Tim and Tommy Colbert with Brad Denton, District Conservationist, NRCS
Tim and Tommy Colbert with Brad Denton, NRCS


This is the sixth in a series of “Profiles of Soil Health Heroes.” This profile features Tim and Tommy Colbert, Chester County, Tennessee. The brothers began farming in 1973. The farming operation is located near the Jack’s Creek and Plainview Communities of Chester County. Their soils are of the Lexington-Providence soil series made up of loess cap over Coastal Plain parent material. Soils are predominantly silt loams with some bottom lands somewhat sandier in texture.

What stands out about the Colbert brothers the minute you get out of the truck, is their can-do attitude. They shared with me and Brad Denton, NRCS District Conservationist, Madison and Chester Counties, the history of their farming and conservation practices. They constructed terraces in the 1970s and 1980s. The entire farm at their headquarters is terraced. It was laid out on the contour. They told me after the terraces were constructed that they reduced the gully and rill erosion and followed the contour for many years.

Like most West Tennessee row-crop farmers, their main enterprise was cotton, and for years they had it as the mainstay of their enterprise. They became one of the earlier adopters of no-till in Chester County. Once they adopted no-till, they stayed the course. They did not practice rotational tillage and use of different implements such as harrows or vertical tillage. Their oldest no-till field is thirty plus years, where all of the other fields have been no-tilled 20 plus years.

Their soil organic matter at 0-6” depth was approximately 1%, ten years ago. They transitioned to a diverse conservation crop rotation approximately seven years ago. They farmed cotton, corn, full season soybeans, and wheat, double cropped soybeans.

Their cropping enterprise consists of approximately 1,700 acres, 450 acres of wheat, double cropped soybeans, 400 acres corn, 825 acres of full season soybeans, and 25 acres Cereal Rye for seed. This year, 2015 is the first time in 29 years that they have not grown cotton.

Since adding diversity and higher residues to their rotations, in addition to their long-term no-till, they have experienced increases of soil organic matter (SOM) on all of their fields. I viewed some of their soil tests and jotted down the % SOM. They were 2.2, 2.7, 3.0, and 4.0%, respectively. They figure their farm average is 2.5 – 3.0 %. You can also see a progression of conservation, from terracing on the contour, to no-till, and to conservation crop rotations.

Table 1. Example of three fields tested 2012. Nitrogen is applied at 200 lbs. acre for dryland corn and 240 for irrigated.

Field number


Organic Matter

Analysis, and pounds per acre

Analysis, and pounds per acre 



3.0 %

Medium, 70

Medium, 98




Medium, 70

Medium, 79




Low, 112

Medium, 108

Field 3 recommended 1500 pounds lime per acre.

They have also invested in Global Positioning System (GPS), yield monitoring, and variable rate soil testing. They soil test every three years, and apply lime and nutrients by variable rates as shown in Table 1. They practice control traffic for spraying and for planting. With no-till and their desire to add cover crops on all acres, they no longer need to follow the contour of the terraces. Since they added this technology, they drive straighter rows, thus increasing yield.

They use Round-up technology. They irrigate on a few fields with center pivot. The Colberts mentioned, that due to size and shape of their fields, they only have approximately three center pivots. Tim and Tommy also mentioned that their desire was to increase organic matter in order not to depend on irrigation as much.

After many years of no-till, Tim and Tommy Colbert added a 5-way cover crop in the fall of 2014. Picture shows planting in April of 2015. Cover crop is approximately 72” in height.

The 5-way mix consisted of 20 pounds cereal rye, 26 pounds wheat, 5 pounds crimson clover, 2 pounds turnips, and 2 pounds tillage radishes. Cover crop is approximately 30” in height, terminated April 7.

The Colberts are always learning and trying new methods to better their stands and the crop’s growing conditions. The first picture above shows 6’ cover crop. The picture shows 2.5’ cover crop. The Colberts left a swath of 200 X 800 feet growing three weeks later, terminated April 28 compared to April 7.

I asked the Colberts, what did you learn from terminating the test plot three weeks later? Without hesitation, Tim and Tommy said “let it grow.” They plan to grow cover 4-6 feet in the future on the entire acres of cover crops.

In many farming operations, I could end here, and say they are doing an outstanding job. This is where their can-do attitude kicks in. They attended some regional conferences on cover crops and soil health. They attend a regularly scheduled round-table of discussion on soil health at Brad Denton’s office. These conferences motivated them to want more from their farming operation. They desired to increase yields with no more inputs, infiltrate more water on the farm, thus improving their profit margin.

