of their manipulation to derive the potential benefits is little understood. A study was undertaken to assess how soil fertility management strategies within an agroforestry system affect soil biodiversity (macrofauna diversity and populations). The study was conducted on-farm during the 1997 Short Rains (Oct 1997—Feb 1998) in western Kenya with the following treatments: (1) control without any input, (2) fertilizer at 120 kg N, 150 kg P and 100 kg K/ha, (3) Tithonia diversifolia biomass at 5 t/ha dry weight and (4) Senna spectabilis at 5 t/ha dry weight. Riparian natural forest and a 6-year grassland fallow were assessed and used as reference standards. Macrofauna diversity and populations were monitored in soil monoliths (25 × 25 × 30 cm) at the beginning of the season, 6 weeks after sowing maize and at maize harvest. Faunal diversity was assessed using the Shannon-Wiener index of diversity (H'). Data were subjected to analyses of variance (ANOVA) in a split-plot design and treatment differences evaluated using least significance difference (LSD) at P=0.05. Macrofauna diversity and populations of most of the macrofauna groups were significantly higher under natural forest (H' = 2.31) than in all the other treatments (each H' = < 1). Although the 2 organic residues did not affect faunal diversity, addition of senna significantly increased earthworm population by 400% and tithonia by 240% over the control. Even though termite population increased by 145% in senna and 118% in tithonia over the control, the increase was not significant because of high variability between replications of the same treatment. Fertiliser use did not change either the diversity or population of termites and earthworms. The study indicates that: (1) Short-term addition of organic residues do not significantly increase faunal diversity, (2) Soil invertebrate fauna populations can be manipulated by external additions of organic residues such as senna and (3) Changes in land use systems, especially those that reduce the amount, range and diversity of food resources for macrofauna bring about instability in below ground biodiversity. There is therefore a need to clearly define the conditions in which such impairment is critically important to agricultural production and sustainability and to determine what management interventions may be made to alleviate or ameriolate problems resulting from loss of diversity.","PeriodicalId":11421,"journal":{"name":"East African Agricultural and Forestry Journal","volume":"106 1","pages":"131 - 137"},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88096780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Organic and Inorganic Fertilisers on Maize and Traditional Vegetable Yields in Kisii Highlands","authors":"E. Okoko, F. Makini, J. Mureithi","doi":"10.4314/eaafj.v69i1.1809","DOIUrl":"https://doi.org/10.4314/eaafj.v69i1.1809","url":null,"abstract":"ABSTRACT One of the major problems facing resource-poor small-scale farmers producing maize and traditional vegetables in Kenya is a decline in soil fertility. During participatory rural appraisal (PRA) exercises undertaken in Bogetaorio village, Nyamira District, Kenya, farmers attributed low yields of maize and traditional vegetables to declining soil fertility as a result of continuous cropping, burning of crop residues and soil erosion. The PRA further showed that farmers in the region applied low quantities of organic and inorganic fertilisers because of their high costs. A study was therefore started during the Short Rains of 1995 to address the problem of low crop production by improving soil fertility. The objectives of this study were to determine: 1) the effect of both organic and inorganic fertilisers on yield of maize and traditional vegetables and 2) low cost fertilisers for recommendation to farmers in the study area. The treatments varied according to test crops and included varying rates of farm yard manure (FYM) combined with inorganic fertiliser. Application of organic/inorganic fertiliser treatment combinations significntly increased soil nutrient status over the experimental period. The level of soil P, Ca, and K increased by over 70%. The fertiliser treatment combinations generally gave similar yields to the recommended rate of inorganic P and N fertilisers and gave higher yields than FYM/compost treatments alone. In 1998, the combination treatments of 10 t/ha compost + 15 kg P2O5/ha + 15 kg N/hagave a maize yield of 7.8 t/ha, which was significantly higher (P<0.05) than yields from the other treatments and was within the range of potential maize yield (7.2–9.0 t/ha) in the region. The fertiliser treatment combinations also increased yield of traditional vegetables significantly (P=0.05) compared to FYM applied alone. Thus, a combination of organic and reduced rates of inorganic fertilisers may be a promising low cost option to the use of the recommended rate of inorganic fertiliser for maize and vegetable production.","PeriodicalId":11421,"journal":{"name":"East African Agricultural and Forestry Journal","volume":"12 1","pages":"89 - 98"},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90096473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Effects of Accel and Carbaryl on Fruit Set and Fruit Quality of Three Apple Cultivars","authors":"G. Ouma, F. Matta","doi":"10.4314/eaafj.v68i4.1795","DOIUrl":"https://doi.org/10.4314/eaafj.v68i4.1795","url":null,"abstract":"Apple trees set more fruit than needed for a full crop. They will retain this heavy set of fruit throughout the growing season resulting in small, poorly coloured low quality fruit. It is important to thin apple fruit to achieve optimum fruit growth and enhance tree vigour. With a heavy crop 70-80% of the fruit may have to be removed. Chemical fruit thinning of apple (Malus pumila Mill) following bloom is a standard practice to improve fruit size, quality, increase return bloom and reduce biennial bearing (Williams, 1979; Looney, 1986). An apple tree with excessive fruit produces many small, low value fruit. In contrast a tree that is over thinned and only has few fruit does not produce to its maximum potential. Insufficient thinning may also lead to alternate bearing, whereby an extremely heavy crop is produced every year. Different factors affect success of thinning apples. Several chemicals such as Vydate, Sevin, NAA (1-napthaleneacetic acid) and Accel are used in different combinations to yield the best