2006,39(4):750-757 Scientia Agricultura Sinica 1 712100 2 547100 Effects of Land Use on Soil Organic C and Microbial Biomass C in Hilly Red Soil Region in Subtropical China WANG Xiao-li 1, 2, SU Yi-rong 2, HUANG Dao-you 2, XIAO He-ai 2, WANG Li-gang 2, WU Jin-shui 2 1 College of Resources and Environment, Northwest Sci-Tech University of Agriculture and Forestry Yangling 712100 2 Huanjiang Experimental Station of Karst Ecosystem, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Huanjiang 547100 Abstract: Objective In order to assess the impacts of land use change on soil organic carbon (SOC) and soil microbial biomass carbon (SMBC), the contents of SOC and SMBC of surface soil samples (0 20 cm) were investigated. Method The dense sampling (the density of sampling for paddy and dry land is 3 4 per ha, for orchard is 2 3 per ha and for woodland is 0.2 0.5 per ha) and the field surveys in Kenfu demonstration area of environmental immigrants of the northwest of Guangxi, a hilly landscape of red soil area of subtropical China were carried out. Result The average contents of SOC, SMBC and the ratio of SMBC and SOC were respectively (17.53±5.02) g kg -1, (278±174) mg kg -1 and (1.56±0.84)% in the area, respectively. The average contents of SOC, SMBC and the ratio of SMBC and SOC of the woodland were (17.53±5.02) g kg -1, (278±174) mg kg -1 and (1.58±0.39)%, respectively. Compared with the woodland, the contents of SOC and SMBC and the ratio of SMBC and SOC of the paddy field increased by 15.5%, 84.0% and 73.9% (P<0.01); The content of SOC of the dry land (17.50±4.89) g kg -1 decreased slightly (P>0.05) compared with the woodland, that of SMBC and SMBC/SOC decreased by 29.1% and 24.2% (P<0.01); The content of SOC, SMBC and SMBC/SOC of the orchard decreased by 26.8%, 46.1% and 26.1% compared with the woodland (P<0.01). In addition, there were significant correlations between SOC and SMBC in different land use except the paddy field. Conclusion This study indicated that the conversion of woodland into paddy field increased the accumulation of SOC and the microbial activity evidently in the hilly landscape of red soil area of subtropical China. However, the conversion of woodland into dry land or orchard reduced the content of SOC and the microbial activity to different degrees. 2005-09-292006-01-20 KZCX3-SW-42640235057 2004BA606A- 08 1979- Tel: 135724100701; E-mail: djjwxl@yahoo.com.cn 1962- Tel 0731-4615222 E-mail yrsu@isa.ac.cn
4 751 Key words: Land use; Subtropics; Hilly red soil region; Soil organic carbon; Soil microbial biomass carbon SOC C N P S [1,2] CO 2 [3] SOC SMBC 1976 Ayanaba [4] 2 Lugo [5] 10 SOC 46% 5090% Follett [6] 0 10 cm57% 52% 36% Islam [7] Dinesh [8] Powers [9] 140 000 ha 0 30 cm 37% 16.5% [10~15] [10] Wang [13] 1980 [14] SOC13 2842% 26% [15] SOC 3SOC SOC SMBC SOC SMBC SOC SMBC SOC N 24 51 E108 15 19.910 6 300 1 389.1 mm 4 8 70.6% 202 396 m [16] 4.70 km 2 1984 1 1.4 500 700 2003 8 3 4 /ha 2 3 /ha 0.2 0.5 /ha 0 20
