apply str vs reduce str

gistfile1.clj

user=> (def input (take 10000 (cycle (map char (range (int \a) (int \z))))))
#'user/input
user=> (bench (reduce str input))
Evaluation count : 1800 in 60 samples of 30 calls.
             Execution time mean : 33.756996 ms
    Execution time std-deviation : 278.588482 µs
   Execution time lower quantile : 33.542863 ms ( 2.5%)
   Execution time upper quantile : 34.797430 ms (97.5%)
                   Overhead used : 4.038278 ns

Found 6 outliers in 60 samples (10.0000 %)
	low-severe	 2 (3.3333 %)
	low-mild	 4 (6.6667 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
nil
user=> (bench (apply str input))
Evaluation count : 86580 in 60 samples of 1443 calls.
             Execution time mean : 692.983707 µs
    Execution time std-deviation : 1.606027 µs
   Execution time lower quantile : 688.212871 µs ( 2.5%)
   Execution time upper quantile : 694.883263 µs (97.5%)
                   Overhead used : 4.038278 ns

Found 10 outliers in 60 samples (16.6667 %)
	low-severe	 5 (8.3333 %)
	low-mild	 2 (3.3333 %)
	high-mild	 2 (3.3333 %)
	high-severe	 1 (1.6667 %)
 Variance from outliers : 1.6389 % Variance is slightly inflated by outliers
nil