Z. Henkin et al., PHOSPHATE FERTILIZATION PRIMES PRODUCTION OF RANGELAND ON BROWN RENDZINA SOILS IN THE GALILEE, ISRAEL, Agriculture, ecosystems & environment, 59(1-2), 1996, pp. 43-53
Primary production on terra rossa and brown rendzina soils on the hill
s of the Galilee in Israel is severely restricted by nutrient, mainly
phosphorus, deficiency. The purpose of this study was to investigate t
he residual effects of a single application of P fertilizer and the lo
ng-term role of P in the production and botanical composition of herba
ceous vegetation. A fertilizer trial on brown rendzina soil (Lithic Ha
ploxeroll) with P and N treatments was established and monitored for 6
years. Phosphate fertilization consisted of a single surface applicat
ion of 45 or 90 kg P ha(-1) as enriched superphosphate (25% P2O5). In
the first year, yield of herbaceous vegetation in P fertilized plots i
ncreased fourfold compared with the control, and about two-fold during
the following 5 years. In the sixth year, production in the fertilize
d plots diminished, but was still significantly higher than in the con
trol plots. In addition, there was a large increase in the legume cove
r that improved the nutritional quality of the range vegetation. Conce
ntration of P and N in the plants as well as total P and N uptake, inc
reased significantly. Available P concentration in the soil increased
two- to five-fold in the year after fertilizer application and a stron
g residual effect persisted for up to 5 years. A single application of
P (45-90 kg ha(-1)) on brown rendzina soil in the Galilee raised the
total 5-year primary production from 780 g m(-2) dry matter in the con
trol plots to 1840-2100 g m(-2) dry matter in the fertilized plots. Fo
rage quality was also improved for an extended period of over 5 years.
Phosphate nutrition was shown to be the key to raising productivity o
f these soils. The long duration of the effect increases the chance th
at infrequent P fertilization on these rangelands will be economically
feasible in certain conditions.