Plant growth responses to biochar amendment of Mediterranean soils deficient in iron and phosphorus

摘要

This study evaluated the effect of biochar on plant growth under Fe- and P-deficient soil conditions. Lupin and sorghum (sensitive to soil Fe and P deficiency, respectively) were pot-grown on one (Fe) or two (P) soils to which either two biochars of contrasting properties (produced from olive-tree pruning and pine wood) or Fe/P fertilizers or biochars combined with Fe/P fertilizers were added. Without Fe addition, the olive-tree pruning biochar increased lupin growth with results comparable to those of the sole application of the Fe fertilization, while biochars combined with the Fe fertilization did not significantly affect plant growth variables relative to the Fe treatment alone. Biochar did not correct P deficiency in the tested soils. However, the application of the pine wood biochar together with a P fertilizer to a calcareous soil increased sorghum biomass yield by 42% relative to the sole application of the P fertilizer. Biochar addition did not significantly affect root traits, suggesting its scarce influence on nutrient mobilization and uptake efficiency. Although biochar alone did not alleviate nutrient deficiency in the studied soils due to the low Fe and P contents added in available form with the tested materials, the present results suggest that biochar can provide additional benefits combined with the use of fertilizers under nutrient-deficient conditions; and open new options to formulate biochar-based amendments that can play a relevant role in the context of sustainable agriculture.