Increasing adaptation to climate stress by applying conservation agriculture in Southern Africa.

2022 ◽  
pp. 270-283
Author(s):  
Christian Thierfelder ◽  
Peter Steward

Abstract Climate change and soil fertility decline are threatening food security in southern Africa and efforts have been made to adapt current cropping systems to the needs of smallholder farmers. Conservation Agriculture (CA) based on minimum soil disturbance, crop residue retention and crop diversification has been proposed as a strategy to address the challenges smallholder farmers face. Here we analyse the potential contributions of CA towards adaptation to the effects of climate change by summarizing data on infiltration, soil moisture dynamics and crop productivity under heat and drought stress. The data were taken in the main from CIMMYT's on-farm and on-station trial network. Data show that CA systems maintain 0.7-7.9 times higher water infiltration than the conventional tilled system depending on soil type, which increases soil moisture during the cropping season by 11%-31% between CA treatments and the conventional control treatment. This leads to greater adaptive capacity of CA systems during in-season dry spells and under heat stress. A supporting regional maize productivity assessment, analysing the results of numerous on-farm and on-station experiments, showed that CA systems will outperform conventional tillage practices (CP), especially on light-textured soils, under heat and drought stress. With higher rainfall and low heat stress, this relation was more positive towards CP and on clay soil there was no benefit of practising CA when rainfall was high. The long dry season and limited biomass production of CA systems in southern Africa require complementary good agricultural practices to increase other soil quality parameters (e.g. increased soil carbon) to maintain higher productivity and sustainability over time. This can be addressed by combinations of improved stress-tolerant seed, targeted fertilization, inclusion of tree-based components or green manure cover crops in the farming system, scale-appropriate mechanization and improved weed control strategies.

2014 ◽  
Vol 50 (4) ◽  
pp. 591-610 ◽  
Author(s):  
A. R. NGWIRA ◽  
JENS B. AUNE ◽  
C. THIERFELDER

SUMMARYAn 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−1lower than under CP+F. Results suggest that about 6.0 mg ha−1of 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−1greater 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.


2022 ◽  
pp. 151-175
Author(s):  
W. Trent Bunderson ◽  
Christian L. Thierfelder ◽  
Zwide D. Jere ◽  
R. G. K. Museka

Abstract The Conservation Agriculture (CA) system promoted by Total LandCare (TLC) and the International Maize and Wheat Improvement Center (CIMMYT) is based on 14 years of experience grounded on the principles of minimum soil disturbance, good soil cover and crop associations. The platform to promote CA in Malawi was to build a strong base of knowledge about best practices through an innovative non-linear research-extension approach. Long-term on-farm trials were conducted in multiple sites across Malawi to compare yields and labour inputs of CA with conventional ridge tillage on the same footing. Results showed the superiority of CA in terms of maize and legume yields with significant savings in labour and resilience to climate change. The results provided the basis to upscale CA although adoption was lower than expected. Key challenges included: (i) lack of exposure and training; (ii) conflicting extension messages; (iii) misconceptions about inputs and tools for CA; (iv) resistance to change unless CA is clearly seen to be a better practice; (v) fears about controlling weeds, pests and diseases under CA; and (vi) perceptions that increased termites and earthworms are harmful to soils and crops.


2014 ◽  
Vol 30 (4) ◽  
pp. 328-348 ◽  
Author(s):  
Christian Thierfelder ◽  
Leonard Rusinamhodzi ◽  
Amos R. Ngwira ◽  
Walter Mupangwa ◽  
Isaiah Nyagumbo ◽  
...  

AbstractThe 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.


Author(s):  
Mark Cooper ◽  
Kai P. Voss-Fels ◽  
Carlos D. Messina ◽  
Tom Tang ◽  
Graeme L. Hammer

Abstract Key message Climate change and Genotype-by-Environment-by-Management interactions together challenge our strategies for crop improvement. Research to advance prediction methods for breeding and agronomy is opening new opportunities to tackle these challenges and overcome on-farm crop productivity yield-gaps through design of responsive crop improvement strategies. Abstract Genotype-by-Environment-by-Management (G × E × M) interactions underpin many aspects of crop productivity. An important question for crop improvement is “How can breeders and agronomists effectively explore the diverse opportunities within the high dimensionality of the complex G × E × M factorial to achieve sustainable improvements in crop productivity?” Whenever G × E × M interactions make important contributions to attainment of crop productivity, we should consider how to design crop improvement strategies that can explore the potential space of G × E × M possibilities, reveal the interesting Genotype–Management (G–M) technology opportunities for the Target Population of Environments (TPE), and enable the practical exploitation of the associated improved levels of crop productivity under on-farm conditions. Climate change adds additional layers of complexity and uncertainty to this challenge, by introducing directional changes in the environmental dimension of the G × E × M factorial. These directional changes have the potential to create further conditional changes in the contributions of the genetic and management dimensions to future crop productivity. Therefore, in the presence of G × E × M interactions and climate change, the challenge for both breeders and agronomists is to co-design new G–M technologies for a non-stationary TPE. Understanding these conditional changes in crop productivity through the relevant sciences for each dimension, Genotype, Environment, and Management, creates opportunities to predict novel G–M technology combinations suitable to achieve sustainable crop productivity and global food security targets for the likely climate change scenarios. Here we consider critical foundations required for any prediction framework that aims to move us from the current unprepared state of describing G × E × M outcomes to a future responsive state equipped to predict the crop productivity consequences of G–M technology combinations for the range of environmental conditions expected for a complex, non-stationary TPE under the influences of climate change.


