Fall 2001

Northcentral

Staying Balanced
Weather, commodity prices, and higher nitrogen and natural gas prices have diverted the attention of many farmers away from their phosphorus (P) and potassium (K) fertilization programs. Both nutrients have been mined from soils for the past several years in various areas. This is long enough to see measurable reductions in soil test levels. Past research has shown that initially higher soil nutrient levels decline faster than lower ones. Keeping nutrients in balance helps make farming enterprises more efficient in many ways.

Balanced nutrition leads to greater production efficiency through yield increases and quality enhancements. A greater volume of a high quality commodity creates lower costs per unit, such as a bushel, a ton, or a hundred weight. Lower per-unit costs means that operations can weather greater fluctuations in the market and remain profitable.

Balanced nutrition can increase the efficiency of applied nutrients. While nitrogen (N) use has been increasing, P and K use has remained flat or has decreased slightly in many states. Research has shown time and again that sufficient levels of P and K in the soil are required to make the best use of N. Widening N:K and N:P ratios that have been observed in some states are an indicator of possible nutrient imbalance. With adequate P and K, money spent on a unit of N can go a lot farther toward generating additional revenue.

Balanced nutrition is a sound planning strategy. Weather can fluctuate greatly from year to year, month to month, and day to day. There is no way in advance to manage for such variations. Ensuring that nutrients remain balanced is an appropriate strategy regardless of weather conditions. When the plant is under stress, its ability to absorb nutrients will be restricted. Under such conditions, ensuring an adequate supply of all needed nutrients in the soil can reduce yield and quality impacts from the adverse conditions. Under favorable growing conditions, balanced fertility improves a producer's opportunity to take advantage of a greater yield potential.

The corn crop will face additional yield reduction as we move into the grain filling period under moisture stress and above average temperatures.

In some cases, growers are making the decision that some feed value can be captured from moisture stressed corn by taking it for silage or green chop when faced with little hope of any appreciable grain yield. When taking the corn for forage, growers are warned to pay attention to levels of nitrate in the plant tissue, owing to the risk of livestock poisoning. Also consider that nutrient removals for phosphorus (P) and particularly for potassium (K) rise dramatically when the corn is harvested as forage rather than as grain.

Most soybean fields are shorter than normal due to the dry conditions. Fields with high aphid infestations are showing the added stress of the dry weather and the aphid feeding. Fields that were fortunate to receive a bit of rainfall have improved in appearance, even if aphid numbers are still high. The impact of the aphids on yield is still unknown, and growers are being encouraged to experiment with control options where infestations are high. Make observations carefully, and look for management variations that may prevent aphid damage.

Yields of winter wheat have been above average with many producers harvesting record yields of excellent quality wheat. Wheat yields were closer to average in the areas affected with snow mold but were better than expected for the most part.

Potatoes in Prince Edward Island are in a drought situation. Need for fungicides has been negligible, but the drought is likely to reduce final yields.

For forage crops, dry weather has reduced second cut yields and third cut regrowth is very slow and uneven. Many fields are showing symptoms of potato leafhopper damage, particularly in new seedings. Some pastures have very little growth and livestock are being supplemented with hay. Remember that fertilization with K promotes persistence best when applied before the season's last six weeks of growth.

Research being carried out by Len Kryzanowski of Alberta Agriculture, Food and Rural Development is evaluating how landscape variability influences plant nutrient availability. Using soil nutrient resin strips and plant nutrient uptake, Len is evaluating the seasonal pattern of soil nutrient release, and crop uptake, by spring seeded crops. Results to date indicate that while large variability on nitrogen (N) supply rates from the soil reflect the impact of historic management on soil redistribution in the field, there was minimal variation in phosphorus (P) and potassium (K) levels. However, balancing the variable N with adequate P and K will help to develop predictive models for use by farmers implementing variable rate fertilizer management in an attempt to optimize fertilizer use.

