Search

The aim of this thesis was to improve understanding of the role of organic inputs and soil organic matter (SOM) for crop production in contemporary arable farming in Europe. For this purpose, long-term experiments were analysed on the additional yield effect of organic inputs and savings in mineral fertiliser. In addition, a farm survey was conducted to find drivers and barriers for the use of organic inputs and to assess if arable farmers in Europe perceive a deficiency of SOM. The findings in this thesis suggest that at least on the shorter term, on average, there seems to be no immediate threat from a deficiency of SOM to crop production in arable farming in Europe. The long-term experiments showed that with sufficient use of only mineral fertilisers, on average, similar yields could be attained over multiple years as with the combined use of organic inputs and mineral fertiliser. This was reflected in the farm survey, in which a large majority of farmers indicated not to perceive a deficiency of SOM. Analysis of long-term experiments also showed that more mineral fertiliser N was saved when using farmyard manure at high N rates (with mineral fertiliser application) than at low N rates (without mineral fertiliser application), based on comparisons at equal yield. Specific crops and environments did benefit from organic inputs and more SOM in terms of crop production. Long-term experiments showed that organic inputs give benefit to crop production in wet climates and on sandy soils. In addition, farmers perceived a higher deficiency of SOM on steep slopes, sandy soils, wet and very dry climates. The additional yield effect of organic inputs was significant for potatoes. More in general, farmers who cultivated larger shares of their land with specialized crops (including potatoes, sugar beets, onions and other vegetables) than cereals perceived a higher deficiency of SOM. It seems that while the functions of SOM can be replaced with technical means to a large extent (e.g. tillage, use of mineral fertilisers), there are limits to this technical potential when environmental conditions are more extreme and crops are more demanding. The farm survey revealed that farmers perceive a trade-off between improved soil quality on the one hand and increased pressures from weeds, pests and diseases and financial consequences on the other hand when using organic inputs. If policies aim to stimulate the maintenance or increase of SOM, more insight is needed into the conditions that regulate the pressures of weeds, pests and diseases in response to organic inputs. Financial consequences (at least on the short term) should also be accounted for. More importantly however, benefits from SOM for crop production cannot be taken for granted. Only in specific situations such benefits will exist. If European policies on SOM aim to include benefits for crop production, focus should be on areas with more extreme environmental conditions (very dry or wet climates, steep slopes, sandy soils), or cropping systems with more specialized or horticultural crops rather than cereals.

In de praktijk lopen telers vaak tegen problemen aan van een slechte bodemkwaliteit. Intensieve bouwplannen, steeds zwaardere mechanisatie, uitloging (Ca-uitspoeling), piekneerslagen en de schaalvergroting in de landbouw leiden tot vermindering van de fysische bodemvruchtbaarheid en de structuur van de bodem. Dit veroorzaakt: toenemende problemen bij de bewerkbaarheid van de bodem; minder efficiënt gebruik van meststoffen; verhoogd risico van uit- en afspoeling van nutriënten; wateroverlast; verlaging van de opbrengst. Om de bodemstructuur te verbeteren, worden door industrie en handel zogeheten bodemverbeteraars en kalkmeststoffen aangeboden. Er is een grote variatie in type producten, de wijze waarop ze werken en de mate waarin ze een directe dan wel indirecte invloed op de bodemvruchtbaarheid kunnen hebben. Objectieve informatie over het effect van deze producten op de gewasopbrengsten en de fysische, chemische en biologische bodemvruchtbaarheid ontbreekt. Uit eerdere proeven is bekend dat effecten van bodem verbeterende maatregelen vaak pas na enkele jaren zichtbaar worden. Om het effect van verschillende bodemverbeteraars op opbrengst en bodemeigenschappen op de langere termijn te toetsen, zijn proefvelden aangelegd op drie kleilocaties (Kollumerwaard, Lelystad en Westmaas) en twee zandlocaties (Vredepeel, Valthermond). Op deze proefvelden zijn bouwplannen toegepast die gangbaar zijn voor de betreffende regio. Eventuele positieve effecten worden sterker met het verstrijken der jaren. Bovendien zijn deze het duidelijkst te onderscheiden wanneer op alle locaties hetzelfde gewas wordt geteeld. Daarom stonden er in het laatste jaar op alle proefvelden aardappels. In de proef zijn de ontwikkeling van de gewasopbrengst, de gewaskwaliteit en de bodemeigenschappen gevolgd over een periode van zes jaar (2010-2015).