2020 ◽  
Vol 3 (1) ◽  
pp. 1-17
Author(s):  
Mbewe Jacqueline ◽  
Kabwe Harnadih Mubanga

Purpose: Climate change affects local and global rainfall patterns and hence has a counter effect on smallholder agriculture. Impacts of climate change on agriculture are largely due to rainfall variability resulting in reduced yields due to crop-water stress and emergency of pathogens and diseases. In Zambia, climate change has been manifested through increased intensity of droughts and floods. These rainfall anomalies adversely affect agriculture and food systems. In order to survive the impacts of climate change and variability, smallholder farmers in Chongwe have adopted their livelihoods and farming systems to the new climatic patterns.Methodology: This study assessed how smallholder farmers in Chongwe District have adopted their livelihoods as a response to changed climatic conditions. It also investigated the perceptions of smallholder farmers as regards changes in aspects of their climatic conditions. Data collection involved a critical review of literature related to climate change and agriculture, observations, semi- structured interviews with 60 smallholder farmers and eight key informants. The data were analysed using multiple analysis techniques which included the descriptive statistics, One-way analysis of Variance (ANOVA), and the post-hoc Least Square Difference for pairwise comparisons of incomes from different livelihoods engaged in by smallholder farmers .The gendered comparisons of livelihood engagement was done using the chi-square test of association.Findings: The results showed that all farmers perceived occurrence of changes in climatic conditions in the light of changed rainfall patterns in that there has been uncertainty in onset of rains, short rainy season, more intermittent rainfall and increased frequency of intra-seasonal droughts. These changes have led to farmers to adopt such farming techniques as potholing in preference to oxen and tractor ploughing when farming is done on smaller pieces of land. There was a significant difference in the mean annual incomes generated from on-farm livelihoods (ZMW 3677.59; n=58) and off-farm livelihoods (ZMW 6840.91; n = 58) (p= 0.001). Farmers generated the highest income returns by engaging in casual work (ZMW 10307.69; n = 13) compared to every other livelihoods common in the area such as gardening (p=0.002), petty trade (p=0.002) and on-farm livelihoods (p=0.001).Contribution to policy, theory and practice: It was therefore concluded that diversification of income through diversified livelihoods would help smallholder farmers enhance their resilience in the face of changed climatic conditions. On-farm livelihoods should not always be the main income source for farmers as results indicated that farmers engaged in casual work generated higher incomes than those who depended on farming. It was recommended that policy direction should be towards introduction of a gender responsive credit facility that can help improve women’s engagement in off-farm income generating livelihoods, as well as encourage climate change resilience.


2014 ◽  
Vol 18 (4) ◽  
pp. 1525-1538 ◽  
Author(s):  
H. C. Winsemius ◽  
E. Dutra ◽  
F. A. Engelbrecht ◽  
E. Archer Van Garderen ◽  
F. Wetterhall ◽  
...  

Abstract. Subsistence farming in southern Africa is vulnerable to extreme weather conditions. The yield of rain-fed agriculture depends largely on rainfall-related factors such as total seasonal rainfall, anomalous onsets and lengths of the rainy season and the frequency of occurrence of dry spells. Livestock, in turn, may be seriously impacted by climatic stress with, for example, exceptionally hot days, affecting condition, reproduction, vulnerability to pests and pathogens and, ultimately, morbidity and mortality. Climate change may affect the frequency and severity of extreme weather conditions, impacting on the success of subsistence farming. A potentially interesting adaptation measure comprises the timely forecasting and warning of such extreme events, combined with mitigation measures that allow farmers to prepare for the event occurring. This paper investigates how the frequency of extreme events may change in the future due to climate change over southern Africa and, in more detail, the Limpopo Basin using a set of climate change projections from several regional climate model downscalings based on an extreme climate scenario. Furthermore, the paper assesses the predictability of these indicators by seasonal meteorological forecasts of the European Centre for Medium-Range Weather Forecasts (ECMWF) seasonal forecasting system. The focus is on the frequency of dry spells as well as the frequency of heat stress conditions expressed in the temperature heat index. In areas where their frequency of occurrence increases in the future and predictability is found, seasonal forecasts will gain importance in the future, as they can more often lead to informed decision-making to implement mitigation measures. The multi-model climate projections suggest that the frequency of dry spells is not likely to increase substantially, whereas there is a clear and coherent signal among the models of an increase in the frequency of heat stress conditions by the end of the century. The skill analysis of the seasonal forecast system demonstrates that there is a potential to adapt to this change by utilizing the weather forecasts, given that both indicators can be skilfully predicted for the December–February season, at least 2 months ahead of the wet season. This is particularly the case for predicting above-normal and below-normal conditions. The frequency of heat stress conditions shows better predictability than the frequency of dry spells. Although results are promising for end users on the ground, forecasts alone are insufficient to ensure appropriate response. Sufficient support for appropriate measures must be in place, and forecasts must be communicated in a context-specific, accessible and understandable format.


