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ISSUE 4  May 24, 2001

 

INOCULATE SOYBEANS AND OTHER LEGUMES WITH CORRECT BACTERIA

Legume crops such as alfalfa, sweet clover, soybeans and dry edible beans fix nitrogen from the soil air to a form usable by the plant. To do this they form a symbiotic partnership with specific strains of compatible bacteria. These rhizobia bacteria enter the root hairs of young legume seedlings and induce the formation of nodules. The nodule is the site of nitrogen transformation by these bacteria.

Soil is the natural home for nodule-forming bacteria. They may or may not be present in adequate numbers, or they may or may not be of the correct strain of rhizobia bacteria to produce effective nitrogen fixing nodules.

Active working and efficient nodules are light pink to reddish in color and are found in clusters along the main root of most legume plants. The nodules will vary in size depending on the species on which they are found. If nodules are white or green they are probably inactive and are not efficient in fixing nitrogen.

The life of nodule-forming bacteria in the soil is influenced by soil aeration, soil fertility, high temperatures, low soil moisture and soil alkalinity. Bacteria may live for a number of years, but in dry soil they gradually lose their potential to produce nodules. In sandy soils, bacteria may live only two or three years.

The following table lists the specific bacteria name and type that is needed by legumes grown in North Dakota.

 

Inoculant

Legume

Bacteria name

Code or type

Alfalfa/sweetclover

Rhizobioum meliloti

A

Dry beans (pinto, navy, blacks, kidneys, pinks and cranberry)

Rhizobium leguminosarum-
(Biovar phaseoli)

D

Field pea/lentil

Rhizobium leguminosarum-
(Biover viceae)

C

Chickpea (Garbanzo)

Rhizobium strain

CG

Lupin

Bradyrhizobium sp.

H

Soybean

Bradyyrhizobium japonicum

S

Shelf life of commonly used peat base inoculants is often very short if not refrigerated. Studies have shown that inoculum stored at 75 degrees F for two to three months has a sharp reduction in living bacteria. If refrigerated at 40 degrees F or lower, the bacteria live for more than a year. Preinoculated seed, if in warm storage or carried over the summer months under warm storage conditions, should be re-inoculated before planting to encourage effective nodulation of the plant.

 

DETERMINATION OF CANOLA STANDS BY HOOP METHOD

Established stands of canola are important to growers for both yield potential and weed competition. Minimum stands (plant populations) of 3-4 plants per sq. ft. An easy method to determine canola plants stands is the "hoop or circle" method. Use of a "hula hoop" or making one with a stiff wire or rod would also work. The area of a circle can be calculated:

3.14 x (radius in inches)2=sq. feet/circle
             144

Below are some calculated examples:

Hoop or circle diameter

Sq. feet/hoop

30 inches

4.9

32 inches

5.6

34 inches

6.3

36 inches

7.1

38 inches

7.9

When checking fields, toss the hoop at 10-12 sampling sites while scouting a field. Sample representative areas and stands throughout the field. Count the number of plants within the hoop at each throw and record. Average the number of plants found over the samples counted. To determine canola plant stands:

Ave. Number plants/hoop count     =     number of plants per sq. foot
           sq. ft./hoop

example: 34 inch hoop with 44 plants ave./hoop count
44   =   7 plants/ft. sq.
6.3

Number of plants per Acre:
7 plants x 43,560 sq. ft./A=304,920 plants/A

If planting populations are 2 or less per sq. ft. then one should carefully scrutinize the stand. Is the sparse stand fairly uniform throughout the field. If this is true it perhaps can be left to grow, branch and compensate for the low populations. Other factors to consider would be weed control and competition with weeds, reseeding risks of planting late and hitting hot weather during bloom stage, seed and replanting costs, chemicals and possible herbicides residues for other crop choices.

Duane R. Berglund
Extension Agronomist

dberglun@ndsuext.nodak.edu

 

HYPERSPECTRAL IMAGES MAY HELP RECORD CROPPING IN FUTURE

The EO_1 satellite for NASA has been testing some new technology that may identify specific vegetation in the future. The instrument aboard is the Hyperion, a way to detect light in 220 distinct wavelengths-not the 3 or even 30 presently used with Landsat satellite technology. The Hyperion's measurements allow scientists to distinguish different land surface features-not only vegetation from water, but soybeans from corn, pine trees from oaks and sand from dust. Due to the high speeds of air and space vehicle motion, data has been acquired for broad bands in which spectral radiation is integrated within the sampled areas in ranges, such as 0.1 mm

for Landsat. In hyperspectral data, the interval narrows to 10 nanometers (a micrometer, mm, contains 1000 nanometers; 1 nm = 10-9m), a narrow band.

From these multiple narrow bands, an image is built-push broom-like-by a succession of lines, each containing 664 pixels. The imaging can even be used on a high altitude aircraft platform, rather than a satellite, such as NASA's ER-2 (a modified U-2) to give a typical swath range of 11 km (a kilometer, km, is 1000 meters or 0.621 mile or 3280 feet so 11 km = 6.831 miles = 36,080 feet). The Hyperion is capable of resolving 220 spectral bands with a 30 meter resolution. It can image a 7.5 km by 100 km (750 square km or 304 square mile or 194,876 acres) land area per image and provide detailed spectral mapping across all 220 channels with high radiometric accuracy. See and read more on this new technology at http://eo1.gsfc.nasa.gov/Technology/Hyperion.html  or  http://earthobservatory.nasa.gov/Library/EO1/ .

