Research on restrictive nutrient factors to Eucalyptus grandis plantation in Sichuan
FENG Mao-song,ZHANG Jian,YANG Wan-qin,ZHONG Yu(College of Forestry and Horticulture,Sichuan Agriculture University,Ya′an,Sichuan 625014,China)
Restrictive nutrient factors of Eucalyptus grandis plantation in Sichuan were analyzed by correlative test.Results showed as follows:(1) Available P,exchangeable Ca, exchangeable Mg are most important restrictive factors of production,and synthetic effect of Fe,Cu and Zn cannot be neglected,but N,K,Mn in soil are least restricted due to enough providing.(2) Ca,Mg,P,Fe,B,N,Zn and Cu are important foliar nutrient concentration indexes as a sign of nutrient supply and absorption.(3) Nutrient balance relations between N,Ca,Zn,Cu,P,Mn and other elements are more important.High concentrations of N,Zn,Cu,Mn and low concentrations of P,Ca imply high forest production.