Returning straw to the field is the most significant straw utilization technique for China’s green development. It can provide nutrients for crop growth and improve soil organic matter content. However, there are no standard parameters for measuring the nutrient content of straw directly returned to the field. In addition, the nutrient content of straw in the field is disregarded and the least researched. Therefore, to address these issues, the current research examines the main nutrient composition of straw returned directly to fields and the potential substitution of straw for chemical fertilizers. This study used the latest data on the crop straw-to-grain ratio and straw’s direct return to the field from the Database of Agricultural Crops Straws Resources in China (DACSRC) as the basis for a detailed estimation of the amount of crop straw nutrient resources and straw’s direct return to the field. The straw nutrient resources were measured based on straw yield and the nitrogen (N), phosphorous (P₂O₅), and potassium (K₂O) contents. The results reveal that the maximum amount of straw returned directly to the fields in China was 517 teragram (Tg), while 128 Tg (25%) of the total was not collected but left on the field. The North China region had an enormous amount of direct straw return at 176 Tg (34%), while South China had the least amount at 26 Tg (5%). The amounts of seasonally available N, P₂O₅, and K₂O from straw directly returned to fields are 2 Tg, 1 Tg, and 7 Tg, respectively. In addition, the amount of available straw nutrient resources returned to the field per hectare (ha) was 78 kg. The quantity of straw-originating seasonally available nutrients corresponds to 23% of the chemical fertilizers applied, which can substitute 10% N, 9% P₂O₅, and 58% K₂O. The study provides critical insights on effective ways to improve straw fertilization through an increased rate of straw returned directly to fields and releasing seasonal nutrients.

Enormous quantities of straw in China are burnt in open fields or discarded randomly, leading to a serious waste of biomass resources and environmental pollution. To accelerate sustainable development, straw resources must be used efficiently and reduce carbon emissions. Based on a systematic literature review, this study summarizes China’s latest development in straw utilization. It analyzes the accounting methods, carbon emission reduction effects and potential of straw utilization. The study highlights that straw utilization in China can be categorized into five-dimensional straw utilization models (FDSUM). The cost of collection, storage and transportation, and straw utilization technology are the main factors affecting straw utilization. FDSUM contributes greatly to agricultural carbon reduction. Straw-to-fertilizer has the highest contribution, and straw-to-fuel has the largest carbon emission reduction potential. The carbon emission reduction from straw–to-fuel utilization in 2020 was 63.43 × 10⁹ kg CO₂. In addition, China has not developed a standardized carbon accounting method for straw utilization. China needs to prioritize straw-to-fertilizer and straw-to-fuel conversion and develop low-carbon production technologies. This study will serve as a reference to further improve the utilization of straw in China and provide preliminary ideas for establishing a unified national carbon accounting system for straw utilization.

The significance of this research is on maize, rice, sorghum, millet, groundnut, soybeans and cowpea straw for stronger sustainability in Ghana’s economic development. Quantifying and re-use of crop straw resources in Ghana is still at the infancy stage hampering the efficient recycling of these resources in a sustainable manner. Sustainability is straw as a renewable resource to improve soils, livestock production, generate renewable energy and reduce pollution for development. The aim of this research was to estimate the crop straw yield from 2006 to 2016 and identify the various utilization modes for major cereals and legumes in Ghana. In addition the distribution of maize, rice, sorghum and cowpea straw across major producing regions was calculated. Results obtained showed that 77,404,709.75 tonnes of cereals and legumes straw were produced in Ghana from 2006 to 2016. Cereal straw recorded a 72.3% yield whilst legume straw recorded 26.8%. Maize and groundnut straw recorded the highest yield of 37,323,264.16 and 12,495,288.96 tonnes respectively. Brong Ahafo region of Ghana had the highest maize straw yield with the Northern region recording readily availability of both cereals and legumes straw resources. The major re-use methods of straw in Ghana are as livestock feed, fertilizer, cooking fuel, for sale and as a substrate for mushroom production. We recommend strategies the government can adapt to develop policies geared towards the accurate recording of straw and their comprehensive utilization in Ghana. The efficient utilization of straw resources will reduce soil erosion, improve soil fertility, serve as feed for livestock, reduce pollution, generate biofuels plus generate employment to benefit the rural economy.

Hydrogen gas will be an essential energy carrier for global energy systems in the future. However, non-renewable sources account for 96% of the production. Food wastes have high hydrogen generation potential, which can positively influence global production and reduce greenhouse gas (GHG) emissions. The study evaluates the potential of food waste hydrogen-based power generation through biogas steam reforming and its environmental and economic impact in major Ghanaian cities. The results highlight that the annual hydrogen generation in Kumasi had the highest share of 40.73 kt, followed by Accra with 31.62 kt, while the least potential was in Tamale (3.41 kt). About 2073.38 kt was generated in all the major cities. Hydrogen output is predicted to increase from 54.61 kt in 2007 to 119.80 kt by 2030. Kumasi produced 977.54 kt of hydrogen throughout the 24-year period, followed by Accra with 759.76 kt, Secondi-Takoradi with 255.23 kt, and Tamale with 81.85 kt. According to the current study, Kumasi had the largest percentage contribution of hydrogen (47.15%), followed by Accra (36.60%), Secondi-Takoradi (12.31%), and Tamale (3.95%). The annual power generation potential in Kumasi and Accra was 73.24 GWh and 56.85 GWh. Kumasi and Accra could offset 8.19% and 6.36% of Ghana's electricity consumption. The total electricity potential of 3728.35 GWh could displace 17.37% of Ghana's power consumption. This electricity generated had a fossil diesel displacement capacity of 1125.90 ML and could reduce GHG emissions by 3060.20 kt CO₂ eq. Based on the findings, the total GHG savings could offset 8.13% of Ghana's carbon emissions. The cost of power generation from hydrogen is $ 0.074/kWh with an annual positive net present value of $ 658.80 million and a benefit-to-cost ratio of 3.43. The study lays the foundation and opens policy windows for sustainable hydrogen power generation in Ghana and other African countries.