Winter 2010-2011

Northcentral

The focus of the IPNI U.S. Northcentral Regional program this winter has been nutrient interactions and the need for improved recommendation systems to meet future needs. Scott has presented various parts of this story in Minnesota, Alabama, Ontario, and Indiana. Still to go are more meetings in Minnesota. Additionally, Scott has assembled some information on weather extremes and nutrient management, which was talked about in Florida. To keep up with the new information available, visit http://nanc.ipni.net/ or search for “ipninanc” to find Scott on Twitter.

The combination of good yields and good prices for the major field crops of the region have led many producers to take a look at their soil test levels, and compared to past years, considerably more fall fertilizer has been spread to build or maintain soil P and K levels. Producers who haven't sampled recently would be well-advised to look at the general trends for soil test P and K, and soil pH, in their region, in IPNI's recently published summary of soil test levels for the 2010 crop year.

A regional soil test summary report for 2010 is available. Click here for more information.

Also see the current issue of Better Crops for an article on all nutrients and all of North America.

A Successful Crop is the Result of Doing Many Things Right
In early December last year I attended the Manitoba Agronomists Conference where I was asked to give a presentation on the topic of “Nitrogen Fertilization of Winter Wheat”.  I was glad I was asked to come and attend the conference, because as in most cases when I attend an agronomy conference I often learn much from listening to the other presenters, and the discussion after each presentation between the participants and the presenter.

One presentation I enjoyed greatly was a on the topic of “Integrated Weed Management (IWM) for Herbicide Tolerant Canola Systems” presented by Dr. Neil Harker, a weed scientist with Agriculture and Agri-Food Canada, working at Lacombe, AB. I expected Dr. Harker to discuss herbicide management practices, but what he really stressed was many of the necessary and beneficial agronomic practices that go along with herbicide applications. He said that, unfortunately, many people think of “Integrated Weed Management” as only wise choice and rotation of herbicides for weed control. However, he stated the following, “Real IWM involves at least two, and possibly more than two, weed control methods (one of which can be herbicides). Cultural, physical, or biological methods are necessary in addition to herbicides to constitute real IWM. Real IWM is also NOT just biological, or just physical, or just cultural; it is a combination of methods. The greater the diversity of method combinations, the less likely is a weed biotype to adapt and resist a single method.” I will summarize and discuss some of these cropping practices mentioned by Dr. Harker.

1. Effective Planting and Fertilization. Inadequate crop stands compete poorly with weeds, and in some cases require an additional herbicide application to the first one, as sub-standard crop stands allow weeds to germinate and establish easier. Depth of planting is important, so is an adequate target crop stand, with enough, but not excessive packing and precision placement of a balanced fertilizer blend with needed nutrients. These nutrients should be supplied at a sufficient, but not too high of a rate. The low mobility fertilizers such as P and K should be placed close enough to the seed-row to facilitate early uptake and crop use, while mobile nutrients such as N and S can be placed further away from the seed-row. This is especially so for N fertilizers, such as urea (46-0-0) because as it hydrolyzes in the soil it will release ammonia that if present in excess concentrations can kill germinating seeds and reduce crop stands. Another important aspect is time of planting so crops are early enough to make good use of the short and limited growing season, but not too early to be adversely damaged by early and severe spring frosts.
2. Use Competitive Crop Varieties. There can be considerable competitive differences between different varieties of the same crop species. Choosing a variety that germinates quickly and develops a crop canopy sooner will reduce the successful germination and establishment of weeds.
3. Early Time of Weed Removal Using the Chosen Herbicide. If applied earlier rather than later, considering the appropriate crop stage, weed seedlings are better controlled, the crop that is tolerant of the herbicide gains a growth advantage, and this leads to greater crop yields and less weed seeds in harvested grain.
4. Use Crop Diversity and Rotation. Changing crop types in a diverse rotation constantly affect which weeds are most successful to grow and set seed for a future weed population. For example, if only spring planted cereal crops such as wheat and barley are grown, an annual grassy weed such as wild oat tends to do well and increase in infestation. However, if a broadleaf crop is grown in rotation with the wheat or barley crops, more diverse and effective grassy weed herbicides can be applied, and wild oat populations can be reduced. Another very effective strategy is to include a fall-planted crop such as winter wheat in rotation. This can effectively reduce both annual grassy and broadleaf weed presence in a field. But, if winter wheat is grown every year a winter annual grassy weed such as Downey brome can severely infest a field. The key principle to follow is crop diversity and rotation.

