Fertilizer shanks to promote soil decompaction in the seeding operation

Abstract

Intensification of soil compaction process under no-tillage (NT) is motivating the search for alternatives to mitigate soil compaction state. This study evaluated changes in soil physical and hydraulic properties caused by seeder with fertilizer shanks at different depths compared with the double discs lagged seeder, to investigate the possibility of soil decompaction by sowing under NT in southern Brazil. The study was conducted in a clayed Oxisol, for 27 years under NT. Treatments were three planting mechanisms: S0.10m: cutting disc combined with shank acting to 0.10m depth; S0.15m: cutting disc combined with shank acting to 0.15m depth and, D0.07m: double discs lagged acting to 0.07m depth in an experimental randomized block design with four replications. We evaluated the soil mechanical resistance, water infiltration rate, soil bulk density, pore size distribution and unsaturated hydraulic conductivity. Results indicated that the use of seeder with fertilizer shanks acting at 0.15m deep promoted the soil decompaction by the reduction of penetration resistance and increase of porosity and unsaturated hydraulic conductivity. To have significant increase in water infiltration rate the fertilizer shanks of the seeder must be deepened to the lower limit of the compacted surface layer.

Seeding furrow opening mechanisms and the soybean planting in lowland areas

“…In the macroporosity, the shank at 0.23 m provided an average increase of 41%, when compared to the other treatments (double disk, shank at 0.13 m and raised bed + shank at 0.12 m). Similar results are described by DRESCHER et al (2017), where the Shank at 0.15 m resulted in greater total porosity and macroporosity in the 0.07-0.15 m layer in a compacted Oxisoil, when compared to the double disk and shank at 0.1 m. In relation to microporosity, there was no influence of the treatments in any of the analyzed layers, presenting an average value of 0.34 m 3 m -3 . This result was expected, since this property is directly dependent on the soil texture, with little influence by anthropic management (SILVA & KAY, 1997).…”

“…The magnitude of the benefits derived from the use of shanks in the rupture of the compacted layer is dependent on several factors. Among them are the intrinsic characteristics of the soil, the type of mechanism used and especially the depth of action (DRESCHER et al, 2017), since the mobilization of the soil allows the reduction of the density, which along with moisture, determines the degree of mechanical resistance to root penetration.…”

“…In this context, the natural characteristics of these soils, associated to the circumstances of the mechanized preparation, generate changes in the porous spaces, causing the phenomenon known as soil compaction (ALAOUI et al, 2011). Among the main consequences of this process, it is possible to mention the reduction of the total porosity (JUNIOR Coelho et al et al, 2016), decrease in the continuity and size of porous spaces (BJÖRKLUNDA et al, 2016), reduction of water infiltration capacity (DRESCHER et al, 2017) and the increase in mechanical resistance to penetration (CORTEZ et al, 2014).…”

Management of superficial straw associate with strategy of physical improvement of the soil in the emergence of weeds

“…In the collection position, there was a difference in both evaluated years, with the shank effect in the sowing row, in this case, being independent of its working depth, decreasing the SD and increasing the TP, hence providing improvement for the soil physical state. Using a fertilizer shank at greater depths, when establishing the maize crop, provided a greater SD reduction and TP increase in the sowing row, being able to even break the compacted soil layer (from 0.07 to 0.15 m), resulting in improved root development (Drescher et al, 2017).…”

Performance of cover and corn plants in different mechanical and biological management associations

“…Scarification provides disruption of compacted layers and soil breakdown, creating macropores and improving soil permeability that facilitate root growth and corrective movement in the soil (Prado et al, 2014;Guedes Filho et al, 2015). Another mechanical alternative is the use of seed boots on the seeder, which can improve the soil physical characteristics, such as reduced density and increased porosity in the sowing furrow, thus promoting yield gains in crops such as corn and soybean (Giacomeli et al, 2016;Drescher et al, 2017;Trentin et al, 2018). Green manures, in addition to improving the soil physical condition, have improved their protection against weather conditions, also recycling nutrients and reducing fertilizer expenses (Fageria, 2014;Nascente et al, 2016).…”