Farm systems, soil chemical properties, and clay dispersion in watershed áreas

Abstract

The objective of this work was to evaluate the effect of different farm systems on clay dispersion and its relationship with soil chemical properties and the no-tillage system participatory quality index (IQP), in watershed areas in the west of the state of Paraná, Brazil. The farm systems evaluated were: no-tillage; no-tillage with crop succession; no-tillage with soil disturbance; and conventional system. In addition, the farm systems were evaluated for their IQP. Soil samples were collected at 0.0-0.20-m soil depth, in 40 agricultural areas and in 6 native forests considered as references. The degree of clay dispersion, total organic carbon, pH (CaCl2), exchangeable potassium (K+), available phosphorus (P), exchangeable calcium and magnesium (Ca2++Mg2+), and potential acidity (H+Al3+) were determined. A linear multiple regression model was fitted by the method of least squares. The averages of clay dispersion degree per watershed were compared at 5% probability. The farm systems were compared by Scott-Knott’s test. Soil chemical properties showed a higher influence on clay dispersion than the different farm systems assessed. The no-tillage system alone showed the highest content of organic carbon, which was similar to those of the native areas. The conventional system and the no-tillage system with soil disturbance showed a lower IQP and a higher degree of clay dispersion than the areas with the no-tillage system alone. The IQP allows distinguishing the conventional system from the no-tillage system.

Adoption of the no-tillage system in Paraná State: A (re)view

“…When classifying the farms as NT or NTS (Table 4), we noted that only two cases (5.4 %) were classified as NTS, agreeing with the three principles simultaneously, while the rest did not meet one or more principles. Nunes et al (2020a) found 10.3 % of NTS among farms evaluated by the PQI methodology in western Paraná, a percentage higher than that in this study. Thus, the adoption of NTS in this study is limited to 5 % of farms, which corroborates the estimate that most of the area in use in Brazil is NT and not NTS.…”

“…These indicators are crop rotation intensity (RI), crop rotation diversity (RD), persistence of straw (PS), soil tillage frequency (TF), correct terracing (CT), soil conservation evaluation (SC), balanced soil fertilization (BF), and adoption time (AT), for which ideal situations are known to promote soil quality over time (Itaipu Binacional and Febrapdp, 2011;Rollof et al, 2011a). It is worth noting that the three pillars of the NTS are included in the IQP by the RD, PS, and TF indicators for crop rotation, permanent soil cover, and minimum soil disturbance (Nunes et al, 2020a), but the methodology is not restricted only to these and evaluates a set of conservation practices. 2 0 1 2 / 2 0 1 3 2 0 2 0 / 2 0 2 1 2 0 0 0 / 2 0 0 1 2 0 0 1 / 2 0 0 2 2 0 0 2 / 2 0 0 3 2 0 0 3 / 2 0 0 4 2 0 0 4 / 2 0 0 5 2 0 0 5 / 2 0 0 6 2 0 0 6 / 2 0 0 7 2 0 0 7 / 2 0 0 8 2 0 0 8 / 2 0 0 9 2 0 0 9 / 2 0 1 0 2 0 1 0 / 2 0 1 1 2 0 1 1 / 2 0 1 2 2 0 1 3 / 2 0 1 4 2 0 1 4 / 2 0 1 5 2 0 1 5 / 2 0 1 6 2 0 1 6 / 2 0 1 7 2 0 1 7 / 2 0 1 8 2 0 1 8 / 2 0 1 9 2 0 1 9 / 2 0 2 0 From a structured questionnaire that can be used by farmers, technicians, and extensionists, the information is transformed into quantitative indicators, assigning a score and classification for the NTS quality, as well as indicating the strengths, weaknesses and potential improvements to be made.…”

Stability, labile organic carbon, and glomalin of biogenic aggregates in sandy soils under management systems in the subtropical region of Brazil

“…In their study, the management system with the least soil disturbance (continuous no-tillage) exhibited the highest dispersion degree of the clay fraction compared to systems that promoted greater soil tillage, regardless of the agricultural implementation used or the intensity of soil disturbance. However, the negative mechanical effects of soil disturbance on clay fraction dispersion can be partially neutralized by proper soil chemical management and fertilization of the production system, as pointed out by Nunes et al (2020).…”