Frédéric Baudron

Failing to Yield? Ploughs, Conservation Agriculture and the Problem of Agricultural Intensification: An Example from the Zambezi Valley, Zimbabwe

Abstract Agricultural intensification, or increasing yield, has been a persistent theme in policy interventions in African smallholder agriculture. This article focuses on two hegemonic policy models of such intensification: (1) the ‘Alvord model’ of plough-based, integrated crop-livestock farming promoted in colonial Zimbabwe; and (2) minimum-tillage mulch-based, Conservation Agriculture, as currently preached by a wide range of international agricultural research and development agencies. An analysis of smallholder farming practices in Zimbabwes Zambezi Valley, reveals the limited inherent understanding of farmer practices in these models. It shows why many smallholder farmers in southern Africa are predisposed towards extensification rather than intensification, and suggests that widespread Conservation Agriculture adoption is unlikely.

Re-examining appropriate mechanization in Eastern and Southern Africa: two-wheel tractors, conservation agriculture, and private sector involvement

The need for sustainable intensification in Eastern and Southern Africa (ESA) is widely recognized as a requirement to achieve food security with minimum negative social and environmental consequences. In current Research & Development programs, much emphasis is placed on increasing the efficiency with which land, water and nutrients are used, whereas farm power appears to be a ‘forgotten resource’. This is a major concern when farm power in ESA countries is declining due to the collapse of most tractor hire schemes, the decline in number of draught animals and the growing shortage of human labour. A consequence of low levels of farm mechanization is high labour drudgery, which makes farming unattractive to the youth and disproportionally affects women. Undoubtedly, sustainable intensification in ESA will require an improvement in access to farm power. In this paper, we suggest this can be achieved through the use of small, multipurpose and inexpensive power sources such as two-wheel tractors (2WTs) coupled with the promotion of energy saving technologies such as conservation agriculture (CA), whilst ensuring the profitability for farmers, service providers and other private sector actors in the supply chain. We argue that appropriate mechanization in Africa, a paradigm largely abandoned three decades ago, may be re-examined through the combination of these three elements.

Gender and conservation agriculture in East and Southern Africa: towards a research agenda

It is remarkable that despite wide-ranging, in-depth studies over many years, almost no conservation agriculture (CA) studies consider gender and gender relations as a potential explanatory factor for (low) adoption rates. This is important because CA demands new ways of working with the farm system. Implementation will inevitably involve a reallocation of mens and womens resources as well as having an impact upon their ability to realize their gender interests. With respect to intra-household decision-making and the distribution of benefits, CA interventions have implications for labour requirements and labour allocation, investment decisions with respect to mechanization and herbicide use, crop choice, and residue management. CA practice may impact upon the ability of households to source a wide variety of crops, wild plants, and insects and small animals for household nutrition. Gender biases in extension service design can sideline women. This paper examines the limited research to date on the interactions between CA interventions and gender in East and Southern Africa, and, based on the gaps observed, sets out a research agenda. It argues that attention to gender in CA is particularly timely given the increasing interest in CA as a means of adapting to climate change.

Ecological Intensification: Local Innovation to Address Global Challenges

The debate on future global food security is centered on increasing yields. This focus on availability of food is overshadowing access and utilization of food, and the stability of these over time. In addition, pleas for increasing yields across the board overlook the diversity of current positions and contexts in which local agriculture functions. And finally, the actual model of production is based on mainstream agricultural models in industrialized societies, in which ecological diversity and benefits from nature have been ignored or replaced by external inputs. The dependence upon external inputs should exacerbate the negative impacts on the environment and on social equity. Strategies to address future global food security thus require local innovation to increase agricultural production in a sustainable, affordable way in the poorest regions of the world, and to reduce the environmental impact of agriculture and its dependence on non-renewable resources. Ecological intensification, the smart use of biodiversity-mediated ecosystem functions to support agricultural production, is portrayed as the most promising avenue to achieve these goals.