Winter wheat planting is rapidly approaching. Growers planning to graze wheat this coming winter and spring should aim for top forage yields to maximize profit from animal performance. Phosphorus (P) fertility plays a key role in early season growth and tiller development and can therefore have a dramatic impact on overall wheat forage production. One Texas study showed that forage yield increase from P fertilizer ranged from 40 to 107 percent. Estimates from this study further showed that net return, based on stocker gain estimates, from P fertilization ranged from about $21 to $63/A. Additionally, the importance of P fertility in wheat grain production can't be overstated. Studies from across the Great Plains and other wheat producing regions have demonstrated as much. Adequate P fertility is necessary to ensure that other fertilizer inputs such as N are used to maximum efficiency. Whether producing wheat for grain, forage, or both, complete and balanced fertility is a part of the profit equation that can't be ignored.

Fall Field Visits
Field visits in the late part of the growing season and prior to harvest can provide important clues to yield limiting factors. Nutrient deficiencies often show up when the grain filling period puts heavy demand on the nutrient supplying power of the soil. Weed escapes, or late germinating species compete with crops for water and nutrients. Some insect species attack late in season and contribute to lodging, ear drop in corn, grain quality deterioration, and other factors that reduce profits.

Midwest farmers and their advisers are finding potassium deficiencies more often than in the past, especially in soybeans. By the time these visible deficiency symptoms appear, yield potential has already been substantially reduced. The "hidden hunger" effects (FIG. 1), such as decreased water efficiency, reduced photosynthetic activity, and general decline in plant health, can rob yield---and profit--- without visible signs. So if you find symptoms in your field visits, you can be assured that there is a problem to be corrected.

Figure 1. Corn leaf nutrient deficiencies late in the season.
"Hidden hunger" may rob yield potential long before such
symptoms occur.

Observations from these field visits can be a great help in identifying sources of field variation that may be identified in reviewing yield maps later this winter. If possible, log GPS coordinates of the problem areas, so that they can be directly related to yield maps. Take photos of the deficiencies to file for future reference. Inexpensive digital cameras may be used to simplify this record-keeping.

Starter Fertilizer
Fall may be the best time to consider spring needs for starter fertilizer. That allows plenty of time to acquire any needed starter application equipment and develop a nutrient management plan. Waiting until spring for the starter decision usually means it won't get done. Now is the time to evaluate soil tests and yield levels and to plan on-farm tests to evaluate starter use. For larger planter systems, be sure to plan a system that provides uniform distribution across rows. Early planting, reduced tillage, and more intensive management in general, are increasing the likelihood of a response to starter fertilizer for many Midwest farmers. Don't overlook the possibilities.

The cost of cutting back on inputs, such as fertilizer, could be heavy this year. Many in agribusiness are wondering about the effect from nutrient use reductions during the past three drought years. Unused crop nutrients, such as nitrogen, potassium, sulfur, magnesium and boron, become mobile in the very sandy soils of the coastal plain and are subject to leaching from the primary plant root zone. Also, some early 2001 season forecasts called for another dry season. Thus, less than normal nutrient carryover to the 2001 cropping season teamed with continued conservative fertilizer use has likely set a stage for crops to be experiencing nutrient shortfalls as this season progresses with good rainfall and growing conditions.

Such a growing season, as being experienced in 2001, does allow growers some flexibility. There are usually opportunities to apply fertilizers during the growing season. For some crops this would involve ground applied granular or liquid products and for others like cotton, foliar applications of nitrogen, potassium and boron have proven effective. Certified Crop Advisors (CCAs) have been trained to help growers predict the need for in-season nutrition and to suggest materials and methods of application which allow crops to benefit most.

The full influence from inadequate plant nutrition will remain unknown for many fields as there is seldom a comparison with an area receiving a different rate of fertilization. However, there are several harvest indicators. Watch for delayed maturity, poorly filled grain and ears, lodging, and/or a low test weight for corn. For cotton, yield will be one factor but so will early cut-out, poor fiber quality, or leaf diseases such as Stemphylium. Again, CCAs are trained and qualified to search for and identify these yield/quality limiting conditions on a crop by crop and field by field basis.

There is a strong "back-to-the-basics" take home message from this season so far. It is that a good cropping season or a good market season can seldom be predicted. Thus, farmers and their advisors must plan accordingly and be prepared to benefit from that good season when it arrives. This requires an understanding of crop nutrition needs by growth stage and a plan for delivery of those nutrients prior to and during the growing season. Such a plan can serve to deliver crop nutrients as needed during both the good and poor seasons.

