Thistle crops in marginal lands after compost addition: Plant biomass and effect on soil physical, chemical and biological properties

9 páginas.- 4 figuras.- 35 referencias.- Additional supporting information may be found online in theSupporting Information section at the end of this article.

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.

This work was funded by the Iberdrola Fundation (Young Researchers Pro-gram) and the Spanish Ministry of Economy and Competitiveness (AGL2014-55717-R project). María T. Domínguez acknowledges Universityof Sevilla for her postdoctoral fellowship (V Plan Propio de Investigación),and Marco Panettieri the Spanish Ministry of Science, Innovation and Universities fo This post-doctoral fellowship number IJCI-2016-27693.

Peer reviewed