Abstract

GIESBRECHT, Matthew; WIEBE, Frank  and  TOEWS, Holger. Soybean (Glycine max L.) Performance and Physicochemical Properties of a Cambisol Under Two Crop Succession Systems. Investig. Agrar. [online]. 2024, vol.26, n.2, pp.75-89. ISSN 2305-0683.  https://doi.org/10.18004/investig.agrar.2024.diciembre.2602804.

The objective of this study was to evaluate the effect of two crop succession systems under no-till (NT) on the physical and chemical properties of the soil, as well as soybean yield, in a Cambisol. The experiment was conducted on a farm located in the Paratodo village, Pdte. Hayes, Paraguay, using a strip plot design with two Cover Crops (CC) as treatments: Megathyrsus maximus cv. Gatton Panic (Gatton) and a soybean/wheat/soybean succession (Wheat). The variables evaluated were aboveground biomass (BIOM), gravimetric moisture (GM), nitrogen concentration (NO3-N and NH4-N), bulk density (BD), penetration resistance (PR), infiltration rate (IR), soybean plant height, and soybean yield (Glycine max L.). Data were analyzed using analysis of variance with the Scott y Knott test at 5% significance, a t-test for two samples with equal variances, and trends were described through linear and polynomial regressions. The Gatton treatment demonstrated a greater capacity for retaining GM during the fallow and crop development stages, with average values throughout the trial of 19,2% for Gatton and 15,4% for Wheat. Additionally, Gatton recorded 2,09 times more BIOM at the start (11.311 vs. 5.390 kg ha⁻¹) and decomposed 1,88 times more crop residue, showing a higher daily decomposition rate compared to Wheat, with values of 12,7 kg ha⁻¹ day⁻¹ and 9,5 kg ha⁻¹ day⁻¹, respectively. BD was 3% lower in Gatton (1,32 g cm⁻³) compared to Wheat (1,36 g cm⁻³), and it increased with soil depth (25-50 cm). Wheat recorded critical PR values exceeding 3 MPa at sowing at depths of 5-15 cm and at the end of the trial at depths of 5-20 cm. Soybean plant height was 11.2% higher with Gatton (99,6 cm vs. 89,6 cm), which also achieved greater grain yield (3.336 kg ha⁻¹) compared to Wheat (2.929 kg ha⁻¹), with a difference of 13,9%. The production system based on a CC with Megathyrsus maximus cv. Gatton Panic improves the soil’s physicochemical properties and increases soybean yield.

Keywords : biomass; agricultural residues; cover crops; nitrates; soybean.

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