Indirect contributions of forests to dietary diversity in Southern Ethiopia

We assess whether forests contribute indirectly to the dietary diversity of rural households by supporting diverse agricultural production systems. We applied our study in a landscape mosaic in Southern Ethiopia that was divided into three zones of increasing distance to Munesa Forest—“near,” “intermediate,” and “distant.” A variety of research tools and methods, including remote sensing, participatory methods, farm survey, and yield assessment, were employed. Diets of households were more diverse in the near zone than in the other two zones (6.58 ± 1.21, 5.38 ± 1.02, and 4.41 ± 0.77 food groups consumed daily in the near, intermediate, and distant zones, respectively). This difference was not explained by food items collected from Munesa Forest but by biomass flows from the forest to farmlands. Munesa Forest contributed an average of 6.13 ± 2.90 tons of biomass per farm and per year to the farms in the near zone, in the form of feed and fuelwood. Feed from the forest allowed for larger livestock herds in the near zone compared with the other two zones, and fuelwood from the forest reduced the need to use cattle dung as fuel in the near zone compared with the two other zones. These two biomass flows contributed to the availability of more manure to farmers closer to the forest (908 ± 853 kg farm -1 , 771 ± 717 kg farm -1 , and 261 ± 487 kg farm -1 in the near, intermediate, and distant zones, respectively). In turn, increased manure enabled a larger percentage of farms to cultivate a diversified homegarden (87, 64, and 39% of farms in the near, intermediate, and distant zones, respectively). Homegardens and livestock products provided the greater contribution to household dietary diversity closer to the forest.

RESTORING CROPLAND PRODUCTIVITY AND PROFITABILITY IN NORTHERN ETHIOPIAN DRYLANDS AFTER NINE YEARS OF RESOURCE-CONSERVING AGRICULTURE

Long-term in situ soil and water conservation experiments are rare in sub-Saharan Africa, particularly in Eastern Africa. A long-termexperiment was conducted (2005–2013) on aVertisol to quantify the impacts of resource-conserving agriculture (RCA) on runoff, soil loss, soil fertility and crop productivity and economic profitability in northern Ethiopia. Two RCA practices were developed from traditional furrow tillage practices: (i) derdero+ (DER+) and terwah+ (TER+). DER+ is a furrow and permanent raised bed planting system, tilled once at planting time by refreshing the furrow and 30% of crop residue is retained. TER+ is ploughed once at planting, furrows are made at 1.5 m intervals and 30% crop residue is retained. The third treatment was a conventional tillage (CT) with a minimum of three tillage operations and complete removal of crop residues. Wheat, teff, barley and grass pea crops were grown in rotation. Runoff, and soil and nutrient loss were measured in plastic sheet-lined collector trenches. Significantly different (P < 0.05) runoff coefficients (%) and soil losses (t ha−1) averaged over 9 yrs were 14 and 3, 22 and 11 and 30 and 17 for DER+, TER+ and CT, respectively. Significant improvements in crop yield and gross margin were observed after a period of three years of cropping This study demonstrated that RCA systems in semi-arid agro-ecosystems constitute a field rainwater conservation and soil fertility improvement strategy that enhances crop productivity and economic profitability. Adoption of RCA systems (DER+ and TER+) in the study area requires further work to improve smallholder farmers’ awareness on benefits, to guarantee high standards during implementation and to design appropriate weed management strategies.

