通过对湘北第四纪红土红壤地区四川桤木、台湾桤木和荒地样地枯落物持水能力、土壤水分物理性质、土壤渗透性研究，探讨了桤木人工林土壤水文特征。结果表明，四川桤木枯落物累积量最多，且最大持水量达到24.76 t•hm-2，是台湾桤木的1.22倍，但荒地的枯落物的吸水性能较好；土壤总孔隙度和非毛管孔隙度全是台湾桤木>四川桤木>荒地。毛管空隙和毛管持水量都是是荒地最大，分别是28.80%，58.41mm，土壤最大持水量是台湾桤木最大24.55mm，荒地最小197.74mm；0-45cm层土壤渗透参数是台湾桤木>四川桤木>荒地，四川桤木和台湾桤木的K10是荒地的1.04和1.19倍， 土壤渗透速度与渗透时间呈乘幂函数关系。说明桤木人工林能够改善该地区的土壤结构，具有良好的土壤水文特征。

专业名词
第四纪红土红壤：the red developed from quaternary red clay
四川桤木Alnus cremastogyne Burli
台湾桤木Alnus formosana
枯落物litter
渗透 water infiltration
土壤水文Soil Hydrological
土壤水分物理性质Soil water physical characteristics
枯落物累积量 litter storage
土壤总孔隙度soil total porosity percent
毛管孔隙度capillary pore percent
非毛管孔隙度non-capillary pore percent
最大持水量maximum moisture content
毛管持水量capillary moisture conten
乘幂 Power

Come through the research of the Alnus cremastogyne burli & Alnus formosana which grow in the red developed form quaternary red clay and the waster simple land litter water keeping ability, Soil water physical characteristics & Soil water infiltration in north Hunan area, the soil hydrological of manmade alnus forest is studied.

The result shows that ,the Alnus cremastogyne burli litter accumulation is very much ,and the maximum moisture content is 24.76t.hm-2,which is 1.22 times of the Alnus formosana.But the wasteland litter absorbent ability is better, the Alnus formosana > Alunus cremastogyne burli in both the capillary pore percent and capillary pore percent .Wasteland is the highest in capillary pore percent and capillary moisture content, the numeral is 28.80%,58.41mm,the soil maximum moisture content is the Alnus formosana 24.55mm,the wasteland is the lowest with the minimum 197.74mm; The 0-45cm layer soil water infiltration parameter is Alnus formosana > Alnus cremastogyne burli>wasteland. The K10 numeral of Alnus formosana & Alnus cremastogyne burli are 1.04 & 1.19 times of the wasteland. The soil water infiltration speed are power of the infiltration time.

It shows that the manmade alnus forest could improve the soil structure ,to make the soil keep a very good soil hydrological characteristics.

是按原文翻译的，但是我觉得原文有几处不恰当
文中说了四川桤木，台湾桤木与荒地，这三种的对比，而实际上对比的是四川桤木人工林，台湾桤木人工林及荒地，这三种土壤的保水性的不同，所以在文中所有的桤木后面应该加上人工林地或是人工林几个字。

还有最后一句，应该是桤木人工林区具有良好的土壤特征，而原文的主语是人工林有土壤水文特征

一点见解，请参考

下面是按我的改正来翻译的，并调整了一下开头的语序，更加流畅了。
Come through the research of Litter water keeping ability, Soil water physical characteristics & Soil water infiltration, between the Alnus cremastogyne burli forestland , Alnus formosana forestland andWasteland of the red developed form quaternary red clay area in north Hunan area, the soil hydrological of manmade alnus forest is studied.

The result shows that ,the Alnus cremastogyne burli forestland litter accumulation is very much ,and the maximum moisture content is 24.76t.hm-2,which is 1.22 times of the Alnus formosana forestland .But the wasteland litter absorbent ability is better, the Alnus formosana forestland > Alunus cremastogyne burli forestland in both the capillary pore percent and capillary pore percent .Wasteland is the highest in capillary pore percent and capillary moisture content, the numeral is 28.80%,58.41mm,the soil maximum moisture content is the Alnus formosana forestland 24.55mm,the wasteland is the lowest with the minimum 197.74mm; The 0-45cm layer soil water infiltration parameter is Alnus formosana forestland > Alnus cremastogyne burli forestland >wasteland. The K10 numeral of Alnus formosana forestland & Alnus cremastogyne burli forestland are 1.04 & 1.19 times of the wasteland. The soil water infiltration speed are power of the infiltration time.

It shows that the manmade alnus forest could improve the soil structure ,to make the soil keep a very good soil hydrological characteristics.