Ecohydrological Functions Of Sympodial Bamboo Shoot Stands And Its Dynamics Of Soil Fertility

An experimental stand has been established with three superior species for shoot production, Dendrocalamus latiflorus Munro,Dendrocalamopsis oldhami Keng f.,and Dendrocalamus brandisii Kurz, on cutover of Chinese Fir, in Nanjing county, Fujian province, where the ecohydrological functions, soil fertility dynamics and productivity of sympodial bamboo ecosystem have been monitored continuously for five years. The main study contents are the eco-hydrological functions of sympodial bamboo stands, leaf litter and its decomposition, soil fertility dynamics of sympodial bamboo stand, and the sustainable management techniques of sympodial bamboo shoot stand. Results has shown that:1. The canopy rainfall interception of sympodial bamboo stand has a positive relationship with both precipitation and stand density; both the throughfall and stem flow has a positive relationship with precipitation, and a negative relationship with stand density. Sympodial bamboo stands are easer to produce stem flow than Moso bamboo stands and other kinds of forests, and the minimum precipitation for producing stem flow is 2.1mm/time. The canopy rainfall interception and its interception rate, throughfall and its rate, stem flow and its coefficient are 128.1mm(year-1, 14.51%, 689.1 mm(year-1, 78.02%, 66.0 mm(year-1 and 7.47% respectively in D. latiflorus stand with 3(4m planting space.2. The bamboo species order of the stand litter storage is D. latiflorus > D. brandisii >D. oldhami; the stand litter storage of D. latiflorus is 2.90~4.97 t(hm-2, and that of D. oldhami is only two third of the D. latiflorus'. It has a positive relationship with stand density. The litter has a potential ability to absorb water equaling to 2.7~2.9 times of its own dry weight. The bamboo species order of the maximum water storage rate is D. brandisii > D. latiflorus >D. oldhami, and but the potential ability of precipitation interception is D. latiflorus > D. brandisii >D. oldhami. 3. The mean of the soil porosity of the D. latiflorus stand with three planting spacing is 52.5~54.4%, and its potential maximum water storage is 315.3~326.3mm, which is less than that of Moso bamboo stands a little.. 4. The minimum precipitation producing soil surface runoff is 3~5mm in D. latiflorus stand. Both the soil surface runoff and sand loss have a positive linear relationship with precipitation, and a negative relationship with stand density. Its soil surface runoff, sand loss and soil erosion are 38.1mm(a-1,0.16t(hm-2(a-1和16.0t(km-2(a-1 respectively in D. latiflorus stand with 5(6m planting space, which are 1.8, 2.24, 2.24 times than that of the D. latiflorus stand with 3(4m planting space. The soil surface nutrient loss also has a relationship with some factors including stand density, precipitation, soil surface runoff, and bamboo stand growth stage, etc. Generally, the main nutrient elements loss has a negative relationship with stand density. The loss of the main nutrients, such as NO3-, NH4+, PO43- and K+, in D. latiflorus stand with 3(4m planting space are 0.107 kg(hm-2(a-1, 0.202 kg(hm-2(a-1, 0.057 kg(hm-2(a-1, 1.781 kg(hm-2(a-1 respectively.5. Both the soil surface runoff (R) and the sand loss (S) have a positive relationship with throughfall (Pt) of D. latiflorus stand and the rain interval (T), but a negative relationship with the canopy rainfall interception (Pi) and stem flow (Ps).6. There are similarly occurrence rule of leaf litter in sympodial bamboo stands with different species. The leaf litter fall during whole year with two peaks in June and in March-April respectively and one low valley in November-December. But the difference between the first peak and low valley is not obvious as that in Moso bamboo stand. The bamboo species order of the leaf litter occurrence is D. latiflorus > D. brandisii >D. oldhami. The leaf-litter amount of D. latiflorus stand, D. brandisii and D. oldhami, with 3(4m planting space, are 3.96 t(hm-2(a-1, 3.56 t(hm-2(a-1, and 2.85 t(hm-2(a-1 respectively. If mother culm amount is added each clump, their leaf li...