In de praktijk lopen telers vaak tegen problemen aan van een slechte bodemkwaliteit. Intensieve bouwplannen, steeds zwaardere mechanisatie, uitloging (Ca-uitspoeling), piekneerslagen en de schaalvergroting in de landbouw leiden tot vermindering van de fysische bodemvruchtbaarheid en de structuur van de bodem. Dit veroorzaakt: toenemende problemen bij de bewerkbaarheid van de bodem; minder efficiënt gebruik van meststoffen; verhoogd risico van uit- en afspoeling van nutriënten; wateroverlast; verlaging van de opbrengst. Om de bodemstructuur te verbeteren, worden door industrie en handel zogeheten bodemverbeteraars en kalkmeststoffen aangeboden. Er is een grote variatie in type producten, de wijze waarop ze werken en de mate waarin ze een directe dan wel indirecte invloed op de bodemvruchtbaarheid kunnen hebben. Objectieve informatie over het effect van deze producten op de gewasopbrengsten en de fysische, chemische en biologische bodemvruchtbaarheid ontbreekt. Uit eerdere proeven is bekend dat effecten van bodem verbeterende maatregelen vaak pas na enkele jaren zichtbaar worden. Om het effect van verschillende bodemverbeteraars op opbrengst en bodemeigenschappen op de langere termijn te toetsen, zijn proefvelden aangelegd op drie kleilocaties (Kollumerwaard, Lelystad en Westmaas) en twee zandlocaties (Vredepeel, Valthermond). Op deze proefvelden zijn bouwplannen toegepast die gangbaar zijn voor de betreffende regio. Eventuele positieve effecten worden sterker met het verstrijken der jaren. Bovendien zijn deze het duidelijkst te onderscheiden wanneer op alle locaties hetzelfde gewas wordt geteeld. Daarom stonden er in het laatste jaar op alle proefvelden aardappels. In de proef zijn de ontwikkeling van de gewasopbrengst, de gewaskwaliteit en de bodemeigenschappen gevolgd over een periode van zes jaar (2010-2015).

Sinds 2006 gelden gebruiksnormen voor stikstof en fosfaat, die grenzen stellen aan de aanwending van organische mest op de bodem. Deze regels hebben indirect gevolgen voor de aanvoer van organische stof met dierlijke mest naar de bodem. Dit leidt soms tot zorg over de bodemvruchtbaarheid op lange termijn. Blijft het organische stofgehalte in de bodem wel op een goed niveau? Koeien & Kansen-deelnemers lopen voor op de bestaande regelgeving om problemen in een vroeg stadium te onderkennen. In dit artikel schetsen we de ontwikkelingen en gaan we in op het beheer, in het bijzonder voor bedrijven op droge zandgrond.

When agricultural researchers visit farms in order to gather information for their research programmes, farmers rarely get proper feedback. Research information on scientific concepts such as soil fertility and nutrient balances is often considered too abstract for them. Researchers in Kenya returned to farmers to discuss their results in the context of Farmer Field Schools. Through the workshops that ensued, they managed to find a common language to bridge the communication gap.

Resultaten van de KringloopWijzer laten grote verschillen zien in stikstof- en fosfaatopbrengsten, die op verschillende bedrijven worden bereikt in maïs- en grasland. Deels wordt dat veroorzaakt door de manier waarop de bemesting wordt uitgevoerd. Met perceelsgericht bemesten kan de potentie van het land meer worden benut.

In deze brochure worden handreikingen gegeven voor de praktijk, waarbij zowel strooiselbewonende, bodembewonende en pendelende regenwormen aan bod komen.

In deze brochure worden handreikingen gegeven voor de praktijk, waarbij zowel strooiselbewonende, bodembewonende en pendelende regenwormen aan bod komen.

Sinds 2006 gelden gebruiksnormen voor stikstof en fosfaat, die grenzen stellen aan de aanwending van organische mest op de bodem. Deze regels hebben indirect gevolgen voor de aanvoer van organische stof met dierlijke mest naar de bodem. Dit leidt soms tot zorg over de bodemvruchtbaarheid op lange termijn. Blijft het organische stofgehalte in de bodem wel op een goed niveau? Koeien & Kansen-deelnemers lopen voor op de bestaande regelgeving om problemen in een vroeg stadium te onderkennen. In dit artikel schetsen we de ontwikkelingen en gaan we in op het beheer, in het bijzonder voor bedrijven op droge zandgrond.

