News

Rice and Sweet Sorghum Harvest

Weather conditions have been good for harvesting research plots at the University of Missouri-Fisher Delta Center this fall. Sweet sorghum biomass yields for energy research have been high (35 to 40 tons per acre).  Yields from traditional crops such as corn and rice have been average.  Below are links to video silage cutter and plot combine harvesting plots from my iPhone.

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Sweet Sorghum Planting Date x Harvest Date Study for Biofuel Production

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Rice Variety x Nitrogen Experiment on clay soil at Fisher Delta Research Center

Installing Gutter Drain Pipe

Many homeowners have excessive water near or under their houses.  Over the summer, some of my wife’s flowers next to our house became sick from waterlogged soil.  To remedy the problem,  I installed a buried pipe from a gutter downspout to help with our drainage.   The supplies cost $34.  Here are steps of how I did the job.

1. I purchased 12 feet of 4-inch perforated, corrugated black drain pipe long enough to move water away from the house into the grass in the yard ($8), one downspout adapter ($5), one 90 degree elbow fitting, and 4 bags of gravel ($3/bag). If you have soil with slow infiltration (high clay content) or a slope back towards the house, you will need a longer pipe to drain to the nearest ditch. img_20962. I dug a 1 foot deep trench with a shovel through our flower bed into the yard, carefully piling the grass sod to use later.

img_20983. I placed the pipe in the trench to be sure it fit.

img_20924. Then I removed the pipe, distributed two bags of gravel along the bottom of the trench, put the pipe back in, poured the last two bags over the top, and put a narrow strip of landscaping cloth over the top to prevent plant roots from growing into the pipe perforations.

img_21055. I filled in the trench with soil and pressed the grass sod back where I dug it.

img_2109 6. The final step was to cover the flower bed with landscape cloth, plant fall flowers, and spread pine mulch.

img_2117For the next few days, I watered the section of replaced sod and flowers until they established new roots.

Missouri Irrigation App

Water is an important factor affecting crop yields. The University of Missouri Extension Service developed an on-line program (app) to help farmers produce higher crop yields by improving irrigation management. There is no charge to farmers. This bulletin gives information about the Crop Water Use (CWU) application and explains how to set up fields to track soil moisture.IMG_8112

How Does The Application Work? The application estimates crop water use from weather data. An equation for calculating evaporation from soil and plants (called evapotranspiration, ET) is used. The application also calculates daily soil water deficit balances for each field. Reports include indexes to help farmers determine when to irrigate.

Crop Water Use.  The University of MO Extension automatically downloads data each day from a mesonet of agricultural weather stations located across Missouri.  ET is calculated from solar radiation, temperature, humidity, and wind. CWU uses the Standardized short crop Penman-Monteith Evapotranspiration (ETo) equation which was developed by a task committee of the American Society of Civil Engineers.  ETo is the amount of combined water lost from a reference crop (grass) and soil evaporation.

ETo is multiplied by a crop coefficient, which is specific for the crop and growth stage. The crop coefficients, except for rice, come from UN Food and Ag Organization publication FAO-56. Beginning at planting, growth stages are predicted from heat units for corn, rice, and cotton. Calendar days are used for soybean. This information is used to estimate daily crop water use (ETc).

Soil Water Balance. Daily soil water deficit is reported similar to a checkbook registry which tallies rainfall and irrigation as deposits and ETc as withdrawals. The soil water deficit becomes more negative in periods of low rainfall. When the soil profile is full (field capacity), the deficit balance is 0. As water is extracted, the balance becomes negative.

Acknowledgements. Funds  for field research to validate this app were provided by Cotton Incorporated, Howard G. Buffett Foundation, and United States Department of Agriculture- Agricultural Research Service. 

The app utilizes weather data from the Missouri Agricultural Weather Station network.  For this reason, currently, it will not work outside of the state of Missouri.  

 

Soil Testing in Tanzania

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Dr. Gene Stevens used a Garmin GPS receiver to navigate between soil sample grid points in Tanzania.

In July 2014, I collected soil samples on a 8,000 acre research/demonstration farm near Mombo, Tanzania.   Shallom Farm is being co-developed by Dr. Parseko Kone, a Tanzania Regional Commissioner,  and Floyd Hammer, founder of  Outreach International.  Much of the farm is covered with small trees and thorny vines.  To avoid getting lost and having a record of where I collected samples, I used GPS to navigate between sampling locations. Angelo Lopes, a student from Brazil, helped me develop a grid point system for the farm and saved the way points on my Garmin GPS receiver before I left the United States.  The farm was divided into 25 acre cells.  Each cell has a letter and number.  They are  labeled west to east with letters (A to Z) and north to south with numbers (1 to 14).

Grid points for soil sampling.
Grid points for soil sampling in Tanzania.

The most suitable areas for growing maize on the farm are in the northwest and southwest corners so I focused my sampling in those locations. The headquarters (Boma) is located close to the center of the farm on a hill.  Each afternoon, the Maasai herdsmen from a local village drive the cattle into pens.  In the morning, they turn them out to graze.

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Cattle are held in pens made from tree branches.
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A Maasai man sharpens a knife on a rock.

The east side of the farm has stream channels that are dry most of the year.  In the rainy season, which is October to March, water flows in the streams. If berms could be constructed to hold water in reservoirs , irrigation might be used to water crops in the dry season.

