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ABSTRACTRice is an important food crop in Ghana. However, its production has constantly been below 40% of the demand, and most of the requirements meet from imports. Such low production level is largely attributed to farmers’ sub-optimal crop and water management practices. As an effort toward sustainably improving rice yield, three-season on-farm participatory experiments were conducted within the Biem watershed in Ghana to determine the potential of good agricultural practices (GAP) for closing the rice yield gap with agronomic and economic sustainability. Good agricultural practices were compared with 23 farmers’ traditional practices on lowland rice growth and yield, profitability, and nutrient use efficiency. The effect of alternate wetting and drying (AWD) with GAP on grain yield of rice was also determined. Rice yield was on average 28% higher under GAP than farmers’ practices (FP). Alternate wetting and drying did not have significant effect on rice yield when compared to continuous flooding. However, when GAP was combined with AWD, rice yield was 13% higher than under FP. Furthermore, the results of the study indicate that major gains in nitrogen use efficiency (+1.48 kg grain kg−1 N; +2.4%), and net profit (+694.35 USD ha−1; +59%) were achievable through the adoption of GAP. There is therefore, a high potential to close the lowland rice yield gap and achieve rice self-sufficiency through the adoption of GAP in the lowlands of the Inland valley of Ghana and similar rice production regions of West Africa.

ABSTRACTRice production in Ghana is limited by low varietal choices, which puts farmers at a disadvantage in meeting the market demand for consumers. The objectives of this study were to (i) assess the yield potentials of improved rice varieties developed by the Africa Rice Center (AfricaRice), and (ii) to allow farmers to select improved varieties of their choice based on growth and yield, as observed in the field, in order to ensure a high adoption rate, increase productivity and food security. Two seasons (i.e. 2020 major and 2020–2021 minor) field experiments were conducted at two lowland within the Mankran watershed in the Ashanti region of Ghana. The experiment comprised thirteen (13) improved varieties and two local checks and was conducted using recommended good agronomic practices. The key findings of the study showed that growth and yield parameters vary significantly between varieties across locations. The biplot analysis showed that varieties FARO 66, SAHEL 317, and Amankwatia are the best in the major season while WITA 9, GT 11, ARS-957-BGJ-171-15-D-B, NERICA L36, and AGRA were the best in the minor season at both locations. Farmers’ preference for the varieties was based not only on growth and yield but on resistance to lodging, pests, and diseases. In conclusion, the best performing varieties have demonstrated yield potential which is about 92% higher than the yield of the local checks and can be recommended for adoption by farmers. Future breeding programs on these varieties should include the most preferred attributes by farmers in this study.

Food security issues continue to be a challenge in most parts of the globe, especially in sub-Saharan Africa (SSA). Several research attempts on addressing this issue have mainly been on nutrient replenishment using combined nutrient application of organic amendments and mineral fertilizer inputs. However, there is limited information available on the potential mechanisms underlying nutrient interactions associated with co-application of organic amendments and mineral fertilizers. Therefore, this review focuses on the mechanisms underlying crop nutrient interactions, with particular emphasis on improved nutrient synchrony, priming effect, general soil fertility improvement and balanced proportion of nutrients required by crops. Following a brief overview of the mechanisms, the review describes four common pre-determined nutrient ratios required by plants depending on its life cycle, environment and genotypic characteristics in order to attain the crop’s maximum genetic potential. The review concludes with the need for future research to understudy mechanisms causing nutrient interaction under cropping systems, so as to apply nutrients at the most appropriate time to synchronize nutrient release with crop uptake, with the utmost goal of promoting sustainable crop production and enhancing food security.

The practice of crop rotation is known to significantly influence soil nutrient dynamics, depending on the type of rotation and the crops involved. As such, a field study was conducted to find out the effect of continuous cassava-maize rotation, where mineral fertilizer was only applied to the maize crop, on soil nutrients dynamics and soil quality thereof under varying rotation periods. The study revealed that Soil Organic Matter (SOM) and levels of soil nutrients, such as total nitrogen, available phosphorus and exchangeable cations (potassium, calcium, magnesium, and sodium) significantly declined with rotation period. Long term maize–cassava rotation led to subsoil (20–50cm) acidification. Soil quality as measured by Carbon Management Index (CMI) on the different aged rotations decreased with age, with the longest rotation period giving the least quality. These results and observations imply that long term cassava-maize rotation reduced soil quality and the resilience of the cropping system for continuous sustainable crops production. A regression analysis of soil nutrients with CMI under the continuous cassava-maize rotation identified the crucial role of soil total N (r2 = 0.56) and exchangeable K (r2 = 0.44) in sustaining productive cassava-maize rotation system and improved soil quality within the semi-deciduous forest agro-ecological zone. It is thus, recommended that enhanced and targeted organic and inorganic fertilization regime could be deployed on the cassava-maize rotation system to improve the inherently low levels of nutrients and increase crop yields.