State lawmakers pushing for a constitutional amendment to provide open-space funding are right - New Jersey needs to find a stable source of money to preserve farmland, historic sites and undeveloped areas.

But the best thing we can say about their proposed solution is that it should keep the issue in the spotlight and provide a starting point for a much-needed debate.

The state is out of money for projects to create parks and recreation areas and to preserve land to protect our drinking water, rivers and bays. Voters consistently support open-space spending, but the money from the latest bond referendum, $400 million approved in 2009, has all been spent.

Earlier this month the Senate Environmental and Energy Committee approved putting a constitutional amendment before voters. The amendment would dedicate 6 percent of corporate business tax revenues for the next 30 years to open space programs - Green Acres, Blue Acres, historic preservation and farmland preservation.

Sponsors say the proposal has the advantage of using an existing revenue stream, and amending the state constitution would mean that future governors and lawmakers wouldn't be able to raid the funds, as has happened in the past.

Most of the state's environment groups are supporting the idea, showing much more unanimity than they did last year, when competing plans in the state Assembly and Senate failed to gain traction.

The Assembly plan would have asked voters to approve another $200 million in borrowing, adding to the state's already-unwieldy debt load. The Senate had a better proposal. It would have dedicated 2.4 percent of sales tax revenue, up to $200 million per year, for the next 30 years. That would represent less than half of the expected increase in sales tax revenue during that time.

We still think that's a sensible approach, more sensible than diverting funds from the corporate business tax.

The problem is that 4 percent of the business tax is already dedicated to environmental purposes. It is used to replace old underground storage tanks and to clean up hazardous waste spills. The Senate's current proposal takes that money away, with no real plan to replace it.

Since this kind of environmental damage is concentrated in the state's old industrial areas, the current proposal would take money away from urban areas in order to build soccer fields in the suburbs. That hardly seems like a fair trade-off.

So while we're glad the Legislature is still working on this issue, we think that work is far from done.