【作者】 杨洁；

【导师】 郭晓敏； 杜天真；

【作者基本信息】 江西农业大学 ， 森林培育， 2011， 博士

【摘要】 果业在江西是仅次于水稻和蔬菜的第三大产业,在江西经济中占有重要地位,尤其是柑橘类产业在全国总种植面积排名第二,是江西果业的支柱。柑橘园林生态系统是区域生态系统的重要组成部分,针对江西柑橘果业开发中存在的严重水土流失问题和柑橘园水文特征,以椪柑(Citrus reticulata Blanco cv. Ponkan)为研究对象,通过在江西省水土保持生态科技园的15个标准径流小区和宁都县东坑、城源两个小流域脐橙园内,对林外降雨、林内降雨、树干茎流、枯落物截流、地表径流以及土壤含水量的动态变化的长期观测,研究椪柑林生态系统的水分分配、运输以及动态变化等,掌握水分循环的过程及规律,探讨红壤坡地柑橘园林水土保持措施对水文过程及其效益的影响。研究内容包括降雨特征分析、冠层截留、土壤水分动态特征、坡面产流产沙特征以及入渗和产流的模型模拟。主要研究成果如下：1.研究区内降雨量、降雨强度的年内、年际变化根据研究区2001-2010年降雨观测资料的分析表明：研究区域雨水资源丰富,多年平均降雨1317mm,平均雨强为1.68mm/h,2001-2010年间共降雨1508场次。全年降雨量的70.9%集中在3-8月份,其余7个月的降雨量只占全年降雨量的29.4%。全年降雨呈双峰型曲线,一年中最大降雨出现在4月份,5、6、7月逐渐回落,而8月份出现又一峰值,多年平均降雨量最小值在12月。通过采用Mann-Kendall趋势分析法,对2001-2010年10年来降雨量特征的分析,得出年际降雨量特征存在时间段上波动,基本保持稳定状态；春季、秋季和冬季表现出不显著下降趋势,只有夏季表现出不显著上升趋势；汛期保持平稳趋势,主汛期和非汛期分别呈现不显著下降和上升趋势。2.椪柑林地冠层截留和枯落物特性椪柑林冠截留率平均为29.61%,茎流率为25.67%,而穿透雨比例占44.72%,也就是说70.39%的降水将进行第二次分配。单株林冠截留量与林外降雨量的关系表现为林外降雨量增大,林冠截留的降雨也随着增大,二者呈现显著线性相关。当降雨量低于20mmm时,二者相关性更强；当降雨量超过20mmm后,二者的相关性较差。说明林冠的截留能力存在一个最大值,即容许最大截留量,或林冠截留容量。茎流量与林外降雨量关系密切,林外降雨量越大,茎流量也越大,二者呈显著的线性相关关系。43场降雨的茎流量观测数据平均为4.72mm,占到林外降水量的25.67%。试验显示碰柑枯落物的最大持水率为325.73%,为枯落物自身干重的3.26倍。3.不同水保措施下椪柑林地土壤水分分布、特征与变化由于地表径流和壤中流的作用,全年土壤平均含水量随着深度的增加基本呈增加的趋势,0-10cm土层土壤含水量在11%-29%之间,10-20cm土层土壤含水量在12%-31%之间,20-30cm土层土壤含水量在14%-32%之间,30-40cm土层土壤含水量在18%-38%之间。通过对各处理措施小区的比较,在10cm土层,狗牙根(Cynodon dactylon (L.) Pars.)带状覆盖的平均土壤含水量最高,20cm和30cm土层,百喜草(Paspalum riatatu)带状覆盖含水量最高,40cm土层百喜草全园覆盖的含水量最高。坡地椪柑林地生草种植能够有效拦截径流,蓄积水分,使降雨和地表径流蓄积在坡面上,而不是顺坡流失,条带植草覆盖因其耗水量小所以保水效果最好。多年未翻耕的裸露小区,平均土壤含水量保持在较高水平,表明地表结皮可降低蒸发保持土壤水分。各处理小区土壤水分随季节的变化有着较为一致的变化趋势。在10cm土层,整体看来,各小区的土壤含水量一年内随季节变化的特征都有三峰两谷。第一次峰值出现在春季4月,6月份的土壤水分含量最大,达到第二个峰值。8月份土壤含水量全年最低,呈现土壤水分的第一个低谷,到10月份,土壤含水量回升,达到第三个峰值,12月份土壤含水量较低,呈现土壤水分的第二个低谷。在20cm土层、30cm土层和40cm土层,土壤含水量随季节的变化与10cm土层有着相似的变化趋势。水保措施对土壤水分的保持具有重要作用,植被覆盖度越高,土壤水分含量的变化越小4.不同处理下红壤坡地椪柑林地产流产沙特征降雨是地表径流的主要来源,2001-2010年从试验观测数据中选取了59场独立的单场降雨,进行了回归分析,径流量随雨量、雨强、历时增大而增大,与雨量相关性最高,与雨强的相关性次之,与降雨历时的相关性最差。这说明降雨量显著影响径流量；而雨强对径流量的影响程度不如降雨量对径流量的影响程度显著。统计分析2001-2010年降雨产流观测数据,结果表明水土保持措施均能显著提高坡地果园的减流效益。红壤坡地泥沙量与降雨量、30min.降雨强度、降雨动能呈显著线性相关,但泥沙量与降雨量的相关性普遍小于径流量与降雨量的相关性；大暴雨和特大暴雨是红壤坡地椪柑林地产生土壤流失的主要降雨类型。此外,泥沙量与降雨径流量显著相关,且相关性较泥沙量与降雨量、30min.降雨强度、降雨动能和前期降雨量更为密切。5.不同处理椪柑园地侵蚀性降雨及降雨侵蚀力特征不同处理椪柑园地侵蚀性降雨标准差异很大,侵蚀性降雨标准从小到大的顺序为清耕果园9.8mm、耕作组10.37mm、梯田组11.34mm、林草措施组14.69mm。降雨侵蚀力与降雨量的年际变化基本一致,即降雨量大的年份降雨侵蚀力值也大,而降雨量小的年份降雨侵蚀力也小。6.不同处理径流泥沙年际变化特征通过对各试验小区的年际径流泥沙特征变化分析得出：各小区的径流泥沙随着时间的延长,呈现出不同程度的减少趋势。通过在椪柑园实施水土保持植物、耕作和工程措施,可以起到了很好的蓄水保土效应,对于增加椪柑产量,改善当地的生态环境具有明显的促进作用。更多还原

【Abstract】 Citrus reticulata Blanco cv. Ponkan is an important economic fruit tree in Jiangxi Province. Study of the ecosystem effects on hydrological processes of Citrus reticulata Blanco cv. Ponkan is an important part of exploring hydrological processes of regional forest ecosystem. Standard runoff plots are set in the Jiangxi Provincial Soil and Water Conservation Eco-science Park. Through years of observation, testing and experiments, effects of soil and water conservation and hydrological on citrus forest in red soil slope are studied. This research explores the hydrological effects mechanism of the different artificial building models on citrus forest and concludes the means of planting citrus forest to protect water and soil resources