Posts Tagged ‘Conservation agriculture’

Gender, nutrition- and climate-smart food production: Opportunities and trade-offs

Posted by Carelia Juarez on , in Journal Articles

Published in Food Security  5 (5) : 709-721, 2013

Beuchelt, T.D.; Badstue, L.B.

Future food and nutrition security is threatened by climate change, overexploitation of natural resources and pervasive social inequalities. Promising solutions are often technology-focused and not necessarily developed considering gender and social disparities. This paper addresses issues of gender and human development opportunities and trade-offs related to promoting improved technologies for agricultural development. We examined these aspects for conservation agriculture (CA) as part of a cropping system with nutrition- and climate-smart potential. The paper is based on a literature review and field experiences from Zambia and Mexico. Findings point up situations where the promotion of CA for smallholders in developing countries may have undesired effects from gender and human development perspectives, specifically relating to drudgery, nutrition and food security, residue use, assets, mechanization and extension. The direction and magnitude of potential trade-offs depend on the local context and the specific intervention. The analysis is followed by a discussion of opportunities and pathways for mitigating the trade-offs, including gender transformative approaches; engagement with alternative or non-traditional partners with different but complementary perspectives and strengths; “smart” combinations of technologies and approaches; and policies for inclusive development.

From adoption claims to understanding farmers and contexts: A literature review of Conservation Agriculture (CA) adoption among smallholder farmers in southern Africa

Posted by Carelia Juarez on , in Journal Articles

Published in Agriculture, Ecosystems and Environment, 2013

Andersson, J.A.; D’Souza, S.

This literature review of Conservation Agriculture (CA) adoption among smallholder farmers in southern Africa (Malawi, Zambia and Zimbabwe) analyses the historical background of the upsurge in CA promotion, the various definitions of CA that have emerged since the 1990s, the barriers to its adoption, as well as uptake figures and adoption studies. First tested as soil and water conservation measures, large-scale promotion followed a reframing of CA as a production-enhancing set of practices. Different definitions of what constitutes and is promoted as CA in southern Africa complicates the assessment of adoption across the region, while a commonly used, reductionist notion of CA adoption – as the uptake of minimum tillage – in adoption data collection, casts doubts on the validity of adoption figures. As CA uptake is often also incentivized by means of input support (fertilizers, seeds, herbicides) provided by promotional projects, adoption claims have limited value. Current CA adoption studies are methodologically weak as they are biased by the promotional project context in which are carried out, and build on farm-scale analyses of standard household surveys. A more thorough analysis of farming households and their resource allocation strategies is required to understand the farm-level adoption constraints different types of farmers face. As contextual factors appear key influences on smallholders’ farming practices, studies focusing on the wider market, institutional and policy context are also needed if we are to understand (limited) CA adoption in southern Africa.

Tradeoffs in crop residue utilization in mixed crop-livestock systems and implications for conservation agriculture

Posted by Carelia Juarez on , in Journal Articles

Published in Agricultural Systems 121 : 96-105, 2013

Moti Jaleta, Menale Kassieb and Bekele Shiferaw

Crop residue use for soil mulch and animal feed are the two major competing purposes and the basic source of fundamental challenge in conservation agriculture (CA) where residue retention on farm plots is one of the three CA principles. Using survey data from Kenya and applying bivariate ordered Probit and bivariate Tobit models, this paper analyzes the tradeoffs in maize residue use as soil mulch and livestock feed in mixed farming systems. Results show that both the proportion and quantity of maize residue used for soil mulch and livestock feed are strongly affected by livestock holding. More livestock holding decreases the proportion of maize residue retained as soil mulch and increases the proportion used as feed. Farmer knowledge about alternative use of crop residues and farmer perception of soil erosion risk (proxied through plot steepness) positively affect the amount of residue farmers retain on maize plots. Results imply that crop residue use assoil mulch in conservation agriculture is challenged in mixed crop–livestock systems and particularly by smallholder farmers owning cross-bred and exotic dairy animals. In general, reducing the use of crop residues as livestock feed through the introduction of alternative feed sources, better extension services on the use of crop residue as soil mulch and designing context specific strategies and interventions could facilitate the adoption and expansion of CA-based practices in mixed crop–livestock systems.

