Grain yields in Exp. 3 are shown in Fig. 1.
The average grain yield in CA-treated plots was significantly higher than in control plots (P < 0.01).
Since this site (HK4) had a low available P content and a
high pH similar to HK3, higher grain yield from the CA plots can be
explained by the aforementioned effects of CA on soil P availability.
Grain yields showed a better response to NP fertilizer in CA plots
than in non-CA plots (Fig. 1).
The results are consistent with
findings that CA reduced leaching of applied mineral N fertilizer
and promoted better use of applied nutrients (Lehmann et al.,
2002; Steiner et al., 2007).