Oct 29, 2015Water quality key factor when establishing new vineyard
Vineyard weed control, irrigation strategies and nutrient management all are key elements in effective crop management. Water quality concerns should rise to the top of that list, according to a western Michigan grower and irrigation consultant.
Chris Lattak of Nye Heritage Farms in St. Joseph, Michigan, who’s also a consultant for Trickl-Eez, told grape growers “the most important thing in establishing a new vineyard is weed control. Irrigation and nutrient management is right there, but you have to pay special attention to your water quality.”
“The number one factor in doing that is weed control,” Lattak said during the Viticulture Field Day in Benton Harbor, Michigan. “We have to keep that row around the plant free of weeds. Number two, an important factor is a combination of irrigation and nitrogen. That will be the number one way to get that plant into production as soon as possible – within three years.”
In keeping vineyard rows clean, manual practices can be used, as well as pre-emergent weed sprays, “which has a relatively high expense compared to the next option we’ve looked at most recently, where we will put down a row of black plastic like we use in vegetables. Or with the woven mulch that they use in blueberries. With those methods, we’ve seen as much as four times the vegetation growth compared to an un-irrigated, manually weed controlled row of grapes.”
Very important to that process is the irrigation, “and with that is the actual water quality itself,” Lattak said. “We need a good quality water sample that’s showing us our pH’s, our hardness, calcium, potassiums, sodiums – we need those levels so we can see what that water is doing for us.”
“If you’re watering blueberries that want a 5 or 5.5 pH soil with an 8 pH water, you’re actually going to be raising that water pH. It’s the same with grapes. If you want a 6, and you’re watering with a 7.2, that’s going to have a negative effect.
“Even more important are the bicarbonate levels. Here in this part of (southwest) Michigan, we have extremely elevated bicarbonate levels because of all the calcium in the soil,” Lattak said. “What those bicarbonates will do is actually lock up the nutrients that you’re putting into your irrigation system. It’s doing the same thing with your foliar sprays that you’re doing with your speed sprayer.
“What you have to do there is look at those water samples; look at different methods of dealing with your pH – whether it’s an acidifier, sulfuric acid, a conditioner. Like we use AMS with Roundup in grapes or any weed spray, you’re using that conditioner as a sacrificial lamb to bind up with the bicarbonates so that your glyphosate can do its job.”
Growers also need to “take into account the bicarbonates when you’re using fungicides, insecticides and the negative effect that the water can have,” he said.
“So you need to buffer that. In some instances, if you can trade off and use rainwater in your sprays, or in my case where things are so bad we’re actually using reverse osmosis systems in order to get a good clean water,” Lattak said. “When you do that, then you have to use less of all of your inputs because everything works so much better because you’re not being tied up by the bicarbonates.
“So you can back off on your spreader stickers – your acidifiers. You can back off on the levels of your fungicides. Instead of using maximum rate, you can step it back and still get better efficacy by using less product. That’s how I’ll pay for my system – by using less product over the years and then, after about three years, I’ll be making money.”
Lattak said a lot of grape growers don’t have a background in irrigation, “so it’s kind of starting from ground zero.”
“When it comes to weed control versus no weed control, hands down weed control is the number one factor in getting good growth in those initial couple of years,” he said.
Lattak cited evaluations of farm operations in order to detect common factors that were preventing fertilizers from performing effectively. A common denominator shared by the farms with unexpectedly poor results was inadequate water quality.
“Poor water quality, especially hard water, can have a very negative impact on the effectiveness of plant nutrition and pesticides when applied either as foliar applications or in irrigation systems, inhibiting the effectiveness of the nutrients,” he said.
Hard water contains calcium and magnesium carbonates and bicarbonates. These minerals, along with high levels of iron, manganese or sodium, “greatly inhibit” nutrient absorption and plant health, Lattak said.
It’s important to know exactly what minerals are contained in a system’s water source and growers need to understand how to manage them.
“Every water source you use for irrigation or foliar applications should be tested at least twice a year,” Lattak said.
There are different water treatment options for foliar applications, irrigation sources or drinking water. Potential solutions include switching water sources, if possible, and using rainwater or water form a lake or stream if it is known that those sources do not have high levels of bicarbonates, or to use water treatment units that have proven to be effective at ionizing the bicarbonates and other minerals in the water.
In grape production, Lattak said, excessive vegetative shoot growth can be managed using nutritional supplements that enhance root growth and reproductive dominance. For example, applications of cobalt can trigger aggressive root development and cytokinin production that regulates shoot growth.
Lattak cited findings showing a direct connection between the flavor profile of red grapes and the levels of chloride and copper in the plant sap. Plants with higher chloride and lower copper levels produce very astringent tasting fruit. Plants with higher copper levels seem to produce fewer tannins, which leads to a sweeter tasting fruit.
Maintain proper flow
Lattak discussed drip irrigation and fertigation strategies that can be effective in new vineyard development.
“One of the first things you think about irrigation is it is really a chemical application,” he said. “You’re adding the most important nutrients – hydrogen and nitrogen. Maintaining water at the appropriate levels of soil is very important. If there’s too much water in the soil, roots can’t breathe. If there’s too little water, the roots are starving. If you don’t have enough water, plants are not picking up enough materials and it will impact yield.
“It’s a business of Goldilocks – getting the right amount and maintaining the right amount is dependent on the weather parameters you’re in,” he said.
“Why use a plastic and drip system? It can help you outpace diseases,” Lattak said.
A new vineyard should feature a drip system to aid root development, but it should not be addressed by a drip system alone, Lattak said.
“You will need a supplemental system – there is overhead irrigation out there. And then, you shouldn’t take down the overhead irrigation. If you run into a situation in the spring when you need it for frost control, you will have it available.”
An efficient water pumping system that includes pressure-monitoring gauges at various points also is crucial for new vineyard success.
“Know how long it takes to get water out there, the soil type, how quickly the nutrients are going to pass through,” he said.
Use of filtering devices is recommended in order to keep sediments from clogging the lines.
“You need to understand the relationship of how to deliver water to the system over time, in order to leave minerals you added to the system at the roots so the plant can take them up,” Lattak said. “Filters are a good idea. If you put anything in the system, filter it before it goes out to the holes in the plastic. Anytime you lose water going to those plants, you’re losing potential production, which means you’re losing money.”