752 39 cm 15 77 309 92 193 671 12 13 0.25 mm SOC [17] Vario-MAX C/N 2.0 mm -K 2 SO 4 SMBC [18] LSD - K-S SPSS13.0 1 SOC (17.53±5.02) g kg -1 6.19 33.61 g kg -1 SOC (18.20±4.53) g kg -1 SOC 15.5% P<0.01 SOC SOC 26.8% P<0.01 SOC P>0.05 2 [19] SOC SOC SOC SOC 1 SOC 87.2% 10 25 g kg -1 2 79% 15 30 g kg -1 10 25 g kg -1 91% 88% 99% 10 15 g kg -1 σ SOC σ 4.53 5.44 g kg -1 σ=2.78 g kg -1 - K-S α=0.05 P>0.05 1 1 SOC P=0.04 SOC P>0.05 SOC [20] SOC Table 1 The contents of SOC and SMBC and the ratio of SMBC and SOC under different land use K-S Items Land-use Sample Mean S.D. C.V. (%) Minimum Maximum Skewness Kurtosis P numbers SOC g kg -1 SMBC mg kg -1 / SMBC/SOC (%) Paddy field 77 21.01 aa 5.44 26 9.27 33.61-0.26-0.26 0.88** Dry land 309 17.50 bb 4.89 28 6.19 30.98 0.18-0.48 0.45** Woodland 193 18.20 bb 4.53 25 7.58 31.15 0.09-0.28 0.76** Orchard 92 13.31 cc 2.78 21 6.34 21.99 0.33 0.64 0.69** Total 671 17.53 5.02 29 6.19 33.61 0.28-0.43 0.04 Paddy field 71 539 aa 218 40 136 971 0.32-0.82 0.49** Dry land 168 208 cc 89 43 17 550 0.77 0.97 0.28** Woodland 128 293 bb 111 38 90 624 0.85 0.33 0.10** Orchard 73 158 dd 61 39 24 310 0.14-0.40 0.84** Total 440 278 174 63 17 971 1.68 3.17 0.00 Paddy field 71 2.75 aa 1.28 46 0.45 6.00 0.54-0.54 0.23** Dry land 168 1.20 cc 0.42 35 0.14 2.51 0.68 0.55 0.11** Woodland 128 1.58 bb 0.39 24 0.66 2.41 0.05-0.54 0.27** Orchard 73 1.17 cc 0.40 35 0.21 2.14 0.17-0.07 0.98** Total 440 1.56 0.84 54 0.14 6.00 2.18 6.26 0.00 5% 1%** K-S (P >0.05) Different lowercase and capital letters after the means mean respectively the differences at the 0.05 and 0.01 levels. ** means normal distribution by one-sample Kolmogorov -Smirnov test (P>0.05)
4 753 Table 2 The classification standards of soil organic matter in the second soil survey of China Class Level SOM (%) SOC (g kg -1 ) 1 Very high >4.0 >23.20 2 High 3.0 4.0 17.40 23.20 3 Middle 2.0 3.0 11.6 17.40 4 Little low 1.0 2.0 5.80 11.60 5 Low 0.6 1.0 3.48 5.80 6 Very low <0.6 <3.48 SMBC SOC SOC SMBC SMBC 3 SMBC 83.6% 100 500 mg kg -1 4 82% 300 900 mg kg -1 100 500 mg kg -1 94% 92% 99% 20 300 g kg -1 SMBC σ=218 mg kg -1 σ 61 111 mg kg -1 SMBC SOC 1 SMBC Fig. 1 Histogram of SOC content Fig. 3 Histogram of SMBC content Fig. 2 Distribution of SOC under different land use SMBC 278±174 mg kg -1 17 971 mg kg -1 1 SMBC (293±111) mg kg -1 SMBC 84.0% 29.1% 46.1% SMBC P<0.01 Fig. 4 Distribution of SMBC under different land use
754 39 P=0.00 P>0.05 SOC [21,22] SMBC/SOC 0.5% 4.0% SMBC/SOC 0.1 % 6.0 %(1.56±0.84)% 1 SMBC/SOC (2.75±1.28)% SMBC/SOC (1.58±0.39)% (1.20±0.42)% (1.17±0.40)% SMBC/SOC SMBC SOC SMBC SOC SMBC R 2 =0.2601 n=440 5 6-A SOC SMBC 6-B 6-C 6-D 1996 SOC SMBC SMBC/SOC 46% 1 Fig. 5 Relation between SOC and SMBC A B C D Fig. 6 Relations between SOC and SMBC under different land use (A paddy field, B dry land, C wood land, D orchard) SOC SOC (18.20±4.53) g kg -1 SOC 15.5% P<0.01 SOC P>0.05 SOC 26.8% P<0.01 [23] SOC
