scholarly journals Minireservoirs Could Save Farmers with Sandy Soils

Eos ◽  
2020 ◽  
Vol 101 ◽  
Author(s):  
Kate Wheeling

A recently revived subsurface water retention technology could conserve water and drastically increase crop yields in arid landscapes with sandy soils like sub-Saharan Africa.

2016 ◽  
Vol 371 (1703) ◽  
pp. 20150316 ◽  
Author(s):  
L. D. Estes ◽  
T. Searchinger ◽  
M. Spiegel ◽  
D. Tian ◽  
S. Sichinga ◽  
...  

Rapidly rising populations and likely increases in incomes in sub-Saharan Africa make tens of millions of hectares of cropland expansion nearly inevitable, even with large increases in crop yields. Much of that expansion is likely to occur in higher rainfall savannas, with substantial costs to biodiversity and carbon storage. Zambia presents an acute example of this challenge, with an expected tripling of population by 2050, good potential to expand maize and soya bean production, and large areas of relatively undisturbed miombo woodland and associated habitat types of high biodiversity value. Here, we present a new model designed to explore the potential for targeting agricultural expansion in ways that achieve quantitatively optimal trade-offs between competing economic and environmental objectives: total converted land area (the reciprocal of potential yield); carbon loss, biodiversity loss and transportation costs. To allow different interests to find potential compromises, users can apply varying weights to examine the effects of their subjective preferences on the spatial allocation of new cropland and its costs. We find that small compromises from the objective to convert the highest yielding areas permit large savings in transportation costs, and the carbon and biodiversity impacts resulting from savannah conversion. For example, transferring just 30% of weight from a yield-maximizing objective equally between carbon and biodiversity protection objectives would increase total cropland area by just 2.7%, but result in avoided costs of 27–47% for carbon, biodiversity and transportation. Compromise solutions tend to focus agricultural expansion along existing transportation corridors and in already disturbed areas. Used appropriately, this type of model could help countries find agricultural expansion alternatives and related infrastructure and land use policies that help achieve production targets while helping to conserve Africa's rapidly transforming savannahs. This article is part of the themed issue ‘Tropical grassy biomes: linking ecology, human use and conservation’.


Author(s):  
Nwauwa Linus OnyekaEzealaji

This study unanimously confirms that rural infrastructure is a sine qua non for significantly improving the quality of human life and phenomenally accelerating the process of agricultural development in Africa. Infrastructure projects, however, involve huge initial capital investments, long gestation periods, high incremental capital output ratio, high risk, and low rate of returns on investments. Rural infrastructure has direct and strong relationship with farmers’ access to institutional finance and markets, and increasing crop yields, thereby promoting agricultural growth. Agricultural infrastructure has the potential to transform the existing traditional agriculture or subsistence farming into a most modern, commercial and dynamic farming system in Sub Saharan Africa. Increase in investment of agricultural infrastructure leads to increase in output and employment, a full investment formulation that meets the needs of domestic or external (multilateral and bilateral) funding sources will have to be carried out. Overall, a flexible, participatory approach will be needed, with full national and local involvement and commitment, while international partners, including Food and Agricultural Organization (FAO), give initial assistance to New partnership for Africa’s Development (NEPAD) in this process. The paper therefore recommends that technical and financial assistance will be required to help build capacity in African countries to face the challenges and take full advantage of the opportunities flowing from the multilateral trading systems.


Author(s):  
Job Kihara ◽  
Gudeta Weldesemayat Sileshi ◽  
Generose Nziguheba ◽  
Michael Kinyua ◽  
Shamie Zingore ◽  
...  

Author(s):  
Alan H. Lockwood

Hotter weather and higher atmospheric CO2 levels will have profound effects on plants. Crops such as corn and soybeans, have critical temperature thresholds above which yields fall precipitously. High CO2 levels will foster the growth of many weeds over crops, threatening yields. Stimulated growth and release of ragweed allergens will threaten hay fever sufferers and asthmatics. The nutrient content of many crops falls in a high CO2 environment. As crop yields fall, prices rise, and undernutrition increases, particularly among children who fail to develop normally who, as a result, may not achieve normal intelligence. In many nations, particularly in Sub-Saharan Africa, childhood undernutrition already approaches 50%. Feeding the increasing population of the world may become problematic.


