川南毛竹林土壤肥力研究

Soil fertility in a Phyllostachys pubescens forest of southern Sichuan

从土壤剖面特征、土壤水分物理性质、土壤氮磷钾养分和土壤酸化状况等方面分析了川南毛竹Phyllostachyspubescens林土壤的肥力状况和存在的主要问题。结果显示:毛竹林根系活动层(60 cm)土壤结构较好,土壤水源涵养功能的大小和土壤的有机质质量分数随毛竹林成林时间和海拔高度的增加而增加;但土壤黄化、酸化特征较明显,土壤酸性调节主要以施用石灰为主,其中谷底毛竹林改造需石灰量为10.625 t.hm-2,坡面的里白毛竹林为14.811 t.hm-2,岗地毛竹林需石灰量为12.558 t.hm-2;在氮磷钾3种元素中,氮素供应总体上良好,但要获得高产,氮肥的补充也是必需的。毛竹林土壤的钾素供应位于缺乏和很缺乏范围,而土壤中的磷极度缺乏,因此,目前川南毛竹林地磷和钾肥施用是提高毛竹林产量最重要也是最迫切的技术措施。

Growing altitude and bamboo growth history were used to analyze the status and the evolution of soil fertility according to four aspects, namely 1） water-holding capacity, 2） soil acidification in four Phyllostachys pubescens bamboo stands （on a valley bottom, middle slope, upside slope and a valley top） of southern Sichuan, and nutrient status, and profile characteristics of soil. Results showed that 1） soil structure in the rhizosphere was very high; water-holding capacity and organism count in the soil increased with altitude and duration of bamboo growth. However, soil etiolation and soil acidification was obvious. 2） Soil acidity was adjusted with lime; best applications were 10.625t·hm^-2 on the valley bottom, 14.811 t·hm^-2 for the middle slope, and 12.558 t·hm^-2 on the valley top. 3） In all the soils, N for attaining high yield was insufficient; K was insufficient or very insufficient; and P was extremely insufficient. Therefore, at present, N and P fertilization is the best way to increase yield of Phyllostachys pubescens bamboo stands in southern Sichuan.