Effect of Farmer Resource Endowment and Management Strategies on Spatial Variability of Soil Fertility in Contrasting Agro-ecological Zones in Zimbabwe

Author(s):  
E.N. Masvaya ◽  
J. Nyamangara ◽  
R.W. Nyawasha ◽  
S. Zingore ◽  
R.J. Delve ◽  
...  
2015 ◽  
Vol 8 (3) ◽  
pp. 269-282 ◽  
Author(s):  
L. Matumba ◽  
M. Sulyok ◽  
M. Monjerezi ◽  
T. Biswick ◽  
R. Krska

This study investigated the diversity of fungal metabolites in maize across four agro-ecological zones of Malawi. A total of 90 maize samples (for human consumption), collected from farmsteads, were analysed for 235 fungal metabolites using liquid chromatography-tandem mass spectrometry. A total of 65 metabolites were found in the samples. 75% of samples from the hottest agro-ecological zone contained either aflatoxins, fumonisins, deoxynivalenol, zearalenone; or a combination thereof in levels exceeding European Union (EU) maximum levels, whereas the related fraction was only 17% in the cool temperature zone. Aflatoxins, citrinin, 3-nitropropionic acid, monocerin and equisetin were most prevalent and in higher levels in samples from hot agro-ecological zones, whereas deoxynivalenol, nivalenol, zearalenone and aurofusarin were most prevalent in cool agro-ecologies. On the basis of per-capita maize consumption, estimated daily intakes for all samples from hot ecologies were well above the JECFA's provisional maximum tolerable daily intake (PMTDI) of 2.0 μg/kg body weight (bw)/day for fumonisins, whereas the PMTDI of 1.0 μg/kg bw/day for deoxynivalenol was exceeded in relatively more (90%) samples from the cool highlands than the other zones. These results demonstrate the influence of micro-climatic conditions on mycotoxin prevalence patterns and underscores the need for development of agro-ecological specific mycotoxin dietary exposure management strategies.


1998 ◽  
Vol 46 (1) ◽  
pp. 65-75
Author(s):  
S.K. Debrah ◽  
T. Defoer ◽  
M. Bengaly

Technologies for Striga control have not been widely adopted because of the mismatch between technologies and farmers' socio-economic conditions. This study used a participatory rural appraisal technique at the village, household and plot levels to diagnose the extent of the Striga problem in two agro-ecological zones in southern Mali. This has resulted in an understanding of farmers' attitudes and constraints to Striga control, and opportunities for the development of sustainable technologies suitable for a wide range of farming conditions. Results show that the degree of Striga infestation, levels of farmer knowledge and control practices vary substantially across village territories and fields, and that the severity of the infestation is clearly linked with soil fertility condition and farming practices. It was concluded that in general, the Striga control interventions that would most likely appeal to farmers would be those that will simultaneously improve soil fertility and suppress the development of Striga.


2017 ◽  
Vol 8 (2) ◽  
pp. 590-593 ◽  
Author(s):  
A. C. C. Bernardi ◽  
G. M. Bettiol ◽  
G. G. Mazzuco ◽  
S. N. Esteves ◽  
P. P. A. Oliveira ◽  
...  

Knowledge on spatial variability of soil properties is useful for the rational use of inputs, as in the site specific application of lime and fertilizer. Crop-livestock-forest integrated systems (CLFIS) provide a strategy of sustainable agricultural production which integrates annual crops, trees and livestock activities on a same area and in the same season. Since the lime and fertilizer are key factors for the intensification of agricultural systems in acid-soil in the tropics, precision agriculture (PA) is the tool to improve the efficiency of use of these issues. The objective of this research was to map and evaluate the spatial variability of soil properties, liming and fertilizer need of a CLFIS. The field study was carried out in a 30 ha area at Embrapa Pecuária Sudeste in São Carlos, SP, Brazil. Soil samples were collected at 0–0.2 m depth, and each sample represented a paddock. The spatial variability of soil properties and site-specific liming and fertilizer needs were modeled using semi-variograms, the soil fertility information were modeled. Spatial variability soil properties and site specific liming and fertilizer need were modeled by kriging and inverse distance weighting (IDW) techniques. Another approach used was based on lime and fertilizer recommendation considering the paddocks as the minimum management unit. The results showed that geostatistics and GIS were useful tools for revealing soil spatial variability and supporting management strategies. Soil nutrients were used to classify the soil spatial distribution map and design site-specific lime and fertilizer application zones. Spatial analyses of crop needs and requirement can provide management tools for avoiding potential environmental problems, caused by unbalanced nutrient supplies.