Author(s):  
Kwasi Frimpong ◽  
Eddie Van Etten ◽  
Jacques Oosthuzien ◽  
Victor Nufam Fannam

Smallholder farming has become a significant livelihood coping strategy of the population in Ghana. However, in the last decade the upsurge of climate change and the effect of heat stress vulnerability on smallholder farmers in Northern Ghana are alarming. This article investigates the chances of using social protection and climate change adaptation policies towards the management of risks associated with heat stress emanating from climate change. It reviews salient literature on heat stress, social protection, and climate change policies and develops a model upon which both domestic and international interest in climate and social protection policies of Ghana and Sub-Sahara Africa can reduce or aggravate heat stress impacts on smallholder farmers both at their working environment and at household level. It exemplifies the efficacy of the strength of social protection and climate change adaptation policies in Ghana and its impacts on vulnerable rural smallholder farmers and how such situation is replicated in many parts of Africa. It outlines further measures that can be undertaken by governments and international donor agencies to revamp the destitution of smallholder farmers to climate change and heat stress in African region.


Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 518 ◽  
Author(s):  
Nelimor ◽  
Badu-Apraku ◽  
Tetteh ◽  
N’guetta

Climate change is expected to aggravate the effects of drought, heat and combined drought and heat stresses. An important step in developing ‘climate smart’ maize varieties is to identify germplasm with good levels of tolerance to the abiotic stresses. The primary objective of this study was to identify landraces with combined high yield potential and desirable secondary traits under drought, heat and combined drought and heat stresses. Thirty-three landraces from Burkina Faso (6), Ghana (6) and Togo (21), and three drought-tolerant populations/varieties from the Maize Improvement Program at the International Institute of Tropical Agriculture were evaluated under three conditions, namely managed drought stress, heat stress and combined drought and heat stress, with optimal growing conditions as control, for two years. The phenotypic and genetic correlations between grain yield of the different treatments were very weak, suggesting the presence of independent genetic control of yield to these stresses. However, grain yield under heat and combined drought and heat stresses were highly and positively correlated, indicating that heat-tolerant genotypes would most likely tolerate combined drought and stress. Yield reduction averaged 46% under managed drought stress, 55% under heat stress, and 66% under combined drought and heat stress, which reflected hypo-additive effect of drought and heat stress on grain yield of the maize accessions. Accession GH-3505 was highly tolerant to drought, while GH-4859 and TZm-1353 were tolerant to the three stresses. These landrace accessions can be invaluable sources of genes/alleles for breeding for adaptation of maize to climate change.


2016 ◽  
Vol 32 (1) ◽  
pp. 87-103 ◽  
Author(s):  
W. Mupangwa ◽  
M. Mutenje ◽  
C. Thierfelder ◽  
I. Nyagumbo

AbstractContinuous conventional tillage coupled with unsystematic cereal/legume rotations has promoted low crop productivity on smallholder farms. A multi-locational study was established in three agro-ecoregions (AEs) of Zimbabwe. The aim of the study was to determine the effect of four tillage systems (conventional plowing, planting basins, rip-line and animal traction direct seeding systems) on maize (Zea mays L.), cowpea [Vigna unguiculata (L.) Walp] and soybean [Glycine max (L.) Merrill] yields, and evaluate the economic performance of the conservation agriculture (CA) systems relative to conventional plowing. Each farmer was a replicate of the trial over the three cropping seasons. In the high (750–1000 mm per annum) and low (450–650 mm) rainfall AEs, conventional practice and CA systems gave similar maize grain yield. Under medium rainfall conditions (500–800 mm) planting basins, rip-line and direct seeding systems gave 547, 548 and 1690 kg ha−1 more maize yield than the conventional practice. In the high and low rainfall AEs, conventional practice and planting basins had the lowest maize production risk. Cowpea yield was 35 and 45% higher in the rip-line and direct seeding than conventional practice. Soybean yield was higher in rip-line (36%) and direct seeding (51%) systems than conventional practice. Direct seeding system gave the highest net benefits in all AEs. A combination of long-term biophysical and socio-economic assessments of the different cropping systems tested in our study is critical in order to fully understand their performance under different AEs of Zimbabwe.


Sign in / Sign up

Export Citation Format

Share Document