1,721,079 research outputs found
Performance evaluation of various agroforestry species used in short duration improved fallows to enhance soil fertility and sorghum yields in Mali
Get PDFThe general soil fertility and crop yield decline constraints have guided the Malian agricultural research institute (Institut d’ Economie Rurale, IER), the Sahel Program of the World Agroforestry Centre (ICRAF) and the International Crops Research Institute for the Semi Arid Tropics (ICRISAT) to join efforts and undertake research activities aimed at mitigating the constraints in Mali. Thus, from the year 2000, 14 different trees and shrubs are being tested in improved fallow systems to find which ones perform best to replenish soils and improve crop yields. The results have (i) identified most suited species for 1 or 2 yr improved fallows, (ii) determined their impact on sorghum grain yields and (iii) documented the remnant effects of their impact on soil fertility and crop yields..
Improving soil fertility through the use of organic and inorganic plant nutrient and crop rotation in Niger
Get PDFFood production can be increased through the integration of organic and inorganic nutrient sources coupled with proper land management. Niger is one of the poorest countries in the Sahelian zone of West Africa where soil fertility and rainfall are the most limiting factors for crop production. The majority of the people in this region depend on subsistence agriculture for their livelihood. The population pressure has decreased the availability of arable land and the use of extended fallow periods to restore soil fertility is not possible.
Research results have shown that yields can be increased up to five times with the improvement of soil fertility using a combination of soil tillage, organic and inorganic fertilizers than under traditional practice. Crop yields have also been shown to increase substantially using rotation of cereals with legume or intercropping. Yields of pearl millet can be doubled following cowpea as compared to continuous pearl millet cultivation. These combinations can improve soil properties such as Organic carbon content, Cation Exchange Capacity (CEC) and pH..
Overview of long term experiments in Africa
Get PDFThe prevailing low food production in sub-Saharan Africa is an issue of great concern especially since Africa south of the Sahara is the only remaining region of the world where per capita food production has remained stagnant. This chapter reviews long-term experiments in Africa in the context of shifting paradigms related to tropical soil fertility management from first external input paradigm right through to the current Integrated Soil Fertility Management (ISFM) approach, which is a culmination of the participatory methods developed along the paradigm shift. Long term experiments (LTE) are an important source of evidence for soil fertility decline and provide crucial datasets for the development of sustainable management practices for tropical land-use systems and the amelioration of global climatic and environmental change impacts. A survey was undertaken to identify some ongoing long-term trials distributed across east, south and western Africa and in different agro-ecological zones. A long-term Experiment was defined as that extending over a period of over 5 years and more. Results from these trials are discussed in detail. Inference has been drawn from these findings and includes the following key findings: a) All long term trials showed yield decline, often with a relatively rapid fall to a low level equilibrium; b) At all sites, there were positive yield responses to one or more nutrients added as mineral fertilizers, which were consistent for the duration of the experiments highlighting the effectiveness of mineral fertilizers in increasing yield in arable farming systems in Africa; c) Soil organic matter (SOM) also declines significantly when land is cultivated; d) Prolonged treatments using only inputs of organic matter also showed yield declines, although the positive impact were sustained longer than for inorganic fertilizers alone in most cases; e) Rotational treatments, including sequences with legume crops and fallow periods had lower yield declines than monocultures; f) The best results invariably were those treatments that combined inorganic and organic input
Improving cereal productivity and farmers’ income using a strategic application of fertilizers in West Africa
Get PDFIn the past two years, ICRISAT, in collaboration with other International Agricultural Research Centres, National Agricultural Research and Extension Systems, has been evaluating and promoting point or hill application of fertilizer along with “Warrantage” in three West African countries, namely, Burkina Faso, Mali and Niger. The hill application of fertilizers consists of applying small doses of fertilizer in the planting hills of millet and sorghum. The combination of strategic hill application of fertilizer with complementary institutional and market linkages, through an inventory credit system (known as “Warrantage”) offers a good opportunity to improve crop productivity and farmers’ incomes. Results from the two year on-farm trials showed that, on average, in all the three countries, grain yields of millet and sorghum were greater by 44 to 120% while incomes of farmers increased by 52 to 134% when using hill application of fertilizer than with the earlier recommended fertilizer broadcasting methods and farmers’ practice. Substantial net profits were obtained by farmers using “Warrantage”. Farmers’ access to credit and inputs was improved substantially through the “Warrantage” system. The technology has reached up to 12650 farm households in the three countries and efforts are in progress to further scale-up and out the technology to wider geographical area
