## 3 Results and Discussion
### LCA of Maize Production Induced by Laser versus Conventional Maize Production
In regions with extensive agricultural operations, excessive or improper soil fertilization is a significant issue that contributes to ammonia emissions, soil deterioration, groundwater contamination, surface water eutrophication, and greenhouse gas emissions [30]. Additionally, it has an impact on food quality, the deposition of heavy metals on agricultural fields, and greenhouse gas (GHG) emissions. Nutrient loss from farmlands remains a significant contributor to these forms of pollution and results from urea application to the soil. Almost 15% of the total applied urea can be lost to leaching [31]. The primary cause is the use of chemical nitrogen-based fertilizers; the extent of the impacts depends on the type and applied dose of N-based fertilizers [7; 30]. In conventional agriculture, fertilization relies primarily on the use of urea. However, urea is associated with NH\({}_{3}\)  
Figure 2: Results of normalization for maize production irradiated by laser (IL) and non-irradiated (NIL) using ReCiPe 2016. SO\({}_{2}\), and NOx emissions during and after application [31]. The excessive use of applied inorganic fertilizers increases the potential for ecotoxicity and related impacts. The rate of the human toxicity indicators of non-irradiated seeds was more than the irradiated seeds. According to the rate of environmental indicators in Figures 2 and 3, most inputs are related to nitrogen fertilizer consumption, electricity consumption, diesel fuel, and pesticide consumption. Thus, some management approaches should be presented to reduce these indicators. Assessment of Midpoint Ecotoxicity Impacts of Laser-Induced Maize Production Using the CML 2000 and ReCiPe 2016 Methods  
The assessment of the impacts on freshwater ecotoxicity, marine ecotoxicity, and human toxicity was conducted based on one ton of laser-induced grain maize production. The assessment used the midpoint approach from CML 2000 and ReCiPe (H) and was presented in a relative contribution of the impact categories evaluated (Figure 4). The impact on freshwater ecotoxicity using the CML 2000 method was similar to that of the ReCiPe midpoint (H). The primary contributing factors in the CML 2000 method were nickel, copper, and beryllium. In contrast, the ReCiPe midpoint (H) showed the primary impacts of zinc and copper (Figure 5). The results of the CML 2000 and ReCiPe midpoint (H) applications differed because each method considered the toxicity indicators and the characterization factors for the limited substances; this was reflected in the results [32]. These findings agreed with the results presented by [PERSON] and [PERSON] [33], in which copper and nickel discharges were directly linked to freshwater aquatic ecotoxicity, while mercury and chromium discharge caused terrestrial ecotoxicity. Furthermore, the discharge of waste sludge from wastewater treatment plants directly impacts the environment because the heavy metals in the waste sludge negatively affect the soil and farmlands [34]. Figure 3: Comparison of contributions by laser-induced and conventional production to environmental impacts on marine ecotoxicity (ME), freshwater ecotoxicity (FE), and human toxicity (HT). The CML and ReCiPe methods exhibited similar impact rankings for marine ecotoxicity, as shown in Figure 4. However, there was a difference between the two methods for nitrogen and urea-induced impacts. The different discharges are shown in Figure 5. Significant variations occurred in the metal components: hydrogen fluoride and beryllium in the CML method and zinc and copper in the ReCiPe method. Based on these results, we concluded that the midpoint (H) successfully established the inter-subcategory differences, namely the freshwater and marine ecotoxicity, with the marine waters exhibiting the most significant impact from fertilizer use. The primary sources of marine ecotoxicity are industrial activities, power plants, fossil fuels, and the application of phosphate fertilizers [35]. These processes are associated with the release of pollutants into the atmosphere.