scholarly journals Spatial variability and environmental drivers of cassava—arbuscular mycorrhiza fungi (AMF) associations across Southern Nigeria

Mycorrhiza ◽  
2022 ◽  
Author(s):  
Bolaji Thanni ◽  
Roel Merckx ◽  
Pieterjan De Bauw ◽  
Margaux Boeraeve ◽  
Gerrit Peeters ◽  
...  
Keyword(s):  
Arbuscular Mycorrhiza ◽  
Community Composition ◽  
Soil Characteristics ◽  
Sub Saharan Africa ◽  
Environmental Drivers ◽  
Ecological Zones ◽  
Shannon Diversity ◽  
Amf Diversity ◽  
Arbuscular Mycorrhiza Fungi ◽  
Agro Ecological Zones

AbstractCassava, forming starch-rich, tuberous roots, is an important staple crop in smallholder farming systems in sub-Saharan Africa. Its relatively good tolerance to drought and nutrient-poor soils may be partly attributed to the crop’s association with arbuscular mycorrhiza fungi (AMF). Yet insights into AMF-community composition and richness of cassava, and knowledge of its environmental drivers are still limited. Here, we sampled 60 cassava fields across three major cassava-growing agro-ecological zones in Nigeria and used a DNA meta-barcoding approach to quantify large-scale spatial variation and evaluate the effects of soil characteristics and common agricultural practices on AMF community composition, richness and Shannon diversity. We identified 515 AMF operational taxonomic units (OTUs), dominated by Glomus, with large variation across agro-ecological zones, and with soil pH explaining most of the variation in AMF community composition. High levels of soil available phosphorus reduced OTU richness without affecting Shannon diversity. Long fallow periods (> 5 years) reduced AMF richness compared with short fallows, whereas both zero tillage and tractor tillage reduced AMF diversity compared with hoe tillage. This study reveals that the symbiotic relationship between cassava and AMF is strongly influenced by soil characteristics and agricultural management and that it is possible to adjust cassava cultivation practices to modify AMF diversity and community structure. Graphical abstract

scholarly journals Carbon sequestration and selected hydraulic characteristics under conservation agriculture and traditional tillage practices in Malawi

Soil Research ◽  
2020 ◽  
Vol 58 (8) ◽  
pp. 759
Author(s):  
Pacsu L. Simwaka ◽  
Eyob H. Tesfamariam ◽  
Amos R. Ngwira ◽  
Paxie W. Chirwa
Keyword(s):  
Organic Carbon ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Particulate Organic Carbon ◽  
Hydraulic Properties ◽  
Conservation Agriculture ◽  
Sub Saharan Africa ◽  
Ecological Zones ◽  
Agro Ecological Zones

Conservation agriculture (CA) is increasingly promoted among smallholder farmers of sub-Saharan Africa in a quest to improve food security while sustaining the natural resource base of the agro-ecosystems where agriculture is based. The aim of this study was to investigate the effects of CA and traditional tillage on soil organic carbon (SOC) and selected hydraulic properties in two contrasting agro-ecological zones of Malawi. Six farmers hosted on-farm trials in each location, with each farmer having the following treatments: CA with continuous sole maize (CA-SM), CA with maize–legume intercrops (CA-ML), and traditional tillage with continuous sole maize (CT-SM). Soil samples were randomly collected in October 2015, from farmers’ fields located in Chipeni, Chinguluwe, Lemu, and Zidyana where CA had been implemented for 10 years (2005–2015) at six depth intervals: 0–10, 10–20, 20–40, 40–60, 60–80, and 80–100 cm. Bulk density, soil water characteristics, and pore size distribution were determined using undisturbed core samples. At all sites, CA improved total SOC, carbon stocks, and the stable fraction of particulate organic carbon. Maize–legume intercropping under CA had 35%, 33%, and 73% more total SOC than CT-SM in Chipeni, Lemu, and Zidyana respectively. In Chinguluwe and Lemu, CA-ML had 0.54 and 0.50 g kg–1 respectively more stable fraction of particulate organic carbon (POMP) than CT-SM; whereas in Chipeni, CA-SM had 0.73 g kg–1 higher POMP compared with CT-SM. CA also improved soil porosity, pore size distribution, and water retention capacity by increasing the proportion of mesopores and micropores compared with CT-SM. Thus, changing management practices from CT-SM to CA has the potential to improve the soil organic matter and soil hydraulic properties across agro-ecological zones in Malawi, which is important for sustainable agriculture. Farmers should be encouraged to minimise tillage, retain residues as mulch on the soil surface, and practice crop rotation.

