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Parameterisation and evaluation of the FAO AquaCrop model for a South African taro (Colocasia esculenta L. Schott) landrace

Date of Publication
Aug 01, 2015
Description/Abstract

Promotion of taro, a neglected underutilised crop, as a possible future crop under water-limited conditions hinges on availability of information describing its yield responses to water. Therefore, AquaCrop was calibrated and validated for the first time for an eddoe type taro landrace from South Africa, using data from pot, field and rain shelter experiments conducted over two seasons (2010/11 and 2011/12) at two locations (Pretoria and Pietermaritzburg) representative of semi-arid climates. Observed weather and soil physical parameters for specific sites together with measured crop parameters from optimum experiments conducted during 2010/11, were used to develop climate, soil and crop files in AquaCrop and to calibrate the model. Observations from the 2011/12 growing season and independent data were used to validate the model. Model calibration showed a good fit (R2 = 0.789; d-index = 0.920; RMSE = 2.380%) for canopy cover (CC) as well as good prediction for final biomass (RMSE = 1.350 t ha−1) and yield (RMSE = 1.205 t ha−1). Model validation showed good simulation for CC under irrigated conditions (R2 = 0.844; d-index = 0.998; RMSE = 1.852%). However, the model underestimated CC under rainfed (R2 = 0.018; d-index = 0.645; RMSE = 20.170%) conditions. The model predicted biomass (R2 = 0.898; d-index = 0.875; RMSE = 5.741 t ha−1) and yield (R2 = 0.964; d-index = 0.987; RMSE = 1.425 t ha−1) reasonably well for pooled data [field (RF and FI) and rain shelter (100, 60 and 30% ETa)]. The model also predicted biomass (R2 = 0.996; d-index = 0.986; RMSE = 1.745 t ha−1) and yield (R2 = 0.980; d-index = 0.991; RMSE = 1.266 t ha−1) well for the independent data set.

Author or Institution as Author
Tafadzwanashe Mabhaudhi
Co-authors

Albert T. Modi, Yacob G. Beletse

Language
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Parameterisation and testing of the FAO AquaCrop model for a South African bambara groundnut landrace

Date of Publication
Dec 01, 2013
Description/Abstract

The aim of this study was to parameterize and test the generic crop model AquaCrop for a local bambara groundnut [Vigna subterranea (L.) Verdc] landrace. Such a model should be water driven and assist in the promotion of neglected and underutilized species as possible future crops under water-limited conditions. AquaCrop was parameterized for a South African bambara groundnut landrace using data from controlled field and rain shelter experiments conducted during two seasons (2010/2011 and 2011/2012) at Pretoria, South Africa. Observed weather, soil physical, and measured crop parameters from optimum experiments conducted during 2010/2011 were used to develop respective climate, soil, and crop files in AquaCrop and to parameterize the model. Model parameterization for bambara groundnut showed a very good fit for canopy cover (R2 = 0.94, Willmott’s d index of agreement = 0.99, RMSE = 3.37%) and biomass (R2 = 0.96, d index = 0.99, RMSE = 1.29 Mg ha–1). The model also predicted final biomass (RMSE = 1.70 Mg ha–1) and yield (RMSE = 0.29 Mg ha–1) reasonably well. Model testing showed good fit for canopy cover under irrigated (R2 = 0.86, d index = 0.96, RMSE = 9.72%) and rainfed field conditions (R2 = 0.95,d index = 0.97, RMSE = 6.18%) compared with simulation of results from rain shelter experiments. The model simulated final biomass and yield of bambara groundnut very well under field conditions. The model’s performance under rainfed conditions make it particularly suited for extrapolation to marginal areas of agricultural production in South Africa and the region.