Tillage and nitrogen fertilization effects on yield and nitrogen use efficiency of irrigated cotton

Posted by Carelia Juarez on , in Journal Articles

Published in Soil and Tillage Research, 2013

M. Devkota,  C. Martius,  J.P.A. Lamers, K.D. Sayre, K.P. Devkota and P.L.G. Vlek

Management practices may influence yield and nitrogen (N) use efficiency of irrigated cotton (Gossypium hirsutum L.) in irrigated arid lands such as those of the Aral Sea basin. A field experiment was conducted to compare the effects of conservation tillage (permanent raised beds; PB) with conventional plow tillage (CT) under three different N application rates (0, 125 and 250 kg ha−1) on cotton growth, yield, N use efficiency and N balance in irrigated arid lands of Uzbekistan for two years. Raw cotton yield and yield components were not affected by tillage methods in both years. However, yield and yield components significantly increased when N fertilizer rate was increased from zero to 125 kg ha−1 N application. When the N rate was doubled from 125 to 250 kg ha−1, a relatively much lower increment was observed in both tillage methods. The groundwater nitrate concentration was reduced considerably, while efficiency of applied N was increased in 2009, i.e., after introduction of the cover crop in the cotton mono cropping system, compared to 2008. The efficiency of the applied N decreased with increased N application rate. Tillage method did not affect agronomic N use efficiency in both years. However, in the 2nd year, apparent N recovery efficiency was higher in PB than in CT, while physiological N use efficiency with N-250 was 54% lower in PB than in CT. The apparent system N balance was negative with N-0 and N-125, but positive (N loss) with high N application (250 kg ha−1) with both tillage methods. A significant interaction effect between tillage and N level was observed; with N-0, CT had a 32% higher negative N balance than PB. With N-250, CT had a significantly higher positive N balance (N loss), more than twice as high (66 kg ha−1) as for PB. Thus, cotton cultivation in PB with proper N application and the introduction of a winter cover crop can be considered a viable alternative to the present unsustainable CT cotton mono-cropping system in irrigated arid lands, assuming the patterns are confirmed in the long-run.

Optimizing intensive cereal-based cropping systems addressing current and future drivers of agricultural change in the northwestern Indo-Gangetic Plains of India

Posted by Carelia Juarez on , in Journal Articles

Published in Agriculture, Ecosystems and Environment 117  : 85-97, 2013

Mahesh K. Gathala, Virender Kumar, P.C. Sharma, Yashpal S. Saharawat, H.S. Jat, Mainpal Singh, Amit Kumar, M.L. Jat, E. Humphreys, D.K. Sharma, Sheetal Sharma and J.K. Ladha

Increasing scarcity of resources (labour, water, and energy) and cost of production, along with climate variability, are major challenges for the sustainability of rice–wheat system in the northwesten Indo-GangeticPlains (IGP). We hypothesized that adopting the principles of conservation agriculture together with best crop management practices would improve system productivity and overall efficiency, resulting in a higher profitability. To test this hypothesis, we evaluated the performance of four cropping system scenarios (treatments), which were designed to be adapted to current and future drivers of agricultural changes. The treatments including farmers practices varied in tillage and crop establishment methods, residue management, crop sequence, and crop management. Zero-tillage direct-seeded rice (ZT-DSR) with residue retention and best management practices provided equivalent or higher yield and 30–50% lower irrigation water use than those of farmer-managed puddled transplanted rice (CT-TPR). Overall, net economic returns increased up to 79% with a net reduction in production cost of up to US$ 55 ha−1 in ZT-DSR than CT-TPR. Substituting rice with ZT maize was equally profitable but with 88–95% less irrigation water use. Avoiding puddling in rice and dry tillage in maize with residue retention increased yield (by 0.5–1.2 t ha−1) and net economic returns of the succeeding wheat crop. Inclusion of mungbean in the rotation further increased system productivity and economic returns. In summary, our initial results of 2-year field study showed positive effects of CA-based improved management practices on yield and system efficiencies with greater benefits in the second year. There is a need of longer term monitoring to quantify cumulative effects of various interventions and to eventually make recommendations for wider dissemination.

