坡度和埋深对橡胶林凋落叶分解及红外光谱特征的影响
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摘要
橡胶树凋落叶在橡胶林生态系统养分循环中起着重要的作用,研究凋落叶的分解和养分释放特性及其影响因素,对资源的循环利用及指导高效施肥具有重要意义。在海南省天然橡胶主产区选取橡胶林地进行凋落叶原位分解试验,研究坡度和埋深对橡胶树凋落叶干物质分解特性、养分元素释放规律及其物质成分红外光谱特征的影响。结果表明,凋落叶分解速率明显受到坡度和深度的影响;分解9个月后,干物质残留率高低顺序为坡地覆盖(39.6%)>平地覆盖(26.8%)>平地埋深(11.2%)>坡地埋深(6.9%);凋落叶的损失符合Olsen指数衰减模型(P<0.01),各处理凋落叶干物质分解95%所需要的时间分别为29.3、20.5、12.8和13.2个月;各处理C/N比从最初的25.1下降到12.7、14.4、16.2和16.9。分解期间各处理养分残留率差异显著(P<0.05);分解9个月后,坡地覆盖处理S-I养分元素C、N、P、K、Ca、Mg的残留率最高,分别为10.9%、21.6%、10.7%、9.7%、10.4%、7.9%,而坡地埋深处理S-II最低,分别为3.8%、6.5%、3.4%、2.3%、0.8%、2.1%。傅里叶红外光谱(FTIR)分析显示,凋落叶分解前后在3387 cm~(-1)、1734 cm~(-1)处的吸收峰强度明显减弱,表明纤维素、半纤维素、木质素、多糖、脂肪族等碳水化合物遭到分解;1050 cm~(-1)处的吸收峰向低频方向位移了17 cm后变为1033 cm~(-1),表明分解破坏了凋落叶原有的可溶性糖和纤维素C—C键和C—O键伸缩振动。综上所述,埋深处理有利于加速凋落叶物质分解和养分元素释放速率;建议橡胶树生产中将凋落叶与表土混合或压青处理,提高橡胶林养分循环效率。
Leaf litter plays an important role in nutrient recycling in rubber ecological systems. Studying the decomposition characteristics of dry matter and nutrient release and their effects has important significance for resource utilization and the management of high efficiency fertilization. A decomposing-bag experiment was conducted in a rubber forest at the main production areas of natural rubber trees in Hainan Province,China. The objectives were to study the effects of slope and depth on the characteristics of dry matter decomposition, nutrient release, and FTIR( fourier transform infrared spectroscopy) of leaf litter. The results showed that the decomposition rates were significantly affected by varying degrees of slope and depth. The dry matter remaining rates between different treatments were in the following order: covered slopes( 39.6%) > covered flatland( 26.8%) > buried flatland( 11.2%) > buried slopes( 6.9%). Leaf litter loss agreed with an Olsen exponential attenuation model( P<0.01). The time required for 95% leaf litter decomposition was 29.3,20.5,12.8,and 13.2 months,and the C/N ratios decreased from the initial 25.1 to 12.7,14.4,16.2,and 16.9 after 9 months,for the above treatments,respectively. The nutrient remaining rates were significantly different( P < 0. 05) among different treatments during the decomposition stage. After 9 months,the nutrient remaining rate for C,N,P,K,Ca,and Mg on the covered slope was higher than that in other treatments,at 10. 9%,21. 6%,10. 7%,9. 7%,10. 4%,and 7. 9%,respectively; but that in the buried slopes was lower than that in the other treatments,at 3.8%,6.5%,3.4%,2.3%,0.8%and 2.1%,respectively. Analysis of the FTIR spectroscopy characteristics of leaf litter showed the absorption peak strength at waves of 3387 cm~(-1) and 1734 cm~(-1),which obviously became weak after 9 months of decomposition,thus proving the decomposition and transformation of carbohydrates,i. e. cellulose,hemicellulose,lignin,polysaccharide,and fatty acid group compounds. The absorption peak at 1050 cm~(-1) shifted to 17 cm at low frequency and then changed to 1033 cm~(-1),suggesting that decomposition destroyed the original soluble sugar and cellulose C—C and C—O bond stretching vibration.In conclusion,buried leaf litter could contribute to mass loss and nutrient release. Therefore,we suggest that the litter of rubber forests should be mixed with soil or buried in green manuring pits to improve the recycling efficiency of rubber plantation systems.
