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Precision Ag – Variable Rate Applications

Precision Ag – Variable Rate Applications published on No Comments on Precision Ag – Variable Rate Applications

 

by Dennis Burns

ANR Agent Tensas Parish

Recently I was talking to a producer who wanted to learn about making variable rate applications of nitrogen. The first question he asked was: “How much was am I going to save by making the application variable rate?” My response was not what he expected. I said “Don’t look at it as saving money, but as making money.” By matching the optimum nitrogen rate to the corresponding soil/production zone, crop use efficiency is highest and the potential profit from the nitrogen application is maximized.

To make a variable rate nitrogen application, a producer has to define the application zones. This can be based on soil types, Veris Ec soil zones, yield maps, producer knowledge or a combination. The producer’s knowledge of the field along with a yield goal helps determine the nitrogen rate assigned to each zone. The total amount applied to a field with a variable rate application may not be much different than if a producer had gone with a single rate, but by putting the correct rate in the right area the field doesn’t have areas with over or under applications of nutrients.

Soil Sampling is an essential part of variable rate applications, whether it is grid sampling or zone sampling. Each method would benefit from the addition of yield map data to the analysis. Yield maps over several crops and several years can help define the potential yield and profitability of a field. It can also assist with the definition of productivity zones for a field. This is especially obvious when a cropping history is developed over several years.

Variable rate applications of lime, P, K, and other essential nutrients need to be applied in areas defined by the sampling pattern (grid or zone). Variable rate applications of other nutrients is the most cost effective and efficient method for supplying crop needs. Variable rate also allows a producer to match fertility needs to the current crop’s needs. Supplying/maintaining fertility levels enhances the nitrogen efficiency and use by the crop.

The most useful piece of precision ag equipment a producer can own is a yield monitor. A yield monitor gathers the information from the field with which a producer can evaluate how well fertilizers, varieties, etc. performed. Verification strips of a nutrient, nitrogen rate, or another input can be used as a comparison for the rest of the field. Analyzing the results as whole strips and soil/production zones allows a producer to determine the most productive/economical practices to use on their farm.

Precision agriculture, its use, the results, and the incorporation of the practices into a farming operation is a long term process which can enhance the productivity of a farm. For more information or assistance with precision ag applications or yield data on your farm, contact Dennis Burns at 318-267-6709 or R.L. Frazier at 318-267-6714.

 

Wheat Insect Update

Wheat Insect Update published on No Comments on Wheat Insect Update

By Sebe Brown

Extension Entomologist, LSU AgCenter

I have had some reports of armyworms and leaffooted bugs in commercial wheat fields.   True armyworms are primarily an early season (spring) pest with a strong preference for grass crops.  Usually greenish in color with orange strips running down the lateral edges of the body, true armyworms typically feed at night and during overcast days.  During the day, true armyworms can be found under debris and thatch on the soil surface.  In Louisiana infestations normally occur in April, but with the unseasonably warm weather, early infestations from a multitude of pests can be expected.  Scout for this pest during the early morning, late evening or look for larvae on or under the soil surface.  Larvae feed on the foliage of wheat plants from the base and gradually work their way up towards the flag leaf.  Once the wheat has reached milk stage, the plant can tolerate greater levels of defoliation and see little to no yield loss. However, if armyworms begin to feed on or clip the wheat heads substantial yield losses can occur.  Thresholds for Louisiana are 5 or more larvae per square foot with foliage loss occurring.  True armyworms can be controlled with pyrethroids.  If an application for armyworms is justified, use enough carrier to adequately penetrate the wheat canopy.  Applications made during the late morning or afternoon may miss some armyworms in thatch or near the soil surface when direct sunlight and warm temperatures are abundant.

 Leaffooted bugs are similar to stink bugs with regards to their piercing sucking mouth parts and foul odor excreted when they are disturbed.  These insects are characterized by flattened leaf like expansions arising from the hind legs and a white strip running across the central part of the back.  Leaffooted bugs are very flighty and can easily migrate in and out of wheat fields from adjacent weed hosts such as thistle.  Flights of this pest can come from adjacent fields where burndown applications have been recently applied removing their primary host.  Louisiana currently does not have a threshold for these pests and control can be quite difficult with pyrethroids.  This insect is a minor pest of wheat.  However, if your wheat is lodged with them and they have not migrated out of your field within a few days or been blown out by the torrential down pours this spring, a pyrethroid application can be made.  If an application is deemed necessary, a high label rate of a strong pyrethroid should be used.  

 Aphids seem to be less of a problem this season than in previous years. The threshold for green bugs in wheat is 300-800 aphids per linear foot in wheat 6-16 inches in height.  Pyrethroid applications made for other pests such as true armyworms can effectively suppress populations of green bugs.  Many of the fields I have scouted have high numbers of natural enemies. These beneficial insects provide a free service in reducing aphid populations; however, aphids have the ability to outnumber their natural enemies in a short time frame.

 With fungicide applications going out, tank mixing a pyrethroid in while covering ground is an option if insect pests have begun to be a problem.  However, a jar test to assess fungicide/insecticide compatibility may be necessary prior to application.

 For more information concerning insect pest management, contact your local LSU AgCenter parish agent, LSU AgCenter specialist, or your agricultural consultant.

 

 

Wheat Disease Update

Wheat Disease Update published on No Comments on Wheat Disease Update

by Boyd Padgett, Ph.D., Plant Pathologist, LSU AgCenter

I have received a few reports of leaf and stripe rust in commercial fields; however, not at high levels. I have not observed any rust in producer fields in Northeast and Central Louisiana. In my tests around the state (Dean Lee, Red River, Ben Hur, and Macon Ridge), I have observed leaf rust at low levels in my tests located at the Macon Ridge Research Station, at moderate levels at Ben Hur, and stripe rust at low levels in tests at Dean Lee.  These tests are intentionally planted to SUSCEPTIBLE varieties, and are not representative of producer fields planted to resistant varieties. I have also observed powdery mildew in tests located at Ben Hur and the Red River Research Station. This disease is not considered to negatively impact wheat produced in Louisiana. However, if the disease is active (high incidence and severity) and present on the flag leaf prior to heading a fungicide may be justified. I HAVE NOT SEEN THIS SENARIO IN THE PAST 15 YEARS.