Bodemvruchtbaarheid staat steeds nadrukkelijker op de agenda van politiek, overheid, bedrijfsleven en maatschappelijke organisaties. Deze publicatie is vooral geschreven voor medewerkers van deze organisaties, van rijksoverheid tot waterschap, en van productschap tot mestverwerker. Uiteindelijk draait het om de boeren die het land bewerken. Ook zij vinden in deze publicatie achtergronden over alle belangrijke aspecten van bodemvruchtbaarheid. De dertig vragen en antwoorden zijn grofweg in drie groepen ingedeeld. Eerst komen de klassiekers aan bod waarin de basiskennis wordt uitgelegd. De volgende groep vragen behandelt de actuele thema's zoals mestbeleid, energieproductie en klimaatverandering. Tot slot komen in de laatste vragen de kennisagenda en nieuwe ontwikkelingen aan bod.

Bodemvruchtbaarheid staat steeds nadrukkelijker op de agenda van politiek, overheid, bedrijfsleven en maatschappelijke organisaties. Deze publicatie is vooral geschreven voor medewerkers van deze organisaties, van rijksoverheid tot waterschap, en van productschap tot mestverwerker. Uiteindelijk draait het om de boeren die het land bewerken. Ook zij vinden in deze publicatie achtergronden over alle belangrijke aspecten van bodemvruchtbaarheid. De dertig vragen en antwoorden zijn grofweg in drie groepen ingedeeld. Eerst komen de klassiekers aan bod waarin de basiskennis wordt uitgelegd. De volgende groep vragen behandelt de actuele thema's zoals mestbeleid, energieproductie en klimaatverandering. Tot slot komen in de laatste vragen de kennisagenda en nieuwe ontwikkelingen aan bod.

