Population growth and increasing resource demands in Ethiopia are stressing and degrading agricultural landscapes. Most Ethiopian soils are already exhausted by several decades of over exploitation and mismanagement. Since many agricultural sustainability issues are related to soil quality, its assessment is very important. We determined integrated soil quality indices (SQI) within the surface 0–15 cm depth increment for three agricultural land uses: rain fed cultivation (RF); agroforestry (AF) and irrigated crop production (IR). Each land use was replicated five times within a semi-arid watershed in eastern Tigray, Northern Ethiopia. Using the framework suggested by Karlen and Stott (1994); four soil functions regarding soil’s ability to: (1) accommodate water entry (WE); (2) facilitate water movement and availability (WMA); (3) resist degradation (RD); and (4) supply nutrients for plant growth (PNS) were estimated for each land use. The result revealed that AF affected all soil quality functions positively more than the other land uses. Furthermore, the four soil quality functions were integrated into an overall SQI; and the values for the three land uses were in the order: 0.58 (AF) > 0.51 (IR) > 0.47 (RF). The dominant soil properties influencing the integrated SQI values were soil organic carbon (26.4%); water stable aggregation (20.0%); total porosity (16.0%); total nitrogen (11.2%); microbial biomass carbon (6.4%); and cation exchange capacity (6.4%). Collectively, those six indicators accounted for more than 80% of the overall SQI values.

The COVID-19 pandemic has disrupted the global food supply chain and exacerbated the problem of food and nutritional insecurity. Here we outline soil strategies to strengthen local food production systems, enhance their resilience, and create a circular economy focused on soil restoration through carbon sequestration, on-farm cycling of nutrients, minimizing environmental pollution, and contamination of food. Smart web-based geospatial decision support systems (S-DSSs) for land use planning and management is a useful tool for sustainable development. Forensic soil science can also contribute to cold case investigations, both in providing intelligence and evidence in court and in ascertaining the provenance and safety of food products. Soil can be used for the safe disposal of medical waste, but increased understanding is needed on the transfer of virus through pedosphere processes. Strengthening communication between soil scientists and policy makers and improving distance learning techniques are critical for the post-COVID restoration.

Nearly half of the world cereal production comes from soils low or marginal in plant available zinc, leading to unsustainable and poor quality grain production. Therefore, the effects of nitrogen (N) rate and application time on zinc (Zn) and iron (Fe) concentration in wheat grain were investigated. Wheat (Triticum aestivum var. Krabat) was grown in a growth chamber with 8 and 16 h of day and night periods, respectively. The N rates were 29, 43, and 57 mg N kg^-1 soil, equivalent to 80, 120, and 160 kg N ha^-1. Zinc and Fe were applied at 10 mg kg^-1 growth media. In one of the N treatments, additional Zn and Fe through foliar spray (6 mg of Zn or Fe in 10 ml water/pot) was applied. Micro-analytical localization of Zn and Fe within grain was performed using scanning macro-X-ray fluorescence (MA-XRF) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The following data were obtained: grain and straw yield pot^-1, 1000 grains weight, number of grains pot^-1, whole grain protein content, concentration of Zn and Fe in the grains. Grain yield increased from 80 to 120 kg N ha^-1 rates only and decreased at 160 kg N ha^-1 g. Relatively higher protein content and Zn and Fe concentration in the grain were recorded with the split N application of 160 kg N ha^-1. Soil and foliar supply of Zn and Fe (Zn + Fe_s+f), with a single application of 120 kg N ha^-1N at sowing, increased the concentration of Zn by 46% and of Fe by 35%, as compared to their growth media application only. Line scans of freshly cut areas of sliced grains showed co-localization of Zn and Fe within germ, crease and aleurone. We thus conclude that split application of N at 160 kg ha^-1 at sowing and stem elongation, in combination with soil and foliar application of Zn and Fe, can be a good agricultural practice to enhance protein content and the Zn and Fe concentration in grain.

The sub-Saharan Africa (SSA) region bears the blunt of soil pollution mainly due to-haphazard disposal and gross mismanagement of a wide assortment of pollutants generated from within and outside the region. Pollution of agricultural soils in the region is so intense that out of the 80 countries substantially affected by land degradation (soil pollution, inclusive) in the world, 36 are found in Africa, the SSA, in particular. Pollution of soils has resulted into a significant reduction in their ability to support crop growth and yield apart from jeopardizing safety and security of agricultural produce in SSA. Consequences of pollution of soils on human health in the region are inadequately reported, but they range from non-fatal, life-changing effects like skin damage due to acute, invariably fatal incidences of exposure to milt by chronic effects. We show in this review, that while science and advancement in technology has provided a multitude of alternative techniques to pollution control and remediation of affected soils, such techniques are largely inaccessible to most SSA countries. There is also lack of coordination on development, enforcement and implementation of legal and political instruments to tackle the growing risk of pollution to human health from soil contamination across the SSA region. Couple with this, lack of data on status of soil pollution in most SSA countries affects the countries’ capacity to devise and plan policies that can help reduce soil pollution. Countries need to maximize efforts to reverse the status of already polluted pieces of land through strengthening remediation programs, research on how best to gather, maintain and complement soil pollution data and actions that inform decision-making.

Agricultural residues are produced in large quantities and their management is an issue all over the world. Many of these residues consist of plant materials in different degrees of transformation, so returning them back to soil is a management option that closes loops in a circular economy context. The objective of this paper is to summarize current knowledge on the options and effects of reusing agricultural residues as organic soil amendments. The reuse of these residues in soil is a good solution for minimizing the problems associated with their management, while improving soil health and ecosystem functions. While some agricultural residues can be applied directly to soil, others will need previous transformations such as composting to improve their properties. This allows the recovery of plant nutrients and increase in soil organic matter contents, with many positive effects on the soil’s physical, chemical and biological properties, and ultimately, crop production, although potential risks derived from some materials must also be considered. The concept of regenerative agriculture and soil management using organic soil amendments contribute to the significant enhancement of soil biodiversity, the protection of the environment and climate goal achievement.

High anthropogenic activities are constantly causing increased soil degradation and thus soil health and safety are becoming an important issue. The soil quality is deteriorating at an alarming rate in the neighborhood of smelters as a result of heavy metal deposition. Organic biowastes, also produced through anthropogenic activities, provide some solutions for remediation and management of degraded soils through their use as a substrate. Biowastes, due to their high content of organic compounds, have the potential to improve soil quality, plant productivity, and microbial activity contributing to higher humus production. Biowaste use also leads to the immobilization and stabilization of heavy metals, carbon sequestration, and release of macro and micronutrients. Increased carbon sequestration through biowaste use helps us in mitigating climate change and global warming. Soil amendment by biowaste increases soil activity and plant productivity caused by stimulation in shoot and root length, biomass production, grain yield, chlorophyll content, and decrease in oxidative stress. However, biowaste application to soils is a debatable issue due to their possible negative effect of high heavy metal concentration and risks of their accumulation in soils. Therefore, regulations for the use of biowastes as fertilizer or soil amendment must be improved and strictly employed to avoid environmental risks and the entry of potentially toxic elements into the food chain. In this review, we summarize the current knowledge on the effects of biowastes on soil remediation, plant productivity, and soil organic carbon sequestration.