 Producer fields: If rust incidence and severity is low (no pustules on the flag and confined to the lower canopy not active), most plants are fully headed (not flowering), and the variety is rust resistant, a fungicide is probably not needed.

Fungicides are justified if the wheat is at flag leaf to early heading and rust is active (spores are easily seen on the lower canopy). The following conditions are necessary for leaf and stripe rust development.

 Stripe rust development is most aggressive when nighttime temperatures are 50 to 65oF in the presence of intermittent rain or dews. However, development can occur when temperatures are near freezing up to 70oF.  Initial infections on seedling wheat may not have the characteristic striping pattern that occurs on more mature plants.  Seedling infections often occur in ‘thumb-sized’ clusters on the leaves, as opposed to a random distribution that occurs with leaf rust.    Infections may appear as linear rows of small yellow to light orange pustules (stripes) on the lower leaves during late winter or early spring. Striped patterns are typical of infections in older pants.  If conditions remain favorable for development, pustules may cover the entire upper leaf surface, as well as portions of the head. A lifecycle (infection to reproduction) can be completed in 7 to 10 days when conditions are optimum for development.

 Leaf rust is usually evident later in the season than stripe rust. This is because the leaf rust pathogen requires warmer temperatures for development than stripe rust. Initial symptoms of leaf rust begin as light yellow spots, usually on the lower foliage. As the disease develops, small pin-point pustules form on the upper leaf surface. Pustules are brick or dark red and occur randomly on the leaf. Similar to stripe rust, pustules can cover the entire leaf surface if conditions remain favorable for development. The disease develops optimally when nighttime temperatures are 50 to 70oF and leavers remain wet for 6 to 8 hours. Similar conditions will favor the development of leaf and glume blotch caused by Stagonospora and Septoria, respectively.

 For more information concerning wheat disease management, contact your local LSU AgCenter county agent, LSU AgCenter specialist, or your agricultural consultant.

Rice insecticide seed treatment considerations for 2012

Rice insecticide seed treatment considerations for 2012 published on No Comments on Rice insecticide seed treatment considerations for 2012

by Natalie Hummel

You can link to Dr. Natalie Hummel’s weblog by going to: http://louisianariceinsects.wordpress.com/

This article was originally published in Louisiana Farm and Ranch, February 2012. I’m reposting it here for your information. This is an important article to read as growers are making their decision about insecticide seed treatments in rice for the 2012 season.

Authors: Natalie Hummel, Associate Professor and Assistant to the Director & Mike Stout, Professor

We have had quite a few inquiries about using a combination of seed treatments, neonicotinoid and Dermacor X-100, in rice. While this practice is legal, using more than one seed treatment is not a practice that we encourage in most circumstances because it results in more insecticide use in rice production than may be necessary.

The rice industry is considering one of these combinations of seed treatments: 1) Dermacor X-100 and CruiserMaxx or 2) Dermacor X-100 and NipsitINSIDE. Typically, a combination of seed treatments is only being considered when planting rice at low seeding rates, primarily because of concerns about the lack of efficacy of CruiserMaxx and NipsitINSIDE at hybrid seeding rates (25 lbs/acre or less) that we have observed in our rice water weevil demonstration trials and small plot trials. The second scenario is where Dermacor X-100 is being used for rice water weevil management and there is a history of stand reduction because of a sporadic pest infestation, usually chinch bugs or armyworms. Combining seed treatments provides a benefit of protecting the crop from injury by some primary and sporadic crop pests.

As the rice industry moves toward a more sustainable crop production profile, the LSU AgCenter strongly encourages rice producers to be good stewards of these insecticide seed treatments. Stewardship of these seed treatments means avoiding the use of insecticides not needed in the crop. For this reason, we discourage the widespread use of a combination of insecticide seed treatments in rice. We instead encourage the person making the seed treatment decision to consider the spectrum of pests that each insecticide can control, the seeding rate, and the history of crop pests in that field.

It is important to remember that each of the seed treatments controls a different group of insects. Dermacor X-100 belongs to a class of insecticides called anthranilic diamides, which target a specific receptor in the muscle of the insect. Dermacor X-100 is registered to control rice water weevil larvae, borers (Mexican rice borer, Rice stalk borer, Sugarcane borer), armyworms and colaspis (2ee registration for suppression). CruiserMaxx and NipsitINSIDE are both neonicotinoid insecticides that affect the nervous system of target insects. CruiserMaxx is labeled to control rice water weevils (larvae and adults), chinch bugs, colaspis and thrips. NipsitINSIDE is labeled to control rice water weevils and colaspis. We do not have data to support the ability of CruiserMaxx or NipsitINSIDE to control chinch bugs, colaspis or thrips in Louisiana, but we anticipate that they will control these pests based on observations from other crops and from rice in other parts of the world. As you study these seed treatments, you can see how a combination of these products can control most of the insects that attack rice in Louisiana. This is part of the reason why there is an inclination toward using a combination of treatments.

