Soil chemical attributes and soybean performance as a function of acidity management and cover crops

Resumo

Seeking strategies to promote acidity correction and increase the availability of Ca at depth in the soil are crucial to
ensure the sustainability of areas managed under no-tillage practices. The objective of this study was to evaluate the soil chemical
attributes and soybean performance after cover crops and acidity management through liming using the method of Ca and Mg saturation
in the eff ective cation exchange capacity (ECEC), and gypsum application at variable rates to increase Ca saturation in the subsurface
The experiment was carried out in Guarapuava, PR, Brazil in an Oxisol, assessing two factors, (1) cover crops: fallow, oat + turnip
and polyculture; and (2) acidity management: without correction and areas with lime (calcitic + dolomitic) or lime + gypsum.
The soil chemical attributes were evaluated: pHCaCl2; exchangeable Al3+; H+ + Al3+; Ca2+; Mg2+; S-SO4
2-; V%; Ca2+/ECEC and Mg2+/ECEC.
The chlorophyll index and soybean performance were evaluated through yield components. The cover crops of oat + forage
turnip and fallow contributed to the reduction of soil acidity in the 0.35 m layer, reaching the range considered ideal (pH = 5.0)
for soybean cultivation. Oats + forage turnip accumulate more Mg2+ and increase base saturation in the 0.05 m layer compared
to fallow and polyculture, while also reducing potential acidity in the 0.15 m layer compared to polyculture. When associated
with gypsum, lime increased Ca2+ levels in the 0.15 m layer and Mg2+ levels in the 0.15 m and 0.35 m layers.