Complementary practices supporting conservation agriculture in southern Africa. A review

Conservation agriculture (CA)—the simultaneous application of minimum soil disturbance, crop residue retention, and crop diversification—is a key approach to address declining soil fertility and the adverse effects of climate change in southern Africa. Applying the three defining principles of CA alone, however, is often not enough, and complementary practices and enablers are required to make CA systems more functional for smallholder farmers in the short and longer term. Here, we review 11 complementary practices and enablers grouped under six topical areas to highlight their critical need for functional CA systems, namely: (1) appropriate nutrient management to increase productivity and biomass; (2) improved stress-tolerant varieties to overcome biotic and abiotic stresses; (3) judicious use of crop chemicals to surmount pest, diseases, and weed pressure; (4) enhanced groundcover with alternative organic resources or diversification with green manures and agroforestry; (5) increased efficiency of planting and mechanization to reduce labor, facilitate timely planting, and to provide farm power for seeding; and (6) an enabling political environment and more harmonized and innovative extension approaches to streamline and foster CA promotional efforts. We found that (1) all 11 complementary practices and enablers substantially enhance the functioning of CA systems and some (e.g., appropriate nutrient management) are critically needed to close yield gaps; (2) practices and enablers must be tailored to the local farmer contexts; and (3) CA systems should either be implemented in a sequential approach, or initially at a small scale and grow from there, in order to increase feasibility for smallholder farmers. This review provides a comprehensive overview of practices and enablers that are required to improve the productivity, profitability, and feasibility of CA systems. Addressing these in southern Africa is expected to stimulate the adoption of CA by smallholders, with positive outcomes for soil health and resilience to climate change.

Nine years of conservation agriculture-based cropping systems research in eastern Africa to soil degradation and mitigate effects of climate change