Here are criteria for you to consider as you make your seed treatment decision. The first is the seeding rate. This needs to be considered because neonicotinoids don’t always provide good control of rice water weevils at low seeding rates. Dermacor X-100 does provide control of rice water weevils at all seeding rates, but it will not control chinch bugs or thrips. According to the chemical manufacturers, neonicotinoids do control other early season pests including chinch bugs, thrips and colaspis. Another challenge at low seeding rates is that the plant stand is thin and is less tolerant to any insects that reduce the stand by killing seedlings. Insects that can reduce the plant stand count include armyworms, chinch bugs, colaspis and thrips. Borers can infest fields after the plant is at the green ring growth stage and reduce yields by causing deadhearts and whiteheads. Remember that if you put out a combination of seed treatments for a sporadic pest and that pest doesn’t infest your field, then you didn’t need to use a combination of seed treatments. We have data that indicate that rice water weevils infest more than 90% of rice fields in Louisiana. This justifies the use of a seed treatment to control rice water weevils as part of a good IPM program. That is not the case for many of our sporadic pests (armyworms, chinch bugs, colaspis, borers, etc.), which rarely occur at levels that justify treatment. Also, keep in mind that we rarely recommend an insecticide treatment for thrips in rice; usually the damage is not severe enough to require an insecticide.

Here are a couple of situations where a combination of seed treatments may be a good management decision. If you are planting rice at a low seeding rate and you anticipate that you will have an infestation of chinch bugs that would justify a pyrethroid treatment, then a combination of seed treatments would be a good option. In this situation, you would be using Dermacor X-100 to control rice water weevils, borers and armyworms and adding a neonicotinoid to control chinch bugs or thrips. Also, if you are planting rice at conventional seeding rates and you are using a neonicotinoid seed treatment to control rice water weevils and colaspis, but you typically have problems with armyworms or borers, then you may want to apply Dermacor X-100 to your seed.

There is one more thing to consider as you make your seed treatment decisions for the 2012 season. The EPA recently approved a Section 24C (special local need) registration for use of Dermacor X-100 in water-seeded rice. If you are interested in this option, a certified seed treater can provide more information. Remember that you CANNOT use the other seed treatments (CruiserMaxx or NipsitINSIDE) in water-seeded rice. The use of CruiserMaxx and NipsitINSIDE in water-seeded rice is illegal and will not provide control of the target pests.

If you have any questions about the seed treatment options registered for use in rice, please contact your local County Agent, or Natalie Hummel (nhummel@agcenter.lsu.edu) for more information.

 

Preparing for the upcoming season using precision ag equipment

Preparing for the upcoming season using precision ag equipment published on No Comments on Preparing for the upcoming season using precision ag equipment

By Dennis Burns & R.L. Frazier

Now is the time to get fields and crops organized for the upcoming season.  When it comes to field names and numbers, consistency is the key to success.  Analyzing yield data or documenting production practices for multiple years makes it virtually a requirement.  Other information such as crops, variety names, chemicals, fertilizers, equipment, etc. can be entered now in preparation for use.  This information can be entered using desktop programs (e.g. APEX, Farm Works, SMS) and copied to the data cards which go in the equipment on the tractors, sprayers, and harvesters.  Or it can be entered directly into the equipment if one of the desktop programs is not available.  Along with these card entries, make a reference notebook with maps and other information that can stay with each tractor, sprayer, harvester, and other equipment.  Time spent now getting data prepared and organized will help keep field operations moving smoothly with fewer glitches to hinder data analysis after the tasks are finished.  For more information or assistance with this or other precision ag applications please contact Dennis Burns (318-267-6709) or R.L. Frazier (318-267-6714) with the LSU AgCenter.

LSU AgCenter Establishes Blog Site for Row Crops Newsletter and Updates

LSU AgCenter Establishes Blog Site for Row Crops Newsletter and Updates published on No Comments on LSU AgCenter Establishes Blog Site for Row Crops Newsletter and Updates

by John S. Kruse 

LSU AgCenter researchers and specialists have created a new avenue for obtaining the Crops Newsletter. Articles published in the Louisiana Crops Newsletter can now also be found at www.louisianacrops.com. Many constituents have expressed their preference for the easy, article-by-article access provided by a website and it is our goal to make science-based information available in forms that are user-friendly. For those that prefer to continue to receive the Newsletter in the current pdf form, rest assured that we will continue to send it out in this form as well. We look forward to serving your needs and hope you enjoy this additional way of accessing the Newsletter.

Influence of Nitrogen Fertilizer Rate, Source, and Time of Application on Improving N Efficiency: Silt Loam

Influence of Nitrogen Fertilizer Rate, Source, and Time of Application on Improving N Efficiency: Silt Loam published on No Comments on Influence of Nitrogen Fertilizer Rate, Source, and Time of Application on Improving N Efficiency: Silt Loam

H.J. “Rick” Mascagni, Jr. and Brenda Tubana

Introduction

            Nitrogen (N) fertilization is a critical cultural practice required for producing maximum corn yield. Many factors, including soil type and crop management systems, determine optimum N rates. Nitrogen is typically knifed-in soon after the crop has emerged and an adequate stand established. Growers often times split N fertilizer applications as part of their management system or, in some cases, due to uncontrollable factors such as excessive or lack of rainfall, may produce soil conditions conducive to N fertilizer loss through denitrification and/or inefficient plant N uptake.  If N is topdressed with a fertilizer containing urea losses may occur due to volatization, which depends to a large extent on climatic and soil factors. If irrigated or rainfall occurs (0.5 inch or greater) within about three days, the fertilize is incorporated and no or minimal volatization losses will occur  Sometimes N applications are delayed or omitted due to inclement weather, while at other times, growers apply the recommended N rate for an expected yield potential. However, as the crop develops yield potential may be higher than expected and additional N may be required. In each of the above situations the question arises, how late can N fertilizer be applied and be effective? The fertilizer N source is also an important component of an effective fertility program. Products are also available such as urease inhibitors (i.e., Agrotain) that minimize urea volatization losses for 7 to 10 days. The objective of this trial was to evaluate N applications, N sources, and an urease inhibitor at different growth stages on a Mississippi River silt loam.