Soil infertility undermines the agriculture-based livelihoods in Malawi, where it is blamed for poor crop yields and the creation of cycles of poverty. Although technologies and management strategies have been developed to reverse the decline in soil fertility, they are under-used by smallholder farmers. This study was conducted to assess with farmers the performance of a range of maize-legume technologies and their benefits on soil fertility management in central Malawi. Farmer participatory experimentation was a focus of the study. The aim was to facilitate learning and the interpretation of experiences, improve the communication of information about the concepts and technologies to farmers, and provide insights for researchers. Using a combination of survey and participatory methods, 136 smallholder farmers from Chisepo were grouped into four resource groups, comprising of better-resourced (RG 1 with 6 farmers), medium resourced (RG 2, 14 farmers), less well-resourced (RG 3, 64 farmers) and least-resourced groups (RG 4, 52 farmers). Analysing their livelihoods for their effects on soil fertility revealed that soil fertility management is a complex activity which is influenced by ownership of assets. Farmers from RG 1 and RG 2 owned more resources including cattle, had larger fields, hired-in labour for timely farm operations, earned more income and invested far more in soil fertility improvement. Farmers from RG 3 and 4 (who are in the large majority) were resource constrained and did not invest adequately in improving soil fertility. They had large food deficits due to poor crop yields. Ganyu labour (casual work done for other farmers for food or cash) was their main strategy to reduce food deficits. Farmers from all the four RGs were interested in working with research to explore strategies to improve soil fertility. They tested various grain- and green-manure-legumes, and mineral N and P fertiliser on maize and the legumes for effects on crop productivity and soil fertility. Associated production risk and interest in technology adoption were assessed. On-farm evaluation was done on maize (cv. MH18) in rotation with pigeonpea cv. ICP 9145,intercropped with groundnut (cv. CG 7), (Mz/Pp+Gn); intercropped with tephrosia (Mz+Tv); intercropped with pigeonpea (Mz+Pp) and in rotation with mucuna (Mz/Mp). These technologies were compared with sole crop maize without fertiliser (Mz−Ft) or with 35 kg N ha-1(Mz+Ft) in experiments with 32 farmers from the four RGs over four years. Economic and risk assessments were made. Maize grain yields (accumulated over the four years) were greater for farmers from RG 1 and 2 than RGs 3 and 4. Mz+Pp and Mz+Tv gave greater cumulative yields than Mz/Pp+Gn and Mz/Mp. The legumes improved maize grain yields by between 0.2 and 4 t ha-1(P < 0.001) over Mz-Ft and additionally they gave legume grain to the household.Mz+Pp was less risky to all RGs, and applying 35 kg N ha-1to the legumes resulted in Mz+Tv, Mz/Pp+Gn and Mz/Mp being least risky to RG 1, RG2 and RG 3. Farmers in RG 1 had the highest returns to labour (USconv2.info.8 day-1with Mz-Ft and US.1 day-1with Mz+Pp) and these increased to 1.9 and 1.7 respectively with 35 kg N ha-1. Mz+Pp intercrop gave consistent positive returns across the RGs and was the only technology to provide positive returns to labour in RG 4. Use of pigeonpea was overall the least risky option, and was especially suited to least-resourced farmers. Application of phosphorus fertiliser (0, 20 kg P ha-1) to legumes significantly (P = 0.05) increased grain and biomass yields for mucuna, groundnut, soyabean, Bambara groundnut and cowpea by 1.0, 0.8, 0.5, 1.0 and 0.3 t ha-1compared with unfertilised plots. Cowpea and fertilised groundnut had larger yields in the home fields than middle fields, but other legumes performed better (P = 0.05) in the middle fields. Maize responses to small amounts of fertiliser (0, 15, and 30 kg N ha-1and 0, 20 kg P ha-1) in two weeding regimes showed that weeding twice significantly (P < 0.001) raised maize yields by 0.4 t ha-1over weeding once (0.9 t ha-1). Stover yields (significant at P < 0.001) were 2.3 and 1.6 t ha-1respectively. Mean grain N kg ha-1was 17.1 and 9.8 for plots weeded twice and once respectively while that of stover were 10.1 and 5.6 kg N ha-1. Applying N at 15 kg N ha-1increased maize yields, but the 30 kg N ha-1increased yield only on more clay soils due to the effects of mid-season dry spells on sandy soils. Except for the physiological efficiency of N (PEN), all agronomic indices of N use showed significant differences due to weeding (agronomic efficiency of applied fertiliser N (AEN) at P < 0.001, recovery efficiency of applied N (REN) and partial factor productivity for N (PFPN) at P < 0.01). The average PENof 40.7and PFPNof 78.8 in plots weeded twice were within the ranges of 40–60 kg grain kg-1N and 40–80 kg grain kg-1N applied respectively. AENand REN values of 38.7 and 0.9 respectively were above the common range of 10-30 kg grain kg-1 N applied and 0.3-0.5 or 0.5–0.8 kg N kg-1. Mean indices from plots weeded just once were all within the ranges stated above but lower than indices from plots weeded twice; suggesting the unsustainability of the use of fertiliser without means to raise its efficiency through better management or combination with organic resources. Weeding twice gave higher returns to labour (USconv2.info.30 day-1) than weeding once (USconv2.info.05 day-1) and gross margins of US5.00 and US.00 with labour taken into account respectively.Farmers need to ensure timely weeding to get decent efficiencies and returns from the fertiliser, especially in drier cropping seasons. Using surveys, focus group discussions and the analytical hierarchy process (AHP), adoption of the ten legumes introduced to farmers in Chisepo was assessed among 136 farmers in 2004 and 84 farmers in 2007. Thirty-five percent of the farmers in 2004 and 22% in 2007 had adopted at least one of the legumes, with food grain legumes predominantly soyabean, groundnut, pigeonpea and to a lesser extent Bambara groundnut and cowpea being most adopted. Mucuna and tephrosia were adopted by few farmers while sunnhemp and grahamiana were not adopted at all. Farmers from RGs 1 and 2 adopted more of the legumes than those from RG 3 and 4. Lack of consistent markets, a lack of seed for planting, as well as land and labour shortages were cited for weak adoption. Soil fertility management by smallholder farmers is influenced by ownership of assets and the majority poorer farmers fail to invest adequately in improving soil fertility. In the absence of such resources, grain legumes will play an important role as a source of both food and organic matter to improve soil fertility. The participatory methods used in the study helped farmers better understand some of the soil fertility concepts and options, including the legumes. There is need to focus on how to assist farmers with practical knowledge to help them best combine organic and mineral fertiliser resources for improving soil fertility, and to develop and promote new dual-purpose legume options that feed humans and the soil. Key words: Adoption, analytical hierarchy process, crop yield, financial returns, food security, household assets, legume integration, livelihoods, NP fertiliser, nitrogen use efficiency, production risk, resource groups, smallholder, soil fertility, weeding.

