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

FruitsSumitomo Chemical Acquires U.S. DuPont Asana Insecticide Business
December 9, 2014
The insect control product will be distributed through Valent U.S.A. Read More
FruitsA Combination Of Culprits Are Related To The Decline In Bee Populations
December 3, 2014
The latest research into Colony Collapse Disorder is focused on a number of issues facing bee populations. Read More
FruitsWet December Predicted For Parched California
November 25, 2014
National Weather Service says above-normal precipitation expected; it may continue through the winter in central and southern parts of the Golden State. Read More
NutsWatch Your Almonds’ Salt Intake
November 24, 2014
Because of the current California drought, almond growers must pay extra attention to soil salinity. Read More
CitrusIndustry Organizations Sound Off On President’s Immigration Plan
November 21, 2014
Agriculture is not given the attention it so sorely deserves when it comes to the immigration debate. Read More
NutsArizona Pistachio And Pecan Growers Benefiting From High Prices
November 21, 2014
Pecan production alone is expected to double in the next 10 years. Read More
IrrigationAlmond Grower Honored For Water Efficiency
November 18, 2014
Ongoing drought highlights the efforts of third-generation Madera County grower Tom Rogers. Read More

The Latest

NutsAlmond Growers Lose Trees In Storm
December 17, 2014
Last week’s welcome rains in California knocked down trees, especially older ones. Read More
NutsAlmond Conference Draws Record Attendance
December 17, 2014
Nearly 3,000 industry professionals attend 42nd annual event in Sacramento, CA. Read More
NutsStudy: Almond Industry Generates More Than 100,000 Cali…
December 9, 2014
Industry is responsible for more than $21 billion in economic output, and adds $11 billion to gross state product. Read More
FruitsSumitomo Chemical Acquires U.S. DuPont Asana Insecticid…
December 9, 2014
The insect control product will be distributed through Valent U.S.A. Read More
FruitsA Combination Of Culprits Are Related To The Decline I…
December 3, 2014
The latest research into Colony Collapse Disorder is focused on a number of issues facing bee populations. Read More
FruitsWet December Predicted For Parched California
November 25, 2014
National Weather Service says above-normal precipitation expected; it may continue through the winter in central and southern parts of the Golden State. Read More
NutsWatch Your Almonds’ Salt Intake
November 24, 2014
Because of the current California drought, almond growers must pay extra attention to soil salinity. Read More
CitrusIndustry Organizations Sound Off On President’s Immig…
November 21, 2014
Agriculture is not given the attention it so sorely deserves when it comes to the immigration debate. Read More
NutsArizona Pistachio And Pecan Growers Benefiting From Hig…
November 21, 2014
Pecan production alone is expected to double in the next 10 years. Read More
IrrigationAlmond Grower Honored For Water Efficiency
November 18, 2014
Ongoing drought highlights the efforts of third-generation Madera County grower Tom Rogers. Read More
FruitsWestern Growers Frustrated By Shutdown Of Ports
November 14, 2014
Pacific Maritime Association is accusing union of intentional work slowdown. Read More
NutsWalnut Thefts Down Thanks To New Measures
November 12, 2014
Officials say first major walnut theft in year occurred this week. Read More
NutsCommunication Key For The Pollination Of Almonds
November 11, 2014
Every communication link is critical when it comes to almonds and honey bees. Read More
NutsTaking A Closer Look At Walnut Scale
November 11, 2014
Close examination of the scale activity on the young wood and scaffolds will show a very high percentage of parasitism. Read More
NutsHeard Of The Tree Of 40 Fruit?
November 11, 2014
Sculptor brings new meaning to grafting as an art form. Read More
NutsTips To Keep Bees Safe When Using Pesticides
November 10, 2014
Here are six precautions for applicators to follow from the Almond Board. Read More
NutsTop 10 Honey Bee BMPs
November 10, 2014
This list will not only help ensure bee health, it can make you a more profitable grower. Read More
NutsNew Practices To Promote Bee Health
November 7, 2014
Almond Board of California’s comprehensive documents offer practical steps for almond growers to take to protect bees. Read More