Weeds in Human Affairs in Sub-Saharan Africa: Implications for Sustainable Food Production

1991 ◽  
Vol 5 (3) ◽  
pp. 680-690 ◽  
Author(s):  
I. Okezie Akobundu
Keyword(s):  
Food Production ◽  
Professional Training ◽  
Sub Saharan Africa ◽  
Sustainable Food ◽  
Ecological Zones ◽  
Sustainable Food Production ◽  
Vegetation Zones ◽  
Sub Saharan ◽  
Annual Weeds ◽  
Agro Ecological Zones

Sub-Saharan Africa (SSA) has the world's largest human population growth rate, some of its poorest soils, and a high incidence of crop pests. Weeds are the major pest in virtually all of the agro-ecological zones of SSA. Parasitic and perennial weeds dominate the savanna vegetation zones whereas rapidly growing annual weeds overwhelm crops in the forest vegetation zones. High weed pressure coupled with inefficient weed control practices have tied up a disproportionate percentage of SSA's economically active population in the primary task of food production and also have kept crop yields down. In the absence of organized weed research and professional training in weed science to meet the needs of the region, improved cultivars of virtually all crops fall prey to weeds, and available arable land becomes limited to that area that can be kept free of weeds. A preponderance of annual weeds in humid parts of SSA together with hard-to-kill perennial grasses and parasitic weeds in the subhumid and arid agro-ecological zones hamper crop production and frustrate farmers throughout the region. Sustainable food production in the region can be achieved by introducing improved weed management technologies and by addressing other food production constraints of the region.

scholarly journals Distribution and Relative Abundance of Bean Leaf Beetles (Ootheca spp.) (Insecta: Coleoptera: Chrysomelidae) in Uganda

Insects ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1048
Author(s):  
Charles Halerimana ◽  
Samuel Kyamanywa ◽  
Samuel Olaboro ◽  
Pamela Paparu ◽  
Stanley T. Nkalubo ◽  
...  
Keyword(s):  
Common Bean ◽  
Relative Abundance ◽  
Species Distribution ◽  
Crop Yields ◽  
Leaf Beetle ◽  
Sub Saharan Africa ◽  
West Nile ◽  
Leaf Beetles ◽  
Ecological Zones ◽  
Agro Ecological Zones

Bean leaf beetles (Ootheca spp.) (Insecta: Coleoptera: Chrysomelidae) are one of Africa’s most destructive pests of common bean and other leguminous crops. The beetles are widely distributed in Africa where they are estimated to cause annual crop yield losses of 116,400 tons of crop yields in sub-Saharan Africa. Despite their importance, little is known about the distribution, relative abundance and damage caused by bean leaf beetles in Uganda. As a result, the development of effective management methods has been hampered. We conducted surveys in six key Ugandan agro-ecological zones to determine the species distribution and relative abundance of bean leaf beetles. Findings indicate that leaf beetles belonging to 12 genera are present, including members of the genera Afrophthalma Medvedev, 1980, Buphonella Jacoby, 1903, Chrysochrus Chevrolat in Dejean, 1836, Diacantha Dejean, 1845, Exosoma Jacoby, 1903, Lamprocopa Hincks, 1949, Lema Fabricius, 1798, Nisotra Baly, 1864, Neobarombiella Bolz and Wagner, 2012, Ootheca Dejean, 1935, Parasbecesta Laboissière, 1940, and Plagiodera Dejean, 1835. We identified only three species belonging to the genus Ootheca: O. mutabilis, O. proteus, and O. orientalis. Seventy percent of all the beetles collected were O. mutabilis and these were present in all agro-ecological zones studied. The Northern Moist Farmlands (21.9%), West Nile Farmlands (12.9%), Central Wooded Savanna (4.4%) and Southern and Eastern Lake Kyoga Basin (1.4%) were the only agro-ecological zones where O. proteus was found. Only one specimen of O. orientalis was found at a single site in the Central Wooded Savanna. The Northern Moist Farmlands had a significantly (p < 0.05) higher bean leaf beetle density than the West Nile Farmlands and Southwestern Highlands. Similarly, the Northern Moist Farmlands had the highest beetle foliar damage per plant (1.15 ± 0.05), while the Southwestern Highlands had the lowest (0.03 ± 0.02). We provide the first information on Ootheca species distribution, abundance and damage in Uganda. Our findings provide a foundation for assessing the importance of Ootheca spp. as common bean pests in Uganda.

