The Experts below are selected from a list of 91938 Experts worldwide ranked by ideXlab platform
Bernard Vanlauwe - One of the best experts on this subject based on the ideXlab platform.
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integrated Soil Fertility management operational definition and consequences for implementation and dissemination
Outlook on Agriculture, 2010Co-Authors: Bernard Vanlauwe, Andre Bationo, Jonas N Chianu, Kenneth E. Giller, Roel Merckx, U Mokwunye, O Ohiokpehai, Pieter Pypers, Ramadjita Tabo, Keith D ShepherdAbstract:Traditional farming systems in sub-Saharan Africa depend primarily on mining Soil nutrients. The African Green Revolution aims at intensifying agriculture through dissemination of Integrated Soil Fertility Management (ISFM). In this paper we develop a robust and operational definition of ISFM, based on detailed knowledge of African farming systems, their inherent variability, and optimal use of nutrients. We define ISFM as: A set of Soil Fertility management practices that necessarily include the use of fertilizer, organic inputs, and improved germplasm, combined with the knowledge on how to adapt these practices to local conditions, aiming at maximizing agronomic use efficiency of the applied nutrients and improving crop productivity. All inputs need to be managed following sound agronomic principles. The integration of ISFM practices into farming systems is illustrated by dual-purpose grain-legume‐maize rotations in the savannahs and fertilizer micro-dosing in the Sahel. Finally, the dissemination of ISFM practices is discussed.
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popular myths around Soil Fertility management in sub saharan africa
Agriculture Ecosystems & Environment, 2006Co-Authors: Bernard Vanlauwe, K E GillerAbstract:The aim of this paper is to demystify some of the popular myths related to tropical Soil Fertility management that have gained hold in the development community and are often being promulgated by NGO's and development agencies in the tropics. Negative nutrient balances at farm scale or at larger scales are very often presented as proof that Soil Fertility is at stake in SSA. However, nutrient balances at plot and farm section scale are not always negative. In areas with large nutrient stocks, short-term nutrient mining is fully acceptable. Fertilizer use continues to face considerable controversy in SSA. In this paper, we demonstrate that fertilizers rarely damage the Soil; that fertilizers are being used in SSA, often with favourable value-to-cost ratios; and that fertilizers do not cause eutrophication in SSA. Rock phosphates are abundantly present in SSA but most are poorly soluble. Adding these phosphates to compost heaps does not enhance the short-term availability of their P. Although organic inputs are essential Soil amendments besides fertilizer, organic inputs alone cannot sustain crop production due to limitations in their quality and availability. Organic resources can also potentially stimulate harmful pests and diseases. Legumes are often advocated as important sources of organic matter but not all legumes fix nitrogen, require inoculation, or are a source of free nitrogen, as even green manures require land and labour. Certain grain legumes with high N harvest indices do not improve Soil Fertility, but remove net amounts of N from the Soil. These myths need correction if we are to harness the role of science in the overall goal of assisting farmers to address the acute problems of poor Soil Fertility for smallholder farmers in SSA.