results.","PeriodicalId":11421,"journal":{"name":"East African Agricultural and Forestry Journal","volume":"436 1","pages":"183 - 190"},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77826992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Provenance Selection of Eucalyptus Microtheca for Afforestation in Arid and Semi-Arid Areas","authors":"Chunyang Li","doi":"10.4314/eaafj.v68i3.1785","DOIUrl":"https://doi.org/10.4314/eaafj.v68i3.1785","url":null,"abstract":"In Australia, the natural distribution of Eucalyptus species is strongly influenced by the resistance of seedlings to drought. Survival strategies in response to water deficit at the initial seedling growth phase have been studied (Bachelard 1986; Wang et al., 1988; Davidson and Reid, 1989; Myers. and Landsberg, 1989; Gibson and Bachelard, 1994; Gibson et al., 1991, 1994, 1995; Lemcoff et al., 1994; Anderson et al., 1996). Some of the adaptive responses to water deficit cause changes in plant structure, growth rates, water use efficiency, tissue osmotic potential and stomatal conductance among others. (Jones, 1992).","PeriodicalId":11421,"journal":{"name":"East African Agricultural and Forestry Journal","volume":"26 1","pages":"119 - 123"},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87337141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of Nutritive Value and Some Functional Properties of Kerstings Groundnut Seeds for Optimum Utilisation as a Food and Feed Resource","authors":"M. Obasi, A. Agbatse","doi":"10.4314/eaafj.v68i4.1794","DOIUrl":"https://doi.org/10.4314/eaafj.v68i4.1794","url":null,"abstract":"Nigeria, like most African countries, faces a serious food crisis, manifest in the inadequate protein intake of its people (Ogundipe and Weingartner, 1992). The staple food in Niger is largely derived from starchy tubers, roots and their products which . are usually deficient in protein. Adequate quantities of protein from animal sources and from legumes such as cowpea (Vigna unguiculata (L.) Walp), soya bean (Glycine max (L.) Merr.) and pigeon pea (Cajanus cajan (L.) Mill sp.) are not usually included in the diet because of their prohibitive cost (Singh et al., 1987, Ogundipe and Osho, 1990). Protein sources are in high demand by the poultry, swine and ruminant feed industry in Nigeria due to a significant decline in the production of cotton and the harsh economic situation which restricts the purchase of soya bean meal. It is therefore necessary to search for additional high-quality and cheaper sources of legume protein to provide adequate food and nutrition in Nigeria and in most developing countries. Alternatives to these situations are not easily found, but a possibility is provided by utilisation of the lesser-known, under-exploited grain legumes which have not been used to an important extent because their nutritive importance has not been fully determined. Among these, kerstings groundnut (Kerstingiella geocarpa Harms) offers good possibilities. Its yield ranges from 350 to 650 kg seed/ha in farmers field, although yields up to 1500 kg seed/ha have been reported in Rhodesia (now Zimbabwe) (Joan, 1976). These yields compare well with yields of pigeon pea of 500 to 1600 kg seed/ha. Kerstings groundnut seeds contain polyphenols, the usual anti-nutrient substances of food grain legumes. To be used as food or feed, the seeds would have to be thermally processed to reduce anti-nutritional substances in the seed (Singh, 1984; Bressani and Elias, 1980; Obasi, 1996). Studies on Kerstings groundnut show that it is a promising legume for the tropics (Hepper, 1963; Duke et al., 1977; Ikeorgu, 1988; Obasi and Ezedima, 1991, 1994; Obasi, 1989). This crop is cultivated in tropical Africa, particularly in Nigeria, Mali, Burkina-Faso, Niger, Benin and Togo and is boiled or ground into a paste for making moi-moi (steamed paste food) or alcara (fried paste food) in a manner similar to the consumption of cowpea.","PeriodicalId":11421,"journal":{"name":"East African Agricultural and Forestry Journal","volume":"25 1","pages":"173 - 181"},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85584578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Selection Intensity and Generation Interval in a Flock of Yankasa Sheep","authors":"O. Momoh, L.N. Nwakalor, B. Abubakar, O. Osinowo","doi":"10.4314/eaafj.v68i3.1789","DOIUrl":"https://doi.org/10.4314/eaafj.v68i3.1789","url":null,"abstract":"Selection has been a frequent quantitative genetic technique used in livestock improvement programmes. The amount of genetic improvement that can be made by selection depends on the selection applied, the heritability of the trait, the average genetic variation and covariation of all traits directly or indirectly related to the traits under selection and the average age of parents when their offspring are born.","PeriodicalId":11421,"journal":{"name":"East African Agricultural and Forestry Journal","volume":"302 1","pages":"147 - 153"},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77184610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inorganic Resources Management for Sustainable Soil Productivity","authors":"J. Okalebo","doi":"10.4314/eaafj.v69i2.1813","DOIUrl":"https://doi.org/10.4314/eaafj.v69i2.1813","url":null,"abstract":"ABSTRACT Most cropland soils in East Africa and the tropics are in general highly weathered, leached and deficient in plant nutrients particularly nitrogen and phosphorus. Over the past 80 years or so, efforts have been made within the region to seek ways and means of building the levels of these 2 nutrients in soils with an overall goal of increasing and sustaining crop productivity. In general, positive crop responses to inorganic fertilisers or resources have been obtained. This paper summarises findings related to some aspects of the management of inorganic resources. These include the use of specific resources, rates, timing and methods of application, towards improved productivity. It is suggested that economic analysis of crop yield and other data are important considerations for future research. An unfavourable economic environment contributes to lack or slow adoption of fanning technologies in the developing world.","PeriodicalId":11421,"journal":{"name":"East African Agricultural and Forestry Journal","volume":"44 1","pages":"119 - 129"},"PeriodicalIF":0.0,"publicationDate":"2003-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73712996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}