L-arginine application triggered soil hydrolytic activity

Application of amino acids to soils is reportedly associated with controversial responses in soil enzyme activities. The effects of L-arginine application on the fl uorescein diacetate (FDA) hydrolysis and protease activity in an oak forest soil was investigated. The FDA hydrolysis and protease activity were regularly measured over a standard incubation period. The addition of L-arginine increased both FDA hydrolysis and protease activity after a lag time of 10 days. After 30 days, the ratio of FDA hydrolysis and protease activity in L-arginine-amended soil samples to those in the control reached 2.0 and 3.7, respectively. Moreover, FDA hydrolysis was found signi fi cantly (r = 0.67, P < 0.05) correlated with protease activity. It was concluded that L-arginine was able to stimulate FDA hydrolysis and protease activity, thereby making the soil hydrolytic system capable of facing more complicated substrates.