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Browsing by Author "Sayre, Ken D."

Now showing 1 - 14 of 14
  • Adapting no-tillage agriculture to the conditions of smallholder maize and wheat farmers in the tropics and sub-tropics
    Erenstein, Olaf; Sayre, Ken D.; Wall, Patrick C.; Dixon, John; Hellin, Jonathan (2006)
    "The purpose of this paper is to summarize some of CIMMYT's experiences with the adaptation of NT to smallholder conditions in the tropics and sub-tropics. The scope of the present paper is too narrow to review all of CIMMYT's NT experiences over the years. Instead, this chapter will focus on three contrasting cases of ongoing research and development across the developing world. These cases follow a section that discusses NT in relation to CA. Following the case studies, the paper continues with a discussion on NT innovation systems and impact pathways." (Excerpt from Introduction)
  • Conservation agriculture and soil carbon sequestration: Between myth and farmer reality
    Govaerts, Bram; Verhulst, N.; Castellanos-Navarrete, A.; Sayre, Ken D.; Dixon, John; Dendooven, L. (Taylor & Francis, 2009)
    Improving food security, environmental preservation and enhancing livelihood should be the main targets of the innovators of today's farming systems. Conservation agriculture (CA), based on minimum tillage, crop residue retention, and crop rotations, has been proposed as an alternative system combining benefits for the farmer with advantages for the society. This paper reviews the potential impact of CA on C sequestration by synthesizing the knowledge of carbon and nitrogen cycling in agriculture; summarizing the influence of tillage, residue management, and crop rotation on soil organic carbon stocks; and compiling the existing case study information. To evaluate the C sequestration capacity of farming practices, their influence on emissions from farming activities should be considered together with their influence on soil C stocks. The largest contribution of CA to reducing emissions from farming activities is made by the reduction of tillage operations. The soil C case study results are not conclusive. In 7 of the 78 cases withheld, the soil C stock was lower in zero compared to conventional tillage, in 40 cases it was higher, and in 31 of the cases there was no significant difference. The mechanisms that govern the balance between increased or no sequestration after conversion to zero tillage are not clear, although some factors that play a role can be distinguished, e.g., root development and rhizodeposits, baseline soil C content, bulk density and porosity, climate, landscape position, and erosion/deposition history. Altering crop rotation can influence soil C stocks by changing quantity and quality of organic matter input. More research is needed, especially in the tropical areas where good quantitative information is lacking. However, even if C sequestration is questionable in some areas and cropping systems, CA remains an important technology that improves soil processes, controls soil erosion and reduces production cost. (CabAbstracts)
  • Conservation agriculture, improving soil quality for sustainable production systems?
    Verhulst, N.; Govaerts, Bram; Verachtert, E.; Castellanos-Navarrete, A.; Mezzalama, M.; Wall, P.; Chocobar, A.; Deckers, Jozef; Sayre, Ken D. (Boca Raton, FL: CRC Press, 2010)
    This chapter presents a detailed definition of conservation agriculture and its influence on soil quality. In a time when food security is becoming an increasingly important issue, the manner in which farmers manage their crops can have huge implications for crop productivity. Where conventional farming practices have always been used, it is evident that soil health is declining. Being aware of the physical, chemical, and biological aspects of soil quality can help researchers and developers maintain and improve soil quality and increase crop production.
  • Conventionally tilled and permanent raised beds with different crop residue management: Effects on soil C and N dynamics
    Govaerts, Bram; Sayre, Ken D.; Ceballos-Ramirez, J. M.; Luna-Guido, M. L.; Limon-Ortega, A.; Deckers, Jozef; Dendooven, L. (2006)
    This article compares levels of soil carbon and soil nitrogen in conventionally tilled and conservation agriculture production systems in Mexico. It is found that conservation agriculture systems have much higher carbon and nitrogen levels over time.