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exploring diversity in Soil Fertility management of smallholder farms in western kenya ii within farm variability in resource allocation nutrient flows and Soil Fertility status
Agriculture Ecosystems & Environment, 2005Co-Authors: Bernard Vanlauwe, Keith D Shepherd, P A Tittonell, P A Leffelaar, K E GillerAbstract:Strong gradients of decreasing Soil Fertility are found with increasing distance from the homestead within smallholder African farms, due to differential resource allocation. As nutrient use efficiency varies strongly along these gradients, such heterogeneity must be considered when designing Soil management strategies, aimed at an improved overall resource use efficiency at farm scale. Here, we quantify the magnitude and study the origin of farmer-induced, within-farm Soil Fertility gradients as affected by biophysical and socio-economic conditions, and investigate farmers’ perceptions of such heterogeneity. Farm transects, participatory resource flow mapping, farmers’ classification of land qualities, and Soil sampling for both chemical and spectral reflectance analyses were performed across 60 farms in three sub-locations (Emuhaia, Shinyalu, Aludeka)
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long term integrated Soil Fertility management in south western nigeria crop performance and impact on the Soil Fertility status
Plant and Soil, 2005Co-Authors: Bernard Vanlauwe, Jan Diels, N Sanginga, Roel MerckxAbstract:Crop response, tree biomass production and changes in Soil Fertility characteristics were monitored in a long-term (1986–2006) alley-cropping trial in Ibadan, Nigeria. The systems included two alley cropping systems with Leucaena leucocephala and Senna siamea on the one hand and a control (no-trees) system on the other hand, all cropped annually with a maize- cowpea rotation. All systems had a plus and minus fertilizer treatment. Over the years, the annual biomass return through tree prunings declined steadily, but more drastically for Leucaena than for Senna. In 2002, the nitrogen contribution from Leucaena residues stabilized at about 200 kg N/ha/year, while the corresponding value for Senna was about 160 kg N/ha/year. On average, the four Leucaena prunings were more equal in biomass as well as in amounts of N, P and cations, while the first Senna pruning was always contributing up to 60% of the annual biomass or nutrient return. Maize crop yields declined steadily in all treatments, but the least so in the Senna + fertilizer treatment where in 2002 still 2.2 t/ha of maize were obtained. Nitrogen fertilizer use efficiency was usually higher in the Senna treatment compared to the control or the Leucaena treatment. Added benefits due to the combined use of fertilizer N and organic matter additions were observed only for the Senna treatment and only in the last 6 years. At all other times, they remained absent or were even negative in the Leucaena treatments for the first 3 years. Most chemical Soil Fertility parameters decreased in all the treatments, but less so in the alley cropping systems. The presence of trees had a positive effect on remaining carbon stocks, while they were reduced compared to the 1986 data. Trees had a positive effect on the maintenance of exchangeable cations in the top Soil. Exchangeable Ca, Mg and K – and hence ECEC – were only slightly reduced after 16 years of cropping in the tree-based systems, and even increased in the Senna treatments. In the control treatments, values for all these parameters reduced to 50% or less of the original values after 20 years. All the above points to the Senna-based alley system with fertilizers as the more resilient one. This is reflected in all Soil Fertility parameters, in added benefits due to the combined use of fertilizer nitrogen and organic residue application and in a more stable maize yield over the years, averaging 2.8 t/ha with maximal deviations from the average not exceeding 21%.
Cees Leeuwis - One of the best experts on this subject based on the ideXlab platform.
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Farmers’ Perceptions as a Driver of Agricultural Practices: Understanding Soil Fertility Management Practices in Cocoa Agroforestry Systems in Cameroon
Human Ecology, 2020Co-Authors: Urcil P. Kenfack Essougong, Maja Slingerland, Syndhia Mathé, Wouter Vanhove, Precillia I. Tata Ngome, Philippe Boudes, Ken E. Giller, Lotte S. Woittiez, Cees LeeuwisAbstract:In Africa, cocoa yields are low, partly due to Soil Fertility constraints and poor management. While peoples’ knowledge, aspirations, and abilities are key factors explaining their behaviour, little is known about the rationales that underpin Soil Fertility management practices (SFMPs) of cocoa farmers. To address this gap, we conducted an exploratory survey in two contrasting regions in Cameroon where cocoa is an important crop: the humid forest and the forest-savannah transition zone. Some 30% of farmers in the transition zone as opposed to 13% in the humid forest expressed concerns about Soil Fertility. The most relevant Soil Fertility indicators for farmers were high cocoa yield, dark Soil colour, ease of tillage, and floral composition. To enhance and maintain Soil Fertility, farmers used residues from weeding (100%), planting of trees (42%), mineral fertilisers (33%), compost (16%), and manure (13%). More farmers in the transition zone than the humid forest implemented SFMPs. Our findings suggest that Soil Fertility perceptions, access to inputs, local practices, and experience influence farmers’ use of SFMPs. The limited use of mineral fertilisers was explained by poor access whereas the use of organic fertilisers and tree planting were mostly constrained by lack of labour and knowledge. Farmers prioritised practices to increase yield and viewed SFMPs to be the least important management practices, although they believe high cocoa yield is an important indicator of Soil Fertility. To foster sustainable cocoa intensification, it is necessary to enhance farmers’ knowledge on SFMPs, increase access to inputs, and ensure returns on investment while considering farmers’ priorities and practices.
