Assessment of land use management and its effect on soil quality and carbon stock in Ebonyi State, Southeast Nigeria.

Evaluating soil quality (SQ) resulting from land management use impact is important for soil carbon (C) monitoring, land sustainability and suitability. However, the data in less developed regions of Africa like Nigeria is scarce, limiting our understanding at global scale. The study evaluated land management use on soil quality in Ebonyi State, Nigeria, a representative region of Africa. Soil samples were collected in 2021 and resampled in 2022 from regions including five land use managements (FS = forest soil; GLS = grass land soil; ACS = alley cropping Soil; SDS = sewage dump-soils; CCS = continuously cultivated soil). Soil physical and chemical properties were analyzed and discussed. The results shows that soil physical properties (bulk density, hydraulic conductivity, aggregate stability) were significantly (P < 0.05) influenced by land use management. Moderate to high bulk density, very low hydraulic conductivity (HC), and low aggregate stability were observed across land management, suggesting potential inhibition to root penetration, poor aeration, and water infiltration. Improved land management practices such as planting of cover crops either for re-grassing or addition of crop residues could be adopted as conservative options for increasing soil quality and encourage additional soil C. Soil pH decreased with the increase in soil depth in all land uses for both years. A higher soil pH of 6.78 (slightly acidic) was seen in SDS and lower mean 6.0 (moderately acidic) was obtained in CCS at 0-20 cm in 2021. The average mean nitrogen content was rated "very high" (0.81 g kg-1 and 0.69 g kg-1) in 2021 and 2022 respectively, suggesting nitrogen might not be a limiting factor for plant growth in the region. During the 2021 and 2022 study periods, the overall average mean C stock were 12.71 g kg-1 and 15.87 g kg-1 respectively suggesting 3.1 g kg-1 C stock increment in 2022. Soil inorganic C also increased by 9.86 g cm-2 in 2022. The study provided crucial information about how land management use affected soil physico-chemical properties including C stock and suggested that C stock could be improved by adopting appropriate land management use practices. The results fill a data gap in under-studied regions, but also facilitate potential land management practices.

Dynamics of soil properties as impacted by contrasting lithology, slope class, and land use types: a case study in semi-arid highlands of northern Ethiopia.

Soil characterization is crucial in creating sustainable platforms for land users to identify areas vulnerable to anthropogenic activities. This study was conducted to investigate the impacts of lithology, slope, and land use on soil properties of a semi-arid highland in northern Ethiopia. Disturbed and undisturbed soil samples collected from 0 to 30 cm depth were analyzed. Most of the assessed physical and biochemical soil properties varied significantly (p < 0.05) with lithology, slope class, and land use type. Shale-originated soils were richer in nutrients than soils of other lithologies. A decrease in slope gradient accounted for an increase in most soil properties, while a reverse trend was observed for sand content, bulk density (BD), water stable aggregates (WSA), mean weight diameter (MWD), structural stability index (SSI), soil organic carbon (SOC), total nitrogen (TN), and available phosphorus (AP). Silt and clay fractions, total porosity, moisture content at field capacity and wilting point, visual evaluation of soil structure, pH, electrical conductivity, calcium carbonate, exchangeable bases, cation exchange capacity, and percent base saturation were found to be higher for cultivated land soils compared to grass land and shrub land soils. Shrub land soils, in contrast, had higher WSA, MWD, SSI, SOC, TN, and AP relative to grass land and cultivated land soils. In summary, slope class and land use type stood out as the major drivers influencing the dynamics and distribution of soil properties other than lithology and their interactions in semi-arid highlands of northern Ethiopia. Thus, from sustainability point of view and in the light of their nutrient retention capability and limitation, more attention should be paid toward ensuring periodic assessment and sustainable management of soils in steep cultivated lands.

Predictors of drought-induced crop yield/losses in two agroecologies of southern Tigray, Northern Ethiopia.

The consequences of prolonged precipitation-deficient periods are primarily substantial water deficit. The spatial characteristics of drylands and various socioeconomic factors worsen droughts' impacts and deepen poverty among agrarian communities, with attendant food security (stability dimension) implications. This study utilizes a combination of climate, remote sensing and field survey data to obtain first-hand information on the impacts of recent (2015 and 2017) droughts on crop yield in southern Tigray, northern Ethiopia. Annual and seasonal rainfall, annual and seasonal Normalized Difference Vegetation Index (NDVI) and Deviation of NDVI (Dev-NDVI), and monthly Standardized Precipitation Index (SPI) (SPI-1, SPI-3 and SPI-12) for June to October, were considered as likely factors that could relate with yield and yield loss in the area. Correlation and multiple linear stepwise regression statistical techniques were used to determine drought-yield relationships, and identify more accurate predictors of yield and yield losses in each of the drought years. The area witnessed a more widespread precipitation deficit in 2015 than in 2017, where the lowland area recorded entire crop (sorghum) losses. Also, droughts manifested spatiotemporal variations and impacts across the two different agroecologies-primarily reduction in vegetation amounts, coinciding with the planting and maturing stages of barley and sorghum. Crop failures, therefore, translated to food shortages and reduced income of smallholder farmers, which denotes food insecurity in the time of droughts. Seasonal rainfall and June Dev-NDVI predicted 66.9% of 2015 barley and sorghum yield-loss, while NDVI predicted 2017 sorghum yield by 96%. Spate irrigation should be further popularized in the low-lying areas of Raya Azebo to augment for future deficiencies in the kiremt rainfall.

Digitalization to achieve sustainable development goals: Steps towards a Smart Green Planet.

Digitalization provides access to an integrated network of unexploited big data with potential benefits for society and the environment. The development of smart systems connected to the internet of things can generate unique opportunities to strategically address challenges associated with the United Nations Sustainable Development Goals (SDGs) to ensure an equitable, environmentally sustainable, and healthy society. This perspective describes the opportunities that digitalization can provide towards building the sustainable society of the future. Smart technologies are envisioned as game-changing tools, whereby their integration will benefit the three essential elements of the food-water-energy nexus: (i) sustainable food production; (ii) access to clean and safe potable water; and (iii) green energy generation and usage. It then discusses the benefits of digitalization to catalyze the transition towards sustainable manufacturing practices and enhance citizens' health wellbeing by providing digital access to care, particularly for the underserved communities. Finally, the perspective englobes digitalization benefits by providing a holistic view on how it can contribute to address the serious challenges of endangered planet biodiversity and climate change.