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Long-term tillage study looks for answers

While working as an agronomist, Merle Anders has ridden through the Thar desert in India on a camel-powered cart, witnessed massive pig kills in lush New Guinea, enjoyed laid-back Tonga and sweated his way through sugarcane fields in Hawaii. And that’s just for starters. For the last few years, though, he’s called central Arkansas home.

“I’ve been around, and let me tell you: there are some great farmers in this state,” said the rice systems agronomist, based at the Rice Research and Extension Center in Stuttgart, Ark. “My philosophy when changing jobs is to also change cultures, languages and crops.”

Long-term study

Any global wanderlust isn’t in evidence as Anders shows off his major research project, a long-term rotation study comparing conventional tillage and no-till systems in rice, soybeans, corn and wheat. In mid-March, standing in ample field residue, Anders said while no-till systems are common in cotton and soybeans, adoption of the practice in rice has been slower… Rice production is incredibly intensive and a lot of that is related to water management. As a result of all these things, the soils are often stripped of organic matter.

“When I came here in 1999, I looked around and realized there were no long-term studies regarding tillage. You can’t make long-term statements off short-term studies. I don’t look at a single aspect of something but prefer to look at the big picture.

“I want to find out if the adoption of conservation tillage (con-till) or no-till really leads to long-term benefits. Will it work? And if it does work, is it economically feasible?”


There are pressures from almost every direction, he said. Farmers are caught in a bad position: fuel and fertilizer prices are spiking and the current administration has proposed cutting farm programs.

“Plus, there’s the added ‘attraction’ of the land tenure system. If a farmer is leasing land, often the landlord is taking a percentage of the crop and the farmer is paying the expenses. The landlord, in that situation, wants maximum yields regardless of what it costs. The farmer wants to cut his costs without impacting yield.”

Landlords, he said, are often against con-till or no-till practices because “there’s a risk yields will drop a bit. Now, to the farmer, a yield drop of a few bushels is worth it because his input costs more than pay for the yield drop.

“I’ve worked around the world and this is one of the few situations in which there’s actually a Catch-22. You can have something good in terms of economic theory and it makes no difference in actuality. The landlord still wants his 25 percent, and he wants that 25 percent to encompass as many bushels as possible.”

In other parts of the United States that isn’t true. “But here you’ve got a crop, rice, that’s expensive to produce and requires strict water management atop every other type of management. The land tenure system certainly exacerbates the pressure on farmers.”

Underpinnings of agriculture

Producers don’t buy a new farm annually — they manage their farms on a long-term basis. Often, said Anders, “We as researchers walk away from that reality because, frankly, it’s inconvenient to do long-term studies. And,” he said, pointing to the ratty-looking no-till field, “looking at this mess, you can see it is inconvenient.”

Behind Anders is a test field broken up into 10 large plots representing seven rotations. Most of the plots represent a single rotation in a two-year/two-phase plan: rice/soybeans or rice/corn. Another plot looks at continuous rice.

“Those three are pretty characteristic of systems you can find around the Delta. We’re also looking at continuous rice with winter wheat, a good example of intensified agriculture. That particular rotation took a hit when we couldn’t get our wheat planted last fall. It was just too wet — something many Arkansas wheat farmers faced.”

There are also two three-year rotations of rice/corn/soybeans and rice/soybeans/corn. “We’re checking earlier findings — good data — that corn will do much better after soybeans than after rice.”

The plots are split evenly with half conventionally tilled and half no-tilled. When the study was set up in 1999, the field was cut to a 0.15 percent grade. The no-till plots haven’t been tilled since. For the tests, all plots are planted the same day with the same planter using the same varieties — Wells and LaGrue.

“Now, within each tillage plot, there’s a line demarcating standard fertility rates based on soil samples. On the other side of that line is an enhanced fertility: a 25 percent increase in nitrogen, phosphorus and potassium. The reason for that is we want to know if we can build fertility and if there is value in doing that.”

What’s been found

Conservation tillage and no-till can be difficult to study, said Anders.