Risk and maize-based cropping systems for smallholder Malawi farmers using conservation agriculture technologies

Posted by Carelia Juarez on , in Journal Articles

Published in Experimental Agriculture, 2013

A.R. Ngwira, C. Thierfelder, N. Eash and D.M.Lambert

Agricultural production in southern Africa is constrained by numerous factors, including low soil fertility, frequent droughts and flooding, limited access to fertilizers and the use of unsustainable management techniques that increase soil erosion rates. Conservation agriculture (CA) is based on the principles of minimum soil disturbance, crop residue retention and crop rotations. CA systems have been proposed to alleviate the negative externalities associated with conventional crop management systems. This study was conducted to examine the riskiness of economic returns of CA technologies based on maize grain yield evaluated in 12 target communities in Malawi from 2005–2011. On average, maize grain yields on both CA treatments exceeded the conventional control treatment by 22.1–23.6%, with differences more distinct in low altitude areas with low rainfall and frequent seasonal dry spells. Stochastic dominance analysis suggest that CA technologies would be preferred by risk-averse farmers, with corresponding differences in risk premiums (compared to conventional maize production systems) ranging between US$40 and US$105. However, these rankings are sensitive to the agroecological zones where the experiments were conducted. The risk premiums associated with the CA technologies in low elevation regions are unambiguous. Risk-averse farmers in higher elevations may need substantial incentives to adopt some CA technologies.


Adapting maize production to climate change in sub-Saharan Africa

Posted by Carelia Juarez on , in Journal Articles

Published in Food Security, 2013

Jill E. Cairns, Jon Hellin, Kai Sonder, José Luis Araus, John F. MacRobert, Christian Thierfelder and  B. M. Prasanna

Given the accumulating evidence of climate change in sub-Saharan Africa, there is an urgent need to develop more climate resilient maize systems. Adaptation strategies to climate change in maize systems in sub-Saharan Africa are likely to include improved germplasm with tolerance to drought and heat stress and improved management practices. Adapting maize systems to future climates requires the ability to accurately predict future climate scenarios in order to determine agricultural responses to climate change and set priorities for adaptation strategies. Here we review the projected climate change scenarios for Africa’s maize growing regions using the outputs of 19 global climate models. By 2050, air temperatures are expected to increase throughout maize mega- environments within sub-Saharan Africa by an average of 2.1°C. Rainfall changes during the maize growing season varied with location. Given the time lag between the development of improved cultivars until the seed is in the hands of farmers and adoption of new management practices, there is an urgent need to prioritise research strategies on climate change resilient germplasm development to offset the predicted yield declines.


Satellite detection of earlier wheat sowing in India and implications for yield trends

