Ap. Schaffers et al., EFFECTS OF DELAYED HAY REMOVAL ON THE NUTRIENT BALANCE OF ROADSIDE PLANT-COMMUNITIES, Journal of Applied Ecology, 35(3), 1998, pp. 349-364
1. Mass losses and nutrient losses from fresh roadside cuttings were s
tudied in the field during a 6-week period. Large amounts (over 50%) a
ppear to be lost from the cuttings. The losses were positively related
to initial nutrient concentrations during this short-term study. Mass
and nitrogen losses were best explained by the initial C:N ratio, pho
sphorus and potassium losses by the initial phosphorus concentration.
2. For potassium the losses were particularly large (up to 90%). For t
his element only, the observed relationship between loss rate and init
ial chemical composition could not be established significantly. It is
concluded that potassium is mainly lost by leaching whereas the major
nitrogen, phosphorus and mass losses are most probably caused by rapi
d microbial decomposition of readily soluble substances. 3. Using exis
ting data on chemical composition of other roadside cuttings, nutrient
losses after different hay removal delay times were modelled for diff
erent plant communities. All or most of the losses were assumed to ret
urn to the soil system. 4. When soil impoverishment is aimed for, cutt
ings should be removed within 1 or 2 weeks in most plant communities.
If removal is delayed longer, the amounts of nutrients removed will of
ten fall below the annual atmospheric input. In plant communities wher
e annual above-ground production of nitrogen and phosphorus are lower
than the annual atmospheric deposition already, rapid removal of the c
uttings may be the only way to maintain at least potassium at a limiti
ng level. 5. The main effect of hay-making on the soil nutrient status
most likely consists of a reduction of the potassium availability, at
least on sandy soils with a low cation exchange capacity and provided
there is little delay in hay removal.