Litterfall, nutrient return, and leaf-litter decomposition in four plantations compared with a natural forest in subtropical China

Abstract

-The amount and pattern of litterfall, its nutrient return, initial chemistry of leaf litter, and dynamics of N, P and K associated with leaf-litter decomposition were studied in 33-year-old plantations of two coniferous trees, Chinese fir (Cunninghamia lanceolata, CF) and Fokienia hodginsii (FH), and two broadleaved trees, Ormosia xylocarpa (OX) and Castanopsis kawakamii (CK), and compared with that of an adjacent natural forest of Castanopsis kawakamii (NF, ~150 year old) in Sanming, Fujian, China. Mean annual total litterfall over 3 years of observations was 5.47 Mg·ha -1 in the CF, 7.29 Mg·ha -1 in the FH, 5.69 Mg·ha -1 in the OX, 9.54 Mg·ha -1 in the CK and 11.01 Mg·ha -1 in the NF respectively; of this litterfall, leaf contribution ranged from 58% to 72%. Litterfall in the OX, CK, and NF showed an unimodal distribution pattern, while for the CF and FH, the litterfall pattern was multi-peak. The highest annual Ca and Mg returns were noticed in the FH and in the CK, respectively. The amounts of N, P, and K which potentially returned to the soil were the highest in the NF. The loss of dry matter in leaf litter exhibited a negative exponential pattern during the 750-day decomposition. Using the model x t = A + Be -kt , the annual dry matter decay constants (k) ranged from 1.157 in CF to 4.619 in OX. Initial lignin concentration and lignin/N ratios showed significantly negative correlations with k (r = -0.916, P = 0.011; r = -0.473, P = 0.041), whereas initial N concentration showed low positive correlations (r = 0.225, P = 0.038). Using the model x t = A + Be -kt , the decay constant of N (k N ) ranged from 0.769 in CF to 4.978 in OX; the decay constant of P (k P ) ranged from 1.967 in the OX to 4.664 in the NF; and the decay constant of K (k K ) seemed very similar among these forests (5.250-5.992). The decay constants of nutrients during leaf-litter decomposition can be arranged in the sequence of k K > k P > k N , except for leaf litter of OX wherelitterfall / nutrient return / litter decomposition / reafforestation / natural forest / Cunninghamia lanceolata / Fokienia hodginsii / Ormosia xylocarpa / Castanopsis kawakamii Résumé -Chute de feuilles, retour de nutriments et décomposition des feuilles de la litière dans quatre plantations en comparaison avec une forêt naturelle en Chine subtropicale. La quantité et la dynamique de chute de litière, le retour des nutriments, la composition chimique initiale des feuilles de la litière et la dynamique de N, Pet K associée à la décomposition de la litière ont été étudiés dans 2 plantations de conifères (Cunninghamia lanceolata, CF and Fokienia hodginsii, FH) âgées de 33 ans et 2 peuplements feuillus (Ormosia xylocarpa, OX et Castanopsis kawakamii, CK), comparativement à une forêt naturelle adjacente de Castanopsis kawakamii, NF, âgée d'environ 150 ans à Sanming, Fujian, Chine. Sur 3 années d'observations, la moyenne annuelle de chute de litière a été de 5,47 Mg·ha -1 pour CF, 7,29 Mg·ha -1 pour FH, 5,69 Mg·h -1 pour OX, 9,54 Mg·hg -1 pour CK et 11,01 Mg·h...

Litterfall deposition and leaf litter nutrient return in different locations at Northeastern Mexico

“…Trap contents were collected at 15-day intervals between December 21, 2006, andDecember 20, 2007. Since area and height above the ground of litter traps as well as the sampling period of collection in litterfall studies are variable, which in many circumstances depends on the total area sampled, type of vegetation, the temporal and spatial variation in litterfall production, and to prevent significant decomposition and leaching loss of nutrients by throughfall between collections resulting in an underestimation of the true litterfall flux of nutrients to the forest soil, in this study, the area of sampling, number of traps and height above soil level, and litter collection period are within the range of previous studies (Ukonmaanaho and Starr 2001;Finotti et al 2003;Read and Lawrence 2003;Yang et al 2004Yang et al , 2006Fang et al 2007;Zhou et al 2007). Litter contents were manually sorted into the following categories: leaves, reproductive structures (flowers, fruits, and seeds) twigs or branches (\2 cm in diameter), and miscellaneous residues (unidentified, fine plant tissue such as bark, pieces of insect bodies or feces).…”

Comparisons of carbon storages in Cunninghamia lanceolata and Michelia macclurei plantations during a 22-year period in southern China

“…The changes in the carbon stocks of the soils in the different forest types might also reflect the differences in quantity and quality of above-and below-ground litter inputs, litter carbon decay (Mo et al, 2002), and root biomass carbon. Yang et al (2004c) noted that the leaf-litter of Chinese fir possesses higher lignin concentration and lignin/N ratio than that of broad leaf tree. In addition, broadleaved trees may allocate more biomass to their roots, especially the fine roots at the shallow soil horizons, which can fix a greater amount of carbon and transfer more root detritus to the top soil (Yang et al, 2004a(Yang et al, , 2004b.…”

Conversion of a natural broad-leafed evergreen forest into pure plantation forests in a subtropical area: Effects on carbon storage

“…IV). Yang et al [51] also noted that leaf-litters of the NF and the broadleaveds were characterized by lower lignin content and narrower lignin/N ratio than those of the conifers. Further, the higher concentration of fine roots in the topsoil in the NF than in the plantations can transfer much more root detritus from roots to superficial soils [49].…”

“…Fifteen 0.5 m × 1.0 m litter traps made of nylon mesh (1 mm mesh size), were arranged in each forest and were raised 25 cm above the ground, and the litterfall was collected at 10-day intervals from January 1999 to December 2001 [51]. The collected litter at each time was oven-dried at 80 °C to constant weight.…”

“…We had reported litterfall and fine-root dynamics and soil biological changes on these forests [8,49,51]. The primary objective of this study was to determine if plantations consisting of broadleaved and coniferous species altered the ecosystem C stocks.…”