Posts Tagged ‘Conservation agriculture’

Effects of tillage and crop residue management on maize yields and net returns in the Central Mexican highlands under drought conditions

Posted by Carelia Juarez on , in Journal Articles

Published in Pedosphere 24 (4476-486, 2014

Romero-Perezgrovas, R.R.Verhulst, N.De la Rosa, D.Hernandez, V.Maertens, M.Deckers, J.Govaerts, B.

In the subtropical highlands of Central Mexico, where the main crop is maize (Zea mays), the conventional practice (CP) involves tillage, monoculture and residue removal, leading to soil degradation and unsustainable use of natural resources and agricultural inputs. Conservation agriculture (CA) has been proposed as a viable alternative in the region, based on reduction in tillage, retention of adequate levels of crop residues and soil surface cover and use of crop rotation. This study began in 2009 when the highlands of Central Mexico suffered from a prolonged drought during vegetative maize growth in July–August, providing an opportunity for the on-farm comparison of CA with CP under severe drought conditions which 21 climate change models projected to become more frequent. Under dry conditions, CA resulted in higher yields and net returns per hectare as early as the first and second years after adoption by farmers. As an average of 27 plots under farmers’ management in 2009, the maize yields were 26% higher under CA (6.3 t ha−1) than under CP (5.0 t ha−1). 2010 was close to a normal year in terms of rainfall so yields were higher than in 2009 for both practices; in addition, the yield difference between the practices was reduced to 19% (6.8 t ha−1 for CA vs.5.7 t ha−1 for CP). When all the 2009 and 2010 observations were analyzed in a modified stability analysis, CA had an overall positive effect of 3 838 Mexican Pesos ha−1 (320 $US ha−1) on net return and 1.3 t ha−1 on yield. After only one to two years of adoption by farmers on their fields, CA had higher yields and net returns under dry conditions that were even drier than those predicted by the analyzed 21 climate change models under a climate change scenario, emission scenario A2.

Durum wheat (Triticum durum L.) quality and yield as affected by tillage-straw management and nitrogen fertilization practice under furrow-irrigated conditions

Posted by Carelia Juarez on , in Journal Articles

Published in Field Crops Research 164 : 166-177, 2014

Grahmann, K.Verhulst, N.Peña-Bautista, R.J.Buerkert, A.;Vargas-Rojas, L.Govaerts, B.

Little is documented about the effect of different tillage and residue management practices on durum wheat (Triticum durum L.) quality. This study aims at examining the effect of tillage–residue management systems on wheat yield and quality in two cropping cycles, 19 years after establishment of tillage–residue management systems in 1992. Wheat grain samples were collected in an experiment with a durum wheat-maize (Zea mays L.) rotation and furrow-irrigation, conducted in the arid Yaqui Valley of north-western Mexico. Main plots had five tillage–crop residue management treatments: conventionally tilled raised beds (CTB) with straw incorporated and permanent raised beds (PB) with straw burned, removed, partly retained or fully retained. Split plots had seven nitrogen (N) fertilizer treatments with different rate (0, 150 or 300 kg N ha−1) and timing of application (basal, 1st node and split between both). Highest yields were obtained with PB-straw partly retained and 300 kg N ha−1 split application in 2010/11 (7.48 t ha−1) and with PB-straw removed and 300 kg N ha−1 applied at 1st node in 2011/12 (8.26 t ha−1). Permanent beds with full residue retention had high yellow berry (YB, opaque and starchy endosperm) incidence, even with 300 kg N ha−1; 19.5% in 2010/11 and 9.4% in 2011/12 of the grain kernels were affected by YB. Four groups of tillage–straw systems with different characteristics in relation to the durum wheat quality and yield were distinguished with a principal component analysis: PB-partly retained with high yields and acceptable quality, PB-straw retained with low quality and acceptable yields, CTB with intermediate quality results and lower yields and PB-straw burned with high quality and low yields. Results indicate a significant effect of timing of N application on durum wheat grain quality in PB. For both cycles and both N rates, the application of mineral N resulted in higher grain quality when all N was applied near 1st node. Grain quality was highest in PB-straw burned, but this practice had the lowest yields. For PB-straw fully retained, 1st node application of N fertilizer is recommended to minimize N immobilization. To obtain stable yields and desirable quality, alternative tillage practices such as PB with full or partial residue retention require adjusted, site-specific N management. Further research is required to identify fertilization strategies in tillage systems with full or partial residue retention that include fertilizer applications after first node to improve grain quality.