Soil infertility undermines the agriculture-based livelihoods in Malawi, where it is blamed for poor crop yields and the creation of cycles of poverty. Although technologies and management strategies have been developed to reverse the decline in soil fertility, they are under-used by smallholder farmers. This study was conducted to assess with farmers the performance of a range of maize-legume technologies and their benefits on soil fertility management in central Malawi. Farmer participatory experimentation was a focus of the study. The aim was to facilitate learning and the interpretation of experiences, improve the communication of information about the concepts and technologies to farmers, and provide insights for researchers. Using a combination of survey and participatory methods, 136 smallholder farmers from Chisepo were grouped into four resource groups, comprising of better-resourced (RG 1 with 6 farmers), medium resourced (RG 2, 14 farmers), less well-resourced (RG 3, 64 farmers) and least-resourced groups (RG 4, 52 farmers). Analysing their livelihoods for their effects on soil fertility revealed that soil fertility management is a complex activity which is influenced by ownership of assets. Farmers from RG 1 and RG 2 owned more resources including cattle, had larger fields, hired-in labour for timely farm operations, earned more income and invested far more in soil fertility improvement. Farmers from RG 3 and 4 (who are in the large majority) were resource constrained and did not invest adequately in improving soil fertility. They had large food deficits due to poor crop yields. Ganyu labour (casual work done for other farmers for food or cash) was their main strategy to reduce food deficits. Farmers from all the four RGs were interested in working with research to explore strategies to improve soil fertility. They tested various grain- and green-manure-legumes, and mineral N and P fertiliser on maize and the legumes for effects on crop productivity and soil fertility. Associated production risk and interest in technology adoption were assessed. On-farm evaluation was done on maize (cv. MH18) in rotation with pigeonpea cv. ICP 9145,intercropped with groundnut (cv. CG 7), (Mz/Pp+Gn); intercropped with tephrosia (Mz+Tv); intercropped with pigeonpea (Mz+Pp) and in rotation with mucuna (Mz/Mp). These technologies were compared with sole crop maize without fertiliser (Mz−Ft) or with 35 kg N ha-1(Mz+Ft) in experiments with 32 farmers from the four RGs over four years. Economic and risk assessments were made. Maize grain yields (accumulated over the four years) were greater for farmers from RG 1 and 2 than RGs 3 and 4. Mz+Pp and Mz+Tv gave greater cumulative yields than Mz/Pp+Gn and Mz/Mp. The legumes improved maize grain yields by between 0.2 and 4 t ha-1(P < 0.001) over Mz-Ft and additionally they gave legume grain to the household.Mz+Pp was less risky to all RGs, and applying 35 kg N ha-1to the legumes resulted in Mz+Tv, Mz/Pp+Gn and Mz/Mp being least risky to RG 1, RG2 and RG 3. Farmers in RG 1 had the highest returns to labour (USconv2.info.8 day-1with Mz-Ft and US.1 day-1with Mz+Pp) and these increased to 1.9 and 1.7 respectively with 35 kg N ha-1. Mz+Pp intercrop gave consistent positive returns across the RGs and was the only technology to provide positive returns to labour in RG 4. Use of pigeonpea was overall the least risky option, and was especially suited to least-resourced farmers. Application of phosphorus fertiliser (0, 20 kg P ha-1) to legumes significantly (P = 0.05) increased grain and biomass yields for mucuna, groundnut, soyabean, Bambara groundnut and cowpea by 1.0, 0.8, 0.5, 1.0 and 0.3 t ha-1compared with unfertilised