Author or Institution as Author
Tafadzwanashe Mabhaudhi
Co-authors

Albert T. Modi, Yacob G. Beletse

Language
Category
Resource Type

Response of taro (Colocasia esculenta L. Schott) landraces to varying water regimes under a rainshelter

Date of Publication
Apr 01, 2013
Description/Abstract

Taro [Colocasia esculenta (L.) Schott] is an underutilised crop in sub-Saharan Africa due to lack of agronomic research on it. There is no information describing water-use and drought tolerance of local taro landraces. Therefore, the objective of this study was to evaluate growth, yield and water-use of three South African landraces of taro under varying water regimes. Three taro landraces [Dumbe Lomfula (DL), KwaNgwanase (KW) and Umbumbulu (UM)] were planted in a rainshelter (14, October, 2010 and 8, September, 2011) at Roodeplaat, Pretoria, South Africa. Three levels of irrigation [30%, 60% and 100% crop water requirement (ETa)] were applied three times a week using drip irrigation. Emergence, plant height, leaf number, leaf area index (LAI) and stomatal conductance were measured in situ. Root length, fresh and dry mass were obtained by destructive sampling. Yield, yield components and water-use efficiency were determined at harvest. Taro landraces showed slow and uneven emergence. Stomatal conductance was respectively, 4% and 23% lower at 60% and 30% ETa relative to 100% ETa. Such a decline was clearer in the UM landrace, suggesting greater stomatal regulation in the UM landrace compared with KW and DL landraces. Plant growth parameters (plant height, leaf number and LAI) were shown to decrease by between 5% and 19% at 60% and 30% ETa, respectively, evapotranspiration relative to 100% ETa. The KW and DL landraces were shown to decrease the most while the UM landrace had moderate reductions in growth. Taro yield was 15% and 46% higher at optimum irrigation relative to 60% ETa and 30% ETa, respectively. Water-use efficiency was relatively unchanged (0.22–0.24 kg m−3) across varying water regimes. On average, the UM landrace had 113% higher WUE than the KW landrace. These findings can be used to differentiate the landraces on the basis of potential drought tolerance.

Author or Institution as Author
T.Mabhaudhia
Co-authors

A.T.Modia, Y.G.Beletseb

Language
Category
Resource Type

Resilience Strategy

Date of Publication
Oct 01, 2016
Description/Abstract

Food insecurity and climate change are having a dire impact on many households in Lesotho. This situation can be addressed together by transforming agriculture and adopting practices that are “climate-smart” and sustainable.

Farmers and rural communities are under the greatest threat from climate change, but they could also play a major role in addressing it. Climate-smart farming techniques such as Conservation Agriculture and improved Home Gardening and Nutrition would increase food production, incomes and food security while making agriculture more resilient to climate change. Besides, sustainable land management practices are essential to protect Lesotho’s natural resources and rural livelihoods.

In this repository website, you will find harmonized visual training materials developed in Lesotho to promote CSA among communities, farmers, students, decision makers and the general public. 

Author or Institution as Author
Bokang Mantutle
Institution
Mauritius
Language
Resource Type
Citation

Bokang Mantutle, 2016. Resilience Strategy.

The Windhoek Declaration for Enhancing Resilience to Drought in Africa

Date of Publication
Oct 01, 2016
Description/Abstract

We, the African Member States and Parties to the United Nations Convention to Combat Desertification (UNCCD), Ministers, Heads of Delegation and Experts, attending the High Level Meeting of the first African Drought Conference (ADC);

Having met in Windhoek, Namibia from the 15 – 19 August 2016;

Congratulate the Government of Namibia and the UNCCD Secretariat for coordinating and organizing the first African Drought Conference, and thanking in particular NEPAD and all sponsors of the ADC.

Recognizing the alarming impacts of the recent 2015/2016 El Nino events as one of the most severe in recent decades
across Africa.

Author or Institution as Author
Namibia
Institution
Namibia
Language
Resource Type
Citation

Namibia, 2016. The Windhoek Declaration for Enhancing Resilience to Drought in Africa.

Think Namibia Factsheet 5

Date of Publication
Oct 01, 2015
Description/Abstract

In Namibia, agriculture and forestry contributes 5.1% to the Gross Domestic Product (GDP) and livestock alone contributes 3.5% which is a contribution of 68.63 % to the Agricultural GDP (Namibia Statistical Agency’s, 2012).