 Procedures

            A field experiment was conducted in 2011 on Commerce silt loam at the Northeast Research Station near St. Joseph to evaluate the influence of N rate, timing, and fertilizer source on corn yield and N fertilizer use efficiency (NFUE). Early-season N rates were injected at about the 3-leaf growth stage (April 16) as 30-0-0-2 solution (UAN) at N rates of 0, 120, 150, 180, and 210 lb N/acre. Urea, with and without Agrotain (3 qts/ton urea), was also hand-broadcast at the rate of 120 lb N/acre at the 3-leaf growth stage. For the early-season N rate of 120 lb/acre using 30-0-0-2, supplemental N rates of 30 and 60 lb/acre were applied at about the 12-leaf (May 23) and early-silk growth stages (June 7). Urea, with and without Agrotain, was hand-broadcast  and 30-0-0-2, with and without Agrotain, was hand-dribbled (to simulate a dribble application) at the 12-leaf and early-silk applications. There were a total of 23 treatments (see Table 2). REV® 28HR20 was planted on March 24 at 32,000 seed/acre. Cotton was the previous crop and all LSU AgCenter recommended cultural practices were followed.

             The experimental design was a randomized complete block with four replications. Grain yield, yield components, plant N, seed N, NFUE, and remote sensing data were determined. Grain yield was determined by machine harvest from the two middle rows of four-row plots and reported at 15.5% moisture. Yield components, seed weight (g/100 seed) and ear size (seed/ear) were also determined from the two middle rows.  Ear-leaf samples were collected at the early- silk growth stage to determine the influence of treatments on the N status of the plant. Seed samples were also collected at harvest. Total N was determined in the plant tissue and harvested seed by the LSU AgCenter’s Soil and Plant Testing Lab. Seed-N uptake (lb N/acre) was calculated by multiplying seed-N concentration by grain yield. NFUE was calculated using the following formula: (seed-N uptake for a given N rate – seed-N uptake for the no-N control) / N rate.   Remote sensing data using a SPAD meter were also determined at the 3- and 12-leaf growth stages. Statistical analyses were performed using the GLM procedure of SAS using a probability level of 0.10.

 Results and Discussion

            Rainfall was extremely low in May with a only a total of 4.9 inches in May and June in this dryland trial (Table 1). However, overall yields were extremely good averaging over 150 bu/acre (Table 2).

             At early-season, urea, urea + Agrotain, and UAN were compared at the 120 lb N/acre rate. Yield response had the following rank: UAN = urea + Agrotain > urea (Table 2). Evidently, there was some N loss due to volatization for the urea fertilizer. There was a 10 day interval between application and the first rainfall event. For the late N applications at the 12-leaf growth stage and early silk, both the 30 and 60 lb N/acre rates increased yields across sources. Yields tended to be a little higher for the early silk compared to 12-leaf applications. There were 11 and 2 day intervals between application and rainfall for the 12-leaf and early-silk applications, respectively. There was a yield response to urea + Agrotain for the 30 lb N/acre late application at the 12-leaf growth stage. When comparing equivalent N rates applied either once early season or split between early season and 12 leaf or early-silk growth stages, yields were similar. The treatment influence on kernel weight and ear size (kernel number) are shown in Table 2.

 Plant and seed N data are presented in Table 3. Leaf N, seed N, seed N uptake, and NFUE had the following rank for the early-season N treatments: UAN>urea+Agrotain>urea. Similar to yield responses, there were only small differences between the 12-leaf and early-silk late N applications for each N trait. Nitrogen fertilizer use efficiency (NFUE) was extremely high, ranging from 0.36 to 0.78 (Table 3). There were no differences in NFUE between the single and split applications, when comparing equivalent N rates. SPAD readings reflected treatment effects similar to yield responses (Table 4).

 

Table 1. Rainfall in St. Joseph, 2011.

Month

Rainfall

 

inches

 

 

March

8.3

April

3.0

May

0.9

June

4.0

July

4.4

August

1.3

 

Table 2. Influence of N fertility treatments on corn yield and yield components on Commerce silt loam, 2011.

 

 

 

N rate

 

 

 

 

 

 

 

ESN1 rate

ESN

source2

 

12-leaf

Early silk

Late N

source

Total N

applied

 

Yield

 

Ears

Kernel

weight

 

Kernels

lb/a

 

———lb/a——

 

lb/a

bu/a

no/a

g/100

no/ear

 

 

 

 

 

 

 

 

 

 

0

0

39.6

31,390

31.7

124

120

Urea

120

116.7

32,700

32.0

293

120

Urea + Ag

120

141.9

32,700

33.4

329

120

UAN

120

145.8

33,350

34.4

365

 

 

 

 

 

 

 

 

 

 

120

UAN

30

Urea

150

160.7

33,350

34.7

327

120

UAN

30

Urea+Ag

150

169.4

32,700

34.1

386

120

UAN

30

UAN

150

165.8

30,740

34.7

423

120

UAN

30

UAN+Ag

150

165.6

32,700

36.0

385

Average

 

 

 

 

165.4

32,370

34.9

380

 

 

 

 

 

 

 

 

 

 

120

UAN

60

Urea

180

170.0

32,050

35.2

386

120

UAN

60

Urea+Ag

180

176.8

34,010

36.2

397

120

UAN

60

UAN

180

160.3

33,350

35.2

357

120

UAN

60

UAN+Ag

180

166.2

32,700

35.1

378

Average

 

 

 

 

168.3

33,030

35.4

380

 

 

 

 

 

 

 

 

 

 

120

UAN

30

Urea

150

168.5

34,660

35.1

361

120

UAN

30

Urea+Ag

150

151.8

33,350

34.9

368

120

UAN

30

UAN

150

168.7

32,700

35.7

389

120

UAN

30

UAN+Ag

150

168.0

33,350

34.3

386

Average

 

 

 

 

164.3

33,520

35.0

376

 

 

 

 

 

 

 

 

 

 

120

UAN

60

Urea

180

177.0

32,700

35.6

403

120

UAN

60

Urea+Ag

180

172.8

34,010

34.4

383

120

UAN

60

UAN

180

166.5

33,350

34.1

381

120

UAN

60

UAN+Ag

180

170.0

32,700

35.1

393

Average

 

 

 

 

171.6

33,190

34.8

390

 

 

 

 

 

 

 

 

 

 

150

UAN

150

166.2

34,010

34.3

374

180

UAN

180

169.8

30,740

33.9

432

210

UAN

210

178.8

34,010

36.7

380

 

 

 

 

 

 

 

 

 

 

LSD (0.10):

 

 

 

 

14.7

NS3

2.7

53

                                                 

1ESN, early-season N injected at about 3-leaf growth stage.