2017 ◽  
Vol 14 (1) ◽  
pp. 187-202 ◽  
Author(s):  
David Pelster ◽  
Mariana Rufino ◽  
Todd Rosenstock ◽  
Joash Mango ◽  
Gustavo Saiz ◽  
...  

Abstract. Few field studies examine greenhouse gas (GHG) emissions from African agricultural systems, resulting in high uncertainty for national inventories. This lack of data is particularly noticeable in smallholder farms in sub-Saharan Africa, where low inputs are often correlated with low yields, often resulting in food insecurity as well. We provide the most comprehensive study in Africa to date, examining annual soil CO2, CH4 and N2O emissions from 59 smallholder plots across different vegetation types, field types and land classes in western Kenya. The study area consists of a lowland area (approximately 1200 m a.s.l.) rising approximately 600 m to a highland plateau. Cumulative annual fluxes ranged from 2.8 to 15.0 Mg CO2-C ha−1, −6.0 to 2.4 kg CH4-C ha−1 and −0.1 to 1.8 kg N2O-N ha−1. Management intensity of the plots did not result in differences in annual GHG fluxes measured (P = 0.46, 0.14 and 0.67 for CO2, CH4 and N2O respectively). The similar emissions were likely related to low fertilizer input rates (≤ 20 kg N ha−1). Grazing plots had the highest CO2 fluxes (P = 0.005), treed plots (plantations) were a larger CH4 sink than grazing plots (P = 0.05), while soil N2O emissions were similar across vegetation types (P = 0.59). This study is likely representative for low fertilizer input, smallholder systems across sub-Saharan Africa, providing critical data for estimating regional or continental GHG inventories. Low crop yields, likely due to low fertilization inputs, resulted in high (up to 67 g N2O-N kg−1 aboveground N uptake) yield-scaled emissions. Improvement of crop production through better water and nutrient management might therefore be an important tool in increasing food security in the region while reducing the climate footprint per unit of food produced.


1997 ◽  
Vol 26 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Charles L. A. Asadu ◽  
Anselm A. Enete

Cassava root yields in three villages in southeastern Nigeria with marked differences in population pressure were related to soil properties using various models. The soils of the low population village, being formed from a different parent material, were more fertile than those of the medium and high population villages and cassava root yields were significantly higher in this village. The specific soil properties which appeared to promote cassava yields included pH and contents of Mn, silt and sand. Absolute values of exchangeable Mg, Ca, acidity and effective cation exchange capacity, although not significantly correlated with root yield, were also most favourable in the low population village. Thus inherent differences in soil properties rather than population pressure may be the major factors contributing to variations in cassava root yields in these villages.


2018 ◽  
Vol 2ndInt.Conf.AGR (Special Issue) ◽  
pp. 127-134
Author(s):  
Mahdi Ibrahim Aoda Aoda ◽  
◽  
Alaa Salih Ati Ati ◽  
Shatha Salim AL-Rawi AL-Rawi ◽  
◽  
...  

Author(s):  
Kaushik Majumdar ◽  
Robert M. Norton ◽  
T. Scott Murrell ◽  
Fernando García ◽  
Shamie Zingore ◽  
...  

AbstractEstimating nutrient mass balances using information on nutrient additions and removals generates useful, practical information on the nutrient status of a soil or area. A negative input–output balance of nutrients in the soil results when the crop nutrient removal and nutrient losses to other sinks become higher than the nutrient inputs into the system. Potassium (K) input–output balance varies among regions that have different climates, soil types, cropping systems, and cropping intensity. This chapter illustrates the farm-gate K balances in major production areas of the world and their impacts on native K fertility and crop yields. On-farm and on-station research examples show significant negative K balances in South Asia and Sub-Saharan Africa, while China, the USA, Brazil, and countries of the Latin America Southern Cone highlighted continued requirement of location-specific K application to maintain crop yields and soil K fertility status at optimum levels.


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