Uittreksel
Increasing phosphorus (P) content in agricultural
soils stimulates crop yield but also increases
phosphorus losses to surface waters and
groundwater (Figure 1).
Adequate P availability in the soil is necessary for crop
growth but above a certain soil P content, yields do
not increase. Below a certain threshold soil P content,
P losses are limited, but losses can increase
exponentially when the soil P content exceeds the
threshold.
Target soil P content
A small ‘target zone’ soil P content with optimal
crop yields and limited P losses can be defined
(Tunney, 2002; McDowell, 2012). Soils with low soil
P content (A in Figure 1) can receive net P inputs (= P
fertilisation input minus crop P output) without large
increases in P losses, whereas soils with large soil P
contents (B in figure 1) can have several years of net P
export without compromising crop yields. Soil P
content should evolve in the next 10-30 years towards
the target zone. This sustainable choice is optimal for
both the environment and yields. Measures for
reaching this goal are (1) an adapted fertilisation
legislation and (2) adequate fertilisation
recommendations (see below).
Figure 1 presents a simplified picture that does not
take hydrology, connectivity or soil characteristics into
account. Moreover, the method to measure soil P
content must be appropriate because results often
depend upon soil characteristics.
(1) Legislation regarding phosphorus fertilisation in
European countries and regions varies from no direct
regulation to strict maximum phosphorus application
rates (Amery & Schoumans, 2014). By taking the risk
for soil P losses into account for identifying the
maximum phosphorus application rate, evolution
towards the target zone can be promoted (Figure 1).
Some European countries already have P application
limits that depend upon the soil P content, stimulating
evolution towards the target zone. Further progress
could be made by using an environmental instead of
an agricultural soil P measurement, and also by
taking hydrology and connectivity into account. To
optimise yields and minimise P losses, legislation
regarding P fertilisation within and outside Europe
should include maximum P application limits
differentiated to soil P content and P loss risk.
(2) The soil P content is generally taken into account
when formulating P fertilisation recommendations.
But even for similar soil-crop situations, fertilisation
advice differs more than threefold in Europe (Jordan-
Meille et al., 2012). New recommendation systems in
some European countries are flowing from updated
models and data, more appropriate safety margins and
new insights into P availability measurements. The
new P recommendations are generally lower than
before (Albertsson, 2008; Krogstad et al., 2008;
Bussink et al., 2011). New environmentally friendly
recommendation systems can largely limit P
fertilisation and costs while maintaining crop yields
(Csathó et al., 2009). Additional research on and
development of new P fertilisation advice that
guarantees optimal yields while limiting P losses
should therefore be encouraged.
Oorspronkelijke taal | Engels |
---|---|
Tijdschrift | SCOPE Newsletter |
Volume | 106 |
Pagina's (van-tot) | 29-30 |
Aantal pagina’s | 2 |
Publicatiestatus | Gepubliceerd - aug.-2014 |
Evenement | Sustainable Phosphorus Summit 2014 - Montpellier, Frankrijk Duur: 1-sep.-2014 → 3-sep.-2014 |