Study On Water Conservation Function Of Four Plantations In Southwest Guangxi

Water conservation function of forest is one of the important functions of forest ecosystem.In order to further reveal the difference of water conservation function of different plantation in southwest Guangxi,we selected four plantations,including 12-years-old Pinus massoniana plantation,12-years-old Castanopsis hystrix plantation,and 12-years-old Mytilaria laosensis plantation and 6-years-old Eucalyptus sprout plantation as the research object,the water-holding capacity of canopy,vegetation layer under canopy and litter layer,the w ater-holding capacity of soi 1 were s compared and analyzed.And used SPSS to do principal component analysis and evaluation.The results are as follows:?1?The biomass of canopy of these four plantations was between 12.18?17.04 t·hm^-2.The order of water holding capacity of canopy layer in four plantations is M.laosensis plantation(12.6t hm^-2)>P.massoniana plantation(12.54t·hm^-2)>C.hystrix plantation(9.27t·hm^-2)>Eucalyptus plantation(8.94t·hm^-2).?2?The biomass of shrub and herb layer in four plantations was massonianaplantation(3.83 t·hm^-2),C.hystrix plantation(3.97t hm^-2),M.laosensis plantation(3.18 t·hm^-2),Eucalyptus plantation(4.65 t·hm^-2).The order of water holding capacity of them is Eucalyptus plantation(3.42 t·hm^-2)>C.hystrix plantation(3.06 t·hm^-2)>P.massoniana plantation(2.87t·hm^-2)>M.laosensis plantation(2.36 t·hm^-2).?3?The amount of litter layer in the four plantations ranged from 4.02 to 7.38 t · hm^-2.The M.laosensis plantation were the largest,followed by C.hystrix plantations and P.massoniana,with Eucalyptus plantations being the smallest.The water holding capacity of litter layer is directly proportional to the litter layer amount.The order of water holding capacity of litter layer in four plantation types is M.laosensis plantation(27.05t·hm^-2)>C.hystrix plantation(15.96t·hm^-2)>P.massoniana plantation(11.59t·hm^-2)>Eucalyptus(11.46t·hm^-2).?4?The maximum water holding capacity of the four types of soils?0?80 cm?was different.The order is M.laosensis plantation(3666.2 t·hm^-2)>C.hystrix plantation(3571.8 t·hm^-2)>P.massoniana plantation(3536.4 t hm^-2)>Eucalyptus plantation(3486 t·hm^-2).The permeability of soil?0?40 cm?was the strongest in M.laosensis,followed by C.hystrix and Eucalyptus plantation,the weakest in P.massoniana plantation.?5?The total water holding capacity of P.massoniana,C.hystrix,M.laosensis,Eucalyptus was respectively 3563.40t·hm^-2,3600.09 t·hm^-2,3708.21 t·hm^-2,3509.82 t·hm^-2.The soil water holding capacity was the highest,accounting for 99.87?99.32%of the total water holding capacity,followed by the litter layer and canopy layer,accounting for 0.33?0.73%and 0.25?0.35%,the lowest was the shrub layer,accounting 0.06 to 0.10%.And we used SPSS to do Principal component analysis.The results showed that the comprehensive evaluation values are between-2.0954 and 3.6191.The water conservancy ability of the M.laosensis.plantation was the strongest,followed by the C.hystrix plantation and theP.massoniana plantation,the Eucalyptus plantation was the worst.