Ca-amendment and tillage: Medium term synergies for improving key soil properties of acid soils

Soil–water relationships in the upper soil layer in a Mediterranean Palexerult as affected by no-tillage under excess water conditions – Influence on crop yield

“…In our case the population of earthworms (Eisenia foetida) was significantly higher in the uppermost 0-10 cm soil layer of NT plots (data not shown). In addition, the 11% higher content in water-stable aggregates (1-2 mm) found under NT in a previous study (Gómez-Paccard et al, 2013), together with a 64% higher mean weight diameter of the size distribution of water stable aggregates under NT (data not published) probably contribute to explain our results. It should also be considered that, as suggested by Douglas et al (1986) in our case NT better preserves the pore continuity and functional macroporosity that presumably developed under the grassland that was present after the cultivation and successive abandonment of our experimental site in the 1990s (Gómez-Paccard et al, 2013).…”

“…In addition, the 11% higher content in water-stable aggregates (1-2 mm) found under NT in a previous study (Gómez-Paccard et al, 2013), together with a 64% higher mean weight diameter of the size distribution of water stable aggregates under NT (data not published) probably contribute to explain our results. It should also be considered that, as suggested by Douglas et al (1986) in our case NT better preserves the pore continuity and functional macroporosity that presumably developed under the grassland that was present after the cultivation and successive abandonment of our experimental site in the 1990s (Gómez-Paccard et al, 2013). Although at the beginning of our experiment, the natural vegetation was cleared using a cultivator (two passes) to 20 cm depth and a power tiller (one pass) to 5-7 cm depth, these tillage operations were probably not sufficient to destroy the soil structure developed under the grassland from a depth of 5 cm to deeper layers.…”

“…Unlike the other properties studied, Ca-amendment significantly increased crop yield. The fact that Ca-amendment affected crop yield but not PCS and GC indices can be explained by the fact that the surviving plants found better chemical conditions for development in the amended plots (Gómez-Paccard et al, 2013).…”

“…In order to balance the Ca/Mg ratio we also added 100 kg ha À1 of MgO from converter basic slag (CBS) and 100 kg ha À1 of MgO in the form of MgSO 4 . In total, we added 3.535 Mg ha À1 of CaO and 0.396 Mg ha À1 of MgO (Gómez-Paccard et al, 2013). This amendment was applied once at the beginning of the experiment and it was incorporated into the top 0-7 cm soil layer in all amended plots with a power tiller.…”

Tillage, fertilization systems and chemical attributes of a Paleudult

“…Thus, there is an initial limited effect of surface liming, which is, however, compensated for by its long-term effect under NT, especially in the deeper layers. The depth effect of liming under NT is caused by the translocation of thin particles of limestone through soil channels, by the formation of complexes among water-soluble organic compounds and Ca and Mg at the soil surface and the subsequent exchange of these cations by Al at deeper layers, as well as the production of non-toxic stable complexes formed by the soil OM and the aluminum (Ernani et al, 2004;Gómez-Paccard et al, 2013;Miyazawa et al, 2002;Oliveira and Pavan, 1996;Roth and Pavan, 1991). In the case of poultry litter, similar mechanisms of translocation of particles and reaction products are expected to occur, since this residue is rich in calcium carbonates and phosphates, in addition to allowing for the formation of water-soluble organic because of the tendency of the lime and the products of its reaction to stay close to the soil surface because alkalinity must be transported from the surface by mass flow to lower layers (Wyngaard et al, 2012).…”