  • The effect of tillage, crop rotation and residue management on maize and wheat growth and development evaluated with an optical sensor
    Verhulst, N.; Govaerts, Bram; Nelissen, V.; Sayre, Ken D.; Crossa, J.; Raes, D.; Deckers, Jozef (Elsevier B.V., 2011)
    Crop growth and development as well as yield are the result of the efficiency of the chosen agricultural management system within the boundaries of the agro-ecological environment. End-of-season yield results do not permit the evaluation of within-season management interactions with the production environment and do not allow for full understanding of the management practice applied. Crop growth and development were measured during the 2004, 2006 and 2008 crop cycles with an optical handheld NDVI sensor for all plots of the different management treatments of a long-term (since 1991) sustainability trial in the highlands of Mexico. Cropping systems varying in (1) tillage (conventional vs. zero tillage); (2) residue management (retention vs. removal); (3) rotation (monocropping vs. a maize [Zea mays L.]/wheat [Triticum aestivum L.] rotation) were compared. The NDVI-handheld sensor was evaluated as a tool to monitor crop growth and development and was found to be an excellent tool for this purpose. There was a strong relation between NDVI and biomass accumulation of maize and wheat. The measurement with the handheld sensor was non-destructive and fast so that a representative plot area could be measured easily and time-efficiently. Zero tillage induced different crop growth dynamics over time compared to conventional tillage. Zero tillage with residue retention is characterized by a slower initial crop growth, compensated for by an increased growth in the later stages, positively influencing final grain yield. Also crop rotation influenced early crop growth, with lower NDVI values for crops sown after wheat than crops after maize. Zero tillage with residue removal had low NDVI values throughout the growing season. Zero tillage with retention of crop residues results in time efficient use of resources, as opposed to conventional tillage, regardless of residue management, and zero tillage with residue removal. The results indicated that different tillage, rotation and residue management practices influence crop growth and development. It is important to monitor and understand crop growth under different management systems to select the right varieties and adjust timing and practice of input supply (fertilizer, irrigation etc.) in a holistic way in each cropping system. (CAB Abstract)
  • Effects of conservation agriculture on runoff, soil loss and crop yield under rainfed conditions in Tigray, Northern Ethiopia
    Araya, T.; Cornelis, W. M.; Nyssen, J.; Govaerts, Bram; Bauer, H.; Gebreegziabher, T.; Oicha, T.; Raes, D.; Sayre, Ken D.; Haile, M.; Deckers, Jozef (Wiley-Blackwell, 2011)
    The aim of conservation agriculture (CA) is to improve soil quality and crop yield whilst reducing runoff and topsoil erosion. An experiment was carried out in a rainfed field using a permanent raised bed planting system for three years (2005-2007) in Adigudem, northern Ethiopia in order to evaluate the effect of CA on runoff, soil loss and crop yield. CA practices were introduced in fields with Vertisols in a randomized complete block design on permanent 5×19 meter plots. Three treatments were evaluated: (1) conventional tillage (CT) with a minimum of three tillage operations and removal of crop residues, (2) terwah (TER) that was similar to CT except that contour furrows were included at 1.5 meter intervals, and (3) derdero+ (DER+), which consists of permanent raised beds with a furrow and bed system, retention of 30% of standing crop residues and zero tillage on the top of the bed. All ploughing as well as the maintenance of the furrows of the permanent raised beds was done using a local ard plough called maresha. Results from monitoring over 3 yr showed that soil loss and runoff were significantly higher (P
  • Infiltration, soil moisture, root rot and nematode populations after 12 years of different tillage, residue and crop rotation managements
    Govaerts, Bram; Fuentes, M.; Mezzalama, M.; Nicol, J. M.; Deckers, Jozef; Etchevers, J. D.; Figueroa-Sandoval, B.; Sayre, Ken D. (Elsevier B.V., 2007)
    The objective of this study was to compare till and zero till systems in terms of their impact on water infiltration, soil moisture content, root diseases and nematode populations. Using a 12 year trial with 16 different treatments, results indicated that no till systems with residue retention were the highest yielding, but there was increased disease and nematode populations in the zero till systems. However, no till systems with residue retention had a lower incidence of disease and pests than no till without residue retention. The researchers point out that while increased root disease may have impacted crop performance, the additional gains to water infiltration and soil moisture content more than offset this to increase yields.
  • Influence of permanent raised bed planting and residue management on physical and chemical soil quality in rain fed maize/wheat systems
    Sayre, Ken D.; Govaerts, Bram; Lichter, K.; Dendooven, L.; Deckers, Jozef (2007)
    Using a long range field trial, this research examines the impact of conservation agriculture practices in permanent raised beds on soil quality and soil organic matter in Central Mexico
  • Influence of tillage, residue management, and crop rotation on soil microbial biomass and catabolic diversity
    Govaerts, Bram; Mezzalama, M.; Unno, Y.; Sayre, Ken D.; Luna-Guido, M. L.; Vanherck, K.; Dendooven, L.; Deckers, Jozef (Elsevier, B.V., 2007)
    This article examines the impact of no till systems in a 12 year trial in the central highlands of Mexico, specifically focusing on effects on microbial biomass and catabolic diversity in rainfed smallholder agricultural systems. A significant finding of the study is that zero till without residue retention is an unsustainable production practice.
  • A minimum data set for soil quality assessment of wheat and maize cropping in the highlands of Mexico
    Govaerts, Bram; Sayre, Ken D.; Deckers, Jozef (2006)
    This article examines the minimum amount of data that should be collected to track changes in soil quality in the transfer of conservation agriculture technologies from researchers to farmers through a combination of treatment descriptions and chemical soil quality indicators. Through the collection and compilation of this minimum data set on farm trials, the researchers were able to discern a significant positive difference in soil quality from conservation agriculture to conventional agriculture practices.
