Soil Physical Quality and Soybean [Glycine max (L.) Merr.] yield as affected by loosening of a soil under no-tillage system

LOZANO L.A.; SORACCO C.G.; VILLARREAL, RAFAEL; RESSIA, J.M.; SARLI, GUILLERMO OLIVERIO; FILGUEIRA, ROBERTO RAUL

REVISTA BRASILEIRA DE CIêNCIA DO SOLO

SOC BRASILEIRA DE CIENCIA DO SOLO

Lugar: Vicosa; Año: 2016 vol. 40

0100-0683

The area under no-tillage system (NT) has been increasing over the last few years worldwide. Recently, the concept of soil physical quality (SPQ) has been proposed, but an agreement about which soil physical properties should be included in the SPQ characterization have not been reached. The objectives of this study were to evaluate the ability of soil physical quality (SPQ) indicators based on statics and dynamics properties to assess the effects of two loosening treatments (chisel at 0.20 m, ChT; and paratill at 0.35 m, DL) on a soil under NT; and to compare the performance of static and dynamic-based SPQ indicators in relation to crop yield. Soil and sampling and field determinations were carried out after crop harvest. Soil water retention curve was determined using tension table, and field infiltration was measured using tension disc infiltrometer. Most dynamic SPQ indicators (field saturated hydraulic conductivity, K0, Effective macroporosity, εma, total and macro porosity connectivity indexes, CwTP, and Cwmac) were affected by the treatments, being higher for DL as compared with NT and ChT (K0 values were 2.17, 2.55, and 4.37 cm.h-1 for NT, ChT, and DL, respectively). In the other hand static based SPQ indicators (calculated from water retention curve) were not capable of distinguish between treatments. Crop yield was significantly lower for DL treatment (NT: 2400 kg ha-1; ChT: 2358 kg ha-1; and DL: 2105 kg ha-1), in concordance with significant higher values of the dynamic SPQ indicators K0, εma, CwTP, and Cwmac in this treatment. This was attributed to the exceptional dry period of January and February. The results support the idea that SPQ indicators based on static properties are not capable to distinguish tillage effects and to predict crop yield, while dynamic SPQ indicators are useful to distinguish tillage effects, and can explain differences in crop yield, when used together with weather conditions information, however, future studies, following years with different weather conditions, would be useful to gain knowledge on this topic.