## 1 Introduction  
About five billion hectares, approximately 36% of the world's land, are under cultivation [1]. This indicates that a large number of countries around the world depend on agricultural production economically [2]. Table 1 expresses the economic impact of the agriculture sector in 10 countries that produce some of the largest shares of the world's total agricultural production. However, this dependence varies depending on the country's location and their climate conditions. For instance, in Southeast Asian regions like Malaysia, Indonesia, and India, the palm is the most prominently produced crop, whereas in other countries like those in South America, maize and cane are prominent. In contrast, in some countries that have dry or semi-dry weather conditions, such as those in the Middle East, the amount of agricultural waste is not comparable to that of the more forested countries; however, agricultural wastes have a lot of applications, especially in rural areas. Due to the large amount of agriculture products like palm oil, cane, maize, wheat, coconut, etc., there are large amounts of agro-waste materials because of the increasing world population. All agricultural residues from the processing and production of agricultural yields (e.g., poultry, crops, meat, fruits, dairy, and vegetables) are named agricultural wastes. In countriesthat do not produce huge amounts of agricultural products, agricultural wastes amount to a lot of thrown-away materials that could be used as useful materials for construction, and this has attracted a lot of attention among researchers to investigate them. The significance of this review becomes apparent when considering the increasing trend in the publication of papers related to the utilization of agricultural wastes in construction (Figure 1). The amount of world agricultural waste is about 998 million tons/year [3]. These huge amounts of wastes are usually thrown away in landfills and could affect the environment's condition due to the discarding of the waste on-site. A point that should not be overlooked is that the utilization of harvest and agricultural residues can vary depending on various factors, including their potential use for energy generation, soil enrichment through practices such as plowing to increase carbon content, and other agricultural applications [4]. The environmental issues of agro-waste materials have motivated scientists to find a way of reusing them as lightweight materials, like using them as aggregate, bar, or additives in concrete, using them to provide insulation, or using them as lightweight materials for construction, as well as protecting the environment from waste materials [5]. Using these materials in construction has a history of thousands of years, and some new ideas for these materials, like using the kernel shells of palms and coconuts, started appearing in studies around two decades ago [6]. Over time, there has always been competition between the \begin{table}
\begin{tabular}{l l l l l} \hline \hline
**Rank** & **Country** & \begin{tabular}{l} **Share of Agriculture** \\ **GDP (2019)** \\ \end{tabular} & \
\begin{tabular}{l} **Population** \\ **(Millions) (2019)** \\ \end{tabular} &
\begin{tabular}{l} **Share of Population in** \\ **Agriculture Sector (2019)** \\ \end{tabular} \\ \hline
1 & China & 7.6\% & 1420 & 25\% \\ \hline
2 & India & 18\% & 1380 & 42\% \\ \hline
3 & United States & 9\% & 334 & 1.3\% \\ \hline
4 & Russia & 4\% & 146 & 5.8\% \\ \hline
5 & I. R. of Iran & 12\% & 86 & 17\% \\ \hline
6 & Brazil & 7.8\% & 212 & 9\% \\ \hline
7 & Pakistan & 21\% & 223 & 36\% \\ \hline
8 & Australia & 2.3\% & 25 & 2.5\% \\ \hline
9 & Italy & 2\% & 59 & 3.8\% \\ \hline
10 & Canada & 1.6\% & 37 & 1.5\% \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Top countries with the highest total agricultural gross domestic production (GDP) (in USD millions) exposed to dry climates and their shares of agricultural GDP and populations (housands) [2].