4 755 [5,24] SOC [25] SOC 3.8% 3 7 [16] 20 50 cm SOC SOC [26] SMBC SOC SOC SOC [10,21,22] SMBC (293±111) mg kg -1 SMBC 84.0% 29.1% 46.1% SMBC [4,6,10,21] [10] SOC 20 50 cm SOC SMBC SMBC/SOC SMBC/SOC 73.9% SMBC/SOC 24.2% 26.1% [4, 6, 21] Highfield 10 SOC 39% 49% SMBC 58% 87% SMBC/SOC 2.5% 1.7% 0.67% [21] 10%10% 100% 100% [27] 1 SOC SMBC SMBC/SOC SOC 21% 28%SMBC SMBC/SOC 38% 40% SMBC SOC SMBC SOC SMBC SMBC/SOC SMBC SOC SMBC SMBC/SOC SOC SMBC SMBC/SOC SOC SMBC SMBC/ SOC SMBC SMBC/SOC SMBC SMBC/SOC SOC [4,6,21,28] References [1] Richard D B, Tania C S, Lisa C, Ian R H. Linkages between soil biota, nitrogen availability, and plant nitrogen uptake in a mountain ecosystem in the Scottish Highlands. Applied Soil Ecology, 2002, 19: 121-134. [2] Parfitt R L, Yeates G W, Ross D J, Mackay A D, Budding P J. Relationships between soil biota, nitrogen and phosphorus availability, and pasture growth under organic and conventional management. Applied Soil Ecology, 2005, 28: 1-13. [3]. LUCC... 2004: 76-100. Ge Q S, Dai J H, He F N. Land use/cover change and carbon cycle of terrestrial ecosystem. In: Chen P Q. Carbon Cycle of the Earth
756 39 System. Beijing: Science Press, 2004: 76-100. (in Chinese) [4] Ayanaba A, Tuckwell S B. Jenkinson D S. The effect of clearing and cropping on the organic reserves and biomass of tropical forest soils. Soil Biology and Biochemistry, 1976, 8: 519-525. [5] Lugo A E, Sanchez M J, Brown S. Land use and organic carbon content of some subtropical soils. Plant and Soil, 1986, 96: 185-196. [6] Follett R F, Schimel D S. The effect of tillage practices on microbial biomass dynamics. Soil Science Society of America Journal, 1989, 53: 1091-1096. [7] Islam K R, Weil R R. Land use effects on soil quality in a tropical forest ecosystem of Bangladesh. Agriculture, Ecosystems and Environment, 2000, 79: 9-16. [8] Dinesh R, Chaudhuri S G, Ganeshamurthy A N, Dey C. Changes in soil microbial indices and their relationships following deforestation and cultivation in wet tropical forests. Applied Soil Ecology, 2003, 24: 17-26. [9] Powers J S. Changes in soil carbon and nitrogen after contrasting land-use transitions in northeastern Costa Rica. Ecosystems, 2004, 7: 134-146. [10].., 1998, 29: 276-278. Chen G C, He Z L. The study of soil microbial biomass of different land use in red soil area of China. Chinese Journal of Soil Science, 1998, 29: 276-278. (in Chinese) [11].. 1998, 9: 365-370. Li Z P, Wang X J. Simulation of soil organic carbon dynamic after changing land use pattern in hilly red soil region. Chinese Journal of Applied Ecology, 1998, 9: 365-370. (in Chinese) [12].. 2004 37 1504-1509. Wen Q, Zhao X R, Chen H W, Tuo D B, Lin Q M. Distribution characteristics of microbial biomass carbon in different soil aggregates in semi-arid area. Scientia Agricultura Sinica, 2004, 37: 1504-1509. (in Chinese) [13] Wang S Q, Liu J Y, Yu G R, Pan Y Y, Chen Q M, Li K R, Li J Y. Effects of land use change on the storage of soil organic carbon: a case study of the Qianyanzhou forest experimental station in China. Climatic Change, 2004, 67: 247-255. [14]. 