Orchard Compaction: A Pressing Problem

A compacted “plow pan” layer often forms about 8 to 10 inches below the surface in both mowed and tilled orchards. This is a widespread problem in orchards regardless of soil type. Growers are often unaware of its presence and impact. In some cases, no-till orchards haven’t been ripped for decades.

Just ask Mark Schmidt, who grows almonds and walnuts in Waterford, CA, located in the northern San Joaquin Valley. He has one block of 20-plus-year-old walnuts that has sandy top soil, but just about 8 inches down a hard pan, or plow pan, has formed. “Just doing normal work on the ground over the years compacted it down,” he says.

Last spring, Schmidt deep-ripped the orchard, and the results were dramatic. “In one year, the growth was just unbelievable, from 1 foot a year, to 3 to 4 feet this past year,” he says. “It was all because of the compaction; the hard pan was cutting off the roots. The roots were just getting by.”

Schmidt, who’s also known in the ag community as a beekeeper, certainly learned a lesson he won’t forget. “This year I ripped that ground both ways; last year I ripped it just one way,” he says. “I did a real massive break-up job this time.”

 

Let Roots “Breathe”

A greater understanding of soils and the effect of compaction on tree growth and yield will help in developing approaches to minimize the problem and increase productivity. Soils are complex mixtures of mineral particles that vary in both size (sand, silt, clay) and arrangement. Soil texture refers to the proportion of sand, silt, and clay in a soil. Soil structure means how the particles are arranged; it largely determines the amount of pore space, the spaces between the particles, in the soil.

Pores are an important part of healthy soils for several reasons. They affect water intake and movement through the profile, the amount of water soil can hold for use by the tree, and drainage below the root zone. Soil water content increases above compacted layers and may create conditions that encourage root and crown diseases. Compacted soils are more subject to runoff and erosion.

We have seen a number of orchards where the ground was wet in the top few inches but water never reached the roots.

Compaction also affects air exchange between the soil and the atmosphere. Did you know that roots need to “breathe?” Roots and the beneficial microorganisms that live in the soil need to take in oxygen and release carbon dioxide.

Microorganisms fix nitrogen from the air and help break down organic matter which releases nutrients to the tree. These are important points to keep in mind because cultural practices have a direct impact on soil quality and sustaining tree health.

 

Lighten Up

As Schmidt learned, soil becomes compacted primarily because of the pressure applied by the weight of orchard equipment. It compresses the soil particles together, causing the soil to be denser with less pore space. It is more difficult for roots to push through dense soil and so root growth can be reduced. The best strategy to minimize compaction is to prevent it from occurring in the first place. The risk for compaction is greatest when soils are wet. Driving on wet soils is the single biggest cause of compaction.

A dry soil is much more resistant to compaction than a moist or wet soil. Sandy soils are particularly susceptible to compaction as the weight of equipment can cause the sand grains to interlock. Soils with high organic matter are also less susceptible to compaction. Test for compaction by probing the soil with a pointed metal rod, bucket auger, soil tube, or shovel. It is more easily done on a somewhat moist soil.

Apply even pressure and push the probe into the soil. Compaction is the resistance found about 8 to 10 inches below the soil. Alleviate compacted layers by ripping or chiseling when the soil is dry. A shank depth capability below the compacted area is necessary. Curved shanks require less draft than straight shanks to loosen the same amount of soil. Space the shanks no further apart than the depth of ripping and cover the width of the middle to within a few feet of the trunks to avoid injury to larger roots. A single shank down the middle is of limited value. Do not worry about injuring smaller roots; root pruning actually stimulates root growth in much the same way that heading cuts in the canopy promote new shoot development.

For nine ways to minimize compaction, go to the next page.