In addition, agriculture plays a critical role in the formal and informal economy supporting 70% of the population directly or indirectly through employment and income generation (Ministry of Environment and Tourism, 2015).

Crop production activities in Namibia are limited, mainly due to the arid climate and low rainfall patterns. Small-scale farmers use traditional methods of production that are characterised by low productivity (Ministry of Foreign Afairs of Finland, 2015).

This weakens the food security of the population and the dependence on rain-fed agriculture increases the vulnerability of farming systems and predisposes rural households to food insecurity and poverty.

It is projected that the reduction in crop yields will have devastating impacts on food security at both national and household levels. Under the current conditions, the agriculture sector in Namibia needs to grow by 4% a year to meet the food requirements for the expanding population (Ministry of Foreign Afairs of Finland, 2015).

In light of these challenges, Namibia needs to adapt its agricultural practices and increase the resilience of livelihoods to be able to withstand the challenges posed by Climate Change to sustain development and growth of the country. This is why Climate Smart Agriculture (CSA) is an important topic for discussion at all levels of the society.

Author or Institution as Author
Emilia Chioreso
Co-authors

Rennie Munyayi

Institution
Think Namibia
Language
Resource Type
Citation

E. Chioreso and R. Munyayi. (2015). Think Namibia Factsheet. Namibia.

Growth, phenological and yield responses of a bambara groundnut (Vigna subterranea L. Verdc) landrace to imposed water stress under field conditions.

Date of Publication
May 01, 2013
Description/Abstract

Bambara groundnut (Vigna subterranea (L.) Verdc.) is an underutilised species with potential to contribute nutritional and food security in marginal areas. Growth, phenology and yield of a local bambara groundnut landrace from Jozini, KwaZulu-Natal, characterised into three selections according to seed coat colour, namely Brown, Red and Light Brown, were evaluated under irrigated and rain-fed field conditions at Roodeplaat, Pretoria, over two seasons (2010/11 and 2011/12). Trials with three replicates were planted under rain-fed and irrigated conditions with seed colour as a subfactor. Emergence (up to 35 d after planting), plant height, leaf number, leaf area index, chlorophyll content index and stomatal conductance were measured in situ. Yield and components of yield were determined at harvest. The Red, Brown and Light Brown landrace selections emerged well (84%, 81% and 51%, respectively). Plant physiological and growth parameters of stomatal conductance, chlorophyll content index, plant height, leaf number, leaf area index and biomass accumulation were lower under rain-fed relative to irrigated conditions. Adaptations were landrace selection-specific, with the Brown and Red landrace selections showing better adaptation to rain-fed conditions. Under rain-fed conditions, bambara groundnut landrace selections flowered, senesced and matured earlier relative to irrigated conditions. Consequently, there were lower yields under rain-fed compared with irrigated conditions. The Red and Brown landrace selections may have drought-avoidance mechanisms. Seed colour may be used as a selection criterion for drought tolerance in bambara groundnut landraces.

Author or Institution as Author
Tafadzwanashe Mabhaudhi
Co-authors

Albert T Modi

Institution
South African Journal of Plant and Soi
Language
Category
Resource Type
Citation

Tafadzwanashe Mabhaudhi & Albert T Modi (2013) Growth, phenological and yield responses of a bambara groundnut (Vigna subterranea (L.) Verdc.) landrace to imposed water stress under field conditions, South African Journal of Plant and Soil, 30:2, 69-79, DOI: 10.1080/02571862.2013.790492

Smallholder Adoption of Conservation Agriculture and Greenhouse Gas Reduction Potential in Mozambique and Lesotho

Date of Publication
May 01, 2013
Description/Abstract

The 2013 AAEA & CAES Joint Annual Meeting in Washington, DC will offer AAEA members, CAES members, and other applied economists a chance to interact and learn over the course of the three day meeting on August 4-6. This year’s meeting features a large amount of educational content including:

More than 150 educational sessions

Over 200 posters on display, with opportunities to interact with their authors

Multiple plenary sessions each day, featuring high-profile speakers

Common research topics include:

International development

Climate change

Biofuels

Linkages between food and health

The Farm Bill

Land use and water resource issues

Regional economics

Business economics

Behavioral economics

The meeting will also feature a number of chances for attendees to connect and network at the welcome and closing receptions, receptions for specific Sections of AAEA, and evening gatherings organized by universities and government agencies.