“To change fertilizer rates, you can just dial up the plane and say, ‘dump more’ or ‘dump less.’ When you start changing tillage, though, the strategies change. What you look for and how you manage are very different.

“For example, no-till fields will stay wet a bit longer. After three years, though, we found they become much more solid. We can go into a field after a couple years of no-till and drive a tractor across it when we can’t even get close to our conventionally tilled fields. Even if a no-till field is flooded, it’s still rigid underfoot.”

No-till has effectively eliminated the plow pan without disrupting the clay layer beneath, he said. “That means we don’t need more water and can, in fact, save a bit more water on no-till. With rice, we save a small amount because we don’t need to flush.”

Farmers ask about yields with no-till. Those vary between rotations, said Anders. “In our no-till plots, rice yields are usually 5 bushels to 7 bushels lower than conventional-till plots. Right now, no-till is economically attractive. This system is very stable.”

Continuous rice doesn’t look as good. “I’m reluctant to say rice is the problem itself. I think we may need to change our fertilizing management. It’s important to remember that we use a single pre-flood nitrogen application.”

In terms of soil quality, there’s “no doubt no-till improves it. The carbon is up, root resistance is down. Initially, we had some trouble with soybeans and traced it back to phytophthora. We dealt with that by changing to resistant varieties — something those involved with con-till and no-till should be aware of. Our yields were 52 bushels on the no-till.”

Finding success

The farmers who are successful with no-till invariably do several things. “First, they’re extremely disciplined about grain carts, tractors and combines moving across fields. Second, they plant early rice and get it out quickly so they can get levees smoothed before fall rains.”

The effectiveness of con-till systems will be enhanced once more shorter duration varieties are available. Breeders are now developing such varieties. As those — and/or cold-tolerant varieties — become available it will be “so much easier to get in and out of a field quickly.”

However, “if farmhands run around like a bunch of cowboys rutting fields up, forget a con-till system. You might as well buy diesel storage because you’re into ‘recreational’ farming.”

Data shows that con-till practices reduce run-off dramatically. In his plots, Anders has seen a reduction 10 times that in conventional fields. He’s also found a 40 percent reduction in phosphorus coming off the con-till fields.


Most farmers have planters that can handle no-tilling. Anders has some advice.

“If they want to try no-till, spiked closing wheels are some of the best investments they can make. That’s the cheapest and best change a producer can make.”

Rice soils don’t do well when planted no-till with typical flat wheels, he said. When the coulters open the soil, they make a flat, shiny wall.

“You can put infinite pressure down, and it will still leave the furrow open. That means you’re left with exposed seed that won’t grow. Spike wheels break the continuity of the wall, and it crumbles in. For that reason, I often tell farmers, ‘Put on the spiked wheels and roll the field after planting.’

“Another thing is, when you have residue on the field, don’t plant when it’s too wet. That causes ‘hair-pinning’ — coulters can’t cut through the residue, they just push it into the ground. When that happens, you can look behind the drill and see the residue just poking up. The seed wasn’t planted in the soil, but the residue. A rule of thumb we use is: if it’s dry enough to harvest, it’s dry enough to plant.”

Find a mentor

One thing essential to success in switching to con-till is to find a mentor.

“That’s absolutely integral to getting through the growing pains. I’m happy to direct interested farmers to someone who’s been working with no-till. You need someone to bounce ideas off and look to for advice.”

Anyone attempting con-till or no-till must also understand that some years no-till yields are better than conventional. Some years the reverse is true.

“You aren’t going to break the yield barrier by switching to no-till. Over time, though, your management requirements won’t be as stringent and yields will be steady. Where you gain with these systems are the huge savings in labor and inputs.”

By adopting this system, farmers are also making a good move in the public’s eyes. “No-tilling improves the environment, the soil quality, sustainability, and water quality. We have the EPA breathing down our necks — many are looking to slap agriculture down. The rice industry can gain a lot by highlighting farmers who are no-tilling.”

e-mail: [email protected]

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