2004 15 593-599. Wu J G, Zhang X Q, Xu D Y. Impact of land-use change on soil carbon storage. Chinese Journal of Applied Ecology, 2004, 15: 593-599. (in Chinese) [15].. 2005 38 544-550. Jiang Y, Zhang Y G, Liang W J, Wen D Z. Profile distribution and storage of soil organic carbon in an aquic brown soil as affected by land use. Scientia Agricultura Sinica, 2005, 38: 544-550. (in Chinese) [16].. 2000 15 3 25-27. Su Y R, Huang Y, Wang K L, Li W X, Zeng F P, Li L, Meng G X, Wei Z S. Ecological and environmental conditions at settlement of environmental immigrants in Southwest China. Environment and Exploration, 2000, 15(3): 25-27. (in Chinese) [17].. 1994: 29-33. Nanjing Agricultural University. Soil Agricultural and Chemistry Analysis (second edition). Beijing: Agricultural Press, 1994: 29-33. (in Chinese) [18] Wu J S, Joergensen R G, Pommerening B, Chaussod R, Brooks P C. Measurement of soil microbial biomass C by fumigation-extractionan automated procedure. Soil Biology and Biochemistry, 1990, 20: 1167-1169. [19]... 2. 1997: 179-189. Lai H B, Li S Q, Fu J P. Soil fertility and assessment in Pan-dian village of Feng-qiu county. In Xu F A, Zhou L Y, eds. Research on Agro-Ecosystem in Plain of Northern Henan Province (Vol. 2). Beijing: China Meteorological Press, 1997: 179-189. (in Chinese) [20].. 1994: 177-182. Mao D R. Research Methods of Plant Nutrition. Beijing: Beijing Agricultural University Press, 1994: 177-182. (in Chinese) [21].... 1994: 28-62. Wu J S. Soil organic matter and the dynamic in its turnover. In: He D Y, eds. Soil Fertility and Fertilization for Cultivated Plants in Southern China. Beijing: Science Press, 1994: 28-62. (in Chinese) [22].. 1997 29(2) 61-69. He Z L. Soil microbial biomass and its roles in nutrient cycle and
4 757 environmental quality assessment. Soils. 1997, 29(2): 61-69. (in Chinese) [23].... 1983: 119-127. Wen Q X, Lin X X. The content and characteristics of soil organic matter in red soil region. In: Li Q K, ed. China Red Soil. Beijing: Science Press, 1983: 119-127. (in Chinese) [24] Tieszen L T.. 1998 22 545-551. Wang Y F, Chen Z Z, Tieszen L T. Distribution of soil organic carbon in the major grasslands of Xilinguole, Inner Mongolia, China. Acta Phytoecologica Sinica, 1998, 22: 545-551. (in Chinese) [25] Luo R Y, Gao Z Q. Effects of Chinese fir, loblolly pine and deciduous oak forests on nutrient states of soils in northern subtropics of China. Pedosphere, 1994, 4(1): 1-10. [26].. 2005 20 529-536. Liu S Z, Guo S L, Wang X L, Xue B M. Effect of vegetation on soil organic carbon of slope land in gully region of Loess Plateau. Journal of Natural Resources, 2005, 20: 529-536. (in Chinese) [27].. 1988 321-326. Lei Z D, Yang S X, Xie S C. Soil Water Dynamics. Beijing: Qinghua University Press, 1988: 321-326. (in Chinese) [28] Powlson D S, Brookes P C, Christensen B T. Measurement of soil microbial biomass provides an early indication of changes in total soil organic matter due to straw incorporation. Soil Biology and Biochemistry, 1987, 19(2): 159-164. ( )