RICE
Rice yields are expected to be down from the record yields in 2000 and rice price is still miserably low. Rice harvest is progressing, with 39 percent harvested in Louisiana, but much less in Arkansas, and Mississippi, and the bootheel of Missouri.

SOYBEANS
Soybean condition in the Midsouth is rated 49 to 77% good to excellent. Irrigation was intense in the more southerly states. Rainfall was sparse in Missouri's north central and northeast regions. Insecticide and fungicide applications were increasing costs in the more southerly states. Pod setting was lowest in Missouri at 49% and highest in Louisiana, Mississippi, and Tennessee at 96%. Yields are anticipated to be fair to good. Cyst nematodes are becoming an increasing concern in many fields.

CORN & SORGHUM
Corn is rated as 54 to 84% good to excellent in the region. The crop has reached dent stage in 45% of the acreage in Missouri and 76% of the acreage in Tennessee. Feed grains specialists in Arkansas, where the large majority of the acreage is irrigated, expect an excellent crop. The sorghum condition is rated similarly. Corn rotation is proving to be important for cotton acres and sorghum rotation is important to soybean acres, to help minimize the populations of damaging reniform and cyst nematodes, respectively.

FORAGES
Alfalfa harvests were continuing in the more northerly states. Grazing and haying of bermudagrass and other warm season pastures has been fair to good where rainfall was adequate. Cool season forage production will begin in several weeks. Farmers and ranchers should consider their cool season grazing, silage, and hay needs for their livestock operations. Fertility inputs should be matched with production goals.

ACTION ENCOURAGED THIS FALL
Many fields need to be soil sampled this fall to determine lime and fertilizer needs. Lime, phosphorus (P) and K needs can be applied on most fields this fall after crop harvest to improve soil fertility before next season. Farmers need to pay particular attention to double-cropped soybean and wheat nutrient removal. Good yields the last few years are draining soil fertility levels where proper fertilization has been neglected. Forages have removed significant amounts of nutrients in hay harvests and these nutrients will need to be replaced to sustain production.

Fertilizer dealers and crop advisers can help farmers develop nutrient management plans this fall to meet yield and profit goals. The place to start is with site-specific soil sampling and soil testing. This information can be coupled with yield records or yield monitoring data for refined nutrient application strategies. Landlords and renters are encouraged to sit down together to develop cost-sharing agreements that will enable continued farming operations in these difficult economic times. Having good fertility and yield data in-hand can greatly improve the planning process, and help convince landowners of the opportunities and benefits of improved fertilization and liming programs …… and just might encourage greater landowner cost-sharing this fall.

Fertilizer management issues of current concern continue to include efficiently managing nitrogen (N) inputs, both inorganic and organic, to avoid nitrate accumulation below the rooting zone. Improved soil test procedures and in-season application techniques are being evaluated and promoted by the research community. The Salinas Valley has been a focal point of such studies in California. Related to the growing dairy and other animal industries in the west, there is concern about manure management related to excessive accumulation of phosphorus (P loading) in the soil as well as N. The NRCS has developed P management guidelines for large CAFOs (confined animal feeding operations) in Washington, Oregon and Utah utilizing the P-Index concept and in Idaho utilizing the P threshold approach. Guidelines utilizing the P-Index similar to the Northwest will likely be completed for California before the end of the year.

Increasing acreage is moving to low pressure irrigation systems (drip or micro-sprinkler) for trees, vines and vegetables which meter water and fertilizer very efficiently. This is in response to cost of water, likelihood of limited future supplies, and environmental (leaching) issues. Continued research is needed to determine how to maximize the positive interactions between nutrients and different irrigation systems. Regulations are being prepared in California to govern content of metal contaminants in P and micronutrient fertilizers. The metal contaminants to be regulated are cadmium (Cd), arsenic (As), and lead (Pb). The proposed regulations have had several public hearings and are expected to be implemented before the end of 2001. The State of Washington has metal regulations in effect similar to the Canadian standards.

Some western dealers have been initiated site-specific fertilizer management programs. However, these programs are still in their infancy compared to the Midwest. Progress is slowed by the diversity of crops in the west and the continuing tight economy. Grain, potato, and tomato harvesters utilizing yield monitors are currently in commercial use.

Crops are progressing normally in the west. There is generally very little to report during mid-season since most crops are irrigated and the weather is stable (warm and dry).