Objective: Biochar and a commercial humic acid-rich product, Humac (modified leonardite), represent soil amendments with the broad and beneficial effects on various soil properties. Their combination has been scarcely tested so far, although the positive impact of their interaction might be desirable. Materials and Methods: The dehydrogenase activity (DHA), microbial biomass carbon (C_mic), soil respiration (basal and substrate-induced), enzyme activities, total carbon (C_tot), and both shoot and root biomass yield were measured and compared in the short-term pot experiment with the lettuce seedlings. The following treatments were tested: the unamended soil (control), the Humac-amended soil (0.8 g·kg⁻¹), the biochar-amended soil (low biochar 32 g·kg⁻¹, high biochar 80 g·kg⁻¹), and the soil-amended with biochar + Humac. Results: The effect of both amendments on the soil pH was insignificant. The highest average values of C_tot and C_mic were detected in high biochar treatment and the highest average values of basal and substrate-induced respiration (glucose, glucosamine, alanine) were detected in the low biochar treatment. The phosphatase activity and fresh and dry lettuce aboveground biomass were the highest in the low biochar + Humac treatment. Conclusions: Even though the combination of both biochar + Humac decreased the microbial activities in the amended soil (C_mic, DHA, enzymes, substrate-induced respiration) at the low biochar dose, they mitigated the detrimental effect of the high biochar dose on respiration (all the types) and the enzyme (phosphatase, arylsulphatase) activities. In contrast to the previously published research in this issue, the effects could not be attributed to the change of the soil pH.

Digestate is commonly used as a liquid organic fertilizer, as it contains nutrients that are important for plant growth and thus help reduce usage of mineral fertilizers. Since the digestate application leads to the release of greenhouse gases (GHGs) into the atmosphere, it is necessary to find a suitable application method and fertilizer rate with minimal gas emissions while providing sufficient nutrients to crops. The aim of this study was to investigate the relationship between selected GHGs and ammonia (NH₃) release into the atmosphere and different rates of digestate applied, i.e., 0, 10, 20, 30, and 40 m³ ha⁻¹. Two digestate incorporation methods were used, i.e., a disc application unit (D) and strip-till (S). The fluxes, i.e., methane (CH₄), ammonia, and carbon dioxide (CO₂), were monitored using the wind tunnel method. Crop growth and potential nutrient utilization by silage maize were assessed through stand condition monitoring by the Normalized Difference Vegetation Index (NDVI) and the Normalized Difference Water Index (NDWI) using remote sensing. Under the given conditions, the digestate rates and the compared application methods had significant effects on the level of fluxes. The rate of digestate was confirmed to affect the yield of silage maize. The yield increased by more than 8% when using the disc applicator. Based on our results, it is advisable to apply digestate by strip-till technology at rates of approximately 20 m³ ha⁻¹.

This study was conducted to understand the long-term influence of biostimulator NeOsol in combination with different manure types on soil’s physical properties and crop status. NeOsol is a soil biostimulator that should stimulate the biological reactions of the soil profile and improve the soil’s physical and chemical properties. A six-year experiment was conducted with eight treatments: NPK, cattle manure, pig manure, poultry manure, and the same four treatments with the NeOsol added on top. The in situ sampling of soil properties provided data on unit draft (UD), bulk density (BD), and saturated hydraulic conductivity (SHC). Furthermore, remotely sensed data were analyzed to describe crop status via three selected vegetation indices (VI), and crop yields were assessed last. The variants treated with NeOsol demonstrated decreases in UD over time; BD, SHC, and VI did not significantly change. The impact on yield was significant and increased over time. When comparing the variants with manure application to those without one, the cattle manure led to significantly higher SHC; the pig manure led to significantly lower UD and BD but significantly higher SHC and yield; and the poultry manure led to significantly lower UD and BD but higher yield.

This study aims to optimize the estimation of reference evapotranspiration (ETo) in data-scarce regions by integrating ERA5-Land reanalysis data with machine learning (ML) models. Daily meteorological data from 33 stations across Turkey’s diverse climate zones (1981–2010) were utilized to train and validate three ML models: Random Forest (RF), Extreme Gradient Boosting (XGBoost), and Extreme Learning Machine (ELM). The methodology involved rigorous quality control of ground-based observations, spatial correlation of ERA5-Land grids to station locations, and performance evaluation under various data-limited scenarios. Results indicate that while ERA5-Land provides highly accurate solar radiation (R_s) and temperature (T) data, variables like wind speed (U₂) and relative humidity (RH) exhibit systematic biases. Among the used models, XGBoost demonstrated superior performance (R² = 0.95, RMSE = 0.43 mm day⁻¹, and MAE = 0.30 mm day⁻¹) and computational efficiency. This study provides a robust, regionally calibrated framework that corrects reanalysis biases using ML, offering a reliable alternative for ETo estimation in areas where local measurements are insufficient for sustainable water management.

Soil physical properties and crop status under cattle manure and Z’Fix in Haplic Chernozem | Václav Novák, Petr Šařec, Kateřina Křížová, Petr Novák, Oldřich Látal | Agricultural Journals