Spatiotemporal Analysis of Potential Impact of Soil Erosion on Maize and Groundnuts Yield in Northern Ghana

Abstract Soil erosion is a threat to the viability of arable land, which has a relationship with crop productivity. This study was carried out in the Northern, North-East and Savannah Regions of Ghana, which have a high agricultural potential. The study examined erosion-yield relationship by comparing estimated erosion rates with maize and groundnut yields in a GIS environment. The study also projected soil erosion and determined its potential effect on the yield of maize and groundnuts. The soil erosion rates were found to be 4.2 t ha-1y-1, 5.1 t ha-1y-1 and 7.1 t ha-1y-1 for the Northern, North-East and Savannah Regions respectively. Projections for the next 10 years showed that, soil erosion will averagely increase by about 12 %, which could reduce the yield of maize and groundnut by 21 % and 16 % respectively by the year 2031, should the current trend continue. The study also found out that crop (maize and groundnut) yield per land area is relatively lower in areas severely affected by soil erosion. Farmers in the study area and areas of similar ecology must be encouraged to adopt Soil and Water Conservation (SWC) strategies to enhance and sustain productivity

Training of Trainers (ToT) on Soil Carbon Sequestration and Crop Production Course Module

As part of the AICCRA project, the West African Science Service Centre on Climate Change and Adapted land Use (WASCAL) and the Regional Universities Forum for Capacity Building in Agriculture (RUFORUM) are tasked to to develop curricula and training materials to accelerate the mainstreaming Climate Information Services (CIS) and Climate Smart Agriculture (CSA) into University’s curricula in Africa. This report describes the activities of a training of trainers (ToT) workshop on Soil Carbon Sequestration and Crop Production course module developed by WASCAL as part of AICCRA curricula development activities. The training programmed was held at the Amonoo-Niezer Conference Centre, KNUST, KUMASI between 13th and 15th September, 2023. Forty-one (42) university lecturers, including nine women from three West African countries benefited from the training programme. The curricula consisted of four sessions on (i) Soils for Sustainable Crop Production, (ii) Climate Change and Crop Production, (iii) Soil Carbon Sequestration and (v) Spatial Estimation and Modelling of Soil Carbon. Four facilitators from the Kwame Nkrumah University of Science and Technology, Kumasi took participants through each of the sessions. For each session, there was theoretical as well as practical training, where participants went to the field and laboratory for data collection and analysis respectively

Estimation of Flow-Duration and Low-Flow Frequency Parameters for the Sumanpa Stream at Mampong-Ashanti in Ghana for the 1985-2009 Period

The study examined the characteristics of the Sumanpa stream’s Flow-Duration-Frequency Curve statistics for a period of 25years (1985-2009) and compared the 1990-1999 and 2000-2009 Flow-Duration-Curves. The high, low and mean Flow-Duration-Curves were also analysed. The discharge records were analysed to develop a general quantitative characterization of the stream’s flow variability. Streamflow data was generated from daily stage data using the rating curve model developed at the stream’s gauge station. Flow-Duration-Frequency-Curves were developed using the Weibull plotting position and used to analyse the catchment’s surface and groundwater storage and stream’s flow characteristics.  The approach placed the midpoints of the moist, mid-range, and dry zones of the curves at 25th, 50th, and 75th percentiles, respectively. The high zone was centered at the 5th percentile, while the low zone was centered at the 95th percentile. For 95% of the time, the streamflowequalled or exceeded 0.14 m3s-1, at 5% it equalled or exceeded 45 m3s-1 and at 50% flow equalled or exceeded 5.53 m3s-1.The ratio of Q90:Q50 for the period was 7.0%; it dropped from 38.0% in 1990-1999 to 30.0% in the 2000-2009 decades. The mean daily flow for the 1985-2009 (30.1m3s-1) has exceedance probability of 26% and the normal flow conditions were between 2.79 m3s-1 and 9.9 m3s-1for the period

Benefits and costs of cultivating rice using biochar-inorganic fertilizer combinations