plots. Cowpea and fertilised groundnut had larger yields in the home fields than middle fields, but other legumes performed better (P = 0.05) in the middle fields. Maize responses to small amounts of fertiliser (0, 15, and 30 kg N ha-1and 0, 20 kg P ha-1) in two weeding regimes showed that weeding twice significantly (P < 0.001) raised maize yields by 0.4 t ha-1over weeding once (0.9 t ha-1). Stover yields (significant at P < 0.001) were 2.3 and 1.6 t ha-1respectively. Mean grain N kg ha-1was 17.1 and 9.8 for plots weeded twice and once respectively while that of stover were 10.1 and 5.6 kg N ha-1. Applying N at 15 kg N ha-1increased maize yields, but the 30 kg N ha-1increased yield only on more clay soils due to the effects of mid-season dry spells on sandy soils. Except for the physiological efficiency of N (PEN), all agronomic indices of N use showed significant differences due to weeding (agronomic efficiency of applied fertiliser N (AEN) at P < 0.001, recovery efficiency of applied N (REN) and partial factor productivity for N (PFPN) at P < 0.01). The average PENof 40.7and PFPNof 78.8 in plots weeded twice were within the ranges of 40–60 kg grain kg-1N and 40–80 kg grain kg-1N applied respectively. AENand REN values of 38.7 and 0.9 respectively were above the common range of 10-30 kg grain kg-1 N applied and 0.3-0.5 or 0.5–0.8 kg N kg-1. Mean indices from plots weeded just once were all within the ranges stated above but lower than indices from plots weeded twice; suggesting the unsustainability of the use of fertiliser without means to raise its efficiency through better management or combination with organic resources. Weeding twice gave higher returns to labour (USconv2.info.30 day-1) than weeding once (USconv2.info.05 day-1) and gross margins of US5.00 and US.00 with labour taken into account respectively.Farmers need to ensure timely weeding to get decent efficiencies and returns from the fertiliser, especially in drier cropping seasons. Using surveys, focus group discussions and the analytical hierarchy process (AHP), adoption of the ten legumes introduced to farmers in Chisepo was assessed among 136 farmers in 2004 and 84 farmers in 2007. Thirty-five percent of the farmers in 2004 and 22% in 2007 had adopted at least one of the legumes, with food grain legumes predominantly soyabean, groundnut, pigeonpea and to a lesser extent Bambara groundnut and cowpea being most adopted. Mucuna and tephrosia were adopted by few farmers while sunnhemp and grahamiana were not adopted at all. Farmers from RGs 1 and 2 adopted more of the legumes than those from RG 3 and 4. Lack of consistent markets, a lack of seed for planting, as well as land and labour shortages were cited for weak adoption. Soil fertility management by smallholder farmers is influenced by ownership of assets and the majority poorer farmers fail to invest adequately in improving soil fertility. In the absence of such resources, grain legumes will play an important role as a source of both food and organic matter to improve soil fertility. The participatory methods used in the study helped farmers better understand some of the soil fertility concepts and options, including the legumes. There is need to focus on how to assist farmers with practical knowledge to help them best combine organic and mineral fertiliser resources for improving soil fertility, and to develop and promote new dual-purpose legume options that feed humans and the soil. Key words: Adoption, analytical hierarchy process, crop yield, financial returns, food security, household assets, legume integration, livelihoods, NP fertiliser, nitrogen use efficiency, production risk, resource groups, smallholder, soil fertility, weeding.

