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Water limitations for agriculture will likely become crucial in the next decades in some regions such as the Mediterranean basin with the current climate change projections. In this context, recent evidence suggests that the application of conservation agriculture, which reduces the frequency and intensity of soil tillage, could confer a higher stability of agricultural systems against climate variability. However, not many experiments have addressed the interaction between tillage type and the resistance to drought in rainfed crops. In this work, we evaluated the resistance to drought of triticale (Triticale hexaploide L.) crops managed with different tillage systems: traditional tillage (TT), reduced tillage (RT) and no tillage (NT). A rainfall exclusion experiment was carried out in a typical wheat/legume Mediterranean rotation in SW Spain, in a long‐term experiment established in 2008 comparing the three tillage systems. Grain yield and different variables related to plant ecophysiology, root development, biomass allocation and colonisation by arbuscular mycorrhizal fungi (AMF) were evaluated over one crop cycle. Tillage type had a significant influence on soil water storage (SWS), such that soils under NT had, on average, a 16% greater SWS than soils under RT or TT. Grain yield was significantly reduced by rainfall exclusion, in particular in the TT, where drought reduced grain yield by 31%. Gas exchange data also showed that plants in the TT system were more sensitive to drought, such that maximum photosynthesis rates were reduced by 25% because of rainfall exclusion in this tillage system. Drought had a negative impact on root biomass across the three tillage systems, especially in the RT, where a reduction in the root:shoot ratio was observed. The effect of tillage on mycorrhizal colonisation was more evident than the effect of drought; in general, conservation tillage systems (RT and NT) tended to have higher values for all AMF traits compared to the TT. In summary, the NT system tended to exhibit more favourable performance in terms of soil water retention, grain yield stability under drought conditions and mycorrhizal symbiosis, which suggests enhanced resource use efficiency in this system. [ABSTRACT FROM AUTHOR]

Algae have an indisputable role in coastal ecosystems, but their accumulation and uncontrolled proliferation cause severe damage for the local municipalities. Fertilization with seaweed has been shown to increase soil fertility and crop production reducing ultimately the need for inorganic fertilizers. However, contradictory results of the compost effect have been reported. In the present work, we aimed at testing the suitability of three composted algae materials obtained in a previous study as soil amendments for vines. The composted materials consisted of pruning waste (P) and seaweed (S) mixed (henceforth, P2S1, P1S1 and P1S2, referring the number to the ratio of P to S). Overall, we observed an increase in soil organic matter, phosphorus (P) and potassium (K) in the soil treated in comparison with soils with inorganic fertilization. A moderate N soil enrichment (ca. 20%) was also detected. The leaf analysis reflected generally the greatest concentrations of NPK for the organic treatments, but this was remarkable only during the first year after seaweed application. A noticeable improvement in grape production was detected especially with the P1S1 compost without compromising grape quality although a decrease in sucrose content was noted with the compost with higher productivity (e.g. P2S1 and P1S1). This slight sucrose drop could be attributable to a greater water availability mediated by the compost or to a dilution factor of the sucrose content caused by a greater number of berries in those vines. These findings suggest that although monitoring of the long‐term effects is needed, the use of seaweed amendments for agriculture could offer a cost‐effective method for coastal municipalities to reduce excessive algae debris while also minimizing the impacts of inorganic fertilization. [ABSTRACT FROM AUTHOR]

The growing interest in bioenergy crops that do not compete with food production for land use has promoted the implementation of low‐input crops on marginal lands. However, these crops can be highly limited by the low soil nutrient and water availability in these lands. In this work, biosolid compost (BC) was applied to improve the quality of a degraded, C‐poor soil under Mediterranean conditions. We evaluated the effects of BC addition on soil physical, chemical and biochemical properties in a field experiment with two native species with potential as bioenergy crops (Cynara cardunculus and Silybum marianum). The addition of BC significantly increased soil C content from <0.9% to >1%, and produced a two‐fold increase in soil P availability. Respiration rates and microbial activity were only slightly improved by BC, while significant increases in the PLFA molar content assigned to general classes of bacteria were recorded. The beneficial effects of BC triggered the percentage of seed germination in S. marianum (from 64% in control plots to 85% in the compost treatment) as well as the production of biomass in both species (two‐fold increase in the second year). Application of BC led to increases in energy yield of 58% for C. cardunculus and of 71% for S. marianum. Considering the low economic cost of BC, its application on marginal soils in combination with C. cardunculus crops, producing much larger biomass than S. marianum, could be considered as an option for degraded Mediterranean soils. [ABSTRACT FROM AUTHOR]

The study of different natural carbon sinks has become especially important because of climate change effects. The restoration of contaminated areas can be an ideal strategy for carbon sequestration. The studied area was affected by toxic Aznalcóllar mine spill in 1998. Restoration process of the contaminated area was based, mainly, on the use of two organic amendments: leonardite (LE) and biosolid compost (BC). The objective of this study was to verify whether the application of these amendments promotes the long-term carbon sequestration in this soil. Five treatments were established: untreated control, biosolid compost (doses 4 and 2) and leonardite (doses 4 and 2). The addition of amendments implied an improvement in soil quality that was directly related to the amendment dose: decrease in bulk density, increase in pH, higher respiration rates and an improvement in the stratification ratio. Dose-dependent changes in the molecular composition of soil organic matter were shown by nuclear magnetic resonance analysis. Both amendments promoted carbon retention, although because of the low mineralization rates of soil organic matter in LE treatments, the carbon storage was higher. The dosage effect on the carbon balance was more important in LE treatments, whereas in the BC treatments, the balance was similar for both doses. Our findings suggest that LE4 significantly increased the total organic carbon and it was the most suitable treatment for long-term carbon storage, because of its molecular composition rich in relatively stable aromatic and lignin-derived compounds. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This article discusses cadmium and zinc bioavailability on metal contaminated soils with vegetation colonizing a canal embankment in a spontaneously developed woodland. According to the authors, the woodland is dominated by two Willow (Salix) species. Salix caprea selectively accumulated cadmium in all stem tissues and uptake was correlated with differences in soil pH. In contrast, S. viminalis regulated tissue cadmium content. Both species regulated tissue Zinc and uptake was not correlated with differences in soil pH. Leaf litter contained elevated metal concentrations, but invertebrate population composition did not appear to be affected.