Influences of leaf litter replacement on soil biochemical characteristics of main planted forests in Qinling Mountains of China

Abstract

Long-term continuous growth of the same tree species in planted pure forest will lead to soil polarization and degradation. Mixed forestation or litter replacement between different needle- and broad-leaved forests are effective measures, except fertilization, to control soil polarization according to the mutual compensation principle of different tree species. Through a two-year leaf litter replacement experiment in 4 typical planted pure forests of Larix kaempferi, Pinus tabulaeformis, Catalpa fargesii and Quercus aliena var. acuteserrata in Qinling Mountains of China, influences of leaf litter replacement on soil biochemical characteristics and their interspecific relationships were studied and main conclusions were reached as follows. (1) Annual leaf litter decomposition rate of broad-leaved forests was 33.70 % higher than those of needle-leaved forests and increased by 8.35%-12.15% when needle-leaved litter was replaced with broad-leaved forests, whereas it decreased by 5.38%-9.49% when broad-leaved litter was replaced with needle-leaved forests. (2) Leaf litter replacement between needle- and broad-leaved forests popularly raised the contents of organic C, available N, P and K in soil, whose content increments in the needle-leaved forests (8.70%-35.84%) were obviously more than those in the broad-leaved forests (3.73%-10.44%), and in the former, the content increments after replacement with the litter of Catalpa fargesii (24.63%-35.84%) were more than those after replacement with the litter of Quercus aliena var. acuteserrata (8.70%-28.15%). Furthermore, the litter replacement was found to make the soil pH of needle-leaved forests developed from light-acid to neutral. (3) Litter replacement of the needle-leaved forests with the broad-leaved litter popularly raised enzyme activities, amounts of microorganisms and contents of micro-biomass C and N in soil, the increments of which after replacement with the litter of Catalpa fargesii were also more than those after replacement with the litter of Quercus aliena var. acuteserrata; while the litter replacement of broad-leaved forests with needle-leaved litter resulted differently depending upon the tree species. Among them, the soil enzyme activities and contents of micro-biomass C and N in the forest of Quercus aliena var. acuteserrata raised while they lowered in the forest of Catalpa fargesii.

Key words： planted forest; soil degradation; litter replacement; litter decomposition; biochemical properties of soil; interspecific relationship

Acknowledgements

This research was supported by the National Natural Science Foundation of China (Grant No. 30471376) and the Talent Plan Foundation of Northwest A & F University, China (2005).

References

1 Allen A S, Schlesinge W H (2004). Nutrient limitations to soil microbial biomass and activity in loblolly pine forests. Soil Biology and Biochemistry, 36(4): 581-589

2 Berg B (2000). Litter decomposition and organic matter turnover in northern forest soils. Forest Ecology and Management, 133(1-2): 13-22

3 Cao P R, Luo S M (1994). Studies on allopathy of teaplant. Journal of South China Agricultural University, 15(2): 129-133 (in Chinese)

4 Cui G F (1996). Depletion mechanism of forest plantation productivity and preventive strategy. World Forestry Research, 9(5): 61-68 (in Chinese)

5 Dilly O, Munch J C (1996). Microbial biomass content, basal respiration and enzyme activities during the course of decomposition of leaf litter in a Black Alder (Alnus glutinosa Gaertn.) forest. Soil Biology and Biochemistry, 28(8): 1073-1081

6 Guan S Y (1986). Soil Enzyme and its Study Methods. Beijing: Agriculture Press (in Chinese)

7 He Y J, Wang Q K, Wang S L, Yu X J (2006). Characteristics of soil microbial biomass carbon and nitrogen and their relationships with soil nutrients in Cunninghamia lanceolata plantations. Chinese Journal of Applied Ecology, 17(12): 2292-2296 (in Chinese)

8 Keeves A (1996). Some evidence of loss of productivity with successive rotations of Pinus radiata in southeast of South Australia. Australian Forestry, 30(6): 51-63

9 Kourtev P S, Ehrenfeld J G, Huang W Z (2002). Enzyme activities during litter decomposition of two exotic and two native plant species in hardwood forests of New Jersey. Soil Biology and Biochemistry, 34(9): 1207-1218

10 Li H T, Yu G R, Li J Y, Liang T, Chen Y R (2007). Dynamics of litter decomposition and phosphorus and potassium release in Jinggang Mountain region of Jiangxi Province, China. Chinese Journal of Applied Ecology, 18(2): 233-240 (in Chinese)