which can provide a scientific reference for citrus fruit industry and sustainable development of ecological environment construction. The study includes analysis of rainfall characteristics, canopy interception, soil moisture dynamics, runoff and sediment characteristics of slope, infiltration and runoff model for simulation. The main results are as follows:1. During the year and annual change of rainfall and rainfall intensity in the study areaAccording to the rainfall observation data of study area from 2001 to 2010 shows that the water resource is rich, average rainfall is 1317 mm, the average rainfall intensity is 1.68mm h-1. The total rainfall is 1508 matches from 2001 to 2010.70.9% of annual rainfall concentrated from March to August, the remaining 6 months of rainfall accounted for only 29.4% of annual rainfall. The trend of rainfall is bimodal curve one year, and the highest rainfall is in April, May, June, July gradually fell, and another peak occurred in August, the minimum annual average rainfall is in December. By using Mann-Kendall trend analysis method, rainfall characteristics of interannual rainfall fluctuations remain stable from 2001 to 2010. The difference not decrease significant in spring, autumn and winter, but increase significant in summer. In flood days it shows steady trend, and it shows no significant change in the main flood season and dry season.2. Citrus forest canopy interception and litter characteristicsInterception average rate of citrus canopy is 29.61%, and stem flow rate is 25.67%, and the proportion of through rain is 44.72%. It is that 70.39% of the precipitation will be the second allocation. The relationship between plant outside the forest canopy interception showed significant correlation. But the correlation is strong when rainfall is less than 20mm and poor when rainfall exceeds 20mm. It proves that there is a maximum canopy interception capacity, allowing the maximum interception or canopy interception capacity. The correlation of stem flow and gross rainfall is close in rainfall outside. There are a significant linear relationship between rainfall outside of forest and stem flow. The average stem flow is 4.72mm in 43 rainfall observations, accounting for 25.67% of precipitation outside the forest. Test shows that the largest citrus litter water-holding rate is 325.73%, and is 3.26 times of their litter dry weight.3. Soil moisture characteristics and changes of citrus under different soil and water conservation measuresThe average soil moisture increases with soil depth increasing because surface runoff and subsurface flow effect. The soil moisture increases from 11% to 29% in 0-10cm, from 12% to 31% in 10-20cm, from 14% to 32% in 20-30cm, and from 18% to 38% in 30-40cm. The soil moisture of 6 Cynodon dactylon (L.)Pars. plot(bermudagrass cover band) is highest in 10cm, and of 4 Paspalum natatu plot (bare check) in 20cm and 30cm is highest. In 40cm layer 4 plot (bare check) is the highest and 1 plot (the whole park bahia grass cover) is highest in plots which set measures. Planting grass in citrus forest can effectively intercept-runoff,accumulate,rainfall and surface runoff to accumulate on