Effect of different doses of acid milk serum on growth in rice culture and on soil chemical attributes

The culture of rice has great potential to constitute the production systems of annual perennial crops, mainly in small properties. This allows this system to integrate with other activities such as the dairy industry, taking advantage of the milk by-product, reducing the environmental liability for disposal in the environment. Therefore, the objective was to evaluate the growth and productivity of rice grains under different doses of acid milk serum (0 m3 ha-1, 5 m3 ha-1, 10 m3 ha-1, 20 m3 ha-1, 50 m3 ha-1, 100 m3 ha-1, and 150 m3 ha-1), in soil applications with monitoring of fertility and electrical conductivity levels. The rice was sown in the UFLA experimental field, using the BRSMG Esmeralda lineage. Seven different doses were used, divided into two applications via soil. No cover fertilization was carried out. Yield and crop growth variables were determined by monitoring the nutrient content in the soil profile and the sodification and salinization capacity of the residue. It was found that the increase in serum doses increased the electrical conductivity and the percentage of exchangeable sodium by 1.75 and 7.75 compared to the control, but did not cause the process of sodification and salinization of the soil. As acid milk serum is a significant source of potassium, its use in the soil did not promote significant grain yield. It was concluded that the acid milk serum in the doses used did not cause sodification or salinization of the soil. This residue is the safe dose that can be used as potassium and nitrogen. The acid milk serum in the tested conditions did not increase the growth of the culture.

Estimation of the Exchangeable Sodium Percentage from the Sodium Adsorption Ratio for salt-affected soils in Bolivia

<p>In order to obtain a more cost-time efficient way to determine the sodicity of salt-affected soils, this study aims to generate a regression model to predict the Exchangeable Sodium Percentage (ESP) from the Sodium Adsorption Ratio (SAR<sub>e</sub>). Based on a database with 84 soil samples from the High Valley of Cochabamba (Bolivia), two linear models were generated: <em>ESP= 0.9725 SAR + 1.5766 </em>(R<sup>2</sup>=0.85, RSE=4.47) and <em>ESP= 0.9197 SAR + 0.3813 </em>(R<sup>2</sup>=0.71, RSE=0.91)<em> </em>with square root transformation. Subsequently, through a set of 18 testing samples and a T-test of paired samples between the predicted ESP and measured ESP values, the efficiency of the generated models was verified with a value of p= 0.063 and 0.209, respectively, in contrast to p= 0.285 from the US Salinity Lab referential model. To improve the performance of the generated models, could be necessary a stratification according to soil sodicity levels and additional samples for the calibration dataset.</p>

THE USABILITY OF HYDROGEL IN INCREASING THE EFFICIENCY OF GYPSUM APPLIED TO SALINE-SODIC SOILS

This study aimed at the assessment of the usability of hydrogel in increasing the efficiency of gypsum applied to saline-sodic soils. The experiment was conducted under laboratory conditions in disturbed soil columns and was set-up in a completely randomized design with six hydrogel application rates (Control, 0.05%, 0.10%, 0.15%, 0.20% and 0.25% weight/weight (w/w) basis) and with three replications. Hydrogel application to saline-sodic soil had significant effects on leachate pH. The highest leachate pH’s were found in the final leachates in the order of 0.05%>0.10%>0.15%, as 9.12, 9.09, and 9.03, respectively. In all of the application rates tested, the highest electrical conductivity (EC) and Na+ leachate losses were obtained after first pore volume of leaching and then decreased gradually with further leaching. Relative to the control, hydrogel application in the rate of 0.05% increased the leaching of Na+ by 8.1% on total. However, due to the absence of statistically significant effects of the treatments on Na+ leaching, an improvement in soil exchangeable sodium percentage (ESP) and pH in saturation extract (pHe) values as an indicator of reclamation was not proven. Use of gypsum together with hydrogel increased saturated hydraulic conductivity of soils in the rates of 28.6%-42.6%, which is especially important for reducing the duration for amelioration of saline-sodic soils. Application of hydrogel to saline-sodic soils along with gypsum can be an efficient management option not only for reducing the risk of physiological drought, but also for reducing the amount of time to reclaim saline-sodic soils.

