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Lijie PU ( ljpu@nju.edu.cn) School of Geographic and Oceanographic Sciences Nanjing University

Response of the Soil Quality to the Land Reclamation in Coastal Areas, Jiangsu Province, China (Key Project of NSFC : No:41230751 ). Lijie PU ( ljpu@nju.edu.cn) School of Geographic and Oceanographic Sciences Nanjing University November, 2013. Main Contents.

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Lijie PU ( ljpu@nju.edu.cn) School of Geographic and Oceanographic Sciences Nanjing University

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  1. Response of the Soil Quality to the Land Reclamation in Coastal Areas, Jiangsu Province, China(Key Project of NSFC : No:41230751) LijiePU (ljpu@nju.edu.cn) School of Geographic and Oceanographic Sciences Nanjing University November, 2013

  2. Main Contents • Why focus on the coastal areas? • Major scientific issues in coastal areas • Main research contents • Completed field works and sampling • Some preliminary achievements

  3. Main Contents • Why focus on the coastal areas? • Major scientific issues in coastal areas • Main research contents and plans • Completed works and field sampling • Some preliminary achievements

  4. Background-1 Land use as a manner of people directly affected the earth surface system • Land cover • Bio-physical control • Land use • People control Social system Population Social/economic pattern Political pattern Culture Technology Ecological system Biogeochemistry Biodiversity Water Air Soil Decision making Selection (knowledge, value, preferred selection) Social-economic-political

  5. Background-2 Land use/cover change (LUCC) is closely related to global environmental change and sustainable development LUCC mechanism Regional-global model Measure, model and understand the human-environment system The interaction of human with biosphere and natural resources

  6. Background-3 High population density, advanced economy, intense LUCC Population and degraded coastline in coastal area Population in coastal areas (<100km) No ~ ＜30% 30% ~ 70% ﹥70% Coastal line Strongly changed changed Minimally changed Coastal city with more than one million population

  7. Background-4 Anthropogenic activities and resource utilization in coastal area are the main topics of LOICZ II Anthropogenic activities and resource utilization in coastal area biogeochemical cycle in coastal area

  8. Background-5 Wetlands in Jiangsu • Area: 5000km2, ¼ coastal wetlands of China • Abundant ecological systems • High rate of deposit (20-25cm year-1, seaward) a b Dongtai County Rudong County

  9. Coastal wetlands development planning in Jiangsu Background-6 • State Councilapproved ”Coastal development planning in Jiangsu (2009-2020)” in 2009 • A total of 1803km2 coastal wetlands will be reclaimed in the next 10 years, over 2/3 reclamation areas in the past 50 years

  10. Background-7 The feature of reclamation in Jiangsu Sea wall Rudong County • High rate • Large scale • Complex land use Salt marsh

  11. Land use pattern after reclamation Space dimension Cropland Forest Residual area Long-term Mid-term Industrial land Time dimension Garden plot Initial stage Forest Residual area Cropland Wind power Sesban Unused land PV power Salt marsh Aquaculture pond Spartinacynosuroides Spartinaalterniflora Spartinacynosuroidesand Phragmitesaustralis Bare flat tidal Phragmitesaustralis Spartinaalterniflora

  12. Main Contents • Why did focus on coastal areas in China? • Major scientific issues in coastal areas • Main research contents and plans • Completed works and field sampling • Some preliminary achievements

  13. 1. How to quantitatively determine the processes of LUCC in coastal areas characterized by constantly changed boundary (coastline) and high-intensity anthropogenic activities? • Natural factors • Deposit • Terrain • Geology • …. great • Sea little • Social factors • Economy • Polity • Planning • Individual behavior • …. great • Reclamation • Tide great

  14. 2. What is the processes of soil quality (physico-chemical properties) evolution and effect of reclamation (anthropogenic activities) on soil properties? time time node time node • Reclamation activities • Sea wall construction • Wetlands to croplands • Plowing • …. time node Tendency? Different stage? • Chemical properties • N,P,K • pH • Salinity • ….. • Physical properties • Soil moisture • Bulk density • Particle size • ….. • Biochemical properties • Microbial biomass C • Enzyme • ….. Turning point?

