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G Model
STILL-2593; No of Pages 2
Soil & Tillage Research xxx (2008) xxx–xxx
Contents lists available at ScienceDirect
Soil & Tillage Research journal homepage: www.elsevier.com/locate/still
Editorial
Conservation tillage and sustainable small farming: Introduction
The papers in this special edition were selected from the contributions to the session IV on ‘‘Conservation Tillage and Sustainable Small Farming’’ of the 2004 CIGR International Conference, held in Beijing, China. This conference brought together scientists working on the issue of Conservation Tillage (CT), one of the pillars under the concept of Conservation Agriculture (CA), which is now gaining worldwide attention. CA is showing promising results as a sustainable farming system, combining stable yields with lower input costs and in many situations, with a considerable reduction in the production of greenhouse gases, contributing to the global need for carbon sequestration. The main technological thrust towards CA originated in South America (Brazil, Paraguay) where farmers started with zero-tillage back in the early 1980s. The conditions in these regions were (and still are) very favorable, leading to a quick and widespread acceptance of the new technology, not in the last place due to the dedicated cooperation of pioneer farmers. The notion of reducing the intensity of tillage, combined with properly and carefully managing crop residue and (where possible) apply crop rotation also attracted farmers and scientists from other parts of the world. More evidence came from scientific experiments and farmers’ experience that CT can also be used in many situations with less favorable conditions such as climates with unreliable or irregular rainfall, cold winters. It was also shown that CT is not restricted to large farms with big tractors and (sowing) machinery. The papers in this issue show the potential of CT in a wide range of geographical, climatological and socio-economical situations. Evidence from research in China, Australia, Iran and Ethiopia is presented. So et al. showed that in Australia no-till improved the structure of a sensitive silty loam by an increased macroporosity which led to a higher availability of water to the crop in the semi-arid climate of NSW. It was shown that changes do not come in a few years, but results in the form of sustained improvement of crop yields are rewarding. Improved soil structure was also reported for vertolsols in Australia by McHugh et al. They found that soil quality, indicated by a lower bulk density, higher macroporosity and increased available water capacity, was improved under no tillage, controlled traffic permanent bed farming. Li et al. underline the need for reduction of random traffic in the field. They demonstrated that in conservation tillage and controlled traffic farming situations, both the energy of rainfall and the energy of wheeling play an important role in the (decrease of) rainfall infiltration. The experimental data confirmed that
rainfall energy is causing surface soil degradation and wheeling energy is causing subsoil degradation. This research was carried out in Australia, but is valid for heavy clays elsewhere in the world as well. Controlled Traffic Farming combined with residue cover gave increased wheat yields on the Loess Plateau of China. Wang et al. reported that this was mainly due to a better structure (lower bulk density) and an increased soil water content in this semi-arid climate. Shallow tillage and no tillage both gave similar results when applied in a CTF system, but the lower input costs of notillage made it the best option. The potential of CTF on irrigated farms with wheat and maize in the North China Plain was shown by Hejin et al., who found that irrigation water requirements were reduced by more than 15% when adopting conservation tillage. The effect was strongest with a high crop residue cover, having a dampening effect on temperature extremes in the top layer of the soil. It is a fact that weakly structured soils in dry climates are difficult to manage. Yet, in Iran, experiments reported by Mosaddeghi et al. indicated that although reduced (chisel plowing) or no tillage on sandy loam soils resulted in poorer structure (expressed as higher bulk density and higher cone index) as compared to moldboard plowing. However, this effect could largely be offset by the application of farmyard manure, thus allowing the use of conservation tillage under less favorable conditions. Maize root lengths were found to be strongly related to cone index. Conservation tillage methods were also found to be feasible for irrigated wheat production in Iran. Javadi et el. assessed the use of reduced tillage methods in various parts of the country and concluded that application of no tillage was leading to lower yields, partly due to lack of appropriate (no tillage) sowing equipment, and partly due to an unsatisfactory structure of the surface soil layer. In most of the regions where tests were done, reduced tillage by chisel instead of moldboard plowing gave yields which were not significantly lower. This was particularly true when crop residue was left in the field. Small scale farming, typical for many regions in the world, is generally seen as a less suitable condition for the application of CT methods. The experiences of a China-Canadian project, as reported by Lafond et al., show there is potential for CT on small farms in Inner Mongolia. Many constraints in the introduction of the method (e.g. dealing with crop residue, weed control, uncontrolled grazing) could be solved by simple and specific technical solutions. Risks for failure in adoption of the CT package could be minimized when sufficient attention is given to training and information for the smallholder farmers.
