studia universitatis babeş-bolyai biologia 2

PHOSPHATASE ACTIVITIES IN A BROWN LUVIC SOIL
– Soil phosphatase activities as affected by the same crop growing in different
plots of the same rotation. We have already mentioned that in 1999 there were, in the
6-crop rotation, two minerally fertilised plots (1 and 4) cropped to maize. Phosphatase
activity measured in unbuffered reaction mixtures was significantly higher
(p maize plot 4;
− acid phosphatase activity: maize (FYM) > maize plot 4 > wheat > maize plot 1 >
clover > soybean;
−
alkaline phosphatase activity: maize (FYM) > maize plot 4 > maize plot 1 ≈
clover > soybean > wheat.
It is evident from these orders that phosphatase activity in unbuffered reaction
mixtures is more pronounced in soil under the legumes (soybean, clover) than under
the cereals (wheat, maize). The reverse is true for acid phosphatase activity and,
with the exception of soil under wheat, also for alkaline phosphatase activity.
Soil phosphatase activities as affected by fertilisation. The three maize plots
in the 6-crop rotation could serve for comparing the effect of mineral (NP) fertilization
(plots 1 and 4) and farmyard-manuring (plot 2) on the soil phosphatase activities.
Each activity was higher in the farmyard-manured maize plot than in the other two,
minerally fertilised maize plots. The differences were significant at p