福建南亚热带草果植被相互作用及其演替规律

牧草＋香蕉＋龙眼组合植被演替规律的试验结果表明，４ａ内，草、果植被地上生物量保持相对稳定的产草量，其中以混播草地套种果树处理的平均干草产量最高，达１２２０５ｋｇｈｍ－２，香蕉产量９６８７．６ｋｇｈｍ－２．牧草对香蕉生长指标的影响不显著（Ｐ＞０．０５），对龙眼生长有一定的促进作用．采用新技术宽窄行种植的香蕉所形成的遮荫，对牧草生长的影响不大．龙眼的生长对牧草的影响也不明显．应用此模式开发南亚热带低山丘陵，具有明显的生态和经济效益．每公顷年平均可获产值１８９４８．１２元（龙眼投产后效益将逐年递增）．并能提高土壤含水量８．８％－２０．１％（秋末），增加土壤有机质６．８６％，夏、秋季降低地表温度１１．３－１９．６℃．５ａ后，龙眼持续生长，树冠逐年扩大，对牧草的生长将产生不利影响，这是植被演变的总趋势，但逐年的演替情况，有待进一步研究

Interaction and Rotation of the Plant Covers of Grass and Fruit Trees in South Subtropical Area in Fujian

The test results of the rotation of combining plant covers consisting of longan, banana and forage grass showed as follows. In the past four years the biomass of grass and fruit plant covers above ground still hept relatively stable. In particular the average hay yield reached at the peak of 12 205 kg·hm -2 and banana yield at 9 687.6 kg·hm -2 in the treatment that fruit trees were interplanted on mixture sowing grass land. There was no evident effect ( P >0.05) of forage grass on the growth index of banana but forage grass could promote the growth of longan. On the growth of forage grass there was no much effect of the shade formed by banana interplanted in different row spacings and of the gorwth of longan. With this pattern there is favourable ecological and economical effectiveness of developing the low hills in south subtropical area. The average annual production value per hectare was 18 948.12 yuan. The effectiveness of the production of longan would increase year by year. Furthermore the water content of soil increased by between 8.8% and 20.1% at the ends of autumns, the soil organic matter also increased by 6.86% and the ground temperature decreased by between 11.3 ℃ and 19.6 ℃ in the summers and autumns. Five years later, longan had been growing more and more vigorously, the crown had been extending and the growth of forage grass was inhibited. That was general trend of the rotation of plant covers. However the details year by year need further studies.