Spring 2002

Northcentral

This spring and early summer are marked by many important fertility management considerations. Starter fertilizer continues to be a sound strategy for corn production. Placement of nutrients near the seed supplies early season crop needs and can lead to significant yield increases and grain moisture reduction. Soybean fertility should also be closely monitored.

Soybeans now account for more potassium removal per acre than corn, emphasizing the need for regular monitoring of soil test levels. Widespread phosphorus (P) needs exist throughout the Northcentral region. Wheat is underfertilized with P in many areas. Banding P during planting is an economically sound strategy for wheat.

Research Results: Continuing experiments underscore the importance of starter fertilizers containing phosphate and potash for both corn and soybeans, particularly in the practice of conservation tillage.

Working with member company agronomists and their retailers, Dr. Adrian Johnston, Western Canada Director of PPI, has developed a regional publication to help in the assessment of nutrient removal by crops. Nutrient removal per unit of crop production is a component of soil fertility planning that is often overlooked. In particular, phosphorus and potassium removal by crops occurs from both the fertilizer applied and soil reserves. This contribution from soil reserves often masks the shortfall in fertilizer addition in the short-term, but can have a long-term impact on future fertility of a soil. By replacing nutrients removed in the crops grown the fertility status of many of the region's soils can be sustained for future generations.

Summer forage crop production is an extremely important enterprise in the Great Plains region. Forage crops such as hybrid bermudagrass and alfalfa have the potential to remove large quantities of nutrients from soils. Where hay is harvested, these nutrients are exported from fields, often resulting in substantial drawdown of soil test phosphorus (P) and potassium (K) levels that ultimately results in reduced yield and stand density. When designing fertility programs for summer hay production, consider that each ton of bermudagrass removes about 12 lb P2O5, and 50 lb K2O, and that each ton of alfalfa removes about 15 lb P2O5 and 60 lb K2O. In fact, considering ten common forage crops, on average forages remove about 45 lb N, 15 lb P2O5, and 54 lb K2O per acre. Also, remember that splitting applications of K under some conditions may be advantageous. Since forages require and remove large quantities of K, maintaining adequate available soil K levels throughout the season is critical. In sandy soils, K is subject to leaching, so multiple applications can provide more consistent season-long fertility, especially in high rainfall areas.

Unless there is a major switch to wetter weather patterns, prospects should be good for early warming of the soil and early planting dates. Since there is no deep snow to melt or frozen soil to thaw, the trend will be for an early warmup. But those early soils will still be cold enough to have a potential benefit from starter fertilizer, especially under reduced tillage and early planting dates.

Crop prices and prospective budgeting have some farmers talking about switching some fields from soybeans to second-year corn. That will mean a need to rethink fertility needs as well. Once the cropping sequence is determined, nutrient plans need to be adjusted to reflect any changes made.

Plan for a good year in 2002. That is always the best strategy, but may be even more critical this year. Margins are tight for farmers and they cannot afford to miss yield opportunities by cutting back on basic nutrients, using second-rate pest management, or short-changing on seed. Start the season right with the best choices available. Also, take time now to set up a strategic plan for scouting fields and keeping records. Set up the record forms on paper or on a computer as you wish, but do it now, so that you will only have to fill in the details during the season. The record component is becoming more critical every year, and you can't build a five-year record plan without starting with year number one. It might as well be 2002.

The first spring fertilization of wheat has been completed in many states. The wet weather has stressed some wheat acreage. Because wheat development had not advanced too rapidly in the western part of the region, the recent record cold temperatures apparently did not harm the crop as badly as had been feared.

Rains in late February and early March have delayed field work and fertilization for spring-planted crops. The rains helped to temporarily reduce dry conditions that persisted through the winter in the eastern half of the region.

Corn planting was delayed in the southern edges of the region, and no-till and conservation-tilled acres will be planted when the soil dries. Some corn acres were replanted. Fertilizer was being applied to sugarcane fields. Some water-seeded rice fields were being flooded in advance of seeding in Louisiana.

Pastures are generally in good condition and livestock conditions are good also. Cows have continued to calve.

Fruit trees are blooming in many parts of the region. Vegetable planting continued in Florida, but some field work was delayed because of rains. Carrot harvest began in Georgia and the onion crop appears in good condition. Strawberries were being harvested in Louisiana.

Soil test summary data collected by PPI for the 2001 crop year indicate there are six states in the region that have more than 58 percent of the soil samples testing medium or below in soil test phosphorus (P). Fifty percent of the region's soil samples tested medium or below in potassium (K). Clearly, there is considerable opportunity to improve soil fertility with P and K for higher yields and more profitable farming.

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 Natural Resources Conservation Service (NRCS) has implemented P management guidelines for large CAFOs (confined animal feeding operations) utilizing primarily the P-Index concept in most western states. Guidelines for California were completed at the end of 2001 and are currently being field-tested.

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 were recently implemented in California to govern content of metal contaminants in P and micronutrient fertilizers. The metal contaminants being regulated are cadmium (Cd), arsenic (As), and lead (Pb). Washington State implemented similar regulations several years ago.

Some western dealers have 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.