In 2014, they made their next step up in their well-rounded conservation program, they added annual cover crops. They had already been following some principles for improving soil health: 1. Keeping the soil covered with 20+ years of no-till and use of crop residues and crop rotations; 2. Reduced disturbances by no-till and reducing pesticides by the use of crop rotations and less monocultures; 3. They had increased diversity, especially with their added crop rotations from their earlier cotton-dominated rotations. 4. The only thing they lacked was continuous root growth. With technical assistance from NRCS and financial assistance from NRCS, Environmental Quality Incentive Program (EQIP), they embarked with 560 acres of cover crops planted in the fall of 2014.

They are very pleased so far with the results of the 560 acres of cover crops. I asked them if they had problems planting. They used a combination of planting methods. They planted the crop fields that came off earlier with a fertilizer truck using 100 pounds of potash as a carrier and broadcast the seed, about 320 acres. They planted the rest of the 240 acres aerially using an airplane. All cover crops were planted by October 1-15.

The Coberts have seen the advantage of leaving the cover crop growing three extra weeks. They have noticed less marestail and morning glory pressure. There was also a cold spell a couple weeks after emergence. The temperature dropped to 48 degrees. The taller residue from the cover crop mix protected the plants. Soybeans in the taller cover were significantly taller.

I asked them to expound on their experiences good or bad and any concerns or changes they would make. As time drew closer for termination of the cover in early April, they were concerned about the field drying out due to the cover up taking approximately 1” of water per day. This did not become a problem. They noted, after rains they could get on the fields 1-2 days earlier without compacting the fields. Where they allowed the test plot to grow three extra weeks longer, they noticed soybean plants twice as tall as the earlier terminated cover. The less cover had 87,000 plants per acre (soybean) compared to 110,000 soybean plants per acre for higher growing cover, killed three weeks later. The planters had no hair pinning problems. They planted corn 2-3 days after termination and the beans 1-2 weeks after termination.

I asked the Colberts if they had any trouble planting in 2.5’ cover or the 6’ cover. They looked at me and grinned; “whatever it takes, we will make this work.
I also asked Tim and Tommy about getting a stand. So many people say for precision agriculture and precision planting, you need some tillage. They planted 28,000 plants per acre for dryland corn and 32,000 plants per acre for irrigated corn. As you can see there are no skips in planting. They use cast iron closing wheels and v-closing wheels. They will continue to experiment on closing wheel combinations with pneumatic or spike closing wheels in the future. Since they have been set up for cotton, they have traditionally planted 38” row cotton and corn. They plan to narrow the row width to 30” corn. For soybeans and wheat, they use John Deere 1590 drill with cast iron closing wheels and a 1530 with V-closing wheels. They seem to like the V-closing better.

Their general weed control is Round-up Power Max with combinations of Valor and Verdict. They use treated seed. Corn is scouted but no additional fungicides are used. Soybeans have always been sprayed with fungicides in the past. They want to continue to scout and see if covers and rotations can reduce fungicide use in soybeans.

The soil is showing the results of long-term no-till. Soil organic matter averages 2.5 -3 % across the farm. The structure still has some weak platy structure, but roots penetrate it readily. Earthworms are plentiful. I was on the farm for this article on June 1. It was the day after 2.4 inches of rain. We easily walked through the field, especially on the taller killed cover without mudding our boots. Earthworms were active. I was also on the farm in late February and at 26 degrees the worms were still active. We expect long-term use of cover will begin to transition the structure to more granular.

The soils infiltrate better after long-term no-till. The Colberts remarked that the water is clear coming out of culverts near terraces. They also noted that they can enter their fields 2-3 says earlier than farmers that use tillage. They also noted that there are more uniform stands since the organic matter has increased. They do not have problems getting stands due to erosion. The stands are very uniform.

Also since increasing organic matter, they now drive their equipment straight, not following contoured terraces. With variable rate fertilizing, yield monitors, and GPS, they can drive straighter and see some yield advantage.

The Colberts are very pleased with the 5-way mix of cover crops. Here you can see the early terminated cover in fore ground and cover killed three weeks later in background. They plan to not only continue the later kill but to expand the cover crop acres by 690 acres. So, in 2015, they plan to plant 1260 acres of 5-way cover crops.

In summary, Tim and Tommy Colbert wanted to increase SOM and improve their yields for 2015. They were already excellent conservation farmers. They had been in a more diverse rotation for seven years, using variable rate technology, yield monitors and GPS steering system. They wanted to maximize the use of rainfall in West Tennessee, through improving infiltration. They embarked on an aggressive first year of planting 5-way cover crop, 560 acres and plan to add approximately 700 more acres in 2015. They have learned a lot in less than a year on planting and managing diverse covers. They plan to lengthen the time of growth to 2-3 weeks before termination. They plan to narrow corn width rows and experiment with closing wheels. I know one thing, “whatever it takes; they will make it happen.”