By combining all the weed control and weed population reduction practices including both herbicide and other agronomic methods mentioned above, not only are weed populations controlled but crop yields and quality are optimized. Reliance on just one weed control method will result in a growth environment that causes selection pressure for a certain weed or weeds to thrive. “Integrated Weed Management”, really relies on integration of a combination of well-planned and used agronomic practices.

Conditions throughout the fall and winter have been overall rather dry across much of the Southern and Central Great Plains Region, and winter wheat condition reflects this. In the latest crop condition report for Texas (January 10) 80% of the crop was rated between fair and very poor while the December Kansas report rated 73% of wheat in that state between fair and very poor. But, wheat is resilient so avoid premature pessimism.  Given the right conditions going forward it can show substantial improvement. Where conditions are favorable going into the spring, topdress N may be needed to boost yield. Remember that topdress N needs to be in the root zone and available for uptake before wheat reaches the jointing stage.

With the favorable grain price environment, it is especially important to make sure that adequate N is available to optimize yield.

Cotton is an important crop in the southern part of the SCGP region. Over the past few months cotton prices have risen dramatically and the outlook for cotton in 2011 is strong. With this optimism, it is important for cotton growers to make sure that adequate fertility is in place to make the most of the opportunity. After all, good nutrient management results in higher yields, improved fiber quality, and greater water and nutrient use efficiency. Following is some basic cotton nutrition information to consider for the coming season. 

Cotton takes up about 60 lb of N for each 480-lb bale produced. Nitrogen is essential for the development of all plant organs including shoots, buds, leaves, roots, and bolls. Uptake of N by cotton peaks at about 2 to 3 lb per acre per day during fruiting. Uptake is limited prior to squaring, and the majority of total N is taken up after first bloom. Therefore, split applications of N (e.g., preplant and at or before first bloom) improve the chances of meeting the crop needs during peak demand periods. Texas Tech University researchers have shown that on the Texas South Plains about 5 lb of N are required per inch of water consumed. Since cotton is an indeterminate perennial, too much N late in the season may cause excessive vegetative growth and should be avoided. Soil and petiole tests can be helpful in determining preplant and midseason N management.

Approximately 25 to 30 lb of P2O5 is taken up per bale of cotton produced. Phosphorus is important in early root development, photosynthesis, cell division, energy transfer, early boll development, and hastening of maturity. Banded application of P may be beneficial, especially where soil test levels are low or in reduced tillage or no-till systems. Insufficient P results in dwarfed plants, delayed fruiting and maturity, and reduced yield. Use soil tests to determine optimum P application rate.

Cotton utilizes about 60 lb of K2O per bale. Potassium is an especially important nutrient in cotton production. It reduces the incidence and severity of wilt diseases, increases water use efficiency, and affects fiber properties like micronaire, length, and strength. It is important in maintaining sufficient water pressure within the boll for fiber elongation. Thus, the need for K increases dramatically during early boll set. About 70% of uptake occurs after first bloom, and uptake peaks at about 2 to 3 lb per acre per day. Potassium deficiency may be expressed as a full season deficiency, or it may not appear until late season since this is the period of greatest demand. A shortage of K reduces fiber quality and results in plants that are more susceptible to drought stress and diseases. Preplant applications of K fertilizer, and in some cases mid-season foliar applications, are effective in correcting K deficiencies. Soil testing is the first step in predicting K needs.

Secondary elements and micronutrients are also critical to profitable cotton production. A high yielding cotton crop can take up as much as 30 lb each of S and Mg. Cotton responds to trace elements like boron, zinc, and manganese where these elements are deficient. Soil tests, plant analyses, field history, and experience should be considered when establishing the need for these elements.