Pages: 1 2

Topics:

Leave a Reply

Nuts Stories
CitrusBiocontrols 2015: Exhibition Sneak Preview
February 25, 2015
We take a look inside the exhibit hall at the Biocontrols 2015 Conference & Tradeshow. Read More
NutsA Better Way To Gauge Chilling Hours
February 24, 2015
Using a new system, the chill portions model, can improve growers’ accuracy. Read More
CitrusNew App Helps Identify Insects, Diseases, And Nutrient Deficiencies
February 24, 2015
Spensa Technologies launches app that helps growers take control of pests and improve soil nutrients. Read More
Crop ProtectionFMC Launches Biological Fungicide With New Mode Of Action
February 18, 2015
The broad spectrum fungicide, Fracture, is labeled for prevention and control of powdery mildew, botrytis, and brown rot blossom blight. Read More
CitrusNew Desalination Technology May Be The Answer To California’s Drought
February 18, 2015
Researchers plan to address concerns with a process that will examine ways to turn seawater into drinkable water. Read More
NutsWalnuts May Improve Memory
February 18, 2015
A University of California-Los Angeles study found greater cognitive function in participants who ate walnuts. Read More
CitrusMegadrought In The West Predicted By End Of The Century
February 18, 2015
Lowering greenhouse gases will reduce risk, scientists say. Read More
The Latest
FruitsMaximize Produce Profits By Focusing On Soil Health
February 27, 2015
Cover crops are just one of the ways you can help boost your trees’ and vines’ performance and your bottom line. Read More
FNV logo
CitrusPMA Announces Funding For Major Produce Marketing Progr…
February 26, 2015
The produce industry is getting into brand marketing in a big way. The Produce Marketing Association (PMA) has announced the launch of a new promotional campaign - FNV - designed to take a page from the marketing strategies of big-money consumer brands like Nike and Apple. Read More
CitrusFDA, Federal Partners Develop New Method For Attributin…
February 25, 2015
Data was analyzed from nearly 1,000 outbreaks to assess which categories of foods were most responsible for making people sick. Read More
CitrusBiocontrols 2015: Exhibition Sneak Preview
February 25, 2015
We take a look inside the exhibit hall at the Biocontrols 2015 Conference & Tradeshow. Read More
NutsA Better Way To Gauge Chilling Hours
February 24, 2015
Using a new system, the chill portions model, can improve growers’ accuracy. Read More
CitrusNew App Helps Identify Insects, Diseases, And Nutrient …
February 24, 2015
Spensa Technologies launches app that helps growers take control of pests and improve soil nutrients. Read More
Crop ProtectionFMC Launches Biological Fungicide With New Mode Of Acti…
February 18, 2015
The broad spectrum fungicide, Fracture, is labeled for prevention and control of powdery mildew, botrytis, and brown rot blossom blight. Read More
CitrusNew Desalination Technology May Be The Answer To Califo…
February 18, 2015
Researchers plan to address concerns with a process that will examine ways to turn seawater into drinkable water. Read More
NutsWalnuts May Improve Memory
February 18, 2015
A University of California-Los Angeles study found greater cognitive function in participants who ate walnuts. Read More
CitrusMegadrought In The West Predicted By End Of The Century
February 18, 2015
Lowering greenhouse gases will reduce risk, scientists say. Read More
CitrusTier 4 Regulations Pique Propane Interest
February 12, 2015
New rules are extending to non-road applications like irrigation engines. Read More
Nuts5 Tips To Combat Tree Nut Weeds
February 10, 2015
Follow these weed management tips to reduce yield loss. Read More
CitrusAgriculture Among Top Paying College Degrees Of 2015
February 9, 2015
Report reveals good news for graduates looking to make some green in farming. Read More
NutsPart 2: The Chinese Walnut Slowdown: Not A Worst Case S…
February 9, 2015
Although U.S. walnut exports to China are down, emerging markets are on deck to help compensate for the decline. Read More
NutsUSDA Designates Almost All California Drought Disaster …
February 5, 2015
Areas of Arizona, Nevada and Oregon are also declared disaster areas. Read More
NutsPart 1: The Chinese Walnut Slowdown: Not A Worst Case S…
February 4, 2015
The California Walnut Board and Commission’s Michelle McNeil shares insight into the recent slowdown in walnut exports to China, and why she doesn’t think there’s reason for concern. Read More
bee keeper
CitrusTop Beekeepers Wanted
February 2, 2015
Bayer CropScience seeks nominations for award honoring innovations in the beekeeping community. Read More
CitrusWhat Growers Need To Know About Maximum Residue Levels
February 2, 2015
Maximum residue level standards vary by market and by country. Here are a few helpful hints provided by Cindy Baker Smith of Amvac Chemical Co. to help you navigate the maze. Read More