The horticulturalist
By JIM JOHNSON
Extension Ag Agent
Rutgers University
Cumberland County

11/01/02 - Water

Water quantity and quality — They are issues, but are they problems?
The availability of water resources is one of the most important issues in agriculture today. For agriculture to survive, it needs to have access to quality water resources. Water is not only a limiting factor for plant production, but it has also become the limiting factor for sales of nursery stock. If our customers can’t water them, they won’t buy! Now that is not news to the nursery industry, but is appears to be to the rest of the world. When political entities look to restrict watering, landscape areas seem to be one of the first uses to be placed on the list and the impact on nurseries can be significant.
One of my basic concerns is that there seems to be a presumption that everyone is irrigating their lawns and landscapes. In certain areas or communities, that is the case. In many areas of the state, however, watering of plants and turf does not commence until wilting starts. That, unfortunately, is about the same time drought restrictions are put in place.
What can one do in the home landscape to maintain plant health during droughts? The political solution for New Jersey seems to be to hand water landscape plants. I have to agree with regulatory personnel that this is indeed a solution that reduces water use. How many of us in our right mind are willing to spend half the night outside holding a garden hose in order to save our plants? It may be less costly both physically and emotionally to purchase new plant material. Unfortunately, large numbers of dead plants have the potential to increase home heating and cooling costs, increase the possibility of soil erosion, and reduce the value of one’s home.
All this occurs while we have documented methods of reducing irrigation water consumption in the landscape with use of high efficiency irrigation systems. The regulatory concern, and rightfully so, is that water use during droughts can be abused. Teaching homeowners why it is important to properly use their irrigation system is an important part of the solution. For example: Does everyone understand that too much water will kill a plant faster than too little water, or that one can over-water more easily with an irrigation system than without one? We must remember, however, that over-watering is not really a function of the irrigation system. It is the attitude of the homeowners toward water conservation that is most important.
How many of us have driven by a home that has its irrigation system running during a rainstorm? It doesn’t matter how sophisticated the irrigation system is. If it is not operated logically, one can waste a great deal of water. With low water reserves in reservoirs and groundwater levels dropping, we cannot afford to waste water. As a homeowner, one must make a decision. Is the irrigation system installed to produce a lawn that will win the green carpet award or is it there to maintain a healthy and vigorous landscape that will resist environmental and pest stresses? I hope it is the latter.
So what is a logical approach? Water only when water is needed. To encourage deep rooting, it is better to apply water once a week than to split it into smaller applications over several days. Work with a professional to assist in the design of your system.
Don’t restrict yourself to one kind of system. It seems that pop-up sprinklers that produce overhead irrigation has become the “golden bullet” for many designers. Overhead irrigation is appropriate for turf areas, but not the best choice for landscape plantings.
Trickle irrigation systems are much more efficient for trees and shrubs. For bedded plant material, spray stakes may be the answer. For individual trees distributed in the lawn area, the use of water bags can be effective when lawn watering is restricted. Very large trees have a more extensive root system that can tolerate longer periods of drought. If water is critical for the very large trees, a temporary trickle system at the drip line is probably the most effective way of maintaining health. An interesting effect may be the creation of a large green ring in the brown grass. But remember, while this may be a logical approach, it is not the law.
Producers of nursery stock have different issues to address. The use of an irrigation system is not restricted during droughts. What is required is that growers develop methods to conserve water resources. Presently, state-of-the-art nurseries are accomplishing this by using highly efficient irrigation systems. For shade trees, trickle systems are used; for field-produced shrubs, traveling booms and center pivots are quite efficient where they can be used. For container plant material, water sensors are being used to irrigate on demand. Water, especially in container nurseries, is also being recaptured in impoundments and being re-used. Conservation of water resources is moving forward, with innovative solutions being developed.
At the non-production end of the spectrum, water that leaves the nursery also is being studied. While water does not regularly move off-site, significant rain events can create situations where it will move. In a project coordinated by the Cumberland Soil Conservation District, we are determining the effect of agricultural practices on water quality in the upper reaches of the Cohansey River. Information developed early in the project, and regarded as preliminary data, supports the U. S. Environmental Protection Agency assessment that siltation is considered to be the leading cause of impairment of water bodies in the Eastern coastal plain. As a consequence, we will be working with growers to install conservation practices to reduce erosion.
With assistance from the New Jersey Department of Environmental Protection, the New Jersey Department of Agriculture, the South Jersey Resource Conservation & Development Council Inc., and Rutgers Department of Environmental Science, we will determine if problems exist and to find ways to help reduce the impact of those identified.
So, what is the bottom line? We are working on the issue of water quality and quantity. We are conducting research to determine the impact of agricultural practices on surface water quality. The water issue becomes a problem when it negatively impacts the financial and emotional well being of agriculture and consumers.
I believe the solution is education. We have much of the technology that is needed and it continues to develop. We need educated consumers of water who focus on plant needs as balanced with conservation. If regulators know that users are focused on those issues, perhaps practical, logical, and workable regulations can be instituted.