Interpreting palaeovegetation and contemporary palaeoclimate from fossil pollen requires information on modern pollen-rain or deposition patterns of pollen/ spores in sediments of tropical deciduous forest (moist as well as dry types) in the area of investigation, which is achieved through the pollen analysis of surface samples, viz. surface soils/sediments, moss cushions (moss polsters), mud samples, spider web samples, leaf surface and bark that reflect modern vegetation and could be of immense help to refine and strengthen the interpretation of fossil pollen samples (Wright 1967; Flenley 1973; Moore & Webb 1978; Birks & Birks 1980; Liu & Lam 1985; Fall 1992). In the science of Quaternary palynology, this type of study has been given various names such as modern pollen-rain studies, modern pollen deposition patterns, modern pollenvegetation relationships, etc. In some advanced literature, the study has been given the name of Response Transfer Function as it serves as a modern analogue for the accurate explanation of the pollen sequences generated from the sedimentary beds in terms of past vegetation and climate in chronological order in the region during the Quaternary Period, especially the Holocene and/or Late Pleistocene epochs (Quamar & Chauhan 2012, 2013b; Chauhan & Quamar 2012a, 2012b). So far as the relationship between the present-day set-up of vegetation and pollen assemblages is concerned, it is not straightforward. Owing to the differences in pollen production, dispersal and preservation (of taxa), some plant taxa are overrepresented in pollen records whilst others are either under-represented or not represented at all (Tauber 1965; Prentice 1985; Prentice et al. 1987; Jackson & Lyford 1999; Sugita 2007) which depends on plant species and climatic conditions (Hicks 2001; Spieksma et al. 2003). Anemophilous species producing high quantities of pollen grains are over-represented, whereas species with zoophilous means of pollination produce lower numbers of pollen grains and are underrepresented in pollen assemblages (Faegri & Iverson 1964). In tropical regions, traditional pollen analysis was once upon a time thought to be impossible (Faegri 1966; Flenley 1973; Bush 1995) owing to the towering diversity of the tropical pollen flora (Flenley 1973), which was previously regarded as a stumbling block for palynologists to manage, in addition to the effect of pollen production and dispersal (on pollen analysis). However, credit goes to Flenley (1973) who for the first time investigated the modern pollen rain in the tropics systematically. Many tropical pollen taxa are rarely or never encountered in samples, despite their pollen production and dispersal to sample sites, but with the aid of modern pollen spectra the modern pollen deposition pattern could be successfully related to the vegetation. 3rd International Conference on Biodiversity & Sustainable Energy Development June 24-26, 2014 Valencia, Spain Extended Abstract Journal of Biodiversity & Endangered Species Like most palaeoecological research, the majority of work on modern pollen spectra has been carried out in temperate regions. However, the increasing interest in palaeoecological reconstruction of past tropical environments over the preceding two decades has led to more work on modern pollen spectra. A number of recent studies have been carried out in tropical areas of Africa (Vincens et al. 1997, 2000; El Ghazali & Moore 1998, Elenga et al. 2000), Australia (Kershaw & Stickland 1990; Kershaw & Bulman 1994; Crawley et al. 1994) and the mainland Neotropics (Grabant 1980; Bush 1991; Islebe & Hooghiemstra 1995; Rodgers & Horn 1996; Bush & Rivera 1998; Bush 2000; Bush et al. 2001, Marchant et al. 2001; Weng et al. 2004). In the Carribean islands, a few studies exist of sedimentary pollen profiles from lowland sites (Hodell et al. 1991; Higuera-Gundy et al. 1999), but modern pollen studies are wanting. Modern pollen rain studies were also conducted in Australia (Walker & Sun 2000), Southern Peru (Weng et al. 2004), Dominican Republic (Kennedy at al. 2005), southern Brazil (Behling & Negrelle 2006), tropical Andes (Rull 2006), northern Ecuador (Moscol Olivera et al. 2009), northeast Bolivia (Gosling et al. 2009), southern Ecuadorian Andes (Niemann et al. 2010), northern Belize (Bhattacharya et al. 2011), etc. and had generated data sets on the transfer functions regarding pollen representation to environmental parameters, as well as indicator taxa for particular ecosystems. Haselhorst et al. (2013) also conducted pollen rain studies in Panama and emphasized a better and more accurate reconstruction of palaeoenvironment and palaeoclimate in long-term pollen rain studies. However, in South Asia, especially India and Sri Lanka, Bonnefille et al. (1999), Anupama et al. (2000), Barboni and Bonnefille (2001) have conducted studies to address the modern pollen deposition pattern in tropical evergreen and deciduous forests. From the Indian context, several studies have also been conducted to address the problem, for example, from the foothills of the Himalaya (Sharma 1985; Gupta & Yadav 1992; Chauhan & Sharma 1993; Quamar and Srivastava, 2013; Ranhotra and Bhattacharayya, 2013), Kashmir (Vishnu-Mittre 1966; Vishnu-Mittre & Sharma 1966, VishnuMittre & Robert 1971), Ladakh (Bhattacharyya 1989a), Himachal Pradesh (Sharma 1973; Bhattacharayya 1989b, 1989c; Bera & Gupta 1990), tropical deciduous scrub vegetation in Rajasthan desert (Singh et al. 1973), eastern Madhya Pradesh (Chauhan 1994, 2008; Quamar & Chauhan 