Resistance of soil to penetration as a parameter indicator of subsolation in crop areas of sugar cane

ROOT parameters of sugarcane and soil compaction indicators under deep strip tillage and conventional tillage

Soil tillage and agricultural traffic generate changes in soil physical attributes and affect the growth of the roots. This study evaluates the impact of system soil tillage on compaction and sugarcane root growth. The experiment was carried out on a Rhodic Kandiudox with two soil tillages (Deep Strip Tillage and Conventional Tillage) and two positions (beds or traffic lane and no traffic lane), totaling four treatments (DST-beds + no traffic lane, DST-traffic lane, CT-no traffic lane and CT-traffic lane). Soil penetration resistance (SPR), bulk density, dry mass, and root system lengths and volumes were evaluated. DST-beds presented lower values for SPR (1.45 MPa) compared to the other treatments (2.55 MPa). This lower SPR did not reflect significant increases in root growth in relation to the DST-traffic lane, meaning that the roots were not confined to the beds. The dry root mass for CT- traffic lane was 35% less than for DST- traffic lane, and CT-no traffic lane reduced of the root dry mass in the layers 0.0-0.2 and 0.2-0.4 m by 62% and 47%, respectively, compared to the DST-beds. Therefore, CT, although widely used, does not create adequate conditions for root development in the first sugarcane cycle, even in lanes with no traffic.

Mycorrhizal fungi arbuscular in forage grasses cultivated in Cerrado soil

The Cerrado is one of the most important regions for agricultural development in the world and is the main productive breadbasket of the Americas. One of the main agricultural activities in the region is high-tech livestock. Cerrado soils are predominantly low in fertility, and arbuscular mycorrhizal fungi play a fundamental role in plant nutrition in this biome. Understanding the behavior of mycorrhizal fungi in the soil under pasture is essential for the development of more efficient and sustainable management practices. Thus, this work aims to verify the activity of arbuscular mycorrhizal fungi in different species of forage grasses cultivated in cerrado soil. To measure mycorrhizal activity, soil spore density factors and mycorrhizal colonization rates in roots of 14 forage grass genotypes were investigated. No significant differences were identified in spore density values between the investigated genotypes. Panicum maximum cv and Mombasa showed the lowest values of mycorrhizal colonization, and the highest values were found in the roots of Brachiaria decumbens. Among the identified genera associated with the rhizosphere of the genotypes studied, Gigaspora, Scutelospora and Sclerocysts are less frequent, which indicates that the association with these fungal genera is less recurrent than with the others.