0167-1987/$ – see front matter ß 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.still.2008.10.009
Please cite this article in press as: Hoogmoed, W.B., Conservation tillage and sustainable small farming: Introduction. Soil Tillage Res. (2008), doi:10.1016/j.still.2008.10.009
G Model
STILL-2593; No of Pages 2
2
Editorial / Soil & Tillage Research xxx (2008) xxx–xxx
This is also the case in Africa: Temesgen et al. in Ethiopia showed that simple adaptations to the traditional animal-drawn ard plow (Maresha) led to a considerable reduction of the draft power needed and allowed breaking up of disturbing layers. Reduced tillage increased yields of the staple foodgrain tef. Using the traditional plow as a basis, chances for acceptance by the farmers were increased. Conclusions from the information given in the papers of this special edition are clearly that CT does not necessarily have to be restricted to regions with favorable conditions, although the
system should not easily be considered as a universal solution. When judiciously applied, with careful adaptation to local conditions, CT is able to provide a sustainable crop production system in many parts of the world. W.B. Hoogmoed Farm Technology Group, Wageningen University, The Netherlands E-mail address: [email protected]
Please cite this article in press as: Hoogmoed, W.B., Conservation tillage and sustainable small farming: Introduction. Soil Tillage Res. (2008), doi:10.1016/j.still.2008.10.009
STILL-2593; No of Pages 2
Soil & Tillage Research xxx (2008) xxx–xxx
Contents lists available at ScienceDirect
Soil & Tillage Research journal homepage: www.elsevier.com/locate/still
Editorial
Conservation tillage and sustainable small farming: Introduction
The papers in this special edition were selected from the contributions to the session IV on ‘‘Conservation Tillage and Sustainable Small Farming’’ of the 2004 CIGR International Conference, held in Beijing, China. This conference brought together scientists working on the issue of Conservation Tillage (CT), one of the pillars under the concept of Conservation Agriculture (CA), which is now gaining worldwide attention. CA is showing promising results as a sustainable farming system, combining stable yields with lower input costs and in many situations, with a considerable reduction in the production of greenhouse gases, contributing to the global need for carbon sequestration. The main technological thrust towards CA originated in South America (Brazil, Paraguay) where farmers started with zero-tillage back in the early 1980s. The conditions in these regions were (and still are) very favorable, leading to a quick and widespread acceptance of the new technology, not in the last place due to the dedicated cooperation of pioneer farmers. The notion of reducing the intensity of tillage, combined with properly and carefully managing crop residue and (where possible) apply crop rotation also attracted farmers and scientists from other parts of the world. More evidence came from scientific experiments and farmers’ experience that CT can also be used in many situations with less favorable conditions such as climates with unreliable or irregular rainfall, cold winters. It was also shown that CT is not restricted to large farms with big tractors and (sowing) machinery. The papers in this issue show the potential of CT in a wide range of geographical, climatological and socio-economical situations. Evidence from research in China, Australia, Iran and Ethiopia is presented. So et al. showed that in Australia no-till improved the structure of a sensitive silty loam by an increased macroporosity which led to a higher availability of water to the crop in the semi-arid climate of NSW. It was shown that changes do not come in a few years, but results in the form of sustained improvement of crop yields are rewarding. Improved soil structure was also reported for vertolsols in Australia by McHugh et al. They found that soil quality, indicated by a lower bulk density, higher macroporosity and increased available water capacity, was improved under no tillage, controlled traffic permanent bed farming. Li et al. underline the need for reduction of random traffic in the field. They demonstrated that in conservation tillage and controlled traffic farming situations, both the energy of rainfall and the energy of wheeling play an important role in the (decrease of) rainfall infiltration. The experimental data confirmed that