  15. 3. How to construct a land productivity model for reclamation areas characterized by high salinity? Perfect Deficient How to construct a soil effectiveness coefficient (including soil physico-chemical properties and management) is an important work.

  16. 4. which environmental risk will happen during reclamation? Environmental risks • PAHs • Rapid urbanization areas (Yangtze River Delta and Pearl River Delta) • Main lakes and basins (Baiyang Lake, Taihu Lakes and Pearl Basin,etc) • Main lakes and basins • (Dianchi Lake, Chaohu Lake, Taihu Lake and West Lake, etc) • Organo-chlorine pesticide • Traditional farming areas • (Sanjiang Plain, Ningxia Plain, Pearl River Delta and Yangtze River Delta, etc) • Heavy metal • Coastal wetlands • （Yancheng, Pearl River Estuary） • Rapid urbanization areas (Beijing, Tianjin, Shanghai, etc) • PCBs • Estuary and delta (Pearl River, Yangtze River, Yellow River and Minjiang River, etc) • Important lakes (Taihu Lake, DayaBay, etc) Nutrient loss • Tillage practices inducing • Fertilization • Pesticide • Chemical amendment • …. • Industry practices inducing • Chemical industry • Fuel • ….

  17. Main Contents • Why did focus on coastal areas in China? • Major scientific issues in coastal areas • Main research contents • Completed works and field sampling • Some preliminary achievements

  18. 1Land use change mechanism in coastal areas Sediment analysis Remote sensing date Reclamation statistics Rate, origin, composition 1980s, 1995, 2000, 2005, 2008, 2010 Scale and rate in history Land use database Forest Orchard Grass Aquaculture pond Salt marsh Built-up land Cropland Water Structural change Spatial change Type conversion Quantitative change Sea-land gradient Reclamation time Sediment Reclamation Determine driving force Natural factor Human factor The mechanism of land use change in the past 30 years in coastal areas of Jiangsu

  19. Model construction Sediment data Land use data Administrative boundaries Economic data Planning Database Factors CA MAS Natural Social Planning Comprehensive model CA MAS Cell state Government Cell neighbourhood Land use change rules Enterprise Conversion rule Individual Sediment Reclamation Construct model Integrate model Test model Optimize model prediction

  20. 2 Assessment of soil quality and land productivity Production potential model (PP) Sub-module Database construction PP model Sunshine duration, effective radiancy, cumulative temperature, precipitation, humidity Radiancy Y=f(Q)*f(T)*f(W)*f(S)*f(I) Photosynthesis PP Temperature Photosynthesis and temperature PP Validation Prediction Precipitation • 1.Productivity accounting data • 2.Field sampling Soil moisture, salinity, nutrient, structure, underground water(Dec, Apr, Sep) Climate PP Soil Experiment design Land PP Dry weight of rice and wheat Crop sample and its corresponding soil sample (two plots/reclamation area, five sub-plots/plot) Crop Assessing and predicting Land productivity in reclamation Land productivity Economic investment, pesticide and fertilizer inputs, etc Management

  21. 3Assess the environmental risk resulting reclamation Artificial rainfall simulation experiment Field fixed-place observation • Bai-urainyperiod (Jun or Jul) • Typhoon period (Sep) • Rainless period (Dec) • Box：1m×1m×0.65m • Artificial rainfall equipment：BX-1 Equipment Time • Intensity：1-2mm/min • Duration：80-100min • Outfall of reclamation area • Ditch Experiment design Position • TN, DTN, Particulate N • TP, DTP, Particulate P • TN、DIN • TP、Orthophosphate Test parameters Parameters Soil heavy metal N/P loss coefficient of land use type Calibrate coefficient Land use pattern N/P loss coefficient in reclamation scale Ecological security on landscape scale Heavy metalenrichment assessment N/P loss risk assessment Gross amount Spatial feature Environmental risk assessment