2007), southwestern Madhya Pradesh (Quamar & Chauhan 2010, 2011a, 2011b, 2012, 2013a; Chauhan & Quamar 2012a, 2012b), Chhattisgarh (Quamar & Bera 2013a, 2013b, 2013c), Silent Valley, south India (Gupta & Bera 1996), Tamil Nadu (Bera & Gupta 1992), Uttar Pradesh (Sharma et al. 2007; Trivedi & Chauhan 2011)), northeast India (Gupta & Sharma 1985; Bera & Gupta 1992; Bera 2000; Basumatary & Bera 2007, 2010; Dixit & Bera 2011, 2012a, 2012b, 2013; Bera et al. 2012, 2013; Basumatary et al. 2013), South and Little Andaman Islands (Singh et al. 2010) and Odisha (Singh et al. 2011), etc. These studies have provided plausible assessments of the palaeovegetation and contemporary climatic scenarios from their respective regions during the Late Quaternary Period. The present communication, however, reviews the modern pollen rain studies carried out so far from southwestern Madhya Pradesh in India, with a view to refine and strengthen the interpretation of fossil pollen records, allowing the improved resolution of palaeoenvironmental changes (Prentice et al. 1991; Separ et al. 1994). The present study reviews the pattern of modern pollen-rain carried out from south-western Madhya Pradesh, India, which largely revealed Extended Abstract Journal of Biodiversity & Endangered Species 3rd International Conference on Biodiversity & Sustainable Energy Development June 24-26, 2014 Valencia, Spain 1 that Tectona grandis (teak), despite being an enormous pollen producer (7500 average number of absolute pollen/flower) (Bhattacharya et al., 1999) and the dominant forest constituent (80 to 95% of the total forest constituents), is recorded mostly in low frequencies, attributable to its low pollen dispersal efficiency as well as poor pollen preservation in the sediments. However, Madhuca indica (Mahua) and other dominant members of Sapotaceae (cf. Manilkara hexandra and Mimusops elangi) have always shown theirs’ typical behaviour in the pollen spectra and representing in high frequencies, which is assigned to its local abundance around the provenance of the samples, coupled with high dispersal efficiency as well as good pollen preservation in the sediments. Meanwhile, the other usual and characteristic associates of teak (Tectona grandis) in the tropical deciduous forests, despite being the common elements of the forests, are underrepresented, sporadically represented or not represented at all, which could be ascribed to theirs’ low pollen productivity owing to entomogamy. Various factors that affect the deposition pattern of the diverse constituents of the tropical deciduous forests dominated by teak (Tectona grandis) have been discussed and suggestions were also given while interpreting the pollen sequences generated from the sedimentary beds in terms of past vegetation and climate in a chronological order in the region during the Late Quaternary Period. This work is partly presented at 3rd International Conference on Biodiversity & Sustainable Energy Development June 24-26, 2014 Valencia, SpainIn Ethiopia, repeated plowing, complete removal of crop residues at harvest and aftermath grazing of crop fi elds have reduced the biomass return to the soil and aggravated cropland degradation. Conservation Agriculture (CA)-based cropping systems may reduce runoff and soil erosion, and improve soil quality and crop productivity. Thus, a long-term tillage experiment has been carried out (2005 to 20123) on a Vertisol to quantify - among others - changes in runoff and soil loss for two local tillage practices, modifi ed to integrate CA principles in semi-arid northern Ethiopia. The experimental layout was a randomized complete block design with three replications on permanent plots of 5 m by 19 m. The tillage treatments were (i) derdero+ (DER+) with a furrow and permanent raised bed planting system, ploughed only once at planting by refreshing the furrow from 2005 to 2013 and 30% standing crop residue retention, (ii) terwah+ (TER+) with furrows made at 1.5 m interval, plowed once at planting, 30% standing crop residue retention and fresh broad beds, and (iii) conventional tillage (CT) with a minimum of three plain tillage operations and complete removal of crop residues. Wheat, teff, barley and grass pea were grown in rotation. Runoff and soil loss were measured daily. Signifi cantly different (p<0.05) runoff coeffi cients averaged over 9 years were 14, 22 and 30% for DER+, TER+ and CT, respectively. Mean soil losses were 3 t ha-1 y-1 in DER+, 11 in TER+ and 178 in CT. A period of at least three years of cropping was required before improvements in crop yield became signifi cant. Further, modeling of the sediment budgets shows that total soil loss due to sheet and rill erosion in cropland, when CA would be practiced at large scale in a 180 ha catchment, would reduce to 581 t y-1, instead of 1109 t y-1 under the current farmer practice. Using NASA/GISS Model II precipitation projections of IPCC scenario A1FI, CA is estimated to reduce soil loss and runoff and mitigate the effect of increased rainfall due to climate change. For smallholder farmers in semi-arid agro-ecosystems, CA-based systems constitute a fi eld rainwater and soil conservation improvement strategy that enhances crop and economic productivity and reduces siltation of reservoirs, especially under changing climate. Adoption of CA-based systems in the study area requires further work to improve smallholder farmers’ awareness on benefi ts, to guarantee high standards during implementation and to design appropriate weed management strategies.