rainfall energy is causing surface soil degradation and wheeling energy is causing subsoil degradation. This research was carried out in Australia, but is valid for heavy clays elsewhere in the world as well. Controlled Traffic Farming combined with residue cover gave increased wheat yields on the Loess Plateau of China. Wang et al. reported that this was mainly due to a better structure (lower bulk density) and an increased soil water content in this semi-arid climate. Shallow tillage and no tillage both gave similar results when applied in a CTF system, but the lower input costs of notillage made it the best option. The potential of CTF on irrigated farms with wheat and maize in the North China Plain was shown by Hejin et al., who found that irrigation water requirements were reduced by more than 15% when adopting conservation tillage. The effect was strongest with a high crop residue cover, having a dampening effect on temperature extremes in the top layer of the soil. It is a fact that weakly structured soils in dry climates are difficult to manage. Yet, in Iran, experiments reported by Mosaddeghi et al. indicated that although reduced (chisel plowing) or no tillage on sandy loam soils resulted in poorer structure (expressed as higher bulk density and higher cone index) as compared to moldboard plowing. However, this effect could largely be offset by the application of farmyard manure, thus allowing the use of conservation tillage under less favorable conditions. Maize root lengths were found to be strongly related to cone index. Conservation tillage methods were also found to be feasible for irrigated wheat production in Iran. Javadi et el. assessed the use of reduced tillage methods in various parts of the country and concluded that application of no tillage was leading to lower yields, partly due to lack of appropriate (no tillage) sowing equipment, and partly due to an unsatisfactory structure of the surface soil layer. In most of the regions where tests were done, reduced tillage by chisel instead of moldboard plowing gave yields which were not significantly lower. This was particularly true when crop residue was left in the field. Small scale farming, typical for many regions in the world, is generally seen as a less suitable condition for the application of CT methods. The experiences of a China-Canadian project, as reported by Lafond et al., show there is potential for CT on small farms in Inner Mongolia. Many constraints in the introduction of the method (e.g. dealing with crop residue, weed control, uncontrolled grazing) could be solved by simple and specific technical solutions. Risks for failure in adoption of the CT package could be minimized when sufficient attention is given to training and information for the smallholder farmers.
0167-1987/$ – see front matter ß 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.still.2008.10.009
Please cite this article in press as: Hoogmoed, W.B., Conservation tillage and sustainable small farming: Introduction. Soil Tillage Res. (2008), doi:10.1016/j.still.2008.10.009
G Model
STILL-2593; No of Pages 2
2
Editorial / Soil & Tillage Research xxx (2008) xxx–xxx
This is also the case in Africa: Temesgen et al. in Ethiopia showed that simple adaptations to the traditional animal-drawn ard plow (Maresha) led to a considerable reduction of the draft power needed and allowed breaking up of disturbing layers. Reduced tillage increased yields of the staple foodgrain tef. Using the traditional plow as a basis, chances for acceptance by the farmers were increased. Conclusions from the information given in the papers of this special edition are clearly that CT does not necessarily have to be restricted to regions with favorable conditions, although the
system should not easily be considered as a universal solution. When judiciously applied, with careful adaptation to local conditions, CT is able to provide a sustainable crop production system in many parts of the world. W.B. Hoogmoed Farm Technology Group, Wageningen University, The Netherlands E-mail address: [email protected]
Please cite this article in press as: Hoogmoed, W.B., Conservation tillage and sustainable small farming: Introduction. Soil Tillage Res. (2008), doi:10.1016/j.still.2008.10.009