Topography

I collected soil samples in the dry season.  In most locations, the  ground was hard and we had to use a hammer to drive the probe into the soil. Oscar, the young man holding the probe, moved from South Africa with his uncle to work on the farm. 

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In my luggage, I carried a portable pH meter, potassium ion electrode, and test kit for measuring phosphorus.  Outreach rented a house at Rosminian Health Center.  It is a charity hospital managed by Sister Jennifer Raduck and Father Ambrose Chuwa.  To analyze the soil samples, I converted the  kitchen in the house into a temporary laboratory.  Most of the soil samples from Shallom Farm were either black shrink-swell clay or red loam soil high in oxidized iron.

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Equipment was not available dry the samples so I let them dry in the sun and used a rolling pin to crush the clods.

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Soil pH was measured in a 1:1 soil/water solution.   The pH meter was calibrated with a pH 7.0 solution.  I used a aluminum sulfate extraction solution for potassium and filtered the liquid before testing it with an ion specific electrode.  The potassium meter was calibrated with 20 and 200 ppm K solutions.

 

Measuring soil pH for acidity in 1:1 water solution.

Measuring soil pH for acidity.
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Portable potassium ion specific electrode.
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Phosphorus was measured using a purple indicator and the intensity of color was matched to a scaled chart.

Most of the samples contained adequate potassium for maize production. The pH levels were usually above 6.0 which is good.  I had difficulty accurately determining the phosphorus levels with the color indicator.  In follow up testing in a conventional laboratory,  we determined that soil phosphorus and sulfur were below critical levels in some of the samples.

P1000378Visiting Tanzania was an enjoyable experience.  I learned several Swahili greeting words such as jambo (hello), habari (how are you?) and mzuri (fine).  Mzuri is pronounced like my home state of Missouri.  I spent time in Mombo, Moshi, and Arusha.  All of the people that I met in Tanzania were very friendly and I hope to go back someday. 

Soil Health in Missouri Cotton Fields

New testing methods for evaluating soil health are being used at the Delta Center.
New methods for evaluating soil health such as active carbon and phospholipid fatty acid test are being tested at the University of Missouri- Fisher Delta Center.

When a cotton farmer sees “worms” in his fields,  it is usually a bad thing.  Boll worms are a major pest which eats the crop.  But when we started sampling producer fields for a research project, we found beneficial earthworms living in cotton fields.

Worms

 

Earthworm in cotton field north of Sikeston, Missouri.
Earthworm in cotton field north of Sikeston, Missouri in April 2013.
Earthworm in cotton field at New Madrid, Missouri.
Earthworm in cotton field at New Madrid, Missouri in Dec 2013.

 

 

 

 

 

 

Planting winter wheat in row middles has become a standard practice to protect cotton seedling from blowing sand in the spring.  We are finding that the wheat residue is an important food source for earthworms and microorganisms.  Without something to eat and adequate water, earthworms  die or fail to reproduce.  With the new interest among farmers in planting cover crop blends and rotating cotton with corn, earthworms will probably have a more balanced diet in the future.

New Madrid County extension agent, Sam Atwell, inspects corn residue in a field before planting cotton.
New Madrid County extension agent, Sam Atwell, inspects corn residue in a field before planting cotton.

We are studying three methods of judging the soil health in cotton fields- soil respiration, active carbon amount, and phospholipid fatty acids.  A healthy soil has microorganisms which digest organic material (food) and respire carbon dioxide gas, just like we do.   To measure soil respiration, we drive metal rings in the soil, cap them with a plastic lid for 30 minutes and use a syringe to pull an air sample through a inline CO2 indicator tube.  As you might expect, microbial respiration tends to be highest in fields which had winter cover crops. Respiration is highest in May and June when there is new residue material and soil moisture from spring rains.  When the soil becomes hot and dry the microbes and earthworms become less active.

Measuring soil respiration in a cotton field without winter wheat residue.
Measuring soil respiration in a cotton field without winter wheat residue.
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Equipment used to measure soil respiration. 

 

 

 

 

 

 

 

 

 

 

 

The main focus of the research project is studying soil active carbon levels in Missouri cotton soils. It can take many years of reduced tillage and careful residue management to significantly increase the percentage soil organic matter just 1%.  But the active carbon fraction of organic matter changes more quickly and has the greatest impact of crop growth.  David Dunn, manager of the Delta Center Soil Test lab, and I are working together testing for active carbon.  We are using a method developed by the Natural Resource Conservation Service.  We are tweaking the procedure to help identify differences.  In the procedure, the amount of soil used in the extraction procedure is critical.  In the process of doing this research, we learned that the Soil Health Lab in Columbia Missouri has a new procedure called a  Phospholipid Fatty Acid (PLFA) test which estimates  the amount of each group of microbes in a soil sample.  Donna Brandt (573-882-0941) is a research specialist at the lab who tests the samples.  Below are some results from our cotton fields in 2013.

Total microbial biomass over time in 2013.
Total microbial biomass May, June, and December in 2013.

Percentage of biomass in different groups of microbes in 2013.

Percentage of biomass in different groups of microbes in 2013.

We still have much to learn about promoting microorganism populations in the soil.  Mycrorrhiza fungi which work symbiotically  with plants to help roots take up more nutrients are found more often in perennial crops than cotton.  Gram negative bacteria tend to be highest in the soil surface/root zone.  They occur in the highest proportion in soils with organic inputs such as manure or cover crops with no-tillage.  Gram positive and actinomycetes usually increase proportionally with soil depth and are less responsive to fresh organic inputs.