2Ag = Agrotain; UAN = 30-0-0-2;

3NS = Non-significant at the 0.10 probability level

 

Table 3. Influence of N fertility treatments on N nutrition of corn on Commerce silt loam, 2011.

 

 

 

N rate

 

 

 

 

 

 

ESN1 rate

ESN

source2

 

12-leaf

Early silk

Late N

source

Total N

applied

 

Leaf N

 

Seed N

Seed N

uptake

 

NFUE3

lb/a

 

———lb/a——

 

lb/a

%

%

lb N/a

 

 

 

 

 

 

 

 

 

 

 

0

0

1.18

1.28

39.7

120

Urea

120

1.57

1.22

82.0

0.36

120

Urea + Ag

120

1.86

1.38

107.9

0.57

120

UAN

120

2.24

1.43

133.0

0.78

 

 

 

 

 

 

 

 

 

 

120

UAN

30

Urea

150

2.30

1.40

116.9

0.52

120

UAN

30

Urea+Ag

150

2.23

1.43

135.0

0.64

120

UAN

30

UAN

150

2.26

1.44

141.7

0.68

120

UAN

30

UAN+Ag

150

2.32

1.45

143.5

0.69

Average

 

 

 

 

2.28

1.43

134.3

0.63

 

 

 

 

 

 

 

 

 

 

120

UAN

60

Urea

180

2.32

1.50

142.4

0.57

120

UAN

60

Urea+Ag

180

2.27

1.55

166.4

0.71

120

UAN

60

UAN

180

2.15

1.50

138.1

0.55

120

UAN

60

UAN+Ag

180

2.36

1.52

145.4

0.59

Average

 

 

 

 

2.28

1.52

148.1

0.61

 
 

 

 

 

 

 

 

 

 

 

 
120

UAN

30

Urea

150

1.40

135.0

0.64

 
120

UAN

30

Urea+Ag

150

1.44

136.1

0.64

 
120

UAN

30

UAN

150

1.48

146.9

0.72

 
120

UAN

30

UAN+Ag

150

1.48

143.7

0.70

 
Average

 

 

 

 

1.45

140.4

0.68

 
 

 

 

 

 

 

 

 

 

 

 
120

UAN

60

Urea

180

1.47

151.7

0.63

 
120

UAN

60

Urea+Ag

180

1.53

149.8

0.61

 
120

UAN

60

UAN

180

1.47

139.1

0.56

 
120

UAN

60

UAN+Ag

180

1.45

142.4

0.58

 
Average

 

 

 

 

1.48

145.8

0.60

 
 

 

 

 

 

 

 

 

 

 

 
150

UAN

150

2.28

1.45

139.3

0.67

 
180

UAN

180

2.50

1.49

146.9

0.60

 
210

UAN

210

2.48

1.48

154.4

0.55

 
 

 

 

 

 

 

 

 

 

 

 
LSD (0.10):

 

 

 

 

 

0.16

0.10

21.7

0.14

 
                                                   

1ESN, early-season N injected at about 3-leaf growth stage.

2Ag = Agrotain; UAN = 30-0-0-2;

3NFUE = N fertilizer use efficiency

Table 4. Influence of N fertility treatments on SPAD readings taken early season and at 12-leaf growth stage on Commerce silt loam, 2011.

 

 

 

N Fertilizer Source

 

 

 N rate1

 

Total N

 

Urea

Urea + Agrotain

 

UAN2

UAN + Agrotain

 

Average

lb/acre   ———————————SPAD Readings ————————————-
 

 

 

 

 

 

 

 

 

 

Early-Season N Application

 

 

 

 

 

 

 

 

120

120

38.5

44.0

46.9

43.1

150

150

48.5

48.5

180

180

51.1

51.1

210

210

52.4

52.4

 

 

 

 

 

 

 

 

 

 

     12-leaf Growth Stage N Application

 

 

 

 

 

 

30

150

49.2

46.4

50.0

50.4

49.0

60

180

50.1

52.2

48.4

51.2

50.5

Average

 

49.7

49.3

49.2

50.8

 

 

 

 

 

 

 

 

LSD (0.10):

 

 

 

3.8

 

 

                   

1N rate applied early-season (3-leaf) and 12-leaf growth stage

2UAN = 30-0-0-2 fertilize solution

 

Influence of Nitrogen Fertilizer Rate, Source, and Time of Application on Improving N Efficiency: Clay

Influence of Nitrogen Fertilizer Rate, Source, and Time of Application on Improving N Efficiency: Clay published on No Comments on Influence of Nitrogen Fertilizer Rate, Source, and Time of Application on Improving N Efficiency: Clay

 H.J. “Rick” Mascagni, Jr. and Brenda Tubana

Introduction

            Nitrogen (N) fertilization is a critical cultural practice required for producing maximum corn yield. Many factors, including soil type and crop management systems, determine optimum N rates. Nitrogen is typically knifed-in soon after the crop has emerged and an adequate stand established. Growers often times split N fertilizer applications as part of their management system or, in some cases, due to uncontrollable factors such as excessive or lack of rainfall, may produce soil conditions conducive to N fertilizer loss through denitrification and/or inefficient plant N uptake.  If N is topdressed with a fertilizer containing urea losses may occur due to volatization, which depends to a large extent on climatic and soil factors. If irrigated or rainfall occurs (0.5 inch or greater) within about three days, the fertilize is incorporated and no or minimal volatization losses will occur  Sometimes N applications are delayed or omitted due to inclement weather, while at other times, growers apply the recommended N rate for an expected yield potential. However, as the crop develops yield potential may be higher than expected and additional N may be required. In each of the above situations the question arises, how late can N fertilizer be applied and be effective? The N fertilizer source is also an important component of an effective fertility program. Products are also available such as urease inhibitors (i.e., Agrotain) that minimize urea volatization losses for 7 to 10 days. The objective of this trial was to evaluate N applications, N sources, and an urease inhibitor at different growth stages on a Mississippi River clay soil.