the slope, not down slope loss. Their water consumption is small in grass cover bands so the water conservation is the best.The seasonal change of soil moisture has a consistent trend. In the 10cm soil layer, the characteristics of soil moisture changes are two valleys and three peaks. The first peak appears in April, and the soil moisture content is maximum in June, reaching a second peak. The soil moisture is lowest in August, and shows the first valley. In October, soil moisture is highest, and third peak. In December, soil water content decreases, shows a second valley. Soil moisture changes in 20cm,30cm and 40cm with the seasons has a similar trend to the 10cm soil layer. Soil and water conservation measures to play an important role in maintaining soil moisture, the higher the vegetation coverage, the smaller the change of soil moisture content.4. Runoff and sediment characteristics of citrus in red soil slope under different soil and water conservation measuresRainfall is the main source of surface runoff.59 separate single rainfall data are selected from the experimental observations from 2001 to 2010, and carried out regression analysis. Runoff increases along with rainfall, rainfall intensity increasing, and the highest correlation with the rainfall is highest, and next is rainfall intensity, and rainfall duration is worst. This shows that rainfall influence runoff significantly.Statistical analysis of rainfall runoff observation data from 2001 to 2010 shows that the soil and water conservation measures can significantly improve effects of runoff reduction. Red soil sediment and rainfall,30min rainfall intensity, rainfall kinetic energy have a significant linear correlation, but the amount of sediment associated with rainfall is generally less than the correlation of runoff and rainfall. Sediment volume with the impact of previous rainfall is more correlative with the previous rainfall, but less than its impact of rainfall. Heavy rain and torrential rain are the major rainfall types which cause soil erosion in citrus of red soil slope. In addition, the amount of sediment and rainfall, runoff are significantly correlated which are more close than the relationship with rainfall, 30min. rainfall intensity, rainfall kinetic energy and the pre-rainfall.5. Characteristics of erosive rainfall and rainfall erosivity under different treatments in citrus forestThe standards variability of erosive rainfall is widely under different treatment in citrus forest. The order of erosive rainfall standard is clean tillage orchard, for 9.8mm, farming groups, for 10.37mm, terraced group, for 11.34mm, and grass measures group, for 14.69mm. The changes of rainfall erosivity and rainfall inter-annual are consistent. 6 Annual variations of runoff and sediment under different treatmentThe characteristics of the inter-annual runoff and sediment show that the runoff and sediment are decreasing trend with time. The soil and water conservation can play a very good role in water and soil conservation effect by plants in the citrus orchards, farming and engineering measures, which can also increase citrus production and improve the local ecological environment.更多还原