Identifying determinants, pressures and trade-offs of crop residue use in mixed smallholder farms in Sub-Saharan Africa and South Asia

Posted by Carelia Juarez on , in Journal Articles

Published in Agricultural Systems, 2014

Valbuena, D.Homann-Kee Tui, S.Erenstein, O.Teufel, N.Duncan, A.Abdoulaye, T.Swain, B.;Mekonnen, K.Germaine, I.Gerard, B. 

Crop residues (CR) have become a limited resource in mixed crop-livestock farms. As a result of the increasing demand and low availability of alternative resources, CR became an essential resource for household activities, especially for livestock keeping; a major livelihood element of smallholder farmers in the developing world. Farmers’ decisions on CR use are determined by farmers’ preferences, total crop production, availability of alternative resources and demand for CR. Interaction of these determinants can result in pressures and trade-offs of CR use. Determinants, pressures and trade-offs are shaped by the specific socio-economic and agro-ecological context of these mixed farms. The objective of this paper is to provide a comparative analysis of the determinants of CR use and to examine some options to cope with pressures and trade-offs in 12 study sites across Sub-Saharan Africa and South Asia. Drawing on socio-economic data at household and village level, we describe how cereal intensification and livestock feed demand influence use, pressures and trade-offs of CR use across study sites, specifically cereal residue. Our results show that in low cereal production and livestock feed demand sites, despite a low demand for CR and availability of alternative biomass, pressures and trade-offs of CR use are common particularly in the dry season. In sites with moderate cereal production, and low–moderate and moderate livestock feed demand, alternative biomass resources are scarce and most residues are fed to livestock or used to cover household needs. Subsequently, pressures and potential trade-offs are stronger. In sites with low cereal production and high livestock feed demand, pressures and trade-offs depend on the availability of better feed resources. Finally, sites with high cereal production and high livestock feed demand have been able to fulfil most of the demand for CR, limiting pressures and trade-offs. These patterns show that agricultural intensification, better management of communal resources and off-farm activities are plausible development pathways to overcome pressures and trade-offs of CR use. Although technologies can largely improve these trends, research and development should revisit past initiatives so as to develop innovative approaches to tackle the well-known problem of low agricultural production in many smallholder mixed systems, creating more sustainable futures.

On-farm evaluation of the effects of the principles and components of conservation agriculture on maize yield and weed biomass in Malawi

Posted by Carelia Juarez on , in Journal Articles

Published in Experimental Agriculture, 2014

Ngwira, A.R.Aune, J.B.Thierfelder, C.

An on-farm study was conducted from 2009 to 2012 with communities in the Manjawira, Mpingu and Zidyana Extension Planning Areas in the Ntcheu, Lilongwe and Nkhotakota districts of central Malawi. The aim of the study was to evaluate the effects of the principles (no-tillage and mulching) and components (fertilization and weeding) of conservation agriculture (CA) on crop productivity and weeds, and the interactions between principles and components, and to suggest strategies for introducing CA to smallholder farmers. The treatments consisted of tillage, fertilizer application, residues management and weed control strategies. While combined analysis showed that mulching is as effective as tillage in controlling weeds, the interaction between site and treatment revealed that in the more humid environment of Zidyana, weed dry matter obtained under no-tillage and residues plus fertilizer (NT+F+R) was 0.6 mg ha−1 lower than under CP+F. Results suggest that about 6.0 mg ha−1 of mulch is required to have a similar effect as tillage in controlling weeds. Fertilizer had an overriding effect on maize yield, regardless of tillage and crop residue management. Mulching was beneficial over tillage in the drier environment of Manjawira, where maize yield obtained under NT+F+R was 1.2 mg ha−1 greater than under CP+F. Our results show that the introduction of no tillage has benefits only if it is accompanied by fertilizer application, retention of crop residues as surface mulch, and improved weed control. Increasing availability and accessibility of inputs (fertilizers and herbicides) to farmers is critical for adoption of CA at scale in Malawi.