 Procedures

            A field experiment was conducted in 2011 on Sharkey clay at the Northeast Research Station near St. Joseph to evaluate the influence of N rate, timing, and fertilizer source on corn yield and N fertilizer use efficiency (NFUE). Early-season N rates were injected at about the four-leaf growth stage (April 15) as 30-0-0-2 solution (UAN) at N rates of 0, 150, 210, and 240 lb/acre. Urea,with and without Agrotain (3 qts/ton urea), was also hand-broadcast at the rate of 150 lb N/acre at the four-leaf growth stage. For the early-season N rate of 150 lb/acre using 30-0-0-2, a supplemental N rate of 60 lb/acre was applied at about the 12-leaf (May 22) and early-silk growth stages (June 2). Urea was hand-broadcast and UAN was hand-dribbled (to simulate a dribble application) at the 12-leaf and early-silk applications. There were a total of 10 treatments (see Table 2). Pioneer 31P42 was planted on March 23 at 32,000 seed/acre. The trial was furrow irrigated. Cotton was the previous crop and all LSU AgCenter recommended cultural practices were followed.

             The experimental design was a randomized complete block with five replications. Grain yield, yield components, plant N, seed N, NFUE, and remote sensing data were determined. Grain yield was determined by machine harvest from the two middle rows of four-row plots and reported at 15.5% moisture. Yield components, ears/acre, kernel weight (g/100 seed), and ear size (kernels/ear) were also determined from the two middle rows.  Ear-leaf samples were collected at the early-silk growth stage to determine the influence of treatments on the N status of the plant. Seed samples were also collected at harvest. Total N was determined in the plant tissue and harvested seed by the LSU AgCenter’s Soil and Plant Testing Lab. Seed-N uptake (lb N/acre) was calculated by multiplying seed-N concentration by grain yield. NFUE was calculated using the following formula: (seed-N uptake for a given N rate – seed-N uptake for the no-N control) / N rate.   Remote sensing data using a SPAD meter were also determined at the 4- and 12-leaf growth stages. Statistical analyses were performed using the GLM procedure of SAS using a probability level of 0.10.

 Results and Discussion

            Rainfall only totaled 4.9 inches in May and June (Table 1). Furrow irrigations were applied on May 22 and June 2. Across treatments, yields ranged from 15.9 (control) to 197.5 bu/acre (Table 2).

             At early season, urea, urea + Agrotain, and UAN were compared at the 150 lb N/ace rate. Yield responses to treatments had the following rank: UAN > urea + Agrotain > urea (Table 2). There was a 11 day interval between application and rainfall. The late application of 60 lb N/acre increased yields similarly for both the 12-leaf and early-silk applications. There was little difference in yield between sources. Kernel weight was slightly higher for the late compared to early-season applications. When comparing equivalent N rates applied either once early season or split between early season and 12 leaf or early-silk growth stages, yields were similar.

 

Leaf and seed N data are presented in Table 3. Leaf N, seed N, seed N uptake, and NFUE responses to early-season N treatments were highest for UAN compared to urea + Agrotain and urea. There were small differences between the 12-leaf and early-silk N applications for each N trait evaluated. When comparing equivalent N rates, there were small differences between single and split applications for any N trait. Nitrogen fertilizer use efficiency (NFUE) was extremely high, ranging from 0.46 to 0.68. The highest NFUE value occurred for the 150 lb N/a UAN treatment applied early season. SPAD readings reflected trends similar to the yield response (Table 4).

 

Table 1. Rainfall in St. Joseph, 2011.

Month

Rainfall

 

inches

 

 

March

8.3

April

3.0

May

0.9

June

4.0

July

4.4

August

1.3

 

Table 2. Influence of N fertility treatments on corn yield and yield components on Sharkey clay, 2011.

 

 

 

N rate

 

 

 

 

 

 

 

ESN1 rate

ESN

source2

 

12-leaf

Early silk

Late N

source

Total N

applied

 

Yield

 

Ears

Kernel

weight

 

Kernels

lb/a

 

———lb/a——

 

lb/a

bu/a

no/a

g/100

no/ear

 

 

 

 

 

 

 

 

 

 

0

0

15.9

33,350

30.4

42

150

Urea

150

114.3

32,700

33.9

270

150

Urea + Ag

150

124.8

32,050

33.4

295

150

UAN

150

164.8

28,780

36.6

414

 

 

 

 

 

 

 

 

 

 

150

UAN

60

Urea

210

187.8

28,780

37.2

441

150

UAN

60

UAN

210

184.4

30,080

38.2

416

Average

 

 

 

 

 

186.1

29,430

37.7

429

 

 

 

 

 

 

 

 

 

 

150

UAN

60

Urea

210

191.1

28,780

37.2

446

150

UAN

60

UAN

210

186.1

34,010

37.6

402

Average

 

 

 

 

 

188.6

31,400

37.4

424

 

 

 

 

 

 

 

 

 

 

210

UAN

210

183.9

32,050

37.6

400

240

UAN

240

197.5

33,350

34.8

471

 

 

 

 

 

 

 

 

 

 

LSD (0.10):

 

 

 

 

 

10.9

NS3

NS

80

                                         

1ESN, early-season N injected at about 4-leaf growth stage.