R O Barnard - One of the best experts on this subject based on the ideXlab platform.
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influence of plant density on variability of Soil Fertility and nutrient budgets in low input east african highland banana musa spp aaa ea cropping systems
Nutrient Cycling in Agroecosystems, 2013Co-Authors: T Ndabamenye, B Vanlauwe, P J A Van Asten, G Blomme, Rony Swennen, B Uzayisenga, J G Annandale, R O BarnardAbstract:The productivity of East African highland (EAH) banana cropping systems is declining, particularly in areas with low inherent Soil Fertility. Soil Fertility management requires knowledge of nutrient flows at the interface between the Soil surface and the Soil system. The magnitude of Soil Fertility dynamics and nutrient depletion was studied for a short-term banana plant density trial in three contrasting agro-ecological sites of Rwanda (Kibungo low rainfall with medium Soil Fertility, Rubona high rainfall with low Soil Fertility and Ruhengeri high rainfall with high Soil Fertility) using nutrient stock and partial nutrient balance calculations. Plant density did not influence significantly nutrient mass fractions in plant parts (fruit, leaves and pseudostems) but nutrients contained through shredded leaves and pseudostems and those removed through bunch dry matter increased with plant density. Plant density responses to variation in Soil Fertility and partial nutrient balances seemed to depend on diversity in climate and Soil type. Partial N and K balances (kg ha−1 year−1) were estimated to be strongly negative at Rubona and Ruhengeri while Ca and Mg were positive at Kibungo and Ruhengeri but negative at Rubona. This study showed that partial nutrient balances associated with Soil nutrient stocks can provide the first order of magnitude of nutrient depletion in low input EAH banana cropping systems. This brings attention from agricultural researchers and farmers to develop options that can improve the productivity of these systems, where resource availability for improved nutrient management is scarce.
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Influence on plant density on variability of Soil Fertility and nutrient budgets in low input East African highland banana (Musa spp. AAA-EA) cropping systems
'Springer Science and Business Media LLC', 2013Co-Authors: Ndabamenye T, Vanlauwe B., J G Annandale, Van Asten P, Blomme G, Swennen Rony, Uzayisenga B, R O BarnardAbstract:The productivity of East African highland (EAH) banana cropping systems is declining, particularly in areas with low inherent Soil Fertility. Soil Fertility management requires knowledge of nutrient flows at the interface between the Soil surface and the Soil system. The magnitude of Soil Fertility dynamics and nutrient depletion was studied for a short-term banana plant density trial in three contrasting agro-ecological sites of Rwanda (Kibungo low rainfall with medium Soil Fertility, Rubona high rainfall with low Soil Fertility and Ruhengeri high rainfall with high Soil Fertility) using nutrient stock and partial nutrient balance calculations. Plant density did not influence significantly nutrient mass fractions in plant parts (fruit, leaves and pseudostems) but nutrients contained through shredded leaves and pseudostems and those removed through bunch dry matter increased with plant density. Plant density responses to variation in Soil Fertility and partial nutrient balances seemed to depend on diversity in climate and Soil type. Partial N and K balances (kg ha -1 year -1 ) were estimated to be strongly negative at Rubona and Ruhengeri while Ca and Mg were positive at Kibungo and Ruhengeri but negative at Rubona. This study showed that partial nutrient balances associated with Soil nutrient stocks can provide the first order of magnitude of nutrient depletion in low input EAH banana cropping systems. This brings attention from agricultural researchers and farmers to develop options that can improve the productivity of these systems, where resource availability for improved nutrient management is scarce. © 2013 Springer Science+Business Media Dordrecht.status: publishe
Jan Diels - One of the best experts on this subject based on the ideXlab platform.
