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    An Assessment of Inherent Chemical Properties of Soils for Balanced Fertilizer Recommendations for Cocoa in Ghana
    (2018-04-04) Ekwe L. Dossa; A. Arthur; W. Dogbe; Abdoulaye Mando; A. A. Afrifa; S. Acquaye
    Sustainable cocoa production in Ghana would require a shift in fertilizer recommendations from general applications to site-specific recommendations of fertilizers that account for initial fertility status and actual nutrient needs of soils on which cocoa is grown. A soil fertility survey was conducted in the major cocoa regions of Ghana covering the major benchmark soils. Two hundred and twenty four plots were sampled and composite surface soils collected and analyzed for selected fertility characteristics. The results show that most of the cocoa soils have low inherent fertility characterized by low C, N and exchange capacity. All the cocoa soils sorb P, which may limit availability of P in the soil solution. The soils generally are acidic, and soils in Western region, especially the Ferralsols, show the most acidic reaction with substantially measurable exchangeable Al. The results suggest that these differential characteristics of the surveyed soils should be considered in formulating balanced site-specific fertilizer for cocoa in Ghana.
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    Improving Fertilizer Recommendations for Cocoa in Ghana Based on Inherent Soil Fertility Characteristics
    (2018-04-04) Ekwe L. Dossa; A. Arthur; W. Dogbe; Abdoulaye Mando; D. Snoeck; A. A. Afrifa; S. Acquaye
    In Ghana, cocoa has traditionally been grown as a low input crop, which has caused soil fertility deterioration, and thus, the need to integrate fertilizer use into cocoa agricultural practices. However, fertilizers recommended to farmers are general in nature and do not account for specific crop needs and inherent soil fertility conditions. This study evaluates the use of a soil diagnosis model to determine fertilizer recommendations for cocoa based on inherent soil fertility characteristics in the cocoa growing zones of Ghana. The site-specific fertilizer formulations were tested against blanket recommendations (Asaase Wura and Cocofeed) in farmers’ settings from 2009 to 2011. The results showed that DS-formulated site-specific fertilizer performed better than all blanket fertilizers in Western soils especially on the Ferralsols which are very acidic and depleted of base cations. On the other soil conditions, the site-specific formulations were comparable to the blanket formulations. Trend analysis of cocoa response to applied fertilizer suggests that P is a major determinant of cocoa productivity and that P2O5 rates >120 kg ha−1 would be required, when justified economically, for optimal cocoa yield, while potassium could be kept at around 45 kg K2O ha−1. In view of these results, the cocoa fertilizer formulas proposed for western regions of Ghana could be revised according to the DS model recommendations by taking into consideration the optima presented above. For the other cocoa regions, the DS would not be economic and therefore, proposed formulas should keep P2O5 and K2O around the optima above-presented while compensating for nutrients exported by the crop.
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    Soil Fertility Management in Sub-Saharan Africa
    (2017-05-04) Cargele Masso; Generose Nziguheba; James Mutegi; Corinne Galy-Lacaux; Wendt John; Klaus Butterbach-Bahl; Lydia Wairegi; Anjan Datta
    Most of the population in sub-Saharan Africa depends on agriculture for livelihood, which is mainly practiced by resource-constrained smallholder farmers. Due to persistent low crop yields, food and nutrition insecurity, farmers have been opening new lands through deforestation or encroachment into marginal lands where possible, seeking for additional yields, which has aggravated soil erosion, land degradation , and eutrophication of water bodies. Adoption of integrated soil fertility management practices in the smallholder farming systems has been affected by several factors including poor access to improved agricultural inputs, poor understanding of the practices and their benefits, and importantly limited financial capacity. Here we review challenges of soil fertility management in the smallholder farming systems of sub-Saharan Africa. Our major findings are: (1) most countries have not been able to meet the fertilizer target of 50 kg nutrients ha−1 by 2015 in the 2006 Abuja Declaration; over 65% of the smallholder farmers have not used fertilizer and 75% of the agricultural soils have been affected by nutrient depletion. (2) Poor agricultural practices have resulted in an average annual nutrient loss of 50 kg ha−1, which represented an equivalent of US$ four billion lost in 2008 and an estimated economic cost of up to 18% of the gross domestic product in addition to eutrophication of water bodies. (3) Value cost ratios of agricultural inputs that are less than three are common, which has limited the profitability of integrated soil fertility management practices. (4) Proliferation of fake agricultural inputs has been reported in over 40–60% of the cases as a consequence of poor enforcement of quality standards. (5) In addition to blanket recommendations, fertilization has focused on nitrogen, phosphorus and potassium, with little emphasis on secondary and micro-nutrients as well as organic amendments or liming materials in acid soils, which has generally resulted in poor crop responses or low yield increments. (6) Effective adoption of integrated soil fertility management would result in at least doubling the current nutrient agronomic use efficiency in the smallholder farming systems and reduction of the actual yield gap averaged to more than 300% for cereal and legume crops. Based on these findings, operationalization of supportive policies to increase adoption of good agronomic practices and investment in research to develop solutions appropriate to smallholder farmers should be recommended.
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    Innovations in Indian Seed/Biotech Industry'
    (2014-05-05) Carl E. Pray; Latha Nagarajan
    Innovations from public sector research and development (R&D), which were spread by public sector seed corporations were an essential component of the Green Revolution. The modern varieties of rice, wheat, and coarse grains increased food production in India, helped millions of people come out of poverty, and made India self-sufficient in grain production. Now, however, rapid growth in per capita income and population growth in India are pushing up the demand for vegetables, fruits, and coarse grains to feed livestock. The demand for the basic food grains such as rice and wheat is growing too, ifnot as rapidly, and global prices for all agricultural commodities have increased. At the same time, the growth in yields ofbasic food grains in the most productive areas of India such as Punjab is slowing down. Fortunately, unlike in the early period of the Green Revolution, the private sector is now making major investments in R&D, and so, India no longer has to rely entirely on innovative new varieties from the public sector or from the international agricultural research institutes such as the International Rice Research Institute. The objectives of this chapter are three-fold:(i) to assess the current innovation system in the seed and biotechnology sector;(ii) to identify the investments in public agricultural research and innovation; and (iii) to reflect on the policies supporting private research and innovations so that farmers can have the innovative new cultivars1 that they need to meet the rapidly increasing
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    Improving Modeling of Nutrient Cycles in Crop Cultivation
    (2019-12-01) Upendra Singh; Cheryl H. Porter
    Agricultural productivity depends on crops receiving adequate amounts of essential nutrients from the atmosphere, soils, and/or supplied fertilizers and manures. Through the biogeochemical cycling of nutrients, fertile soils supply the following essential nutrients to plants: nitrogen (N), phosphorus (P), potassium (K), sulfur (S), calcium (Ca), magnesium (Mg), iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), boron (B), molybdenum (Mo), cobalt (Co), and nickel (Ni). Deficiency of any of these nutrients results in lower productivity. In Europe, North America, and many parts of Asia, the agricultural practice of depleting soil nutrient reserves (nutrient mining) for farming ceased several decades ago. Unfortunately, nutrient mining continues in many developing countries, particularly in Sub-Saharan Africa.