Soil Amendment with Biochar Affects Water Drainage and Nutrient Losses by Leaching: Experimental Evidence under Field-Grown Conditions

Abstract

Leaching of soluble elements from cultivated soils is a major concern to meet the target of agricultural sustainability in most areas. The effect of biochar application to a cultivated soil on water drainage and the consequent solute losses was assessed during a trial carried out over two consecutive growing seasons. Biochar was added to a loam-texture soil, at 0, 1, and 2% d.w. rates. A lysimeter-like set-up arranged in the experimental field-unit, allowed collecting the percolating water. Two multiple linear regressions (ANCOVA models) were applied to detect biochar effect on: (1) The seasonal amount of drained water; and (2) the concentration of solutes in the drained water. The statistical comparison among a set of slope coefficients as affected by treatments (growing season and biochar) was used as modelling approach. The lower biochar application rate (1%) significantly reduced both the amount of drained water and its concentration in solutes. Conversely, the higher biochar application rate (2%) showed no significant effects. Nitrate and chloride showed a significant interaction with biochar application rates. Higher biochar application increased nitrate leaching while reduced that of chloride. Biochar application within a rate no more than 1% resulted in a useful and quite effective technical operation.

Quanti-Qualitative Response of Swiss Chard (Beta vulgaris L. var. cycla) to Soil Amendment with Biochar-Compost Mixtures

“…On the contrary, biochar addition to the soil reduced NO 3 − content in Swiss chard leaves, likely due to the occurrence of a nitrate sorption on biochar surface. Several authors showed that biochar is effective in retaining nitrates in the soil [60][61][62][63][64][65] and attributed this ability to the high pyrolysis temperature (>600 • C) at which the biochar is obtained [66]. According to the literature, the biochar nitrate retention we hypothesized in our experiment could be explained considering the high temperature (650 • C) applied to vine pruning residues for biochar production.…”

Biochar, Vermicompost, and Compost as Soil Organic Amendments: Influence on Growth Parameters, Nitrate and Chlorophyll Content of Swiss Chard (Beta vulgaris L. var. cycla)

“…Biochar is a carbon-rich, solid material obtained by biomass (manure, sewage sludge, wood biomass and crop residues) pyrolysis in an oxygen-limited environment [18][19][20][21]. The effects of their addition to agricultural soils depend on a number of factors, including feedstock properties and processing conditions, application rate, soil type, environmental conditions, and crop species [22,23]. About the latter, the yield response to compost or biochar applications are often contrasting; generally, either positive or negative and sometimes also neutral effects on crop yield and quality have been reported [13,24].…”

Quanti-Qualitative Response of Swiss Chard (<em>Beta vulgaris</em> L. var. <em>cycla</em>) to Soil Amendment with Biochar-Compost Mixtures

“…On the contrary, biochar addition to the soil reduced NO3 -content in Swiss chard leaves, likely due to the occurrence of a nitrate sorption on biochar surface. Several authors showed that biochar is effective in retaining nitrates in the soil [60][61][62][63][64][65] and attributed this ability to the high pyrolysis temperature (>600°C) at which the biochar is obtained [66]. According to the literature, the biochar nitrate retention we hypothisez in our experiment could be explained considering the high temperature (650°C) applied to vine pruning residues for biochar production.…”