中国农业科学 ›› 2019, Vol. 52 ›› Issue (6): 1032-1044.doi: 10.3864/j.issn.0578-1752.2019.06.007

• 土壤肥料·节水灌溉·农业生态环境 • 上一篇    下一篇

近30年海南岛土壤有机质时空变异特征及成因分析

姜赛平1,2,张认连1,张维理1,徐爱国1(),张怀志1,谢良商3,冀宏杰1   

  1. 1 中国农业科学院农业资源与农业区划研究所/农业农村部植物营养与肥料重点实验室,北京 100081
    2 北京师范大学地理科学学部,北京 100875
    3 海南省农业科学院农业环境与土壤研究所,海口571100
  • 收稿日期:2018-08-01 接受日期:2018-11-15 出版日期:2019-03-16 发布日期:2019-03-22
  • 通讯作者: 徐爱国
  • 作者简介:姜赛平,E-mail: saipingjiang@163.com。
  • 基金资助:
    科技部基础性工作专项(2012FY112100);国家重点研发计划(2017YFD0200607);国家公益性行业农业科研专项(201503121-13)

Spatial and Temporal Variation of Soil Organic Matter and Cause Analysis in Hainan Island in Resent 30 Years

JIANG SaiPing1,2,ZHANG RenLian1,ZHANG WeiLi1,XU AiGuo1(),ZHANG HuaiZhi1,XIE LiangShang3,JI HongJie1   

  1. 1 Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences/Key Laboratory of Plant Nutrition and Fertilization, Ministry of Agriculture and Rural, Beijing 100081
    2 Faculty of Geographical Science, Beijing Normal University, Beijing 100875
    3 Agricultural Environment and Soil Research Institute of Hainan Academy of Agricultural Sciences, Haikou 571100
  • Received:2018-08-01 Accepted:2018-11-15 Online:2019-03-16 Published:2019-03-22
  • Contact: AiGuo XU

摘要:

【目的】 土壤有机质(SOM)是评价土壤肥力和土壤碳库的重要指标。由于复杂的成土过程及人类活动的影响,SOM通常存在较强的时空变异性。研究SOM的时空变异特征可为农业种植结构调整、应对全球气候变化提供重要参考依据。【方法】以海南岛为研究区域,通过资料收集、野外调查、采样与分析获取全国第二次土壤普查(1980s)和2012年0—20 cm土层SOM含量数据,首先采用随机森林模型分别对两个时期训练集410个、128个样点SOM空间分布规律进行预测,并通过验证集103个、32个验证点对模型精度进行验证;采用统计学方法,结合农业统计数据,研究时隔30年海南岛不同土地利用类型SOM时空变异特征,并对驱动因素进行探讨。【结果】1980s SOM含量均值为20.57 g·kg -1,呈现出从西南向东北降低的空间分布趋势,全岛SOM含量主要集中在15—20和20—30 g·kg -1两个等级,共占全岛面积的75.29%;2012年SOM含量均值为15.89 g·kg -1,呈现出西南和东北高,西部、南部沿海低的空间分布趋势,SOM含量主要集中在10—15和15—20 g·kg -1两个等级,共占全岛面积的78.28%,而15—20和20—30 g·kg -1两个等级占全岛面积66.04%,同1980s相比减少了9.25个百分点。【结论】 (1)时隔近30年,海南岛SOM含量整体呈减少趋势。2012年SOM平均含量较1980s减少了4.68 g·kg -1,减少率为22.75%。其中水田的SOM含量减少最为明显,减少了6.42 g·kg -1,减少率为27.34%;其次为园地,减少了2.65 g·kg -1,减少率为14.25%;而旱地减少量最小,为1.28 g·kg -1,减少率为8.84%;(2)水稻连作改为稻菜轮作(水田连作改为水旱轮作)、林地开垦为园地、土地利用强度加大是造成海南岛SOM含量下降的主要原因。

关键词: 海南岛, 土壤有机质, 时空变异, 成因分析

Abstract:

【Objective】Soil organic matter (SOM) is an important index for evaluating soil fertility and soil carbon pools. SOM usually has strong spatial and temporal variability for the complicated soil forming process and human activity. Studying the temporal and spatial variability of SOM could provide an important reference for the adjustment of agricultural planting structure and response to global climate change.【Method】The contents of SOM of 0-20 cm soil layer in Hainan Island in 1980s and 2012 were collected and measured by field investigation and soil sampling. RandomForest (RF) model was used to predict spatial distribution of SOM based on the training set of 410 and 128 samples, and then the predictions were validated with validating set of 103 and 32 samples, respectively. Then the spatial and temporal variability and driving factors of different land use types in Hainan Island in resent thirty years were studied by using statistical method combined agricultural statistical data.【Result】The mean value of SOM contents in 1980s was 20.57 g·kg -1, showing a distribution that SOM contents gradually decreased from southwest to northeast parts of the island. And SOM contents were mainly in two levels of 15-20 and 20-30 g·kg -1, which occupied 75.29% area of the whole island. The mean value of SOM contents in 2012 was 15.89 g·kg -1, showing a distribution that SOM contents were higher in the southwest and northeast parts, lower in the west and south parts. And the contents of SOM were mainly in two levels of 10-15 and 15-20 g·kg -1, which occupied 78.28% area of the whole island, but the ratio of 15-20 and 20-30 g·kg -1 levels was 66.04%, which lowered 9.45 percentage points compared with 1980s. The order of SOM contents in different land use types was: paddy field > garden plot > dry land. And there was a significant difference in SOM contents among three land use types in 1980s. In 2012, there was a significant difference in SOM contents between paddy fields and dry land, dry land and garden plot, while the difference in SOM contents between paddy fields and garden plot was not significant. 【Conclusion】 After nearly 30 years, SOM contents of Hainan Island showed a decreasing trend overall. In 2012, the mean value of SOM contents decreased by 4.68 g·kg -1 compared with 1980s, with a reduction of 22.75%. The mean value of SOM contents of paddy field decreased by 6.42 g·kg -1, with a reduction of 27.34%, which was most obvious among three land use types. And the mean value of SOM contents of garden plot decreased by 2.65 g·kg -1, with a reduction of 14.25%, while the mean value of SOM contents of dry land decreased by 1.28 g·kg -1, with a reduction of 8.84%. Rice crop rotation, land reclamation and increasing multiple crop indexes were the main reasons that caused the decrease of SOM contents in Hainan Island.

Key words: Hainan Island, soil organic matter, spatial and temporal variation, cause analysis