Author(s):  
F. O. Chabi ◽  
G. D. Dagbenonbakin ◽  
C. E. Agbangba ◽  
B. Oussou ◽  
G. L. Amadji ◽  
...  

Soybean is a food security crop in Benin due to its high nutritional value but its yield in the farmers’ cropping system is very low. The present study aims to provide appropriate response to the yield variability among fields in two agro-ecological zones of Benin namely: Southern Borgou zone (AEZ 3 in the north) and cotton zone of central Benin (AEZ 5). Soil samples were collected from 0-20 cm depth in 120 fields (50 in the AEZ 3 and 70 in the AEZ 5). pH (water), soil organic carbon (Walkley and Black method), total nitrogen (Kjeldahl method), CEC (0.01 N ammonium acetate at pH 7 method) and available phosphorus (Bray 1) were determined in the laboratory of Soil Science Water and Environment (LSSEE) of the National Agricultural Research Institute of Benin (INRAB). Cropping system (crop rotations, soil fertility management practices) were also collected using an open ended questionnaire. Classification and regression trees (CARTs) models were used for data analyses. Soybean yield variability among the agro-ecological zones were registered and the highest yield recorded was less than 1 t.ha-1. Considering soil characteristics, soil organic matter level was the most important variable determining yield variability. Furthermore, quantities of P applied and farmyard manure were cropping practices inducing yield variability (86.4% and 15% of the variability respectively). Our results also show that, yield differences noticed among the agro-ecological zones were induced by CEC and pH (water). The study suggested promotion of integrated soil fertility management practices to sustain soybean yield in the study area.


2019 ◽  
Vol 39 (04) ◽  
Author(s):  
Adrien Turamyenyirijuru ◽  
Guillaume Nyagatare ◽  
Robert Morwani Gesimba ◽  
Rhoda Jerop Birech

This study assessed soil fertility in potato farms of Birunga and Buberuka highlands agro-ecological zones (AEZs). It compared nutrients levels (N, P, K, Mg, Ca, Na, S, Mn, Cu, Zn and Fe) and other parameters (pH, organic carbon [OC], cation exchange capacity [CEC], base saturation [BS], bulk density [BD] and texture) of soil samples. ANOVA revealed that pH of soils (5.53-6.50) varied from slightly to moderately acidic, BD fell below optimum for plant growth (Lessthan 1.8gcm-3), texture was sandy loam to sand clay loam. Soil fertility for OC (3.33-5.53%), N (0.15-0.31%) and CEC (10.08-18.60 meq/100g) varied from low to medium; and medium to high for BS (34.78-61.91%); was qualified medium for P (5.75-9.20 ppm), K (0.21-0.54 meq/100g), S (6.46 - 8.15 ppm) and majority of micronutrients. Values from Birunga AEZ were higher than ones from Buberuka AEZ except for BD, CEC, clay, silt, Na and Fe. There were significant differences between farms within locations for all parameters and significant differences between locations for all parameters except Na and Mn.


Soil Research ◽  
2012 ◽  
Vol 50 (7) ◽  
pp. 579 ◽  
Author(s):  
T. Nkheloane ◽  
A. O. Olaleye ◽  
R. Mating

Wetlands are complex ecosystems, often exhibiting considerable spatial variability, making the understanding of soil spatial relationships within them difficult. A study was conducted to evaluate spatial variability of soil physico-chemical properties in two contrasting wetlands in two agro-ecological zones (AEZs) of Lesotho. Soil samples were collected along two transects in mini-pits dug at different depths at 50-m intervals. The collected samples were analysed for particle size, pH, soil organic carbon (SOC), SOC pool, available phosphorus (Av-P), cation exchange capacity (CEC), and base cations. Results showed that within-site variability was very low for sand particles and pH (coefficient of variation <15% for both properties). Soil physical properties generally showed less spatial heterogeneity than chemical properties, which differed widely within and between the study sites. There was generally low correlation between soil properties, and SOC accounted for most of the variation observed at both sites, especially T’sakholo with partial R2 = 94%; at Thaba-Putsoa, partial R2 = 44%. Geostatistical analysis showed that all of the nugget to sill ratios (NSR) showed strong spatial dependence (i.e. NSR of 54–94%) except SOC (T’sakholo stream-bank) with no spatial dependence, with the nugget accounting for 23.43%. We therefore conclude that further wetland studies in Lesotho should attempt to quantify not only the soil properties or processes under investigation but also their spatial variability, because this spatial variability can provide insight into underlying ecosystem processes and may itself indicate wetland condition. In addition, results of stepwise multiple regression showed that SOC and texture could be used across these sites for the sustainable management of these wetlands.


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