ESTIMATION OF THE INFLUENCE OF GRASSLOWING TECHNOLOGY ON THE STATE OF THE SOIL COVER OF PASTURES OF THE SEMI-DESERT ZONE

Managing pasture resources of Western Kazakhstan is complicated due to the deterioration of the physicochemical parameters of soils manifestating degradation and alkalinization as a result of intensive grazing. The research has been aimed at studying the technology of cattle grazing for preserving the physicochemical parameters of soils and increasing the efficiency of pasture use. The assessment and analysis of physicochemical indicators of soils were carried out with standard methods during 2018-2020, which allowed identifying the most optimal grazing technology. The results of research showed that under the influence of intensive grazing, physicochemical parameters worsened, a decrease in the humus reserves by 28.50% was detected, soil degraded to the third degree and became alkaline as a result of increase in exchangeable sodium to 1.66 mg(equiv.)/100g. Technology of moderate cattle grazing favorably affects the physicochemical parameters of the soils of pasture ecosystems. The chestnut soils of the pastures, where moderate grazing technology was applied, remained resistant to degradation and salinization. With this technology, the soil humus was reliably preserved at the level of 1.17%, mobile phosphorus was within the optimal level of 0.88 mg/100g.

Influence of Rice Husk Biochar and Compost Amendments on Salt Contents and Hydraulic Properties of Soil and Rice Yield in Salt-Affected Fields

Soil salinity may damage crop production. Besides proper management of irrigation water, salinity reduction can be achieved through soil amendment. The objectives of this study were to evaluate the effects of rice husk biochar and compost amendments on alleviation of salinity and rice growth. Field experiments were conducted at two salt-affected paddy rice fields located in distinct sites for five continuous crops. Treatments, with four replicates, consisted of continuous three rice crops per year (RRR), two rice crops rotated with fallow in spring–summer crop (FRR), FRR plus compost at 3 Mg ha−1 crop−1 (FRR + Comp), and biochar at 10 Mg ha−1 crop−1 (FRR + BC). Salt contents and hydraulic properties of soils, plant biomass, and plant uptake of cations were investigated. Soil bulk density (BD), exchangeable sodium (Na+), and exchangeable sodium percentage (ESP) were reduced remarkably by biochar application. Biochar application significantly increased other soil properties including total porosity, saturated hydraulic conductivity (Ksat), soluble and exchangeable potassium (K+), K+/Na+ ratio, available P, and total C. Compost application also improved BD, total porosity, and available P, but not exchangeable Na+ and ESP. Total aboveground biomass of rice showed a trend of FRR + BC > FRR + Comp > FRR > RRR. Relatively higher K+ uptake and lower Na+ uptake in rice straw in FRR + BC resulted in a significant two times higher K+/Na+ ratio over other treatments. Our results highlight that biochar amendment is a beneficial option for reducing ESP and providing available K+ and P under salinity-affected P-deficient conditions, hence improving straw biomass.

CHANGES IN THE PHYSICOCHEMICAL PARAMETERS OF CHESTNUT SOILS IN WESTERN KAZAKHSTAN UNDER THE INFLUENCE OF THE GRAZING TECHNOLOGIES

Managing pasture resources of Western Kazakhstan is complicated due to the deterioration of the physicochemical parameters of soils, manifesting degradation, and alkalinization as a result of intensive grazing. The research has been aimed at studying the technology of cattle grazing for preserving the physicochemical parameters of soils and increasing the efficiency of pasture use. The assessment and statistical analysis of physicochemical indicators of soils were carried out with standard methods during 2018 – 2019, which allowed identifying the most optimal grazing technology. The results of the research showed that under the influence of intensive grazing, physicochemical parameters worsened, a decrease in the humus reserves by 10.88-12.35% was detected, soil degraded to the third degree, and became alkaline as a result of the increase in exchangeable sodium to 1.65 cmol (equiv.)/kg. The technology of moderate cattle grazing favorably affects the physicochemical parameters of the soils of pasture ecosystems. The chestnut soils of the pastures, where moderate grazing technology was applied, remained resistant to degradation and salinization. With this technology, the soil humus was reliably preserved at the level of 1.15-2.50%, mobile phosphorus was within the optimal range of 0.87-1.60 mg/100 g. It has been concluded that it is important to use the technology of moderate cattle grazing to improve the management of pasture resources, which is the scientific novelty of the research.