Impacto de níveis de compactação nos componentes de produção da canola e na umidade de um solo argiloso

Abstract

Soil compaction can influence soil porosity and pore diameter, affecting the capillary rise of water. Canola (Brassica napus L.) is a species with a certain tolerance to water stress; however, little is known about its sensitivity to soil compaction, as well as the dynamics of water in the soil. Therefore, the study aimed to evaluate the effect of compaction levels in clay soil on the production components of canola and the capillary rise of water. The experiment was conducted in a greenhouse at the Western Paraná State University, Cascavel, PR, Brazil. The experiment was set up in a randomized block design with four replications. The treatments consisted of six levels of compaction (1.0, 1.1, 1.2, 1.3, 1.4, and 1.5 Mg m-3), established by pressing a mass of soil into PVC pots. The compacted layer was established at a depth of 10 to 30 cm. To assess soil moisture, three sensors were installed at depths of 5 cm, 15 cm, and 25 cm. Sensors 1 and 2 were located in the compacted layer, and sensor 3 was situated in the uncompacted soil. At the end of the canola cycle, plant height, stem diameter, aerial part dry mass, root dry mass, total plant dry mass, number of silicles per plant, number of grains per silicle, thousand-grain weight, root growth, and grain mass per plant were evaluated. Additionally, soil moisture was recorded throughout the canola growth cycle. The data on the components of canola production and moisture were investigated using regression analysis and correlation analysis with a significance level of 5%. Compaction levels increased soil moisture in sensors 1 and 2, specifically in the compacted layers. However, the plant was unable to access this water as it was retained in the micropores. The negative correlation between root growth was confirmed, as was the relationship between the number of siliques per plant, grain mass per plant, and humidity in sensor 2. On the other hand, positive correlations were observed between the components of canola production and sensor 3 (uncompacted layer), specifically when the topsoil layer, which benefited from the moisture, reached sensor 3. Canola proved to be very sensitive to compaction levels, and its production components were negatively affected as soil compaction increased.