Winter wheat acreage is up significantly in the Southeast compared to last season. The average increase among most states was about 25%. The smallest change in wheat acres was in FL, which only increased 8% and the biggest increases were in MS and MO, whose acreages doubled. Wheat acreages for all states in the region are reported in Figure 1.

Figure 1. Wheat acreage in the Southeast United States, 2010-2011.

The large increase in wheat acres might come as a surprise to some who were predicting more cotton and corn being planted due to strong pricing. Interest in peanuts even seemed to have been rejuvenated due to improved pricing. In addition to favorable pricing for competing crops, wheat seed shortages were a concern this past fall and were expected to influence planting decisions. So what happened? Where did all this wheat come from? One of the biggest factors was that cotton, rice, soybean, and corn were all harvested early, giving growers time to get set up for small grain planting.  The drawback to this situation was that growers in several states were so anxious to get the wheat in the ground that they may have set themselves up for problems later with diseases and insects as a result of planting too early. With wheat seed prices being higher than normal, it is expected that a larger portion of the wheat will  be intensively managed to maximize yield and remain profitable. Much of the yield potential in wheat is established at planting; however, poor spring fertility management can often ruin a good crop. Pay close attention to early tiller development, crop color, and crop vigor, and follow local guidelines for managing spring N fertilizer. For a general overview of wheat fertility, check out the IPNI video” “The Right Way to Grow Wheat” at www.youtube.com/PlantNutritionInst.

Make plans now to join us at InfoAg 2011. InfoAg 2009 was a terrific success. Over 650 participants shared in presentations on a wide range of topics on technology applications and data management and interpretation. As with previous InfoAg Conferences, the networking among participants was again a highlight of the experience. New relationships formed at InfoAg will lead to greater benefits and opportunities for those involved. Ideas exchanged in the hallways and the exhibit hall will form the basis for the new deliverables at the next conference.Those who took advantage of the Pre-Conference Tour on Monday picked up some additional first-hand knowledge and interactions.

We are in the process of planning InfoAg 2011, to be held July 12-14 in Springfield, Illinois. 

We have had some excellent suggestions for speakers over the years. From hi-tech innovators giving us a glimpse of what is to come to producers putting all the gear and ideas to work in crop production, InfoAg is an event to stimulate the gray matter. Help shape the program for InfoAg 2011 by suggesting a speaker or topic at www.infoag.org. Early registration and lodging information are also available.

The outlook is mostly rosy as we plan for the 2011 growing season. Reservoirs are filling with water, crop prices are rising, and food exports are strong. Farmers are currently doing advanced planning to make the most of these promising conditions. Grower meetings and agricultural conferences are underway across the region to help farmers learn the latest in crop nutrition, pest control, variety selection, and advanced marketing techniques. Making a living in agriculture becomes more complicated each year. Be sure to take advantage of these meetings to keep current with the latest technology and opportunities.

Nitrogen fertilization practices are presently under scrutiny in the Central Coast area of California. The Regional Water Quality Control Board has issued proposed regulations to decrease the discharge of nitrate to surface and groundwater. The proposal would require many growers to implement a certified irrigation and nutrient management plan to document all N inputs and all N removed in harvested crops.  The goal is to improve the balance of N inputs with removal in order to reduce losses. Classroom time and water monitoring would also be part of the proposed 14-point program.

The Central Coast region has approximately 435,000 acres of irrigated land and approximately 3,000 agricultural operations which may be generating water runoff and leaching. The Salinas River has been identified as having impaired water quality. There are many wells in the region showing high concentrations of nitrates and pesticides.

A recent study by Noel et al. (2008) of the California orange industry calculated that regulatory compliance costs are over $400/acre. This cost was contrasted with the 2006 costs of orange production in Texas, which were slightly over $31/acre. (Hamilton, 2006). These regulatory compliance costs are a significant burden for food, fiber, and animal production in California and have a negative effect on farm profitability and competitiveness.