Garcia Marco, Sonia and Gómez Rey, M.X. and González Prieto, S.J.
Availability and uptake of trace elements in a forage rotation under conservation and plough tillage.
"Soil & Tillage Research", v. 137
After 14 years under conventional plough tillage (CT) or
conservation minimum tillage (MT), the soil available
Al, Fe, Mn, Cu and Zn (0-5, 5-15 and 15-30 cm layers) and their plant uptake were evaluated during two years
in a ryegrass-maize forage rotation in NW Spain (t
emperate-humid region). The three-way ANOVA showed
that trace element concentrations in soil were mainly
influenced by sampling date, followed by soil depth and
tillage system (35-73 %, 7-58 % and 3-
11 % of variance explained, respectively). Excepting for Fe (CT) and Al
(CT and MT), the elemental concentrations decreased with
depth, the stratification being stronger under MT.
For soil available Al, Fe, Mn and Cu, the concentrations were higher in CT than in MT (5-15 and 15-30 cm
layers) or were not affected by tillage
system (0-5 cm). In contrast, the available Zn contents were higher in MT
than CT at the soil surface and did not differ in deeper
layers. The concentration of Al, Fe and Cu in crops were
not influenced by tillage system, which explain 22 % of
Mn variance in maize (CT > MT in the more humid
year) and 18 % of Zn variance in ryegrass (MT > CT in
both years). However, in the summer crop (maize) the
concentrations of Fe, Mn and Zn tended to be higher
in MT than in CT under drought conditions, while the
opposite was true in the year without water limitation.
Therefore, under the studied conditions of climate, soil,
tillage and crop rotation, little influence of tillage
system on crop nutritive value would be expected. To
minimize the potential deficiency of Zn (maize) and Cu
(maize and ryegrass) on crop yields the inclusion of
these micro-nutrients in fertilization schedule is reco
mmended, as well as liming to alleviate Al toxicity on