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Extension > Minnesota Crop News > April 2015

Wednesday, April 29, 2015

Windbreak and crop yield study

Gary Wyatt, Extension educator - agroforestry

Recent land values, farm innovations and management such as adoption of no-till, minimum till, use of wide farm equipment, and windbreak plantings that are just getting old, have led to many windbreaks being removed. In time, windbreaks need to be renovated to restore the multiple benefits they offer rural landscapes. There are cost share programs available to plant new windbreaks and renovate mature plantings through the Natural Resources Conservation Service (NRCS). In most areas where windbreaks were planted, there have been documented crop yield increases.

Thursday, April 23, 2015

Anhydrous Ammonia Applications

Fabian Fernandez, Nutrient management specialist

Anhydrous ammonia (AA) is one of the most widely used nitrogen (N) fertilizer source in Minnesota and the Midwest. Some of the reasons for its importance include the fact that this source is by far the most concentrated N fertilizer with 82% N (less weight of fertilizer per unit of N); it is readily available since AA is used in the manufacture of many commercial N fertilizers; it can be applied several weeks before planting with less N loss potential than other N sources; and most importantly AA normally represents a less expensive source of N. Some of the drawbacks of AA include the need for special facilities to store this gas as pressurized liquid, and special equipment to transport and applied this fertilizer; the application of AA can be slower than that of some other N sources; and because AA is released as a gas, it can pose a risk to human health if not handled properly. Every year as farmers start applying AA, invariably I get asked similar questions which I will try to address today.

New Irrigation Resources

The new Irrigation Extension website is up and running, and we have been able to add some new resources, and update some of the past resources.
Now that spring has sprung, one of the most powerful tools for maximizing irrigated yield is uniform application of irrigation water.  Testing uniformity every few years is a low cost way to make sure that your water is going where you want it. On a pivot with 15 foot nozzle spacing, one bad nozzle 1000 feet from the center can influence the yield on over 2 acres. That one bad nozzle (that costs about $5 to replace) could cost you over $600 in lost yield.
Below is a quick tutorial on irrigation uniformity testing.

A Quick Test to See Whether Your Small Grains Seed or Emerging Seedlings is Still Alive.

With air temperatures dropping down into the high teens overnight, I have fielded a number of calls already this morning with the question whether the earlier seeded wheat, barley, oats (or any crop for that matter) will make it, especially if the ground is frozen solid.

The fastest way to tell is to dig up some seed or seedlings and place them on a wetted-down paper towel at room temperature.  Within 24 hours you should see elongation of the coleoptile of the seedlings.  With seed that had not germinated yet, you may have to wait another day before you see a radicle and coleoptile appear.  If the seed and the germ are damaged by frost they will turn to mush within 24 hours at room temperature.  If the crop had already emerged, you can simply cut the above ground leaf material and place the seedling on the wetted-down paper towel and wait for new growth to elongate. 

PS) Ensure that the paper towel remains moist throughout the duration of the experiment.

Photo 1: Germinated wheat seed with adventitious roots pointing down and coleoptile pointing up. The radicle is hidden between the adventitious roots.




Tuesday, April 21, 2015

Forage Quarterly - Spring 2015

Dear Forage Producer,

The University of Minnesota Forage Team is proud to announce the third edition of the Forage Quarterly. Since spring is here, this issues focuses on establishment and early season management of forage production systems. In this edition we highlight seeding strategies, weed management, cover crops, insect control and identification.

We would like to take this time to highlight the contributors to this edition:
  • Bradley Heins, Ph.D. Assistant Professor. Expertise: Organic Dairy Production. Email: hein0106@umn.edu
  • Bruce Potter. Assistant Extension Professor. Expertise: Integrated Pest Mgt, crops, and forages. Email: bpotter@umn.edu
  • Craig Sheaffer, Ph.D. Professor. Expertise: Alfalfa, forage, and sustainable cropping systems. Email: sheaf001@umn.edu
  • Deborah Samac, Ph.D. Research Plant Pathologist. USDA. Expertise: Disease resistance mechanisms in alfalfa. Email:debby.samac@ars.usda.gov
  • Doug Holen. Regional Extension Educator. Expertise: Crops, small-grains, and forages. Email: holen009@umn.edu
  • Jim Paulson. Regional Extension Educator. Expertise: Dairy nutrition,forages, grazing and organic production. Email: jcp@umn.edu
  • M. Scott Wells, Ph.D. Assistant Professor. Expertise: Forages and cropping systems. Email: mswells@umn.edu
  • Reagan Noland. Graduate Research Assistant. Expertise: forages, cropping systems, and precision agriculture. Email: noland228@umn.edu
  • Roger Becker, Ph.D. Professor. Expertise: Agronomy and weed science. Email: becke003@umn.edu