2Ag = Agrotain; UAN = 30-0-0-2;

3NS = Non-significant at the 0.10 probability level

Table 3. Influence of N fertility treatments on N nutrition on Sharkey clay, 2011.

 

 

 

N rate

 

 

 

 

 

 

 

ESN1 rate

ESN

source2

 

12-leaf

Early silk

Late N

source

Total N

applied

 

Leaf N

 

Seed N

Seed N

uptake

 

NFUE3

lb/a

 

———lb/a——

 

lb/a

%

%

lb N/a

 

 

 

 

 

 

 

 

 

 

 

0

0

0.98

1.29

11.5

150

Urea

150

1.47

1.24

79.8

0.46

150

Urea + Ag

150

1.60

1.20

84.1

0.48

150

UAN

150

2.50

1.23

114.1

0.68

 

 

 

 

 

 

 

 

 

 

150

UAN

60

Urea

210

2.60

1.27

133.7

0.58

150

UAN

60

UAN

210

2.60

1.32

136.0

0.59

Average

 

 

 

 

 

2.60

1.30

134.9

0.59

 

 

 

 

 

 

 

 

 

 

150

UAN

60

Urea

210

1.31

140.3

0.62

150

UAN

60

UAN

210

1.34

139.5

0.61

Average

 

 

 

 

 

1.33

139.9

0.62

 

 

 

 

 

 

 

 

 

 

210

UAN

210

2.57

1.30

134.3

0.59

240

UAN

240

2.65

1.36

149.9

0.58

 

 

 

 

 

 

 

 

 

 

LSD (0.10):

 

 

 

 

 

0.17

0.05

9.1

0.05

                                         

1ESN, early-season N injected at about 4-leaf growth stage.

2Ag = Agrotain; UAN = 30-0-0-2;

3NFUE = N fertilizer use efficiency

Table 4. Influence of N fertility treatments on SPAD readings at the early season and

12-leaf growth stages on Sharkey clay, 2011.

 

 

 

N Fertilizer Source

 

N rate1

Total N

Urea

Urea + Agrotain

UAN

lb/a

lb/a

———————–SPAD readings—————————
              

 

 

 

 

 

 

 

Early-Season N Application

 

150

150

39.6

40.3

54.6

210

210

 

 

59.1

240

240

 

 

56.1

 

 

 

 

 

 

 

 

 

 

 

 

 

12-leaf Growth Stage N Application

 

60

210

54.2

 

56.7

 

 

 

 

 

LSD (0.10):

 

 

3.8

 

                     

 

Nematode Ratings of the Highest Yielding Soybean Varieties for 2012

Nematode Ratings of the Highest Yielding Soybean Varieties for 2012 published on No Comments on Nematode Ratings of the Highest Yielding Soybean Varieties for 2012