scholarly journals Organic and Inorganic Fertilizers Induced Yield Increment of Two Pearl Millet Varieties in Sudanian and Sahelian Agro-ecological Zones in Mali

2018 ◽  
Vol 5 (4) ◽  
pp. 158
Author(s):  
Halimatou Aboubacar Toure ◽  
Kalifa Traore ◽  
Idriss Serme ◽  
Korodjouma Ouattara
Keyword(s):  
Grain Yield ◽  
Pearl Millet ◽  
Agricultural Research ◽  
Block Design ◽  
Sub Saharan Africa ◽  
Research Station ◽  
Yield Gap ◽  
Ecological Zones ◽  
Local Variety ◽  
Agro Ecological Zones

Soil fertility is inherently low in sub Saharan Africa. The objective of this study was therefore to determine millet yield for two varieties in each zone using organic and inorganic fertiliser in two agro-ecological zones in Mali. A two-year experiment was conducted at Agricultural Research Station of Sotuba and Cinzana in 2013 and 2014. A combination of two pearl millet varieties and four fertilizer treatments were used. The fertilizers treatments used were: T1 Control (no application); T2 MANURE of 23:10:17 (5000 kg/ha); T3 NPK of 15: 15: 15 (50 kg/ha) and T4 combination of NPK + MANURE. The experiments were conducted in a randomised complete block design (RCBD) with four replications in a plot size of 10 m x 4.2 m. The varieties evaluated at Sotuba station were Sanioni, an improved local variety and Cho, a local variety while at Cinzana station Sosat, an improved variety form IER /ICRISAT and IBV8001, and an improved variety from ICRISAT were used. At Sotuba high grain with NPK+MANURE (1948 kg ha-1) followed by NPK (1281 kg ha-1), MANURE (1130 kg ha-1)and the Control (813 kg ha-1). In 2014, the grain yield NPK+MANURE) was 1602 kg ha-1, followed by NPK (1502 kg ha-1), MANURE (1466 kg ha-1) and the control (1440 kg ha-1). The grain yield gap for the Control treatment in 2013 (813 kg ha-1) and in 2014 (1440 kg ha1) was high compared to the NPK+MANURE, MANURE and NPK treatment grain yield gap for the same years. In Cinzana In 2013, higher grain yield with the treatments of NPK+MANURE, (1440 kgha-1)> NPK (1429 kg ha-1)> MANURE (1416 kg ha-1)>Control (1276 kg ha-1) were observed . In 2014, the highest grain yield with NPK+MANURE (1915 kg ha-1) followed by NPK (1561 kg ha-1), MANURE (1523 kg ha-1 1) and Control (1121 kg ha-1). The grain yield gap for the combined NPK+MANURE treatment in 2103 (1440 kg ha-1) and in 2014 (1915 kg ha1) was high compared to the others for the fertilizer grain yield gap for both years.

scholarly journals Multi-criterial analysis for modelling Matengo/Ngolo pits agro-ecological zones using fuzzy logic in Southern Tanzania