University of Minnesota Forage Team

In this issue
Alfalfa Assessment: Factors Leading to Winter Injury
Alfalfa Establishment: A Pathway to Increased Yield
Preparing for Successful Alfalfa/Grass Production
Using Herbicides to Establish Alfalfa
Aphanomyces Root Rot of Alfalfa Widespread Distribution of Race 2
Alfalfa Insects: What to Look for, How and When</a>

Click to read the Spring 2015 newsletter.

Click to read past issues of the Forage Quarterly.

Sincerely,

University of Minnesota Extension Forage Team

Sunday, April 19, 2015

Assessing Damage From In-Furrow or Pop-Up Starter Fertilizer for Corn

By Daniel Kaiser
Extension Nutrient Management Specialist

I have been fielding more questions on seed placed fertilizer in areas where rainfall has been sparse this spring and soils are dry. In my previous post I discussed the use of in-furrow starter fertilizer. Placing fertilizer on the seed can help speed up early plant growth but also can substantially reduce stand if a fertilizer is over-applied or soils are dry. How dry is too dry? That is a good question and the answer depends on the soil corn is being planted in. For medium and fine textured soils, the risk of damage typically is lessened when the soil moisture content is 25% or greater.

Thursday, April 16, 2015

New bulletin helps growers manage the rotation from alfalfa to corn

Jeff Coulter, University of Minnesota

Crops that follow alfalfa usually benefit from reduced or eliminated nitrogen requirement from fertilizer or manure, increased yield potential compared to following other crops, and reduced pest pressure. A new Extension bulletin describes management practices for alfalfa termination and the two subsequent corn crops that will help growers utilize the benefits of alfalfa: http://z.umn.edu/rotation

Wednesday, April 15, 2015

How Deep Dare I Drill Wheat, Barley and Oats Down to Find Moisture?

Ideally we like you to seed wheat, barley, and oats at 1.5 to 2 inches of depth.  The idea is that the seed should be placed deep enough to have access to adequate moisture yet shallow enough to emerge as quickly as possible. Seeds too close to the surface absorb moisture but are at risk of dying because roots cannot reach moisture quickly enough to sustain the germination and seedling growth.  Deeper seeding can reduce stand density and plant vigor because the inability of the coleoptile to reach the surface. 

Friday, April 10, 2015

Nitrogen Forecast for 2015: First edition April 9, 2015

John Lamb, University of Minnesota Extension Nutrient Management Specialist

Nitrogen (N) is important for corn, small grains, and sugar beet growth. This year has been OK so far. It has started to rain this week but I would not get too concerned about N losses until I see a large amount of drainage water coming out of the tile lines. In most cases the soil is on the dry side and has room to store the spring moisture. With this in mind, the chances for loss of N fertilizer are low on heavy textured soils. For growers who fall applied their N after the soil temperatures were below 50 degrees, there has been no reason to be concerned about N losses.

New nitrogen guidelines for corn grown on irrigated sandy soils

John A. Lamb, University of Minnesota Extension Nutrient Management Specialist

On March 6, 2015, revised guidelines for fertilizing corn grown on irrigated sandy soils were released by the University of Minnesota. Minnesota has about 500,000 acres of irrigated sandy soils. Corn is grown on about half of these acres in any one year. With the use of irrigation and fertilizer, sandy soils are very productive.

In 2000, the guideline for nitrogen (N) application for sandy soils was around 230 lb N/acre. In 2006, the University of Minnesota joined several North Central Land Grant Universities to develop a common method of developing N guidelines for corn. This method was called the Maximum Return to Nitrogen (MRTN). The goal of this process was to improve the predictability, involve economics, include some adjustment for the user attitude towards risk, and to use a similar method for developing N guidelines across the region. To make the MRTN method work well, a database with a large number of corn responses to N fertilizer was needed. Minnesota had a large number of response information for highly productive non-irrigated soils, but did not have adequate information for corn grown on irrigated sandy soils at the time the MRTN was first developed. Because of a lack of data specific to irrigated soils, a decision was made to use the guideline for corn grown on non-irrigated highly productive soils for corn grown on irrigated sandy soils. This was not a good decision. The MRTN economic involve the ratio of the price of N per pound to the price of corn per bushel. At the common 0.10 ratio ($0.50 N to $5.00 corn) the 2006 guideline was 140 lb N/A with a range of 120 to 165 lb N/A for corn grown after corn or group 2 crops. This was too low.