  22. Main Contents • Why did focus on coastal areas in China? • Major scientific issues in coastal areas • Main research contents and plans • Completed field works and sampling • Some preliminary achievements

  23. Completed works (salt crust)

  24. Cotton Rape Wheat Crop sampling Salt marsh Soil sampling Bare flat Suaedaglauca Spartinaalterniflora

  25. Main Contents • Why did focus on coastal areas in China? • Major scientific issues in coastal areas • Main research contents and plans • Completed works and field sampling • Some preliminary achievements

  26. 5.1 Effect of reclamation on soil salinity • Soil salinity tend to decrease rapidly and reach a stable state in the top 100cm within 30 years after reclamation. • Among land use types, lower soil salt content in forest. • High coefficients of variation (CV)of soil salinity (0-100cm) in early period before fertilizer amendment and sowing. Yan Xu, LijiePu, et al.Journal of coastal research, 2013.9

  27. Fig.4 Correlation coefficient (r) between the CR-reflectance and the corresponding soil salt content in Rudong SAVI (Soil Adjusted Salinity Index) = , where λ1 and λ2 are the average CR-reflectance in the ranges 655–764 nm and 889–903 nm, respectively. where ref908.95 and ref687.41 are the CR-reflectance at the wavelengths of 908.95 nm and 67.41 nm, respectively. Jianguo Li, LijiePu, et al. Chinese Geographical Science, 2013.9

  28. VSSC= -1.1099X+0.3052 where VSSC is the soil salt content in the vegetation-covered area; X is SAVI. Fig.5 Linear regression analysis of soil salt content and NSSRI Fig.7 Predicted soil salt content as a function of meaured soil salt content in Rudong BSSC= -0.7428X+1.9294 where BSSC is soil salt content in the coastal bare flat area and X is NSSRI. Fig.6 Linear regression analysis of soil salt content and SAVI

  29. Reclaimed after 2009, unutilized land Jianguo Li, LijiePu, et al. Chinese Geographical Science, 2013.9 Fig.8 Map of the predicted salt content of soils in Rudong

  30. 5.2 Effect of reclamation on soil physico-chemical properties Tab.1 The descriptive statistics of soil physico-chemical properties in Rudong (0-20cm) • abc: The different lower-case letters indicate significant differences at the P<0.05 level among treatments • Soil bulk density reduced. • %silt and %clay increased, %sand decreased. • The trend of soil pH showed an increment followed by a decrease. • TN, TP, and OM increased gradually over time after reclamation and also reached a stable state after about 30 years for reclamation . Jianguo Li, LijiePu, et al.Soil & tillage research (Under review)

  31. 5.3 Effect of reclamation on soil organic carbon pools • Reclaimed activities could influence the carbon cycle in the wetlands, and even impact on the global carbon budget. • Along with the strengthening of reclaimed intensity, coastal wetlands have been destroyed in recent years. How did the SOC content change in coastal wetlands over time after reclamation? Which factors (including soil physico-chemical properties and crops) could affect SOC in the process of reclamation? Jianguo Li, LijiePu, et al.Soil & tillage research (Under review)

  32. Soil organic carbon density (SOCD) and soil organic carbon storage (SOCD(storage)) were calculated by the following formula: where SOCD is the soil organic carbon density (kg C/m2); Di is the soil bulk density of soil layer i (g cm-3); Ti is the thickness of soil layer I (m); SOC(storage) is the soil organic carbon storage; and Ai is the area of the study region. abc: Different lower-case letters indicate significant differences (P<0.05), at the same depth, among treatments. Fig.2 SOC in different soil layers, among different treatments (1951, 1974, 1982, 2007 and the salt marsh) in Rudong abc: Different lower-case letters indicate significant differences (P<0.05), at the depth of 0-60 cm, among land use types. 123: Different numbers indicate significant differences (P<0.05), at the depth of 0-20 cm, among land use types. Fig.3 Effect of land uses on SOCD in Rudong • SOC tends to increase in the top 60cm over time after reclamation • SOC in the top 10cm shows a rapidest increment • SOC is lower in Rudong than that in Yangtze estuary, Pearl estuary, and Europe, North America due to less organic matter source • In Rudong, SOC in the top 60cm of cotton lands and rice lands is higher than that the aquaculture pond and the salt marsh indicating that the aquaculture pond amendment is not an effective way to increase SOC