Leaf litter plays an important role in nutrient recycling in rubber ecological systems. Studying the decomposition characteristics of dry matter and nutrient release and their effects has important significance for resource utilization and the management of high efficiency fertilization. A decomposing-bag experiment was conducted in a rubber forest at the main production areas of natural rubber trees in Hainan Province,China. The objectives were to study the effects of slope and depth on the characteristics of dry matter decomposition, nutrient release, and FTIR( fourier transform infrared spectroscopy) of leaf litter. The results showed that the decomposition rates were significantly affected by varying degrees of slope and depth. The dry matter remaining rates between different treatments were in the following order: covered slopes( 39.6%) > covered flatland( 26.8%) > buried flatland( 11.2%) > buried slopes( 6.9%). Leaf litter loss agreed with an Olsen exponential attenuation model( P<0.01). The time required for 95% leaf litter decomposition was 29.3,20.5,12.8,and 13.2 months,and the C/N ratios decreased from the initial 25.1 to 12.7,14.4,16.2,and 16.9 after 9 months,for the above treatments,respectively. The nutrient remaining rates were significantly different( P < 0. 05) among different treatments during the decomposition stage. After 9 months,the nutrient remaining rate for C,N,P,K,Ca,and Mg on the covered slope was higher than that in other treatments,at 10. 9%,21. 6%,10. 7%,9. 7%,10. 4%,and 7. 9%,respectively; but that in the buried slopes was lower than that in the other treatments,at 3.8%,6.5%,3.4%,2.3%,0.8%and 2.1%,respectively. Analysis of the FTIR spectroscopy characteristics of leaf litter showed the absorption peak strength at waves of 3387 cm~(-1) and 1734 cm~(-1),which obviously became weak after 9 months of decomposition,thus proving the decomposition and transformation of carbohydrates,i. e. cellulose,hemicellulose,lignin,polysaccharide,and fatty acid group compounds. The absorption peak at 1050 cm~(-1) shifted to 17 cm at low frequency and then changed to 1033 cm~(-1),suggesting that decomposition destroyed the original soluble sugar and cellulose C—C and C—O bond stretching vibration.In conclusion,buried leaf litter could contribute to mass loss and nutrient release. Therefore,we suggest that the litter of rubber forests should be mixed with soil or buried in green manuring pits to improve the recycling efficiency of rubber plantation systems.
引文
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[13]金龙,吴志祥,杨川,管利民,赖华英.不同林龄橡胶凋落物叶分解特性与有机碳动态研究.热带作物学报,2015,36(4):698-705.
[14]陈晓丽,王根绪,杨燕,杨阳.山地森林表层土壤酶活性对短期增温及凋落物分解的响应.生态学报,2015,35(21):7071-7079.
[15]吕瑞恒,李国雷,刘勇,贾黎明,江萍,林娜.不同立地条件下华北落叶松叶凋落物的分解特性.林业科学,2012,48(2):31-37.
[16]王春阳,周建斌,夏志敏,刘瑞.黄土高原区不同植物凋落物搭配对土壤微生物量碳、氮的影响.生态学报,2011,31(8):2139-2147.
[17]何洁,杨万勤,倪祥银,李晗,徐李亚,吴福忠.雪被斑块对川西亚高山森林凋落物冬季分解过程中钾和钠动态的影响.植物生态学报,2014,38(6):550-561.
[18]王文全,赵秀玲,罗艳丽,施宠,马荷,余雄,贾宏涛.牛粪发酵过程中的红外光谱分析.中国牛业科学,2011,37(2):15-19.
[2]张鹏.亚热带森林土壤分解酶活性的季节变化及凋落物分解的研究[D].南京:南京大学,2007.
[3]曹建华,蒋菊生,赵春梅,陈俊明.橡胶林生态系统养分循环研究进展.热带农业科学,2007,27(3):48-56.
[4]李海涛,于贵瑞,李家永,陈永瑞,梁涛.亚热带红壤丘陵区四种人工林凋落物分解动态及养分释放.生态学报,2007,27(3):898-908.
[5]王景,魏俊岭,章力干,常江,郜红建.厌氧和好气条件下油菜秸秆腐解的红外光谱特征研究.中国生态农业学报,2015,23(7):892-899.
[6]Koarashi J,Atarashi-Andoh M,Takeuchi E,Nishimura S.Topographic heterogeneity effect on the accumulation of Fukushima-derived radiocesium on forest floor driven by biologically mediated processes.Scientific Reports,2014,4:6853.
[7]赵春梅,曹建华,李晓波,兰国玉,彭宗波,蒋菊生.橡胶林枯落物分解及其氮素释放规律研究.热带作物学报,2012,33(9):1535-1539.
[8]曹莹菲,张红,赵聪,刘克,吕家珑.秸秆腐解过程中结构的变化特征.农业环境科学学报,2016,35(5):976-984.
[9]Soong J L,Calderón F J,Betzen J,Cotrufo M F.Quantification and FTIR characterization of dissolved organic carbon and total dissolved nitrogen leached from litter:a comparison of methods across litter types.Plant and Soil,2014,385(1/2):125-137.
[10]文海燕,傅华,郭丁.黄土高原典型草原优势植物凋落物分解及养分释放对氮添加的响应.生态学报,2017,37(6):2014-2022.
[11]鲍士旦.土壤农化分析(第三版).北京:中国农业出版社,2005.
[12]马祥庆,刘爱琴,何智英,俞立煊.杉木幼林生态系统凋落物及其分解作用研究.植物生态学报,1997,21(6):564-570.
[13]金龙,吴志祥,杨川,管利民,赖华英.不同林龄橡胶凋落物叶分解特性与有机碳动态研究.热带作物学报,2015,36(4):698-705.
[14]陈晓丽,王根绪,杨燕,杨阳.山地森林表层土壤酶活性对短期增温及凋落物分解的响应.生态学报,2015,35(21):7071-7079.
[15]吕瑞恒,李国雷,刘勇,贾黎明,江萍,林娜.不同立地条件下华北落叶松叶凋落物的分解特性.林业科学,2012,48(2):31-37.
[16]王春阳,周建斌,夏志敏,刘瑞.黄土高原区不同植物凋落物搭配对土壤微生物量碳、氮的影响.生态学报,2011,31(8):2139-2147.
[17]何洁,杨万勤,倪祥银,李晗,徐李亚,吴福忠.雪被斑块对川西亚高山森林凋落物冬季分解过程中钾和钠动态的影响.植物生态学报,2014,38(6):550-561.
[18]王文全,赵秀玲,罗艳丽,施宠,马荷,余雄,贾宏涛.牛粪发酵过程中的红外光谱分析.中国牛业科学,2011,37(2):15-19.