Posted by Carelia Juarez on , in Journal Articles

Published in Agricultural Systems 115 : 137-143, 2013

David B. Lobell, J. Ivan Ortiz-Monasterio, Adam M. Sibley and V.S. Sohu

Wheat is a staple crop throughout much of India, but in many areas it is commonly sown past the optimum window for yields. Recent technologies, such as adoption of no-till practices or earlier maturing cotton and rice varieties, have enabled some farmers to sow wheat earlier, but repeatable and publicly available measurements of sow date trends are lacking. Here we utilize satellite measurements since 2000 to estimate sow dates over a decade throughout wheat growing areas in India. Comparisons with ground-based sow dates in Punjab confirmed the reliability of satellite estimates, and data from two independent satellite sensors were used as a robustness check. We find statistically significant (p < 0.05) shifts toward earlier sowing of wheat throughout much of Haryana and Uttar Pradesh, with insignificant changes in Punjab. A production-weighted average of the entire region indicates that, on average, wheat was sown 1 week earlier by 2010 than it was at the beginning of the decade. Using previously published experimental estimates of yield gains from earlier sowing, we estimate that an overall yield gain of at least 5% averaged across India can be explained by the sow date trend. Given that national yield changes since 2000 have been less than 5%, our results indicate that the sow date shift has been a major factor in yield changes over the past decade, and that the net yield effect of all factors other than sow date has been close to zero, perhaps even negative. The results also indicate that sow dates in much of Haryana and western Uttar Pradesh are nearing or already at the optimum window for yields, so that yield benefits from sow date shifts will likely diminish in the next decade.


Cumulative effects of reduced tillage and mulching on soil properties under semi-arid conditions

Posted by Carelia Juarez on , in Journal Articles

Published in Journal of Arid Environments 91 : 45-52, 2013

 W. Mupangwa, S. Twomlow and S. Walker

 Declining soil productivity is one of the greatest challenges facing smallholder agriculture. This study assessed effects of reduced tillage and mulching on soil organic carbon, bulk density, infiltration and maize yield. Treatments consisted of three tillage methods (conventional ploughing, ripping and planting basins) combined factorially with mulch levels (0, 0.5, 1, 2, 4, 8 and 10 t ha−1). The experiment was run for four growing seasons allowing for a rotation of maize, cowpea and sorghum in some of the fields. A new experimental field was opened each year and maintained in subsequent seasons until the end of the experiment.

Soil organic carbon increased with time in all tillage systems and more SOC gained in planting basins. Soil bulk density decreased with time in all tillage systems irrespective of mulch quantity applied. Ripping loosened the soil much deeper than the other tillage methods. Total infiltration in all treatments was similar over the four seasons. Soil structural changes resulted in increased unsaturated hydraulic conductivity and sorptivity of the clay loam soil. Maize yield increased with time in all treatments. Long term studies need to be conducted to substantiate the results on soil property and crop yield improvements observed in the reported study.

Maximizing productivity and improving nutrition through intercropping quality protein maize and potato

Posted by Carelia Juarez on , in Journal Articles

Published in Acta Agronomica Hungarica 60 (3) : 221-230, 2012

T. R. Chapagain, B. B. Khatri, P. Bhattarai, B. P. Luitel, G. Ortiz-Ferrara and  R. C. Sharma

Intercropping potato with quality protein maize (QPM) could improve the livelihood and nutritional status of the resource-poor farmers who produce and consume them. A study was conducted from 2008 to 2010 to assess the performance of three improved potato varieties in an intercropping system with an improved QPM in the high hills of Nepal. The QPM was sown for four consecutive weeks following potato planting. The commercial potato varieties Janak Dev, Kufri Jyoti and Khumal Seto-1 were used, while the improved QPM was Poshilo Makai-1. Delayed intercropping caused a reduction in the maize yield, but an increase in the potato yield. The highest potato yield was obtained from maize intercropping after four weeks. The grain yield of maize was significantly reduced by late planting beyond the second week. The average weekly rate of increase due to maize intercropping was better for Janak Dev and Kufri Jyoti, while Khumal Seto-1 was less suitable for intercropping. The land equivalent ratio for potato-maize intercropping was 2.23. The results suggest that Poshilo Makai-1 could be incorporated in potato-maize intercropping, leading to higher returns and nutritional benefits. The findings underline the importance of variety and date of intercropping to maximize production. The findings have implications for harnessing higher productivity on resource-poor farms, and could contribute to food and nutritional security for resource-poor farmers.