  33. Main factors affected SOC in reclamation area in Rudong Tab.3 The PCA of soil organic carbon • Tillage practices and management (eignvalue 1=27.2%) has the biggest influence on SOC, followed by soil texture and physico-chemical properties (eignvalue2=16.28%) in Rudong. Jianguo Li, LijiePu, et al.Soil & tillage research (Under review)

  34. Land Sea The SOC sequestration in coastal reclamation area in Rudong Area (ten thousand ha) Year Fig.5 The area of coastal reclaimed lands after 1951 in Jiangsu • SOCD increases gradually as distance increases away from the sea. Furthermore, SOCD tends to increase over time after reclamation. • Mean SOCD in the top 60cm is 2.165 kg m-2 in reclamation areas in Rudong. • A total of about 1.2Tg carbon has been sequestered in the top 60cm due to reclamation since 1951. Fig.4 The spatial pattern of SOCD in Rudong Jianguo Li, LijiePu, et al.Soil & tillage research (Under review)

  35. CO2 emission 20cm Rate ? Duration ? 40cm 50cm 60cm Mechanism ?

  36. 5.4 Effect of reclamation on soil enzyme activity • Soil enzymes are relatively stable proteins possessing a powerfully catalytic function, making them biocatalysts whose activity can be used as an indicator of soil quality and biodiversity. • Five enzymes involved in nutrient and carbon cycling (Urease, Acid Phosphatase, Alkaline Phosphatase, Dehydrogenase, and Amylase) were assayed. • The effects of reclamation time and land use on soil enzyme activities(SEAs).

  37. SEAs in the top 20 cm of soil at all reclamation sites tended to increase gradually during the first 62 years after reclamation, with the exception of dehydrogenase and amylase activity. • The trend of SEA change in Rudongcontrasts with that of soil nutrients and salinity. • SEAs in the top 20 cm were lower in Rudong than that in tropical regions (e.g., India and Puerto Rico) and fresh-water wetlands. abcd: Different lower-case letters indicate significant differences among treatments at the P<0.05 level Figure 1 Variation in upper soil layer (0-20 cm) SEAs during the first 62 years after reclamation in Rudong Jianguo Li, LijiePu, et al. CLEAN – Soil, Air, Water (Under review)

  38. Reclamation of salt marsh for wheat and rape cultivation has significantly enhanced SEAs at a depth of 0-20 cm, especially in soils under the latter crop. ab: Different lower-case letters indicate significant differences among crops at the P<0.1 level Figure 2 The effect of wheat and rape on SEAs in Rudong (0-20 cm soil depth) Jianguo Li, LijiePu, et al. CLEAN – Soil, Air, Water (Under review)

  39. The activities of five enzymes gradually decrease down the soil profile from 0 to 50 cm depth, with extremely low levels observed in the bottom 10 cm. Jianguo Li, LijiePu, et al. CLEAN – Soil, Air, Water (Under review) Figure 3 Variation in SEAs in the top 50 cm of soil at the five study sites

  40. SOC, TP and TN are all significantly and positively related to SEAs in the top 20 cm, indicating that crop cultivation practices (fertilization, tillage regime, and rotation system) play an important role in promoting SEAs in Rudong. Jianguo Li, LijiePu, et al. CLEAN – Soil, Air, Water (Under review)

  41. Thank you！

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