 

VALUE-ADDED SOYBEANS THROUGH PROCESSING

Splitting soybeans into soy meal and crude soybean oil has tucked in profit for the North Central Kansas Processors (NCKP) who process about 30,000 bushels of beans per month. Leaving more oil in their meal due to their processing procedure as compared to larger processors that use solvents for extraction, the protein content of the meal is similar but the energy levels are higher (NCKP averages 7% fat as compared to conventional soybean meal at 1% fat), making the soy meal a good product, especially in swine diets. The press system used was developed by Insta Pro of Des Moines, Iowa and the system begins after the soybeans are cleaned, by friction and pressure heating to over 300F, making a more digestible product for livestock. Presses squeeze out the crude oil separately and the meal, in cake form, is conveyed to a cooler before being ground into soybean meal. At current capacity, four employees work 24 hours a day to run the plant four days per week. The plant cost about $1 million to build, was operational in less than one and a half years and is a limited liability company that allows any farmer to deliver soybeans to the plant.

 

HORMONE SNIFFS OUT MOISTURE

The plant hormone, ABA, may delay the growth of newly sprouted plants so that they have one last chance to check their environment for signs of dryness before initiating growth. There appears to be a novel level of complexity in early plant growth processes that make certain plants better able to cope with stressful conditions such as dry or high salt soils according to recent Rockefeller University research (Proc. Nat. Acad. Sci. 14, 2001). Previously, plant physiologists believed that once seed broke dormancy and began to germinate, that it would continue the growth process. The new research suggests a second checkpoint. The model plant for the study is, you guessed it, a weed-Arabidopsis, a mustard. Postdoctoral fellows running the study have shown that ABA can arrest growth of the weed for up to 30 days. The ABA activates a protein called ABI5, a protein essential to the just germinating plant's ability to protect itself from drought during this delay in development. ABA delays germination, but it is even more efficient at keeping germinated embryos in a resting, protective state if environmental conditions are not right for good growth. Mutant strains of the weed lacking the ABI5 protein had lower survival rates than normal counterparts if faced with drought conditions. Normal plants survived after 36 hours of a drought treatment, on average, while mutants survived only 12 hours. Even more intriguing is that adult plants overproducing the ABI5 protein lost less water on average, too. Normal plants would lose water, while the transgenic line overproducing ABI5 lost water less rapidly. These findings may also have applications to seed priming-possibly timing seed germination so that it would occur in a more uniform fashion in fields.

 

UNEVEN STANDS NOT AN INDICATION OF CROP HEALTH OR YIELD, YET

Difference in soil moisture, soil temperature and soil_seed contact as well as some very cool nights and slight crusting in areas this year have made for raggedy crop stands in some corn and soybean fields. However, before you panic, thoroughly scout the field to determine if missing plants are just about to emerge or if other problems in the field are causing the missing links down the row. If the seed has germinated and is just emerging, these plants that are late in seeing the light may yet come up to height with the other plants in the field. Until plants are significantly late such as for two to three weeks behind other plants in the field, the crop plants may catch up during the season. Depending on how the environmental conditions continue on corn through to the fifth_leaf stage, the shorter plants can even out with the rest of the field during this time frame or even a little later. In soybeans, by the third to fifth node, plants under good growing conditions can even out across the field if limitations on nitrogen fixation and other nutrient use do not occur. The next eight weeks of crop growth will determine much of the plant health for the season. Moisture availability during flowering in both corn and soybeans will set the stage for potential yield.

Denise McWilliams
Crop Production Specialist

dmcwilli@ndsuext.nodak.edu

 

WHEN IS IT TOO LATE TO PLANT SMALL GRAINS

We are now well past the date considered late for planting small grains. The two factors to consider when dealing with late seeded small grains are, will the crop avoid hot temperatures during vegetative development and will the crop be mature before fall frosts. If you can answer yes to both of these questions then its not to late.

The most critical factor to consider when planting small grains late is temperature. Ideally spring seeded small grains need a three to four week period of cool temperatures, less than 80E F, following planting. This insures adequate vegetative development. Shorter periods result in reduced tillering, and smaller head development. So the correct answer to the question "When should I stop planting small grains?" is, two to three weeks before continuous 80E+ F temperatures begin. If cool temperatures persist then late planted small grains can do well. Conversely, if it gets hot and dry a small grain crop likely will not perform well.

Donít over look the impact of delayed planting on crop quality. As planting is delayed protein content is likely to rise in both wheat and barley. While high protein is desirable in wheat, planting barley late may result in a crop with protein unacceptably high for malt quality. This can be countered in part by reducing nitrogen inputs but is no guarantee.

Michael D. Peel
Small Grains Extension Agronomist

mpeel@ndsuext.nodak.edu


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