Corn & Soybean News
October, 2007, Volume 7, Issue 8
Cooperating Departments: Agricultural Economics, Biosystems and Agricultural Engineering, Entomology, Plant and Soil Sciences, Plant Pathology
In this Issue:
Nutrient Removal of Corn Stover & Soybean Hay
Lloyd Murdock and Greg Schwab, Plant and Soil Sciences
The dry weather has made hay supplies short, prompting many farmers to look to corn stover and whole soybeans as forage sources. Grain producers want to know how much nutrient removal is occurring and the cost of the removal.
A yield of 150 to 175 bu/ac results in about 8,000 lbs/acre of corn stover. The total nutrients in this 8,000 pounds is N = 55, P2O5 = 27 and K2O = 115 pounds per acre. If one calculates that a large round bale of corn stover is about 1,200 lbs then the nutrient removal will be about N = 8, P2O5 = 4 and K2O = 17 lbs/bale. Calculating the cost of nutrients per bale using nutrient prices of N = $0.40/lb, P2O5 = $0.30/lb and K2O = $0.25/lb results in 2 different figures. Most people use only P2O5 and K2O costs because the nitrogen in the stover would likely be lost via denitrification, but P and K would normally be recycled as the residue decomposes resulting in a nutrient removal cost of about $5.50 per bale. If nitrogen is also calculated into the costs, it becomes about $8.50 per bale.
Soybeans baled for hay removes all parts of the plant and the amount of nutrients removed in the hay depends on the stage of growth and the amount of vegetative growth. In the calculations below, two growth stages have been assumed for nutrient removal purposes. The R3 (beginning pod) and the R5 (beginning seed) growth stages because they seem to approximate the growth stage and amount of pod fill in the severe drought areas. The costs of the nutrients removed were calculated using P2O5 = $0.30/lb and K2O = $0.25/lb.
Table 1. Nutrient removal and value of nutrients removed from soybean. Values presented in this table assume average soybean yields.
· Corn stover and soybean hay will remove extra P and K.
· Know these costs when marketing corn stover or soybean hay.
Insect Control in Corn Storage
Doug Johnson, Entomology
There continue to be questions concerning insect control in stored corn storage. At this time of year it is too late to employ many of the important strategies. But let’s have a quick review.
First and foremost: “store clean dry grain in clean dry bins”. This will solve the vast majority of problems. Below find a checklist of good storage techniques.
UK-IPM Checklist for Controlling Insects in Stored Corn
Doug Johnson, Extension Entomologist and Sam McNeill, Extension Agricultural Engineer, University of Kentucky
Before Harvest / Pre-Binning
During Harvest / Binning
Post-Harvest / After Binning
Insecticides and Fumigants Recommended for Corn
Do not use malathion for any treatments. Most forms of malathion are no longer labeled for use and the product no longer provides adequate insect control. See: ENT-16 Insecticide Recommendations for Corn.
Empty bins - applied to walls and floor: Tempo7 SC Ultra. (DO NOT APPLY TO GRAIN!), Actellic® 5E, or Insecto. Do not use the same product for empty bin and grain “protectant” treatments.
Under Floor Fumigants - Chloro-pic (Can not currently be shipped in small containers, you may find that your local dealer has some on hand or in large e.g 200 lb. bottles), Methyl-Bromide, Phostoxin® / Fumtoxin®. THESE PRODUCTS ARE EXTREMELY DANGEROUS AND REQUIRE SPECIAL EQUIPMENT AND TRAINING!
Protectant - applied directly to the bulk grain: Actellic® 5E. Insecto may be used as a “protectant”, but some buyers will not accept grain treated with this material. Be sure of your market. (If grain is handled and stored properly this is not generally economically advisable.)
Cap out treatment applied to the top 4" of grain - (Do not make this application if a protectant has been applied to the bulk grain): Actellic® 5E and Insecto for beetles and moths or products containing Bacillus thuringiensis, e.g. Dipel7, Javelin7, Sok-B.t.7 etc. for Indian meal moth.
For more information about crop and livestock pests, visit "Insect Management Recommendations".
· Store clean dry grain in clean dry bins.
· Follow the checklists for each stage of storage.
Low Soil pH Values this Fall
Lloyd Murdock, Paula Howe, Greg Schwab and Frank Sikora, Plant and Soil Sciences and Regulatory Services
Soil samples taken from abnormally dry soils likely will result in soil test pH values being lower than actual soil pH values. Soluble salts have accumulated near the soil surface under dry conditions causing the pH to be lowered. Typically, a combination of plant uptake and adequate rainfall to percolate through the soil is sufficient to keep the soluble salt content in the field soils low enough that pH’s on fall soil samples are not noticeably low. The drought has greatly reduced plant growth (thereby lowering the total amount of salts taken up by the plants), and lack of rainfall to leach high levels of salts deeper into the soil causing pH’s to be abnormally lowered.
In 1991, a similar condition existed, causing Ken Wells and Grant Thomas (former UK Agronomy Professors) to check soil samples from two Jessamine County drought-stricken tobacco fields. The samples were split with the pH measured on one-half of the sample as taken and the other half was leached to remove soluble salts before the pH reading. The soil pH rebounded after leaching of soluble salts from the sample. This will also occur in the field when we get normal rainfall.
Table 1. Soil pH results from soil samples taken under dry conditions in 1991.
There are two ways to handle this problem.
1) The samples with very low pH’s compared to previous samples can be resampled in late February or March after we have saturated the profile.
2) When soil pH is measured in a salt solution it is usually about 0.5 units lower than pH measured in water, but the buffer pH will not be affected by these high salts. To calculate a lime recommendation, assume that the current water pH is about 0.5 units lower than normal and that the buffer pH has not been affected. Using the table in AGR-1 apply lime if needed this fall using the estimated water pH and the actual buffer pH.
· Dry soils results in lower reported water pH values.
· Buffer pH values should be accurate.
Crop Management: Early Bird Series
Chad Lee, Plant and Soil Sciences
While commodity prices are higher, the cost of production is also increasing rapidly, making the final net profit a challenge. Producers need to maximize their pre-pay dollars.
Three meetings across Kentucky will be targeting issues relating to pre-pay decisions on seed, seed treatments, foliar fungicides, hybrids, varieties and fertilizer options. In addition, each of these meetings will include a topic on grain storage options. The locations, dates and contact information follows:
Sedalia, Sedalia Restaurant: Thursday, November 15, 2007: contact Lincoln Martin, (270) 527-3285.
Owensboro, Daviess County Extension Office: Friday, November 16, 2007: contact Clint Hardy, (270) 685-8480.
Shelbyville, Shelby County Extension Office: Tuesday, November 20, 2007: contact Brittany Edelson, (502) 633-4593.
The meetings are scheduled to begin at 9:00 am and will conclude between 2:30 and 3:00 pm. Lunch will be sponsored by the Kentucky Soybean Board and the Kentucky Corn Growers Association.
Pesticide education credits and certified crop advisor continuing education credits will be sought.
· Make the most of pre-pay dollars.
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