Monday, April 6, 2015

Should You Consider In-furrow Starter for Corn in 2015?

By Daniel Kaiser
Extension Nutrient Management Specialist

The use of starter fertilizer placement on the seed (known as in-furrow placement) is commonplace in many areas of Minnesota. I commonly receive questions on the value of in-furrow starter fertilizer when corn prices are low. The application of liquid fertilizer with the planter presents additional costs which may or may not be warranted depending on the year and where a field is located within Minnesota. The results of several field trials have recently been summarized in a new publication “Banding Fertilizer on the Corn Seed”. There are a few things to consider the when and what when utilizing starter fertilizer banded on the corn seed.

Ready, Set, Go.

The first spring wheat and oats have already been seeded, although winter will officially with us one more day according to the calendar. Is it too early to already be thinking spring and seeding small grains?  Federal crop insurance guidelines stipulate that small grains are insurable when planted on or after March 21.  And although this may be part of your decision process, mother nature doesn't keep a Julian calendar. So can we already seed small grains successfully?  In 2012 I write a post that describes the requirements to get small grains established successfully and quantifies some of the risks of planting early.  I have provided link to it here.

Bottom-line: The weather forecast for the remainder of the month is trending just slightly above average for both daytime highs and well as nighttime lows. If the frost has come out at least 12 inches and the soil temperatures are reaching 40 degrees F for most of the day, I think spring wheat and oats can be seeded successfully at this time.

Friday, April 3, 2015

Did my earliest seeded wheat, barley, and oats survive this latest cold snap?

The latest cold snap may have you wonder whether the earlier planted wheat and barley have a snowball’s chance in hell to produce a healthy seedling and stand? Wheat, barley and oats do not germinate until the soil temperatures reach 40 F. The germination process starts with the uptake of water, breaking the dormancy and starting the development of the sprout. Once the dormancy is broken the energy stored in the seed is used for the growth and development as well as respiration (basically maintenance). If the temperatures are low or even freezing the growth and development of young seedling slows down or even stops. However, respiration continues albeit at a lower rate and continues to deplete the energy stored in the seed. This will eventually decrease the vigor of the seed and may prevent the sprouted seed to produce a healthy seedling.

With the freezing temperatures the first concerns is whether this can kill the sprouted seed. Reports from the literature indicate that sprouted wheat and young seedling will likely survive temperatures in the low twenties. A quick first check of the color of radicle (first root) and coleoptile (first leaf) is the first step: a white and firm radicle and coleoptile will indicate that the sprout is not damaged by frost after the seed has been allowed to thaw out. . A second test to determine viability of seed is to dig up seed and bring it home, place it between moist paper towels, and keep it at room temperature. If the seed is viable the sprouts should start to grow within 24 hours.

Minimum Stands for Winter and Spring Cereals

Most winter cereals have broken dormancy by now and thus is it time to evaluate stands and decide whether to keep the stand and thus the field or move on to plan B.  The same is true for any early seeded spring cereals. The easiest time to do a stand count is probably when the crop is in the two- to three-leaf stage since tillers are not visible yet, making counting easier.

To do a stand count, use one of the following two methods:

1.      Count the number of plants in a foot of row at several locations in the field.  Take an average and convert in plants per acre using Table 1.

2.      Take a hula-hoop, let it fall, and count the number of plants inside the hoop.  Repeat this at random several times across the field and calculate an average.  Use Table 2 to convert the count to an approximate population per square foot or acre.

Keep stands of 15 or more plants per square foot  (or just over 650,000 plants per acre) this early in the year as the crop (either spring or winter) will for plenty of time to continue to tiller, allowing the crop to reach 85 to 90% of its maximum grain yield potential.  


Table 1.        Average number of plants per foot of row for different row spacing and plant densities per acre.
                                                           

Plants per acre (times 1 million)
Row Width
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5









6”
9.2
10.3
11.5
12.6
13.8
14.9
16.1
17.2
7”
10.7
12.1
13.4
14.7
16.1
17.4
18.7
20.1
10”
15.3
17.2
19.1
21.0
23.0
24.9
26.8
28.7
12”
18.4
20.7
23.0
25.3
27.5
29.8
32.1
34.4


Table 2.        Adjustment factors to multiply the number of plants inside a hoop and convert the number in to number of plants per acre.

Hoop Diameter
Multiply by


30”
8,900
32”
7,800
34”
6,900
36”
6,200
38”
5,500





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