# Application of Fly Ash Obtained from the Incineration of Municipal Solid Waste in Agriculture
## 5 The Impact of Using MSWI in Agriculture
The analysis of the soil to which different concentrations of ash were added showed an increase in the potassium content of the soil; the Fe content of the soil remained almost unchanged; the following microelements, manganese, calcium, nickel, copper, and zinc, had progressive increases with the increase in concentration of added ash. The potassium content of the soil gradually increased with the increase in the concentration of ash applied to the soil, from 45.5 (control) to 70.0 mg/kg [50] (Table 5) [50]. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Fly Ash** & **0** & **1** & **2.5** & **5** & **10** & **15** \\
**(t/h)** & & & & & & \\ \hline Na & 1180 & 1215 & 1180 & 900 & 850 & 1025 \\ K & 3900 & 4280 & 6500 & 7050 & 8290 & 10,150 \\ P & 45.5 & 36.9 & 46.0 & 50.3 & 46.8 & 70.0 \\ Fe & 325 & 267 & 340 & 263 & 300 & 310 \\ Mn & 03 & 100 & 161 & 195 & 211 & 240 \\ Ni & 5.80 & 5.79 & 6.67 & 8.50 & 12.05 & 15.37 \\ Co & 5.15 & 6.10 & 6.68 & 7.36 & 10.22 & 17.31 \\ Zn & 36.0 & 39.6 & 46.0 & 49.8 & 51.0 & 67.0 \\ Cu & 5.06 & 5.73 & 5.97 & 7.50 & 10.0 & 14.38 \\ Pb & 8.3 & 9.50 & 13.46 & 12.97 & 17.58 & 20.00 \\ Cr & 0.0 & 0.02 & 0.20 & 1.06 & 1.39 & 1.89 \\ Cd & 0.0 & 0.0 & 0.0 & 0.005 & 0.02 & 0.06 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: The influence of fly ash obtained from the incineration of municipal solid waste on the elemental state of the soil (values in mg/kg) (data from [50]). According to [PERSON] et al. [78], with the increase in the concentration of ash applied to the soil, higher values of organic carbon, organic matter, phosphorus, and pH were obtained. According to [PERSON]'s research, fly ash can be used as organic fertilizer at levels of 120 and 180 t ha\({}^{-1}\), due to the content of nutrients that the ash contains [54]. The addition of fly ash to clayey soil reduced bulk density and increased nutrient mobility due to increased soil porosity and soil drainage [79]. The main nutrients necessary for plant growth are phosphorus and potassium, elements found in the composition of ash, which can be used as a partial substitute for chemical fertilizers [80; 81]. According to [PERSON] et al. [13], Swiss chard and alfalfa had similar growth in soils to which ash was added to soils to which chemical fertilizers were added, due to the nutrients in MSWI ash. Ash used in agriculture depends on the type of incinerated waste, the type of soil on which it is applied, the type of crops, the concentration of ash that is applied, and the treatment applied in order not to have a negative impact on the environment and agricultural crops [73; 82; 83]. The improvement in nutrients (sulfates, bicarbonate, carbonates, phosphorus, potassium, boron, calcium, zinc, magnesium, manganese) in acid soils was found after the application of an ash concentration of 5-10%, g/g [84; 85; 86; 87; 88; 89]. The agronomic properties of the soil were improved [66; 67; 68; 69; 70; 71; 72; 73; 74; 75; 76; 77; 78; 79; 80; 81; 82; 83; 84], and the phosphorus retention capacity of the soil and phosphorus adsorption increased [95; 95]. The water retention capacity and plant production were improved, and the acidity of the sandy clay soil was reduced by adding 200-400 t/ha of fly ash [28]. [PERSON] and [PERSON] [96] found that the plants had an improvement in growth in the soil to which fly ash was added, the mobility of nutrients in the soil increased, and the chemical and physical properties were improved by applying the following amounts of fly ash: 0, 25, 75, and 100 tons/ha [28]. Table 6 shows the physical characteristics of the fly ash and the soil [30]. According to [PERSON] and [PERSON] [20], the use of fly ash in agriculture is also profitable from an economic point of view; 10 million hectares of land out of 150 million hectares of cultivated land can be safely occupied for fly ash application per year. At a fly ash dose of 20 mt per hectare, 200 million tons of fly ash per year would be consumed. Fields treated with fly ash would provide an additional yield of 5 million tons of grain per year [20].