Groencompost wordt een aantal belangrijke positieve effecten toegedicht, maar onderzoek laat zien dat het gaat om investeren voor de lange termijn. Praktijkonderzoek Plant en Omgeving heeft samen met de Branche Vereniging Reststoffen (BVOR) en vijf agrarische ondernemers in diverse sectoren gekeken naar de effecten van de toediening van groencompost.

When agricultural researchers visit farms in order to gather information for their research programmes, farmers rarely get proper feedback. Research information on scientific concepts such as soil fertility and nutrient balances is often considered too abstract for them. Researchers in Kenya returned to farmers to discuss their results in the context of Farmer Field Schools. Through the workshops that ensued, they managed to find a common language to bridge the communication gap.

In dit rapport zijn de beschikbare resultaten van Nederlands onderzoek in spruitkool met betrekking tot landbouwkundige en milieukundige gevolgen van bemesting met kunstmeststikstof in de winterperiode op een rij gezet

cum laude graduation (with distinction)

cum laude graduation (with distinction)

In dit rapport zijn de beschikbare resultaten van Nederlands onderzoek in spruitkool met betrekking tot landbouwkundige en milieukundige gevolgen van bemesting met kunstmeststikstof in de winterperiode op een rij gezet

Participatory technology development within the subsistence-farming sector in South Africa is receiving increasing attention. Linked to this is an interest in sustainable development, particularly for agricultural interventions. Ecological approaches to agriculture have largely been considered unable to provide a route for income generation. However, some promising examples of sustainable small-scale farming systems can be found in South Africa. The main aim of this thesis was to identify factors within these development programmes that led to sustainable technology development in the context of subsistence farmers’ livelihoods. This objective was achieved through exploring practically, the concepts derived from the sustainability paradigm. To be sustainable, a farming system should be biologically, technically and socially feasible and viable at farm level, within a positive and enhancing external environment. Sustainability ultimately concerns the relationships between all elements of the farming system and for this reason researching sustainability in agriculture requires a multi-level, multi-aspect and multi-actor approach. Sustainability was explored in three case studies in this thesis and at a number of levels: field level; farm and district level, including organizational interaction. Different aspects were researched that included agricultural technologies, household livelihoods and organizational development. The various actors involved in the technology-development process examined in the three case studies included farmers, change-agents, researchers and local traditional authorities. Interactions at all three levels influenced and contributed to the overall sustainability of the development intervention and this research supports the widely demonstrated conclusion that the challenges faced by agriculture will not readily be solved by technological interventions at the field level alone. The factors at each of the levels that contributed to the sustainability of the develop projects are presented and the lessons learned from the three case studies are also given.

Participatory technology development within the subsistence-farming sector in South Africa is receiving increasing attention. Linked to this is an interest in sustainable development, particularly for agricultural interventions. Ecological approaches to agriculture have largely been considered unable to provide a route for income generation. However, some promising examples of sustainable small-scale farming systems can be found in South Africa. The main aim of this thesis was to identify factors within these development programmes that led to sustainable technology development in the context of subsistence farmers’ livelihoods. This objective was achieved through exploring practically, the concepts derived from the sustainability paradigm. To be sustainable, a farming system should be biologically, technically and socially feasible and viable at farm level, within a positive and enhancing external environment. Sustainability ultimately concerns the relationships between all elements of the farming system and for this reason researching sustainability in agriculture requires a multi-level, multi-aspect and multi-actor approach. Sustainability was explored in three case studies in this thesis and at a number of levels: field level; farm and district level, including organizational interaction. Different aspects were researched that included agricultural technologies, household livelihoods and organizational development. The various actors involved in the technology-development process examined in the three case studies included farmers, change-agents, researchers and local traditional authorities. Interactions at all three levels influenced and contributed to the overall sustainability of the development intervention and this research supports the widely demonstrated conclusion that the challenges faced by agriculture will not readily be solved by technological interventions at the field level alone. The factors at each of the levels that contributed to the sustainability of the develop projects are presented and the lessons learned from the three case studies are also given.

Resultaten van de KringloopWijzer laten grote verschillen zien in stikstof- en fosfaatopbrengsten, die op verschillende bedrijven worden bereikt in maïs- en grasland. Deels wordt dat veroorzaakt door de manier waarop de bemesting wordt uitgevoerd. Met perceelsgericht bemesten kan de potentie van het land meer worden benut.

Groencompost wordt een aantal belangrijke positieve effecten toegedicht, maar onderzoek laat zien dat het gaat om investeren voor de lange termijn. Praktijkonderzoek Plant en Omgeving heeft samen met de Branche Vereniging Reststoffen (BVOR) en vijf agrarische ondernemers in diverse sectoren gekeken naar de effecten van de toediening van groencompost.

Soil fertility is declining in Kenya’s low potential areas. More appropriate soil fertility management technologies are needed, which fit into farmers’ socio-economic circumstances. This working paper presents the methodology and results of an on-farm experiment with the use of compost and liquid manure on maize, using a Participatory Technology Development (PTD) approach. It was done with two groups of farmers. One group was composed of conventional farmers while the second group comprised farmers using a Low External Input and Sustainable Agriculture (LEISA) approach. The PTD work started with debate amongst farmers and researchers on soil fertility management, followed by identification of promising technologies. This study has shown that with a PTD approach, farmers and researchers can come to agreement on technologies to be tested, treatments and research design

Soil fertility is declining in Kenya’s low potential areas. More appropriate soil fertility management technologies are needed, which fit into farmers’ socio-economic circumstances. This working paper presents the methodology and results of an on-farm experiment with the use of compost and liquid manure on maize, using a Participatory Technology Development (PTD) approach. It was done with two groups of farmers. One group was composed of conventional farmers while the second group comprised farmers using a Low External Input and Sustainable Agriculture (LEISA) approach. The PTD work started with debate amongst farmers and researchers on soil fertility management, followed by identification of promising technologies. This study has shown that with a PTD approach, farmers and researchers can come to agreement on technologies to be tested, treatments and research design