Institution
AAEA & CAES
Language
Resource Type

Early establishment performance of local and hybrid maize under two water stress regimes.

Date of Publication
Mar 01, 2013
Description/Abstract

Maize (Zea mays L.) is the major grain crop in South Africa where most subsistence farmers still plant landraces. The objective of this study was to compare two landrace selections of maize with two hybrids popular among small-scale farmers in KwaZulu-Natal, for seed performance and water stress tolerance during seedling establishment. Two variations of a local landrace, white (Land A) and dark red (Land B), were compared to two hybrids, SC701 and SR52. Standard germination test and electrical conductivity were used to assess seed quality under laboratory conditions. Seedling emergence was performed in seedling trays using pine bark at 25% and 75% field capacity (FC), respectively, over a period of 21days. All seed types showed high germination capacity (>93%). There were highly significant differences (p<0.001) among seed types with respect to daily germination and germination velocity index (GVI). Landraces germinated slower than the hybrids. Landraces showed a 20% better root length and 41% lower electrolyte leakage than hybrids. There were differences (p<0.001) in seedling emergence between 25%FC and 75%FC. Hybrids showed better emergence at 75% FC. At 25% FC seedling emergence was drastically reduced (>5% in all varieties). Hybrids emerged faster than the landraces in both water regimes. Landraces performed better than hybrids under stress conditions. This study showed that landraces may have the same viability as hybrids and a better tolerance to stress during early establishment of the crop.

Author or Institution as Author
T. Mabhaudhi
Co-authors

A.T. Modi

Institution
South African Journal of Plant and Soil
Language
Category
Resource Type
Citation

T. Mabhaudhi & A.T. Modi (2010) Early establishment performance of local and hybrid maize under two water stress regimes, South African Journal of Plant and Soil, 27:4, 299-304, DOI: 10.1080/02571862.2010.10639998

Country Climate Smart Agriculture Programme

Date of Publication
Oct 01, 2015
Description/Abstract

Agriculture in Namibia plays a critical role in the formal and informal economy supporting 70% of the population directly or indirectly through employment and income generation. The agricultural sector in Namibia contributes over 10% to the GDP of which 75-80% can be attributed to livestock farming. The livestock industry accounts for 90% of all agricultural production in Namibia with approximately 60% of households owning cattle, including nearly 40% of poor households. Crop production activities in Namibia are limited, mainly due to the arid climate and low rainfall patterns. Rain-fed crops include pearl millet, sorghum and maize are the most dominant crops grown in Namibia. The average yield for these crops ranges from 24.7 ton for pearl millet, 72,438 for maize and 14,819 for wheat. The dependence on rain-fed agriculture increases the vulnerability of farming systems and predisposes rural households to food insecurity and poverty. However, the reduction in crop yields will have devastating impacts on food security at both national and household levels. Under the current conditions, the agriculture sector in Namibia needs to grow by 4% a year to meet the food requirements for the expanding population. In light of these challenges, Namibia needs to adapt its agricultural practices and increase the resilience of livelihoods to be able to withstand the challenges posed by climate change to sustain development and growth of the country.

Author or Institution as Author
Ministry of Environment and Tourism Namibia
Institution
Ministry of Environment and Tourism Namibia
Language
Resource Type
Citation

Ministry of Environment and Tourism Namibia. (20150. Country Climate Smart Agriculture Programme. Namibia.

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