Methodologies for the application of calcium compounds in agropastoral systems: Effects on crop yields

Abstract

Soil acidity (pH <4.4) restricts exploration by the root system and impairs crop yield. To contribute to the development of alternative methodologies for correcting acidity in the surface and subsurface layers of soil, the present study evaluated the effects of seven combinations of application technique (surface, incorporation under soil tillage, or subsurface) and calcium (Ca) compounds (limestone [LS], phosphogypsum [PG], and hydrated lime [HL]) on soybean [Glycine max (L.) Merr.] and maize (Zea mays L.) grain yields and on the absorption of macronutrients and dry matter yield of palisade grass (Urochloa brizantha syn. Brachiaria brizantha ‘Marandu’) in a Typic Hapludalf in an agropastoral system in Brazil. The experimental design was randomized complete blocks with four replications. The results support the following conclusions: (a) applying HL plus PG is a viable alternative to applying LS plus PG for soybean and maize crops, (b) incorporating LS by plowing and harrowing is not a viable alternative to applying LS on the surface, (c) applying HL plus PG on the subsurface is superior to applying HL plus PG on the surface for soybean and palisade grass cultivation, (d) incorporating LS plus PG followed by annually applying LS on the surface improves palisade grass crop yield, (e) annually applying LS plus PG 2 yr before and annually applying LS plus PG increase palisade grass crop yield, and (f) annually applying LS or HL plus PG increases the absorption of Mg and S by palisade grass.

Evaluation of the influence of surface and subsurface acidity correction methodologies on soil compaction in agropastoral systems under no‐till

“…In the second and third growing seasons, the dose of limestone or hydrated lime was calculated based on the results of soil analysis to ensure that Ca occupied 65% of the cation exchange capacity in the 0.0‐ to 0.2‐m layer according to the methodology of Borges et al. (2021): limestone/hydrated lime (Mg ha −1 ) = Ca 2+ saturation in cation exchange capacity − exchangeable Ca 2+ content in cmol c dm −3 at a depth of 0.0–0.2 m. The cation exchange capacity at a depth of 0.0–0.2 m was calculated as the sum of the contents of exchangeable cations: cation exchange capacity = Ca 2+ + Mg 2+ + potassium (K) + + total acidity (hydrogen (H) + + Al 3+ ). Ca 2+ saturation (65%) at a depth of 0.0–0.02 m was calculated as 100 × Ca 2+ /cation exchange capacity.…”

“…The details of soil and crop management in the treatments in the 2017–2018, 2018–2019, and 2019–2020 seasons were described previously by Borges et al. (2021).…”

“…In the second and third growing seasons, the dose of limestone or hydrated lime was calculated based on the results of soil analysis to ensure that Ca occupied 65% of the cation exchange capacity in the 0.0-to 0.2-m layer according to the methodology of Borges et al (2021): limestone/hydrated lime Abbreviations: H, Hydrated lime; HL, hydrated lime; LS, limestone; PG, phosphogypsum. a Surface application.…”

“…Plant roots are primarily responsible for the disruption of plow pans (Micucci & Taboada, 2006), and crops with deeper roots and higher shoot dry mass yield, such as palisade grass, may stabilize soil structure after mechanical disturbance, slowing re-compaction (Chamen et al, 2003;Hamza & Anderson, 2005). The forage dry matter yield of palisade grass on February 12, 2020, was 14057 kg ha −1 (average of seven treatments, Borges et al, 2021).…”

“…Liming at a limestone dose of 1000 kg ha −1 was performed in September 2015; dolomitic limestone with 85% relative total neutralizing power was applied to raise the base saturation to 60%. The details of soil and crop management in the treatments in the 2017-2018, 2018-2019, and 2019-2020 seasons were described previously byBorges et al (2021).…”