Nitrogen use efficiency and optimization of nitrogen fertilization in conservation agriculture

Posted by Carelia Juarez on , in CIMMYT Publications

Nitrogen use efficiency and optimization of nitrogen fertilization in conservation agriculture2014Verhulst, N.;Francois, I.M.Grahmann, K.Cox, R.Govaerts, B. Mexico, DF (Mexico)CIMMYT ii, 6 p. 

98924This is didactic material developed by CIMMYT’s Mexico-based  Conservation Agriculture Program.

Infiltration: A practical guide for comparing crop management practices

Posted by Carelia Juarez on , in CIMMYT Publications

Infiltration: A practical guide for comparing crop management practices2013Verhulst, N.Cox, R.;Govaerts, B. Mexico, DF (Mexico)CIMMYT 8 p. 

98367This material was developed under the CGIAR Research Program on Climate  Change, Agriculture and Food Security (CCAFS) and partly funded by ‘Desarrollo sustentable con el productor’, part of ‘Modernización Sustentable  de la Agricultura Tradicional’, supported by SAGARPA.

Soil aggregate distribution by dry sieving: A practical guide for comparing crop management practices

Posted by Carelia Juarez on , in CIMMYT Publications

Soil aggregate distribution by dry sieving: A practical guide for comparing crop management practices. 2013Verhulst, N.Cox, R.Govaerts, B. Mexico, DF (Mexico)CIMMYT 4 p. 

98395This material was developed under the CGIAR Research Program on Climate  Change, Agriculture and Food Security (CCAFS) and partly funded by ‘Desarrollo sustentable con el productor’, part of ‘Modernización Sustentable  de la Agricultura Tradicional’, supported by SAGARPA.

Yield and yield components: A practical guide for comparing crop management practices

Posted by Carelia Juarez on , in CIMMYT Publications

Yield and yield components: A practical guide for comparing crop management practices. 2013Verhulst, N.Cox, R.Govaerts, B. Mexico, DF (Mexico)CIMMYT 23 p. 

98391This material was developed under the CGIAR Research Program on Climate  Change, Agriculture and Food Security (CCAFS) and partly funded by ‘Desarrollo sustentable con el productor’, part of ‘Modernización Sustentable  de la Agricultura Tradicional’, supported by SAGARPA.

Cracking: A practical guide for comparing crop management practices

Posted by Carelia Juarez on , in CIMMYT Publications

Cracking: A practical guide for comparing crop management practices. 2013Verhulst, N.Cox, R.Govaerts, B. Mexico, DF (Mexico)CIMMYT 4 p. 

98390This material was developed under the CGIAR Research Program on Climate  Change, Agriculture and Food Security (CCAFS) and partly funded by ‘Desarrollo sustentable con el productor’, part of ‘Modernización Sustentable  de la Agricultura Tradicional’, supported by SAGARPA.

Mulch cover: A practical guide for comparing crop management practices

Posted by Carelia Juarez on , in CIMMYT Publications

Mulch cover: A practical guide for comparing crop management practices2013Verhulst, N.Cox, R.;Govaerts, B. Mexico, DF (Mexico)CIMMYT 3 p. 

98383This material was developed under the CGIAR Research Program on Climate  Change, Agriculture and Food Security (CCAFS) and partly funded by ‘Desarrollo sustentable con el productor’, part of ‘Modernización Sustentable  de la Agricultura Tradicional’, supported by SAGARPA.