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Abstract: Soil management practices may change the soil properties. The magnitude of the change varies according to the soil property, the climate, and the type and time of implementation of a particular management system. The aim of this study was to evaluate the effects of no-tillage (NT) on the chemical and biological properties of an Entic Haploxeroll in Central Chile. Soil organic carbon (SOC), microbial biomass and associated indicators , q Mic , q Min , available N, P and K, pH, electrical conductivity (EC), and crop yield were determined in a field experiment having a wheat (Triticum turgidum L.)–maize (Zea mays L.) crop rotation. The change in soil chemical properties was further evaluated using a greenhouse bioassay in which ryegrass (Lolium perenne L.) was grown in soil samples extracted at 0–2, 2–5, and 5–15cm depth. After nine years SOC in the NT treatment was 29.7Mgha−1 compared to 24.8Mgha−1 of CT, resulting in 4.98Mgha−1 C gain. The NT therefore resulted in an average annual sequestration of 0.55MgCha−1 yr−1 in the upper 15cm soil. The soil organic C stored under NT was mainly accumulated in the top 2-cm of soil. The biological indicators showed a greater biological soil quality under NT than under CT. Soil organic C was positively associated with available N, P, and K, but negatively with soil pH. The ryegrass bioassay yielded higher biomass in NT than CT. An improvement in the soil chemical quality of the NT soil was considered to be the main reason for this result. The maize yield under NT had the tendency to improve in time as compared to CT. Wheat, however, had lower yield under NT. It was concluded that NT increased C sequestration and SOC improving the chemical and biological properties of this soil. [Copyright &y& Elsevier]

Abstract: Arbuscular mycorrhizal (AM) fungi improve soil quality by increasing soil structure stability through the glomalin (glomalin related soil protein, GRSP) production, but diverse tillage systems can differentially affect AM activity and the consequential GRSP content in soil. The aim of this study was to evaluate the effect of no-tillage (NT) and conventional tillage (CT) on AM fungal propagules (spore density, total and active fungal hyphae), GRSP content, and its relationship with some physical–chemical soil properties in a Mollisol from Central Chile. For this study, two plots managed for 6 and 10years under NT (NT6 and NT10), were compared with another plot maintained under CT management. In all cases a continuous spring wheat (Triticum turgidum L.)–maize (Zea mays L.) rotation was established. The number of mycorrhizal propagules, total soil carbon (T-C) and GRSP content in NT6 was higher compared to CT and NT10. This trend was also observed for water stable aggregates (WSA) and water drop penetration time. Significant relationships were found between total mycelium and GRSP (r =0.58, p <0.05), GRSP and WSA (r =0.66, p <0.01) and between GRSP and T-C (r =0.60, p <0.05), suggesting an active role of AM fungi and GRSP on soil aggregation, particularly under NT6 management. In addition, the long-term NT management (NT10) produced a decrease in the parameters here assayed which suggest the application of one moderate plowing when parameters such as T-C and/or GRSP show a decrease in long-term programs of reduced or NT management applied in medium/heavy soils. [Copyright &y& Elsevier]