Biochar is a carbon rich material obtained by the incomplete combustion of biomass. Agronomically, biochar is used as a soil amendment, usually in combination with other amendments such as fertilizer or compost. For environmental purposes, biochar serves as a means of sequesting carbon, thus mitigating climate change. It also has remediating properties such as adsorbing contaminants from water and soils. In this study, different rates of rice straw biochar combined with various inorganic fertilizer rates were applied on rice fields. The field experiment was conducted in both the major season and minor season of the year 2018. The minor season cultivation had two fields: minor season main and minor season residual. The minor season residual field did not have biochar reapplied to it because it was to assess the residual effect of the biochar applied during the major season. The economic costs were computed from the cost involved in the activities of the rice production processes. Rice yield was harvested at maturity and the yield converted into revenue using prevailing selling price. Net Present Values (NPVs) and Benefit Cost Ratios (BCRs) were computed for each treatment. The results indicated that the use of biochar as soil amendment in rice production is costly during the first production cycle, however, its residual effect is able to yield benefits that outweigh the costs, thus making biochar usage profitable in the second cropping season. Generally, the major season (first cropping cycle) had low BCRs, ranging from 0.54 to 1.33 compared with those of the minor season residual fields (second cropping cycle), which were between 1.22 and 1.84. The minor season residual fields had NPVs that were generally higher (−724 to 2069) than those of the major season (−2757 to 1300)

Multi-Level Land Cover Change Analysis in the Forest-Savannah Transition Zone of the Kintampo Municipality, Ghana

This study presents a multi-level analysis of land cover change in the Kintampo Municipality of Ghana using Landsat TM, ETM + and Landsat 8 images from 1986, 2001 and 2014, respectively. The expected and observed annual rates of land cover change for the periods 1986 to 2001 and 2001 to 2014 were analyzed at temporal and intra and inter-land cover levels using post-classification change detection. The results reveal that the expected annual rate of land cover change for the time intervals is 2.55 %. The observed annual rate of change from 2001 to 2014 is 2.63 %, which is greater than the expected value. This shows that land cover changed faster than expected in this period. The observed intra-land cover gains and losses for woodland is 2.49 % which is less than expected for the change periods. This suggests that the observed gain and loss in woodlands are attributable to random changes. The inter-land cover level changes for both periods reveal that when woodland gained or lost, it did not target shrub/grassland. This shows that the process of gain or loss in woodland in both periods was random. This is an indication that woodland cover is sustained by a slow, natural regeneration process and not by anthropogenic activities. The findings highlight the relevance of multilevel land cover analysis in land cover assessment. The temporal level highlights the need to relate changes in land cover to anthropogenic activities for a better understanding of the changes. The study also revealed that multi-level land cover analysis can facilitate management decisions on whether to reduce loss in woodland or increase gain in woodland cover from shrub land

Spatio-Temporal Trend Analysis of Rainfall and Temperature Extremes in the Vea Catchment, Ghana

This study examined the trends in annual rainfall and temperature extremes over the Vea catchment for the period 1985⁻2016, using quality-controlled stations and a high resolution (5 km) Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) data. The CHIRPS gridded precipitation data’s ability in reproducing the climatology of the catchment was evaluated. The extreme rainfall and temperature indices were computed using a RClimdex package by considering seventeen (17) climate change indices from the Expert Team on Climate Change Detection Monitoring Indices (ETCCDMI). Trend detection and quantification in the rainfall (frequency and intensity) and temperature extreme indices were analyzed using the non-parametric Mann⁻Kendall (MK) test and Sen’s slope estimator. The results show a very high seasonal correlation coefficient (r = 0.99), Nash⁻Sutcliff efficiency (0.98) and percentage bias (4.4% and −8.1%) between the stations and the gridded data. An investigation of dry and wet years using Standardized Anomaly Index shows 45.5% frequency of drier than normal periods compared to 54.5% wetter than normal periods in the catchment with 1999 and 2003 been extremely wet years while the year 1990 and 2013 were extremely dry. The intensity and magnitude of extreme rainfall indices show a decreasing trend for more than 78% of the rainfall locations while positive trends were observed in the frequency of extreme rainfall indices (R10mm, R20mm, and CDD) with the exception of consecutive wet days (CWD) that shows a decreasing trend. A general warming trend over the catchment was observed through the increase in the annual number of warm days (TX90p), warm nights (TN90p) and warm spells (WSDI). The spatial distribution analysis shows a high frequency and intensity of extremes rainfall indices in the south of the catchment compared to the middle and northern of part of the catchment, while temperature extremes were uniformly distributed over the catchment