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a semi quantitative approach for modelling crop response to Soil Fertility evaluation of the aquacrop procedure
The Journal of Agricultural Science, 2015Co-Authors: H Van Gaelen, Alemtsehay Tsegay, Nele Delbecque, Nirman Shrestha, Magali Garcia, Hector Fajardo, Roberto Miranda, Eline Vanuytrecht, Berhanu Abrha, Jan DielsAbstract:Most crop models make use of a nutrient-balance approach for modelling crop response to Soil Fertility. To counter the vast input data requirements that are typical of these models, the crop water productivity model AquaCrop adopts a semi-quantitative approach. Instead of providing nutrient levels, users of the model provide the Soil Fertility level as a model input. This level is expressed in terms of the expected impact on crop biomass production, which can be observed in the field or obtained from statistics of agricultural production. The present study is the first to describe extensively, and to calibrate and evaluate, the semi-quantitative approach of the AquaCrop model, which simulates the effect of Soil Fertility stress on crop production as a combination of slower canopy expansion, reduced maximum canopy cover, early decline in canopy cover and lower biomass water productivity. AquaCrop's Fertility response algorithms are evaluated here against field experiments with tef (Eragrostis tef (Zucc.) Trotter) in Ethiopia, with maize (Zea mays L.) and wheat (Triticum aestivum L.) in Nepal, and with quinoa (Chenopodium quinoa Willd.) in Bolivia. It is demonstrated that AquaCrop is able to simulate the Soil water content in the root zone, and the crop's canopy development, dry above-ground biomass development, final biomass and grain yield, under different Soil Fertility levels, for all four crops. Under combined Soil water stress and Soil Fertility stress, the model predicts final grain yield with a relative root-mean-square error of only 11–13% for maize, wheat and quinoa, and 34% for tef. The present study shows that the semi-quantitative Soil Fertility approach of the AquaCrop model performs well and that the model can be applied, after case-specific calibration, to the simulation of crop production under different levels of Soil Fertility stress for various environmental conditions, without requiring detailed field observations on Soil nutrient content.
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long term integrated Soil Fertility management in south western nigeria crop performance and impact on the Soil Fertility status
Plant and Soil, 2005Co-Authors: B Vanlauwe, Jan Diels, N Sanginga, Roel MerckxAbstract:Crop response, tree biomass production and changes in Soil Fertility characteristics were monitored in a long-term (1986–2002) alley-cropping trial in Ibadan, Nigeria. The systems included two alley cropping systems with Leucaena leucocephala and Senna siamea on the one hand and a control (no-trees) system on the other hand, all cropped annually with a maize–cowpea rotation. All systems had a plus and minus fertilizer treatment. Over the years, the annual biomass return through tree prunings declined steadily, but more drastically for Leucaena than for Senna. In 2002, the nitrogen contribution from Leucaena residues stabilized at about 200 kg N/ha/year, while the corresponding value for Senna was about 160 kg N/ha/year. On average, the four Leucaena prunings were more equal in biomass as well as in amounts of N, P and cations, while the first Sennapruning was always contributing up to 60% of the annual biomass or nutrient return. Maize crop yields declined steadily in all treatments, but the least so in the Senna + fertilizer treatment where in 2002 still 2.2 tonnes/ha of maize were obtained. Nitrogen fertilizer use efficiency was usually higher in the Senna treatment compared to the control or the Leucaena treatment. Added benefits due to the combined use of fertilizer N and organic matter additions were observed only for the Sennatreatment and only in the last 6 years. At all other times, they remained absent or were even negative in the Leucaenatreatments for the first 3 years. Most chemical Soil Fertility parameters decreased in all the treatments, but less so in the alley cropping systems. The presence of trees had a positive effect on remaining carbon stocks, while they were reduced compared to the 1986 data. Trees had a positive effect on the maintenance of exchangeable cations in the top Soil. Exchangeable Ca, Mg and K – and hence ECEC – were only slightly reduced after 16 years of cropping in the tree-based systems, and even increased in the Senna treatments. In the control treatments, values for all these parameters reduced to 50% or less of the original values after 16 years. All the above points to the Senna-based alley system with fertilizers as the more resilient one. This is reflected in all Soil Fertility parameters, in added benefits due to the combined use of fertilizer nitrogen and organic residue application and in a more stable maize yield over the years, averaging 2.8 tonnes/ha with maximal deviations from the average not exceeding 21%.
