Effects Of Different Urban Forests Plantations On The Nutrient Contents And The Soil Fertility

Aimed to study the effects of different urban forest plantations on soil fertility, litter and soil samples were collected from eight mono-cultured plantations (Larix gmelinii, Pinus sylvestris var. mongolica, Pinus tabulaeformis var. mukdensis, Phellodendron amurense, Juglans mandshurica, Fraxinus mandshurica, Betula platyphylla, and Quercus mongolica) and one mixed plantation (P. sylvestris var. mongolica+F. mandshurica+Picea koraiensis+P. amurense+B. platyphylla) established in Northeast Forestry University's Urban Forestry Demonstration Research Base in 1950s, with two sites of neighboring farmland and abandoned farmland as the control. The litter in broadleaved forests except Q. mongolica were near neutral, those in needle-leaved forests were acidic. There existed significant differences in the total N and P of the litters among different plantations. The soil in broadleaved forests except Q. mongolica were near neutral, those in mixed plantation, L. gmelinii, P. sylvestris, P. tabulaeformis forests were slightly acidic, and that in Q. mongolica was acidic. The contents of soil organic matter, total N and P, available P and K, and hydrolysable N tended to decrease with soil depth. There existed significant differences in the chemical indices of the same soil layers among different plantations. The correlation between the indices of different urban forest soil is poor, which may be related with the human disturbance and the short time of the cultivation. The soil fertility was decreased in the order of F. mandshurica>P. amurense>mixed plantation>J. mandshurica>B.platyphylla>abandoned farmland>farmland>P. sylvestris var. mongolica>L. gmelinii>Q. mongolica>P tabulaeformis var. mukdensis, suggesting that the soil fertility in broadleaved forest plantations except Q. mongolica and in mixed plantation increased, while that in needle-leaved forest plantations tended to decrease.