Fertilizer microdosing and “Warrantage” or inventory credit system to improve food security and farmers’ income in West Africa
Get PDFThe fertilizer microdosing technology deals with the application of small quantities of fertilizers in the planting hole, thereby increasing fertilizer use efficiency and yields while minimizing input costs. In drought years, microdosing also performs well, because larger root systems are more efficient at finding water, and it hastens crop maturity, avoiding late-season drought. Recent research found that solving the soil fertility problem unleashes the yield potential of improved millet varieties, generating an additional grain yield of nearly the same quantity. Recognizing that liquidity constraints often prevent farmers from intensifying their production system, the warrantage or inventory credit system helps to remove barriers to the adoption of soil fertility restoration. Using a participatory approach through a network of partners from the National Agricultural Research and Extension Systems (NARES), non-governmental organizations (NGOs), farmers and farmer groups and other international agricultural research centres, the microdosing technology and the warrantage system have been demonstrated and promoted in Burkina Faso, Mali, and Niger during the past few years with encouraging results. Sorghum and millet yields increased by up to 120%, and farmers’ incomes went up by 130% when microdosing was combined with the warrantage system. This chapter highlights the outstanding past results and the ongoing efforts to further scale up the technology using Farmer field schools (FFS) and demonstrations, capacity and institutional strengthening, private sector linkages and crop diversification amongst other approache
Long-Term Soil Fertility Trials in Niger, West Africa
Get PDFSoils of tropical Africa have been formed mainly from Pre-Cambrian materials and others from erosion process. Because of the type of parent material, the soils are characterized by poor native fertility surface crusting and low water holding capacity.
In Africa 65% of the agricultural land, 31% of the permanent pasture land, and 19% of the forest and woodland is affected by human-induced soil degradation. Nutrient depletion is the most important element in the land degradation equation.
With increasing population pressure on the land, the traditional farming system (natural fallow) to restore soil fertility is no longer possible. The present farming systems are unsustainable and destructive to the environment with negative plant nutrient balances resulting to mining of nutrients.
Many long term trials show that although application of mineral fertilizers is an effective mean of increasing yields in arable farming systems, mineral fertilizers alone cannot sustain yields in the long run. When mineral fertilizers are combined with crop residue or manure, added to cereal-legume intercrops or rotated, sustainable production can be obtained.
Any future interventions redressing distorted nutrient budgets, to be sustainable have to develop an integrated nutrient management, conceptualized as the judicious manipulation of the nutrient inputs and outputs processes
Effect of Hill Placement of Nutrients on Millet Productivity and Characteristics of Sahelian Soils of Niger: Analysis of Yield Trend After Three Years of Cropping
No full textReports from implementation of the low-input mineral fertilizer microdosing technology have shown up to 120% yield increase. However on the acidic Sahelian soils (pH 4–5 (H2O)) with low carbon content (0.2%), the question is whether applying such small dose would not lead to nutrient mining over years, which ICRISAT set three studies of 3 years each to address. Experiments 1 (2003) and 2 (2008) involved three planting densities, two pearl millet varieties and four fertility management options with removal of crop residue in experiment 1. Experiment 3 (2010) involved the combinations of 4 rates of organic and mineral fertilizers and 10 millet varieties. Both organic and mineral inputs were hill-applied. In all experiments nutrient hill placement resulted in total biomass increase in the second and third years compared to the control. After 3 years of cropping, yield decrease of −2307 kg.ha−1 was observed with the control in experiment 1 between years 1 and 3, while −1238 kg.ha−1 was observed with 6 g NPK per hill which was statistically significant. In experiment 3 yield decrease was −1516 kg.ha−1 with the control and −648 kg.ha−1 with 300 g per hill of organic manure. Soil pH decreased by 0.17 in NPK amended plots whereas it decreased by 0.29 in the others as observed in experiment 1. In all case, biomass decreased but in lower amplitude with organic manure addition
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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