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long term integrated Soil Fertility management in south western nigeria crop performance and impact on the Soil Fertility status
Plant and Soil, 2005Co-Authors: Bernard Vanlauwe, Jan Diels, N Sanginga, Roel MerckxAbstract:Crop response, tree biomass production and changes in Soil Fertility characteristics were monitored in a long-term (1986–2006) alley-cropping trial in Ibadan, Nigeria. The systems included two alley cropping systems with Leucaena leucocephala and Senna siamea on the one hand and a control (no-trees) system on the other hand, all cropped annually with a maize- cowpea rotation. All systems had a plus and minus fertilizer treatment. Over the years, the annual biomass return through tree prunings declined steadily, but more drastically for Leucaena than for Senna. In 2002, the nitrogen contribution from Leucaena residues stabilized at about 200 kg N/ha/year, while the corresponding value for Senna was about 160 kg N/ha/year. On average, the four Leucaena prunings were more equal in biomass as well as in amounts of N, P and cations, while the first Senna pruning was always contributing up to 60% of the annual biomass or nutrient return. Maize crop yields declined steadily in all treatments, but the least so in the Senna + fertilizer treatment where in 2002 still 2.2 t/ha of maize were obtained. Nitrogen fertilizer use efficiency was usually higher in the Senna treatment compared to the control or the Leucaena treatment. Added benefits due to the combined use of fertilizer N and organic matter additions were observed only for the Senna treatment and only in the last 6 years. At all other times, they remained absent or were even negative in the Leucaena treatments for the first 3 years. Most chemical Soil Fertility parameters decreased in all the treatments, but less so in the alley cropping systems. The presence of trees had a positive effect on remaining carbon stocks, while they were reduced compared to the 1986 data. Trees had a positive effect on the maintenance of exchangeable cations in the top Soil. Exchangeable Ca, Mg and K – and hence ECEC – were only slightly reduced after 16 years of cropping in the tree-based systems, and even increased in the Senna treatments. In the control treatments, values for all these parameters reduced to 50% or less of the original values after 20 years. All the above points to the Senna-based alley system with fertilizers as the more resilient one. This is reflected in all Soil Fertility parameters, in added benefits due to the combined use of fertilizer nitrogen and organic residue application and in a more stable maize yield over the years, averaging 2.8 t/ha with maximal deviations from the average not exceeding 21%.
K E Giller - One of the best experts on this subject based on the ideXlab platform.
