Forest‐derived liming by‐products: Potential benefits to remediate soil acidity and increase soil fertility

Abstract

Soil acidification is an important cause of declining crop yields in many countries, including Canada and the United States. Meanwhile, alkaline by-products from forest resources are widely available but underused in agriculture despite their expected benefits on soil pH and fertility. The aim of this study was to determine the effects, throughout a 40-wk laboratory incubation, of six different forest-derived liming materials on soil pH and Mehlich-3-extractable major nutrients in two acidic soils. Lime mud, two wood ashes (papermill biosolids and wood bark), two biochars (maple and pine), and a de-inking paper sludge (DPS) were applied at calcium carbonate equivalence-based rates, according to the amount of lime required to achieve a target pH of 6.5 on each soil. A calcitic lime (CL) was used as a reference. All forest-derived materials except pine biochar were equally effective as CL in increasing the pH of the two acidic soils after 40 wk of incubation. Lime mud quickly raised the pH after soil incorporation, and then the pH progressively declined. By contrast, DPS upon decomposition gradually increased soil pH over time. In terms of liming value based on dry mass of each material, lime mud was needed at the lowest amount (0.8 CL unit) to increase pH to the target value. Wood ash, particularly from wood combustion, was a significant direct source of P, K, and Mg, whereas maple biochar supplied large amounts of available K and Mg. This study demonstrated that forest-derived alkaline by-products can efficiently remediate soil acidity and improve soil fertility. 1 INTRODUCTION Soil acidification is a major concern responsible for degradation of agricultural land in many countries, including Canada and the United States. It affects about 30% of total Abbreviations: CCE, calcium carbonate equivalence; CL, calcitic lime; DPS, de-inking paper sludge; LM, lime mud; LR, lime requirement; M700, maple bark biochar produced at 700nonbreakingspace • C; P700, pine chip biochar produced at 700nonbreakingspace • C; WA, wood ash.

No significant influence of biochar and manure application on nitrogen fate and sequestration by tomato and garlic crops: A field experiment in California, USA

“…Nutrient values in biochar would depend on the feedstock materials. For example, maple biochar could supply large amounts of available K and Mg (Gagnon & Ziadi, 2020). Thus, when organic amendments are used, nutrient budgeting needs to be undertaken so that effective use of all nutrients, especially P and K from the amendments, can be factored in.…”