**3.1 High use of mineral fertilizer and other chemical inputs**

Due to the extensive use of synthetic chemical fertilizers and pesticides, the agricultural sector of developed countries is one of the most significant sources of environmental pollution [22–24]. To increase productivity per unit area, agricultural systems around the world use a lot of chemicals including fertilizers, insecticides, and herbicides [22]. These chemicals and fertilizers contribute to a number of issues, including soil, water, and air pollution, decreased input efficiency, decreased food quality, soil degradation, a lack of micronutrients in the soil, toxicity to various beneficial living organisms present above and below the soil surface, and decreased production. Additionally, overuse of synthetic nitrogen fertilizer may result in large atmospheric emissions of nitrous oxide [25].

**Figure 2.** *World fertilizers consumption (Mt). Sources: IFA and FAOSTAT [26, 27].*

The consumption of fertilizer worldwide has greatly increased since 1961 (**Figure 2**). Global research indicates that the production of synthetic N fertilizers that are added to crops has increased about sevenfold, whereas the yield production of crops has increased by almost 2.4 times [28, 29]. Furthermore, nearly 60% of all synthetic chemical fertilizer production was made up of nitrogen. The significant attention paid to this fertilizer significantly affects natural soil ecosystems, which in turn impacts sustainable agriculture. As a result, producing agricultural products that are chemical-free and high in nutrition is necessary for both human and animal use. To prevent the degradation of natural resources, the focus should be placed on producing high quality and quantity food [29]. Overall, using excess mineral fertilizer has a negative influence on sustainable agriculture.

#### **3.2 Lack of advanced technology**

Adoption of advanced technology by smallholder farmers can enhance their income and livelihood [30–32]. In most developing countries, agricultural practices are dominated by many traditional approaches. For instance, compared to other regions, the sub-Saharan African countries, which rely primarily on rain-fed agriculture, have been adversely affected by climate change and variability [33, 34]. Due to low adoption of advanced irrigation practices like drip irrigation and water harvesting, the region is highly susceptible to climate change and variability. Drip irrigation is a technology that conserves water and reduces water losses through drainage. This technology was developed in response to the incentives present in Israel, a country that suffers from a severe water scarcity problem and which made a concerted effort to develop water-conserving technologies [30]. It is critical to prioritize smallholders' needs in agricultural development programs in an area where they account for an estimated 80% of farms and generate the majority of the region's food [30].

#### **3.3 Climate change impacts**

Climate change and variability are the greatest challenging factors to sustainable agriculture (SA) in the world [16, 21]. Climate change and variability affect the cereal production system through irregular rainfall distribution, flooding, and increasing mean temperature [35]. Most developing countries are highly vulnerable to climate variability due to extremely high dependence on rain-fed agriculture, low development of irrigation schemes [16, 36, 37]. Vulnerability to climate variability is also exacerbated due to a lack of improved technologies, lack of effective early warning systems, and small and fragmented land size [35]. For instance, in Ethiopia, it is anticipated that agricultural production will decrease by 6–33% between 2030 and 2050 due to the effects of climate change and variability [14, 38]. This will cause food and nutrition insecurity and increases the loss of life in the country. The effects of climate change on agriculture will depend on the rate and severity of the change and how successfully farmers can adapt. The impact of climate change and variability is very evident in developing countries as compared to developed countries. In order to guarantee sustainable agriculture and food security, developing countries need to receive a lot more attention.