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effect of farmer management strategies on spatial variability of Soil Fertility and crop nutrient uptake in contrasting agro ecological zones in zimbabwe
Nutrient Cycling in Agroecosystems, 2010Co-Authors: E N Masvaya, J Nyamangara, R W Nyawasha, Shamie Zingore, Robert J Delve, K E GillerAbstract:Variability of Soil Fertility within, and across farms, poses a major challenge for increasing crop productivity in smallholder systems of sub- Saharan Africa. This study assessed the effect of farmers' resource endowment and nutrient manage- ment strategies on variability in Soil Fertility and plant nutrient uptake between different fields in Gokwe South (ave. rainfall *650 mm year -1 ; 16.3 per- sons km -2 ) and Murewa (ave. rainfall *850 mm year -1 ; 44.1 persons km -2 ) districts, Zimbabwe. In Murewa, resource-endowed farmers applied manure ((3.5 t ha -1 year -1 ) on fields closest to their home- steads (homefields) and none to fields further away (outfields). In Gokwe the manure was not targeted to any particular field, and farmers quickly abandoned outfields and opened up new fields further way from the homestead once Fertility had declined, but homefields were continually cultivated. Soil available P was higher in homefields (8-13 mg kg -1 ) of resource-endowed farmers than on outfields and all fields on resource constrained farms (2-6 mg kg -1 ) in Murewa. Soil Fertility decreased with increasing distance from the homestead in Murewa while the reverse trend occurred in Gokwe South, indicating the impact of different Soil Fertility management strategies on spatial Soil Fertility gradients. In both districts, maize showed deficiency of N and P, implying that these were the most limiting nutrients. It was concluded that besides farmers' access to resources, the direction of Soil Fertility gradients also depends on agro-ecological conditions which influence resource management strategies.
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popular myths around Soil Fertility management in sub saharan africa
Agriculture Ecosystems & Environment, 2006Co-Authors: Bernard Vanlauwe, K E GillerAbstract:The aim of this paper is to demystify some of the popular myths related to tropical Soil Fertility management that have gained hold in the development community and are often being promulgated by NGO's and development agencies in the tropics. Negative nutrient balances at farm scale or at larger scales are very often presented as proof that Soil Fertility is at stake in SSA. However, nutrient balances at plot and farm section scale are not always negative. In areas with large nutrient stocks, short-term nutrient mining is fully acceptable. Fertilizer use continues to face considerable controversy in SSA. In this paper, we demonstrate that fertilizers rarely damage the Soil; that fertilizers are being used in SSA, often with favourable value-to-cost ratios; and that fertilizers do not cause eutrophication in SSA. Rock phosphates are abundantly present in SSA but most are poorly soluble. Adding these phosphates to compost heaps does not enhance the short-term availability of their P. Although organic inputs are essential Soil amendments besides fertilizer, organic inputs alone cannot sustain crop production due to limitations in their quality and availability. Organic resources can also potentially stimulate harmful pests and diseases. Legumes are often advocated as important sources of organic matter but not all legumes fix nitrogen, require inoculation, or are a source of free nitrogen, as even green manures require land and labour. Certain grain legumes with high N harvest indices do not improve Soil Fertility, but remove net amounts of N from the Soil. These myths need correction if we are to harness the role of science in the overall goal of assisting farmers to address the acute problems of poor Soil Fertility for smallholder farmers in SSA.
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exploring diversity in Soil Fertility management of smallholder farms in western kenya ii within farm variability in resource allocation nutrient flows and Soil Fertility status
Agriculture Ecosystems & Environment, 2005Co-Authors: Bernard Vanlauwe, Keith D Shepherd, P A Tittonell, P A Leffelaar, K E GillerAbstract:Strong gradients of decreasing Soil Fertility are found with increasing distance from the homestead within smallholder African farms, due to differential resource allocation. As nutrient use efficiency varies strongly along these gradients, such heterogeneity must be considered when designing Soil management strategies, aimed at an improved overall resource use efficiency at farm scale. Here, we quantify the magnitude and study the origin of farmer-induced, within-farm Soil Fertility gradients as affected by biophysical and socio-economic conditions, and investigate farmers’ perceptions of such heterogeneity. Farm transects, participatory resource flow mapping, farmers’ classification of land qualities, and Soil sampling for both chemical and spectral reflectance analyses were performed across 60 farms in three sub-locations (Emuhaia, Shinyalu, Aludeka)
