This study sought to determine the effects of foliar fertilization (FF) on both the quantity and quality of maize grains using principal component analysis (PCA). This chemometric approach enabled the selection of the best foliar treatment model for enhancing maize yield and quality. The results were analyzed via PCA, providing valuable insights into identifying the FF recipe with the greatest influence on maize grain production and quality. These field experiments were run during the time period 2020–2022 in the university’s experimental field. Seven experimental variants with three repetitions were tested, including a control group and various FF formulations labeled V1 through V7, each with different chemical compositions. FF applications were conducted during specific vegetative phases of the maize, respectively, in stages 15–16 BBCH (5–6 unfolded leaves) and 20–22 BBCH (10–12 unfolded leaves), with application rates varying from 2 to 6 Lha¹ according to the product’s chemical properties. The application of FF treatments positively impacted both the production and quality of maize grains, as evidenced by specific quality indices such as moisture, protein, lipid, carbohydrate, fiber, and mineral content.

Urease and nitrification inhibitors represent ways to reduce nitrogen losses; their presence modifies microbial and enzymatic activity in the soil, affecting pH and organic matter (OM), which in turn affects the mobility of heavy metals. To evaluate the effect of urea with inhibitors, pH, OM content, and pseudo-total and mobile metal content (Cu, Cd, Ni, Pb, Cr, Zn, and Mn) were determined in soil samples fertilized with six different urea variants with inhibitors. The modification in the pseudo-total content of heavy metals following fertilization (%) was as follows: Cu (−39.26 ÷ −8.82), Cd (10.74 ÷ 15.40), Ni (5.76 ÷ 18.84), Pb (−13.30 ÷ 12.46), Cr (−15.55 ÷ 11.60), Zn (35.10 ÷ 162.76), and Mn (−1.32 ÷ 12.17). The pH was situated in the range of 7.05 to 7.17, while OM content showed an average increase of 16%. The determined pollution indicators revealed an accumulation of Zn in the soil. The results showed a trend of accumulation of bioavailable heavy metals, with the greatest increase for Mn (43%). Only in the case of Zn, there was a decrease in mobile content with the lowest value when applying two urease inhibitors and one nitrification inhibitor. Inhibitors modify the OM content and soil pH, influencing the mobility and bioavailability of heavy metals.

Liming is an essential practice for neutralizing soil acidity, influenced by factors like lime particle size and application rate, addressing challenges from climate change, acid rain, nitrate leaching, and mineral oxidation. This study evaluated the efficiency of fine (0.1 mm) and coarse lime (1–2 mm) applied at rates of 3 t/ha and 6 t/ha in mitigating soil acidity, with a particular focus on their impact on subsoil characteristics. Over two years, key soil parameters were monitored, including pH, cation exchange capacity (CEC), and exchangeable base cations (Ca²⁺, Mg²⁺, K⁺), along with exchangeable aluminum (Al³⁺). Fine lime particles demonstrated superior effectiveness compared to coarser ones, leading to faster and more uniform pH increases due to their greater surface area and higher solubility. Lime application significantly improved CEC by reducing exchangeable aluminum and increasing calcium availability, particularly in the topsoil. While these effects were most pronounced in surface layers, aluminum toxicity remained a concern in deeper soil levels. Strong positive correlations were observed between lime application and soil parameters such as pH, CEC, and exchangeable cations, while aluminum showed a negative correlation. Principal component analysis confirmed the benefits of higher lime doses, with fine lime producing rapid improvements and coarse lime offering a slower but sustained effect on soil health.

Liming is a common practice for improving the quality of soils affected by acidity, due to climate change, acid rain, nitrate leaching, and oxidation of sulphide minerals. This study aimed not only to assess the efficiency of fine and coarse lime application at 3 t/ha and 6 t/ha doses in mitigating soil acidity, but also to determine which of the options has a stronger impact on improving subsoil characteristics. Over a period of two years, several key parameters were monitored: pH, exchangeable base cations (Caexch, Mgexch, and Kexch), and Alexch. In the topsoil, the highest increase in pH was observed 6 months after the ap-plication of 3 t/ha fine lime, while in the subsoil, only a modest increase was noted. The highest values of exchangeable base cations in the topsoil were: Caexch = 9.06 cmol/kg soil; Mgexch = 1.15 cmol/kg soil; Kexch = 0.360 cmol/kg soil. These were recorded 24 months after applying 6 t/ha of fine aglime, and were higher than those obtained in the subsoil. While in topsoil Alexch reached 0 at T3, in subsoil, the largest decrease was 38% at T3. The release rate of ca Ca and its mobility depend on the particle size and dose of aglime, playing an important role in alleviating aluminium toxicity.

Waste and by-products from the food industry put pressure on the environment. FAO defined food losses as losses along the food chain between producer and market, while safe and nutritious food is thrown away as waste. About a third of the food produced is wasted. A significant amount of food is disposed of as waste, especially in developed countries, and this also means the disposal of resources used to produce food. Food waste is not only an economic problem, but also an environmental and moral problem. Food diverted to landfills directly contributes to climate change by emitting methane (CH4), a significant greenhouse gas 25 times stronger than carbon dioxide (CO2) Even when all actions have been taken to use the waste food, some inedible parts will remain and can be turned into compost to feed and nourish the soil. A promising approach for improving soil services and crop productivity is the transformation of food by-products and waste into soil amendments. Industrial by-products of food processing and manufacturing represent 14% of the total food waste generated. These by-products of food processing present a significant opportunity to reuse the waste by transforming it into amendments for degraded soils. The purpose of this work is to present how different types of by-products from the food industry (bentonite, keratin) can be used as soil improvers, reducing the impact of food production on the environment