  • The role of conservation agriculture in sustainable agriculture
    Hobbs, Peter R.; Sayre, Ken D.; Gupta, Raj (Royal Society Publishing, 2007)
    The paper identifies conservation agriculture as the most sustainable agricultural approach for the future. Conservation agriculture is defined as a style of farming that incorporates no-till (NT) to ensure minimum soil distribution, and constant soil covering though utilization of mulch, with rotations. The benefits of tillage are elaborated upon, followed by an explanation of the principles of conservation tillage. The authors cite the benefits of conservation agriculture - improved soil properties, strengthened biotic conditions, more efficient use of natural resources, smaller environmental impact, smaller greenhouse gas emissions, and smaller impact on global warming - as reasons why conservation agriculture is a better food production system than conservation tillage. The authors utilize case studies from the irrigated maize–wheat systems of Northwest Mexico and from the rice–wheat areas of the Indo-Gangetic Plains of South Asia to elaborate upon these arguments. The paper concludes that despite dwindling land and natural resources available for food production, integration of conservation agriculture will help to meet the needs of the rising global population.
  • Stable high yields with zero tillage and permanent bed planting?
    Govaerts, Bram; Sayre, Ken D.; Deckers, Jozef (Elsevier B.V., 2005)
    Given that subtropical highlands around the world are experiencing problems of environmental degradation, this article examines conservation agriculture methods for maize and wheat to combat soil erosion and fertility decline. While methods of rotating crops and maintaining residues proved to be effective over the long range of the study, it took some 5 years for yield benefits to emerge. Moreover, the research also demonstrated that there was not a significant difference in yield when some of the surface cover was removed. It is suggested that this could be a positive sign in encouraging smallholder adoption as it allows for multiple uses of crop residues for fertility gains and the maintenance of livestock.
  • Using NDVI and soil quality analysis to assess influence of agronomic management on within-plot spatial variability and factors limiting production
    Verhulst, N.; Govaerts, Bram; Sayre, Ken D.; Deckers, Jozef; François, I. M.; Dendooven, L. (2008)
    This study uses remote sensing technology to map the spatial variability of crop performance within trial fields using conservation agriculture practices. Using zero tillage and residue removal, it is discovered that crop performance is unevenly distributed within the field with lower elevations offering higher performance. However, retaining soil cover allows for uniform distribution of crop performance. Subsequently, the article concludes that maintaining soil moisture is the most important element of the production system and recommends retention of cover for best performance throughout the field.
  • Wheat yield and tillage-straw management system × year interaction explained by climatic co-variables for an irrigated bed planting system in northwestern Mexico
    Verhulst, N.; Sayre, Ken D.; Vargas, M.; Crossa, J.; Deckers, Jozef; Raes, D.; Govaerts, Bram (Elsevier B.V., 2011)
    Wheat is an important food and income source and estimated demand for wheat in the developing world is projected to increase substantially. The objectives of this study were to gain insight into (i) the effect of tillage-straw system on yield and yield components (number of grains per meter squared and thousand kernel weight), (ii) the relation between climatic conditions and yield and yield components, (iii) the explanation of tillage-straw system × year interaction for yield and yield components by climatic co-variables. Wheat grain yield and yield components were measured in a long-term trial established in 1992 under irrigated, arid conditions in northwestern Mexico. Five tillage-straw management systems (conventionally tilled raised beds [CTB] with straw incorporated and permanent raised beds [PB] with straw burned, removed, partly retained or fully retained) were compared for a wheat-maize rotation. Daily climatic data were averaged over six periods corresponding approximately to advancing wheat growth stages. The PB-straw retained and PB-straw removed had the highest yields (average yield of 7.31 and 7.24 t ha-1, respectively) and grains per m2. The PB-straw burned had the lowest yield (average yield of 6.65 t ha-1) and grains per m2, but the highest thousand kernel weight. Maximum temperature was positively correlated to final grain yield during tillering and head differentiation, but was negatively correlated to thousand kernel weight during grain-filling. For the tillage-straw system year interaction, three groups of management systems were distinguished for yield and grains per m2: PB-straw burned, CTB-straw incorporated and PB where straw is not burned. The CTB-straw incorporated had a positive interaction with year in favorable years with high radiation and evapotranspiration. The PB-straw burned was relatively more affected by excess water conditions and showed positive interactions in years with high relative humidity. The PB-straw retained was the most stable in different climatic conditions, indicating that this management system could contribute to maintaining wheat yield in a changing climate scenario. (Cab Abstracts)