Effects of Moisture and Temperature on the Soil Nitrogen Mineralization of Sassafras Tzumu Plantations in Rainy Area of West China

PurposeIn order to predict the nitrogen supply potential and the response of soil nitrogen mineralization to temperature and water content of Sassafras tzumu plantation in the Rainy Area of West China.

MethodA laboratory incubation experiment was conducted to study the nitrogen mineralization characteristics of S. tzumu plantations under different temperatures (5, 15, 25 and 35℃) and water contents 20%, 40%, 60% and 80% field water capacity (FWC).

ResultThe net ammonification rate, net nitrification rate and net nitrogen mineralization rate increased first and then decreased with the increase of temperature and water content, in particular, the maximum values were at 25℃+60% FWC treatment and were significantly different from other treatments (P<0.05), except the treatment of 25 ℃+80% FWC. The response model of soil nitrogen net mineralization rate (y₃) to temperature (x₁) and water content (x₂) was y₃=−1.671 3+0.278 0x₁+7.541 3x₂−0.005 6x₁²−6.404 4x₂²+0.008 8x₁x₂ (R²=0.952, n=48). The optimum temperature and water content for promoting soil nitrogen mineralization were 25.6 ℃ and 61% FWC, respectively. Soil nitrogen mineralization was the most sensitive in the range of 5-15 ℃.

ConclusionThe S. tzumu plantations in rainy area of West China can adapt to the trend of global warming, increase soil available nitrogen content, and have good potential for nitrogen supply.