1 材料与方法
1.1 材料
图1 试验期间试验区域月降雨量、最大风速、月平均、最大和最低气温历史气象数据来源于中国气象数据网(http://data.cma.cn)儋州站(59845)。 Fig. 1 Monthly precipitation, maximum (max.) wind speed, monthly mean, maximum and minimum (min.) air temperature over the study period. Historical weather data are provided by the website (http://data.cma.cn) at Danzhou City station (59845). |
1.2 方法
表1 橡胶林样地土壤理化性质Tab. 1 Soil physical-chemical properties of experiment sites at different rubber plantation ages |
| 树龄 Plantation age | pH | 有机质 Organic matter/(g•kg-1) | 全氮 Total N/(g•kg-1) | 有效磷 Available P/(mg•kg-1) | 速效钾 Available K/(mg•kg-1) |
|---|---|---|---|---|---|
| 幼龄 | 4.42 | 12.36 | 0.65 | 13.67 | 45.39 |
| 成龄 | 4.94 | 14.18 | 0.71 | 11.43 | 49.80 |
1.3 数据处理
2 结果与分析
2.1 橡胶落叶产量动态
图2 不同树龄橡胶林落叶产量月动态变化*表示同一月份2种树龄处理间差异显著(P<0.05),**表示处理间差异极显著(P<0.01)。 Fig. 2 Monthly dynamic changes of leaf litter production at different rubber plantations ages * indicates significant difference (P<0.05), ** indicates extremely significant difference among treatments (P<0.01) between two rubber plantation ages at the same month. |
2.2 橡胶落叶养分含量动态
图3 不同树龄橡胶林落叶养分含量月动态变化*表示同一月份2种树龄处理间差异显著(P<0.05),**表示处理间差异极显著(P<0.01)。 Fig. 3 Monthly dynamic changes of nutrient content of leaf litter at different rubber plantations ages * indicates significant difference (P<0.05), ** indicates extremely significant difference among treatments (P<0.01) between two rubber plantation ages at the same month. |
2.3 橡胶落叶C、N、P化学计量比动态
图4 不同树龄橡胶林落叶碳氮磷化学计量比动态变化*表示同一月份2种树龄处理间差异显著(P<0.05),**表示处理间差异极显著(P<0.01)。 Fig. 4 Monthly dynamic changes of ecological stoichiometry of C, N, and P of leaf litter at different rubber plantations ages * indicates significant difference (P<0.05), ** indicates extremely significant difference among treatments (P<0.01) between two rubber plantation ages at the same month. |
2.4 橡胶落叶养分归还动态
图5 不同树龄橡胶林落叶养分归还动态变化*表示同一月份2种树龄处理间差异显著(P<0.05),**表示处理间差异极显著(P<0.01)。 Fig. 5 Monthly dynamic changes of nutrient return of leaf litter at different rubber plantations ages * indicates significant difference (P<0.05), ** indicates extremely significant difference among treatments (P<0.01) between two rubber plantation ages at the same month. |
2.5 橡胶落叶养分利用效率
表2 不同树龄橡胶林落叶养分利用效率Tab. 2 Nutrient use efficiency of litterfall in different rubber plantation ages |
| 树龄 Plantation age | C | N | P | K | Ca | Mg |
|---|---|---|---|---|---|---|
| 幼龄 | 2.30±0.06a | 52.50±2.18a | 625.42±36.60a | 108.62±4.00a | 100.25±6.43a | 522.67±28.06a |
| 成龄 | 2.27±0.07a | 51.43±1.40a | 614.95±29.48a | 97.63±5.23b | 99.70±6.14a | 509.52±23.14a |
注:同列不同小写字母表示不同水分间差异显著(P<0.05)。 | |
Note: Different lowercase letters in the same row indicate significant difference among different rubber plantation ages (P<0.05). |
2.6 橡胶林落叶产量与气候因子之间的关系
图6 橡胶林月落叶产量与气候因子的冗余分析实线为气候因子,虚线向量为落叶量; **表示处理间差异显著(P<0.01);Rel.H:空气相对湿度;Precip.:降雨量;T:月平均温度;Min.T:月平均最低温度;Max.T:月平均最高温度;Max.W:月最大风速;Young:幼龄林叶凋落物量;Mature:成龄林叶凋落物量。 Fig. 6 Redundancy analysis (RDA) calculated from monthly leaf litter production (bold line vectors) in rubber plantations and climatic factors (dash line vectors) over one year The solid line is the climate factor, and the dotted line vector is the amount of fallen leaves; ** indicates significant difference among treatments (P<0.01); Rel.H: Relative humidity; Precip.: Precipitation; T: Mean temperature; Min.T: Mean minimum temperature; Max.T: Mean maximum temperature; Max.W: Maximum wind; Young: Monthly leaf litter production of young rubber plantation; Mature: Monthly leaf litter production of mature rubber plantation. |