Charles Overstreet, Extension Nematologist

Highest yielding cultivars in Group III and Early Group IV Soybean Varieties

Soybean Variety

Soybean Cyst Nematode

Reniform Nematode

Root-knot Nematode

Delta Grow 4460RR

R 3

NA

S

Pioneer 93Y92

R 3, MR 14

NA

NA

Progeny 3911RY

S

S

S

Progeny 4211

R 3, MR 5, 14

S

S

Rev 44R22Tm

S

NA

S

S42-T4 Brand

R 3

S

S

S44-D5 Brand

R 3,  MR 14

NA

NA

 Highest Yielding Group IV Late Soybean Varieties

Soybean Variety

Soybean Cyst Nematode

Reniform Nematode

Root-knot Nematode

Armor 55 R 22

R 3, MR 14

NA

NA

Armor X1210

S

S

S

Armor X1211

S

S

S

Asgrow 4832

R 3

S

S

Asgrow 4932

R 3

S

S

Delta Grow 4670 R2Y

S

S

S

Delta Grow 4875 R2Y

R 3, MR 14

S

S

Delta Grow 4975 RR

MR 5

NA

S

Dyna-Gro 31RY45

R 3, MR 14

S

S

GoSoy 4810 LL

R 3

NA

NA

HBK R4829

MR 3

NA

S

HBK R4924

R 3, MR 14

S

S

HBK RY4721

R 3, MR 14

S

S

Miami 949LL

R 3

NA

NA

Morsoy 4707

R 3

S

S

Morsoy Xtra 46X29

NA

S

S

Morsoy Xtra 46X71

R 3

S

S

Pioneer 94Y70

R 3, MS 14

NA

S

Pioneer 94Y80

R 3, MS 14

NA

S

Pioneer 94Y82

R 3, MR 14

NA

S

Progeny 4510RY

S

NA

S

Progeny 4611RY

R 3, MR 14

S

S

Progeny 4710RY

S

NA

S

Progeny 4750RR

MR 3

NA

S

Progeny 4807RR

R 3

NA

S

Progeny 4811RY

R 3, MR 14

S

S

Progeny 4906RR

S

NA

S

Progeny 4911RY

S

S

MR

Soybean Variety

Soybean Cyst Nematode

Reniform Nematode

Root-knot Nematode

Progeny 4928LL

MR 3

NA

NA

REV @46R73TM

NA

S

S

REV @47R53TM

NA

S

S

REV @48R10TM

R 3

NA

S

REV @48R21TM

NA

S

S

REV @48R22

NA

NA

S

REV @48R33TM

NA

S

S

REV @49R10TM

NA

NA

S

REV @49R11TM

R 3

NA

S

REV @49R22TM

NA

NA

S

REV @49R43TM

NA

S

S

S08-14087 RR

R 3, MS 14

S

S

S08-17361

R 3, MS 14

NA

NA

Schillinger 457.RCP

R 3, MS 14

NA

S

Schillinger 458.RCS

MR 3

NA

S

Schillinger 478.RCS

MR 3, MS 14

NA

S

Schillinger 495.RC

MR 3, MS 14

NA

S

Highest Yielding Group V Soybean Varieties

Soybean Variety

Soybean Cyst Nematode

Reniform Nematode

Root-knot Nematode

AGS 568 RR

S

NA

MR

AGS 5911 LL

NA

NA

NA

AGS 597 RR

S

NA

S

Armor DK5363

MR 3

NA

S

Armor X1213

S

S

S

Armor X1215

S

S

S

Asgrow 5232

R 3

S

S

Asgrow 5332

R 3

S

S

Asgrow 5632

R 3

S

S

Delta Grow 5110R2Y EX

MR 5

S

MR

Delta Grow 5545RR

S

S

MS

Delta Grow 5555RR

R 1, 3, 5, 9

NA

S

Delta Grow 5625R2Y

S

S

S

Dyna-Gro 32RY55

R 3, MR 14

S

R

Dyna-Gro 35F55

R 1, 3

NA

S

Dyna-Gro 35P53

MR 2

NA

S

Dyna-Gro 37RY52

R 3, MR 14

NA

S

Dyna-Gro 39RY57

R 3

NA

R

GoSoy 5111 LL

R 3

NA

NA

HBK R5529

MR 1, R 2

NA

S

HBK RY5121

R 3

S

S

Soybean Variety

Soybean Cyst Nematode

Reniform Nematode

Root-knot Nematode

HBK RY5421

NA

S

S

HBK RY5521

NA

NA

S

Morsoy 5168

NA

S

S

Osage

S

NA

MS

Pioneer 95Y01

R 3, MR 14

NA

S

Pioneer 95Y10

R 3, MR 14

NA

NA

Pioneer 95Y20

NA

NA

NA

Pioneer 95Y31

R 3, MR 14

NA

S

Pioneer 95Y50

NA

NA

S

Pioneer 95Y70

NA

NA

S

Progeny 5111RY

R 3

S

MR

Progeny 5330RR

R 1, MR 2

NA

MR

Progeny 5610RY

R 3, MR 14

NA

R

Progeny 5655RY

S

S

S

Progeny 5711RY

R 3

S

S

Progeny 5811RY

S

S

S

Progeny 5960LL

NA

NA

MR

REV @51R53TM

S

S

S

REV @56R63TM

MS 3

S

MS

S54-V4 Brand

R 3

NA

S

USG 75Z98

S

NA

NA

 Letter designations for nematode reaction are: S = susceptible, MS= moderately susceptible, MR= moderately resistant, R= Resistant, and NA= no information available. All information in this table was provided by the seed companies or the University of Arkansas variety testing program at http://www.arkansasvarietytesting.com/crop/data/5.

 Soybean cyst nematode (SCN) continues to be a very minor nematode pest in our state. Currently, selection of a variety based on this nematode is not very important. None of the varieties on our list have any resistance against the reniform nematode which is found in 60% or more of our soybean fields. A few varieties have some level of resistance against the root-knot nematode.

Corn Insecticide Seed Treatment Options

Corn Insecticide Seed Treatment Options published on No Comments on Corn Insecticide Seed Treatment Options

Sebe Brown, Extension Entomologist

 Selecting corn seed treatments can be a challenging and expensive undertaking faced by many producers across Louisiana.  Corn seed treatments target three spectrums of pests: nematodes, fungal seedling diseases and insects.  This article will address insecticide seed treatment options available for corn.

Insecticide seed treatments are usually the main component of a seed treatment package.  Most corn seed available today comes with a base package that includes a fungicide and insecticide.  The insecticide options for seed treatments include Poncho (clothianidin), Cruiser/Cruiser Extreme (thiamethoxam) and Gaucho (Imidacloprid).  All three of these products are neonicotinoid chemistries.  Cruiser and Poncho at the 250 (.25 mg AI/seed) rate are the most common base options available for corn.  These insecticides are a good foundation; however, do not expect these treatments to give you extended protection from all below ground pests. If sugarcane beetles have been a problem in the past, Cruiser at the 250 or 500 rate will not provide adequate control; consider using Poncho at the 500 rate with 1250 providing better protection.  None of these products provide adequate control of cutworms.  Each company offers treatments that provide differing levels of early season insect protection, outlined below are some options available to producers with regards to insecticide seed treatments.

Pioneer’s base insecticide seed treatment package consists of Cruiser 250 with Poncho/Votivo 1250 available upon request.  Votivo is a biological agent that protects against nematodes.

Monsanto’s products including corn, soybeans and cotton fall under the Acceleron treatment umbrella.  Dekalb corn seed comes standard with Poncho 250.  Producers also have the option to upgrade to Poncho/Votivo, with Poncho applied at the 500 rate.

Agrisure, Golden Harvest and Garst have a base package with a fungicide and Cruiser 250.  Avicta complete corn is also available; this includes Cruiser 500, fungicide, and nematode protection.

Another option is to buy the minimum insecticide treatment available, and have a dealer treat the seed downstream.

Avipel was re-issued a section 18 for field and sweet corn seed in Louisiana.  The exemption is effective from February 24, 2012 through February 24, 2013.  Avipel can only be applied at the dealer and is used as a humane bird repellent.

It is important to note that below ground Bt traits available for western corn rootworm will not work on our strain of root worm in Louisiana.  Look at using in-furrow applications of Counter (organophosphate) or Force (pyrethroid) to help keep rootworms under control.  If an ALS herbicide was used in burndown applications or is anticipated, organophosphate insecticides should not be used.

Insecticide seed treatments are a valuable tool that allows producers a head start on early season protection from a variety of pests.  Minimizing damage below ground will help get this year’s corn crop off to a promising start.

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