2021 ◽  
Vol 911 (1) ◽  
pp. 012080
Author(s):  
S J Nakamo
Keyword(s):  
Fuzzy Logic ◽  
Policy Development ◽  
Sub Saharan Africa ◽  
Agricultural Practice ◽  
Grain Production ◽  
Ecological Zones ◽  
Fuzzy Logic Algorithm ◽  
Sub Saharan ◽  
The Impact ◽  
Agro Ecological Zones

Abstract It has known that grain production is declining globally, leading to food insecurity becoming increasingly apparent in tropical countries, particularly in Sub-Saharan Africa. Countries in Sub-Saharan Africa must concentrate on indigenous agricultural methods to mitigate the impact of climate change on grain production while preserving ecological balances and achieving sustainable goals. Matengo/Ngolo pits, practised on steep slopes in the Matengo highlands, southern Tanzania, are indigenous knowledge invented by local communities over the past 300 years. Despite its effectiveness in increasing agricultural productivity, soil moisture retention, and other environmental advantages, Matengo/Ngolo agricultural technique has resulted in severe land cover changes that substantially influence other producing sectors. Understanding the agro-ecological zones is essential for enhancing policy development for the expansion and restrictive of Matengo/Ngolo pits practice that intercepting by decreasing its influence on the shrinkage of other ecological services, achieving sustainable agricultural practice in the Matengo highlands. Therefore, this study employed the multi-criteria parameters under the fuzzy logic algorithm in ArcGIS 10.8 for modelling the Matengo/Ngolo pits agro-ecological zone to realize sustainable land management in Matengo highlands.

scholarly journals Variability of Colletotrichum gloeosporioides Isolates the Causal Agent of Anthracnose Disease of Cassava and Yam Plants in Ghana

2016 ◽  
Vol 5 (1) ◽  
pp. 01-09 ◽  
Author(s):  
Zippora Appiah-Kubi ◽  
Apetorgbor A. Kofi ◽  
Moses Emmanuel ◽  
Appiah-Kubi David ◽  
Marfo Esther
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Random Amplified Polymorphic Dna ◽  
Economic Loss ◽  
Growth Characteristics ◽  
Sub Saharan Africa ◽  
Causal Organism ◽  
Ecological Zones ◽  
Anthracnose Disease ◽  
Plant Parts ◽  
Agro Ecological Zones

Cassava and yam plants are important staple foods of millions of people in the tropical world and provide food security in most parts of sub-Saharan Africa. Their production however is affected by anthracnose disease caused by Colletotrichum gloeosporioides, (Penz.) Penz. and Sacc contributing to 30-70% economic loss in both crops. A study was carried out to determine if variations exist between isolates of C. gloeosporioides on the two crops occurring in different agro-ecological zones of Ghana.  Anthracnose-diseased samples of cassava and yam plant parts (leaves and stem/vine) were collected from four agro-ecological zones of Ghana (Forest, Forest-Savannah Transition, Guinea and Coastal Savannah). Isolations of the causal organism C. gloeosporioides were made. The isolates were investigated on the basis of growth characteristics on Potato Dextrose Agar (PDA): presence or absence of setae, colour of cultures, dimensions of conidia. Pathogenicity of isolates was determined and molecular analysis conducted using Random Amplified Polymorphic DNA (RAPD). Results showed both similarities and variations in cultural, morphological and growth characteristics of the pathogen. Isolates from yam caused pathogenic lesions on cassava and yam plant sections and vice versa.  Forty-four isolates of C. gloeosporioides from cassava and yam compared by RAPD analysis grouped the isolates into three main clusters. Within two of the clusters are six polymorphic sub-groups relating to host and geographical origin. The different polymorphic sub-groups indicated that there are several sub-populations of C. gloeosporioides isolates, which either singly or in association, involved in the yam and cassava anthracnose infections in the field. Isolates from different ecological zones, with similar morphological features, clustering in a polymorphic sub-group suggest a common origin for some of them.

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