Posts Tagged ‘Sustainable intensification’

Decomposing maize yield gaps differentiates entry points forintensification in the rainfed mid-hills of Nepal

Posted by gabrielamartinez on , in Journal Articles

56913Author: Devkota, K.P.; McDonald, A.; Khadka, A.; Khadka, L.; Paudel, G.; Devkota, M.

Published in: Field Crops Research, 2015, vol. 179, p. 81–94.

The central mid-hills region of Nepal is characterized by rainfed production systems where maize (Zeamays) is the principal crop during the monsoon (kharif) season. In general, maize yields in the hillsare judged to be intractably low and few efforts have systematically assessed either the water-limitedproductivity potential or identified sensible entry points toward sustainable intensification that can beselectively matched to the needs and constraints faced by different types of farmers. This study combinesfield surveys, on-farm field experiments, and simulation modeling (DSSAT) to explore opportunitiesfor closing maize yield gaps in these ecologies. Among surveyed households, the mean grain yield ofmaize under current farmer practice was 2.0 t ha−1whereas good agronomic practices increased maizeyields up to 6.5 t ha−1(i.e. exploitable yield gap of 4.5 t ha−1). Recognizing that farmers rarely adoptfull technology packages, the value of single agronomic interventions was also explored with all othermanagement factors maintained as per prevailing farmer practice. Averaged across sites and two seasons,non-limiting fertilizer rates (175:60:60 kg NPK ha−1) increased grain yields by 1.8 t ha−1followed by theuse of hybrids (1.4 t ha−1), higher plant population (0.9 t ha−1), and improved weed control (0.9 t ha−1).These results were also reflected in changes to the economic performance of the system with grossmargins increasing from a ‘farmer practice’ base of $202 ha−1(B:C = 1.86) to $339 ha−1(B:C = 2.14) withhybrid adoption, $454 ha−1(B:C = 2.88) with higher plant population, $646 ha−1(B:C = 2.52) with non-limiting fertilizer, and $611 ha−1(B:C = 3.37) with careful weed control. Further gains in profitability wereachieved with layered agronomic interventions, which increased gross margins to $857 and $763 ha−1(B:C = 2.95 in both) in conventional tillage (CT) and minimum (strip tillage; ST) systems, respectively.Divergence between grain yield gains and economic performance criteria highlights the importance ofconsidering both perspectives. For resource-poor households, maintaining optimal plant population canincrease B:C by more than 50% with small investments ($7 ha−1). Simulation results also suggest thatadditional potential productivity advantages are achievable with timely planting (e.g. 19% higher meanyield for short duration hybrid with less inter-annual variability). Cultivation of longer duration hybridscan also increase yield potential over their shorter duration alternatives, although trade-offs with yieldpotential of the second crop in the rotation must be considered. These results highlight several pathwaystoward intensification in the hills of Nepal that have varying investment requirements, inferred risks,and implications for the different dimensions of sustainability and food security.

Are there systematic gender differences in the adoption of sustainable agricultural intensification practices? Evidence from Kenya

Posted by Carelia Juarez on , in Journal Articles

Published in  Food Policy 49 (1117-127, 2014

 Ndiritua, S.W.Kassie, M.Shiferaw, B.

This paper uses sex-disaggregated survey data at the plot level to test whether there are systematic gender differences in the adoption of multiple sustainable intensification practices (SIPs) in Kenya. We analyze plot level adoption decisions of SIPs by male, female or joint plot managers within the household, controlling for household characteristics, asset wealth and land quality factors that condition investments in intensification options. Using a multivariate probit model, we find gender differences in the adoption pattern for some SIPs. Compared to male plot mangers, female managers are less likely to adopt minimum tillage and animal manure in crop production, indicating the existence of certain socioeconomic inequalities and barriers for female farmers. However, we find no gender differences in the adoption of soil and water conservation measures, improved seed varieties, chemical fertilizers, maize-legume intercropping, and maize-legume rotations.

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.

Conservation agriculture in southern Africa: advances in knowledge

Posted by Carelia Juarez on , in Journal Articles

Published in Renewable Agriculture and Food Systems, 2014

Thierfelder, C.; Rusinamhodzi, L.; Ngwira, A.R.;Mupangwa, W.; Isaiah, N.; Kassie, G.T.; Cairns, J.E.

The increasing demand for food from limited available land, in light of declining soil fertility and future threats of climate variability and change have increased the need for more sustainable crop management systems. Conservation agriculture (CA) is based on the three principles of minimum soil disturbance, surface crop residue retention and crop rotations, and is one of the available options. In Southern Africa, CA has been intensively promoted for more than a decade to combat declining soil fertility and to stabilize crop yields. The objective of this review is to summarize recent advances in knowledge about the benefits of CA and highlight constraints to its widespread adoption within Southern Africa. Research results from Southern Africa showed that CA generally increased water infiltration, reduced soil erosion and run-off, thereby increasing available soil moisture and deeper drainage. Physical, chemical and biological soil parameters were also improved under CA in the medium to long term. CA increased crop productivity and also reduced on-farm labor, especially when direct seeding techniques and herbicides were used. As with other cropping systems, CA has constraints at both the field and farm level. Challenges to adoption in Southern Africa include the retention of sufficient crop residues, crop rotations, weed control, pest and diseases, farmer perception and economic limitations, including poorly developed markets. It was concluded that CA is not a ‘one-size-fits-all’ solution and often needs significant adaptation and flexibility when implementing it across farming systems. However, CA may potentially reduce future soil fertility decline, the effects of seasonal dry-spells and may have a large impact on food security and farmers’ livelihoods if the challenges can be overcome.

Molecular characterization of soil bacterial communities in contrasting zero tillage systems

Posted by on , in Journal Articles

Published in Plant and Soil 329(1-2): 127-137

Molecular characterization of soil bacterial communities in contrasting zero tillage systems

Javier A. Ceja-Navarro, Flor N. Rivera, Leonardo Patiño-Zúñiga, Bram Govaerts, Rodolfo Marsch, Antón Vila-Sanjurjo and Luc Dendooven

It is well known that agricultural practices change the physical and chemical characteristics of soil. As a result, microbial populations can also be affected. The aim of this study was to analyze the effect on soil bacterial communities of zero tillage (ZT) under maize monoculture (MM) with crop residue removal (-R) (MM/-R treatment), compared to a ZT system under wheat monoculture (WW) with crop retention (+R) (WW/+R treatment). Phylogenetic analysis was used to characterize soil bacterial communities. Phylogenetic groups found exclusively in MM/-R were Caldilineales, Chromatiales, Oscillatoriales, Legionellales, Nitrosomonadales and unclassified ∂-Proteobacteria, while Bacillales, Burkholderiales, Pseudomonadales and Rubrobacteriales were found only in WW/+R. Sequences of bacteria related to fluorescent Pseudomonas sp. were detected only in WW/+R. Acidobacteria, a largely unknown group of bacteria, were the dominant group in both treatments with a relative proportion of 0.703 and 0.517 for MM/+R and WW/-R respectively. It was found that zero tillage with removal of crop residue in soil cultivated with a monoculture of maize strongly reduced microbial diversity (H = 3.30; D = 0.9040) compared to soil where crop residue was retained in a wheat zero tillage situation (H = 4.15; D = 0.9848).