11 Li X F, Han S J, Zhang Y (2007). Indirect effects of precipitation on litter decomposition of Quercus mongolica. Chinese Journal of Applied Ecology, 18(2): 261-266 (in Chinese)

12 Liu Z W, Duan E J, Fu G, Cui F F, Gao W J (2007). A new concept: Soil polarization in planted pure forest. Acta Pedologica Sinica, 44(6): 1119-1126 (in Chinese)

13 Liu Z W, Gao W J, Pan K W, Du H X, Zhang L P (2006). Discussion on the study methods and models of litter decomposition. Acta Ecologica Sinica, 26(6): 1993-2000 (in Chinese)

14 Lu R K (1999). Agro-Chemical Analysis Methods of Soil. Beijing: Chinese Agriculture Scientific Press (in Chinese)

15 Ma X Q, Huang B L (1997). Advance in research on site productivity decline of timber plantations. Journal of Nanjing Forestry University, 21(2): 77-82 (in Chinese)

16 Michael A K, Sten S (2004). Microbial enzyme activities in leaf litter, humus and mineral soil layers of European forests. Soil Biology and Biochemistry, 36(8): 527-1537

17 Nanjing Institute of Soil Science, Chinese Academy of Sciences (1985). Study Methods of Soil Microorganisms. Beijing: Science Press (in Chinese)

18 Pang X Y, Liu S Q, Liu Q, Lin B, Wu Y, He H, Bao W K (2004). Degradation and control of soil organic matter and nutrient pool under sub alpine spruce plantation in western Sichuan. Acta Pedologica Sinica, 41(1): 126-133 (in Chinese)

19 Sariyildiz T, Anderson J M, Kucuk M (2005). Effects of tree species and topography on soil chemistry, litter quality, and decomposition in Northeast Turkey. Soil Biology and Biochemistry, 37(9): 1695-1706

20 Song X G, Hu T X, Xian J R, Li W, Wu W G, Xiao C L (2007). Responses of litter decomposition and nutrient release to simulated nitrogen deposition in an evergreen broad-leaved forest in southwestern Sichuan. Chinese Journal of Applied Ecology, 18(10): 2167-2172 (in Chinese)

21 Vance E D, Chapin F S (2001). Substrate limitations to microbial activity in taiga forest floors. Soil Biology and Biochemistry, 33(2): 173-188

22 Vitousek P M, Matson P A (1985). Disturbance, nitrogen availability, and nitrogen losses in an intensively managed loblolly pine plantation. Ecology, 66(4): 1360-1376

23 Wang Q K, Wang S L, Gao H, Yu X J (2005). Dynamics of soil active organic matter in Chinese fir plantations. Chinese Journal of Applied Ecology, 16(7): 1270-1274 (in Chinese)

24 Wang Q K, Wang S L, Yu X J, Zhang J, Liu Y X (2007). Effects of Cunninghamia lanceolata-broadleaved tree species mixed leaf litters on active soil organic matter. Chinese Journal of Applied Ecology, 18(6): 1203-1207 (in Chinese)

25 Xiao C Y, Ruan H H, Tu L B (2002). Biological characteristics of different forest soils in Nanjing-Zhenjiang mountain area. Chinese Journal of Applied Ecology, 13(9): 1077-1081 (in Chinese)

26 Xue L, Kuang L G, Chen H Y, Tan S M (2003). Soil nutrients, microorganisms and enzyme activities of different stands. Acta Pedologica Sinica, 40(2): 280-285 (in Chinese)

27 Xue L, Wu M, Xu Y, Li Y, Qu M (2005). Soil nutrients and microorganisms in soils of typical plantations in south china. Acta Pedologica Sinica, 42(6): 1017-1023 (in Chinese)

28 Yang W Q, Deng R J, Zhang J (2007). Forest litter decomposition and its responses to global climate change. Chinese Journal of Applied Ecology, 18(12): 2889-2895 (in Chinese)

29 Zhou L K (1980). Science of Soil Enzyme. Beijing: Science and Technology Press (in Chinese)

30 Zhu J J, Li F Q (2007). Forest degradation/decline: Research and practice. Chinese Journal of Applied Ecology, 18(7): 1601-1609 (in Chinese)