Effect of Soil Conditioning on Soil Penetration Resistance and Traction Power Demand of Ploughing

Soil compaction and degradation due to improper tillage are problems involving significant natural and economic damages. On compacted soils, suitable cultivation can be implemented only with higher energy and traction force input. In our study, the effect of a soil conditioner (Neosol) was examined on the penetration resistance of the soil and the traction power demand for ploughing in the experiment set up in the East-Slovak Plain in 2017 ‒ 2018 to justify several preliminary results showing that long-term soil conditioning results in enhanced root system, improved soil structure, cultivability, water- and salt regime. We found a positive effect of Neosol application with both investigated parameters and its long-term effect was also justified. The penetration resistance values of the soil of the untreated plot were 17 ‒ 23% higher, while the traction power demand values were 9 ‒ 32% lower in comparison with the Neosol treated plot in the first and the second year of the study, respectively. We assume the cumulative positive effect of soil conditioning on the physical soil properties in the study area, therefore the long-term application of Neosol is recommended for farms having similar soil properties.

Biopolymer Hydrogel Based on Acid Whey and Cellulose Derivatives for Enhancement Water Retention Capacity of Soil and Slow Release of Fertilizers

This study describes the development of a renewable and biodegradable biopolymer-based hydrogel for application in agriculture and horticulture as a soil conditioning agent and for release of a nutrient or fertilizer. The novel product is based on a combination of cellulose derivatives (carboxymethylcellulose and hydroxyethylcellulose) cross-linked with citric acid, as tested at various concentrations, with acid whey as a medium for hydrogel synthesis in order to utilize the almost unusable by-product of the dairy industry. The water uptake of the hydrogel was evaluated by swelling tests under variations in pH, temperature and ion concentration. Its swelling capacity, water retention and biodegradability were investigated in soil to simulate real-world conditions, the latter being monitored by the production of carbon dioxide during the biodegradation process by gas chromatography. Changes in the chemical structure and morphology of the hydrogels during biodegradation were assessed using Fourier transform infrared spectroscopy and scanning electron microscopy. The ability of the hydrogel to hold and release fertilizers was studied with urea and KNO3 as model substances. The results not only demonstrate the potential of the hydrogel to enhance the quality of soil, but also how acid whey can be employed in the development of a soil conditioning agent and nutrient release products.

Renewable Mixed Hydrogels Based on Polysaccharide and Protein for Release of Agrochemicals and Soil Conditioning

The study deals with the combination of biopolymers to develop hydrogels intended for agriculture application. The aim is to propose a renewable and eco-compatible solution to enhance agrochemicals and water efficiency and contribute to maintaining soil fertility. We developed a set of hydrogels based on casein and chitosan for water retention and release of agrochemicals, in particular nitrogen fertilizer urea. The weight ratio of biopolymers, from 0.5 to 2, was investigated to understand the influence of their content on the morphology, swelling, swelling-drying cycles, and water retention in soil. The average content of urea in the hydrogels was 30% of the total weight, and up to 80% was released in the soil in 50 days. The biodegradation of the hydrogels in soil has been investigated by the burial method and monitoring the release of CO2. Results demonstrated that by increasing the content of chitosan, the biodegradation time is prolonged up to 20% in 90 days. The obtained results support the ultimate purpose of the work that the combination of two biopolymers at proper weight ratio could be a valid alternative of the marketed hydrogels with the final goal to promote soil fertility and water retention and prolong biodegradation.