Long-Term Effects of Liming on Health and Growth of a Masson Pine Stand Damaged by Soil Acidification in Chongqing, China

Abstract

In the last decades, the Masson pine (Pinus massoniana) forests in Chongqing, southwest China, have increasingly declined. Soil acidification was believed to be an important cause. Liming is widely used as a measure to alleviate soil acidification and its damage to trees, but little is known about long-term effects of liming on the health and growth of declining Masson pine forests. Soil chemical properties, health condition (defoliation and discoloration), and growth were evaluated following application of limestone powder (0 (unlimed control), 1, 2, 3, and 4 t ha−1) in an acidified and declining Masson pine stand at Tieshanping (TSP) of Chongqing. Eight years after liming, in the 0–20 cm and 20–40 cm mineral soil layers, soil pH values, exchangeable calcium (Ca) contents, and Ca/Al molar ratios increased, but exchangeable aluminum (Al) levels decreased, and as a result, length densities of living fine roots of Masson pine increased, with increasing dose. Mean crown defoliation of Masson pines (dominant, codominant and subdominant pines, according to Kraft classes 1–3) decreased with increasing dose, and it linearly decreased with length densities of living fine roots. However, Masson pines (Kraft classes 1–3) in all treatments showed no symptoms of discoloration. Mean current-year twig length, twig dry weight, needle number per twig, needle length per twig, and needle dry weight per twig increased with increasing dose. Over 8 years, mean height increment of Masson pines (Kraft classes 1–3) increased from 5.5 m in the control to 5.8, 6.9, 8.3, and 9.5 m in the 1, 2, 3, and 4 t ha−1 lime treatments, and their mean DBH (diameter at breast height) increment increased from 3.1 to 3.2, 3.8, 4.9, and 6.2 cm, respectively. The values of all aboveground growth parameters linearly increased with length densities of living fine roots. Our results show that liming improved tree health and growth, and these effects increased with increasing dose.

Significant alteration of soil bacterial communities and organic carbon decomposition by different long‐term fertilization management conditions of extremely low‐productivity arable soil inSouthChina

“…Quicklime is conventionally applied to increase the soil pH, enhance the mobilization of nutrient ions and reduce the toxic effect of heavy metal ions (Li et al ., ). We observed a significant increase in the soil pH but little impact on the nutrient content after quicklime treatment.…”

Phosphorus addition mitigates N<sub>2</sub>O and CH<sub>4</sub> emissions in N-saturated subtropical forest, SW China

“…In China, the exponential increase of reactive nitrogen (N) input into the biosphere since the 1970s has likely led to more carbon (C) being sequestered in the biosphere (Cui et al, 2013;Shi et al, 2015). However, enhanced emissions of N 2 O and CH 4 due to chronic N pollution potentially offset the cooling effect by C sequestration (Liu and Greaver, 2009;Tian et al, 2011). Microbial nitrification and denitrification in soils account for about 60 % of N 2 O emissions globally (Ciais et al, 2013;Hu et al, 2015).…”

Dynamic changes in soil chemical properties and microbial community structure in response to different nitrogen fertilizers in an acidified celery soil

“…Oh et al (2006) also found that calcium cyanamide was effective in stopping soil acidification in tea fields (with an initial pH of 4.5) when applied at almost the same rate as in our study. In traditional liming treatments in China, a large amount of burnt limestone powder (49.5% CaO, usually applied at greater than 2000 kg$ha -1 ) is recommended to obtain increased soil pH (Li et al, 2014). The burnt limestone powder in China is usually not granulated, combined with often humid weather, may result in a proportion of the calcium oxide (CaO) reacting with water (H 2 O) and carbon dioxide (CO 2 ) to produce calcium bicarbonate (CaHCO 3 ).…”