Northcentral

Don't let nutrient deficiencies and depleted soils creep up on you. Many people are unaware of the quantities of phosphorus (P) and potassium (K) removed from the field with a crop harvest. The most recent USDA summary of average U.S. 2003 yields for alfalfa, corn, wheat, and soybeans are 3.24 tons/A, 142.2 bu/A, 44.2 bu/A, and 33.4 bu/A, respectively. Considering these crops and yield levels, using coefficients published by PPI, corn and alfalfa remove the most P per acre, at 63 and 49 lb P2O5/A, respectively. Soybeans come in third at 27 lb P2O5/A. Wheat is fourth, with a U.S. average removal of 22 lb P2O5/A. By far, K removal from fields is highest with alfalfa, at an estimated 2003 U.S. average of 194 lb K2O/A. Soybeans come in a distant second, removing an average of 47 lb K2O/A. Average K removal by corn and wheat follow with an estimated 41 and 15 lb K2O/A, respectively. Because the actual amounts of P and K removed can vary with different conditions and yield levels, it is best to take a few grain or forage samples and have them analyzed to determine nutrient content. Combine this knowledge with yield records to calculate how much P and K are being removed from your fields. Attention paid to his aspect of nutrient management will help prevent nutrient deficiencies and depleted soils from catching you unaware.

Despite recent scattered thunderstorms with heavy downpours and hail, nearly 70% of Ohio's corn and soybean crops remain in good-to-excellent condition, according to the Ohio Agricultural Statistics Service. The figure for Michigan is about 50%. Completion of planting is about two days later than last year, and even farther behind the past five-year average. In Virginia, excessive rain has lowered the hay quality, delayed soybean planting, and raised concerns about nitrogen (N) depletion.

Cool and wet weather affects availability of N from the soil, from manures, and from previous crop residues. A soil nitrate test this month will be very helpful. Cool weather slows down mineralization of N from organic matter. Excess rain can either leach nitrate out of coarser-textured soils, or drive denitrification in finer-textured and poorly drained soils. Either process results in less N for the crop.

Nitrogen recommendations pose a major challenge for improvement. At a N forum held in Niagara Falls this past March, experts agreed that N needs vary more year to year than they do within fields. We don't yet have reliable prediction models based on the weather, but past experience indicates that wet years demand more N than dry years.

Plant tissue samples collected during the season can be used to diagnose nutrient imbalances. While for some nutrients this diagnosis may not be in time to take corrective action, it provides information for future nutrient management. Remember, nutrients that are mobile in the plant can generally move from old to young tissue when insufficient soil supplies exist. As a result, it is the older leaves that show the deficiency first.

The results of plant analysis alone should not be used to make fertilizer recommendations. Most crop advisers prefer to consider plant tissue analysis along with soil test results, a record of nutrient applications (including any manure), cropping history, and recent pesticide applications. Consider using a laboratory that can demonstrate proficiency in analytical testing and provide a reasonable turn-around on the results, with clear interpretation.

Alfalfa is an important summer forage crop in the Great Plains Region. A critical fact to remember in alfalfa and other hay production is that substantial amounts of nutrients are removed from fields with crop harvest. Consider, for example, that each ton of alfalfa removes about 56 lb nitrogen (N), 15 lb P2O5, and 60 lb K2O. These are general figures… actual removal rates can vary significantly. Nutrient concentration and removal can be affected by soil type, soil fertility level, variety, and management practices. Of course, alfalfa is a legume, so supplemental N needs are usually minimal relative to biomass production. On the other hand, the need for fertilizer phosphorus (P) and potassium (K) in high yield alfalfa production can be great. Soil test information is helpful in designing an effective fertility program. Additionally, to make sure that P and K soil levels do not decline in alfalfa production growers should consider applying amounts of these nutrients at least equivalent to removal in crop harvest. The need for other nutrients such as sulfur and boron should be evaluated since they can also be important in maintaining high yields.

Soil moisture across much of the western part of the Southeast region has been adequate to surplus. The eastern part of the region has suffered from drought patterns similar to the pattern experienced in 2002. Recent rains have alleviated some of the moisture stress and enabled most farmers to plant. The image below illustrates the soil moisture ranking in the Southeastern states on May 25.

Soybeans - By May 30, 29 to 55% of the planted soybean acreage had soybeans emerged, while 95% of the planted acreage was emerged in Mississippi and 70% in Louisiana. Group 4 maturity is dominating the acreage in Mississippi and several surrounding states are having some success with early maturity groups also. More farmers are considering earlier plantings of earlier maturity group varieties, to help avoid summer drought during reproductive growth… and to capture better prices in the earlier market, before soybeans are harvested in the Midwestern states.

Corn - Corn has tasseled in most states and is silking in others. Heavy rains in the western part of the region have resulted in increased nitrogen (N) rates at sidedressing, to help compensate for the losses of N by leaching and denitrification (gaseous loss of N under waterlogged conditions.)

Peanuts - The peanut crop is in generally fair to good condition, but tomato spotted wilt virus is appearing in many states. Most of the acreage is beginning to peg. Landplaster (gypsum) had been applied, as is normal in several states, to provide calcium and to prevent deficiency as the nuts develop.

Warm season forages - Good forage growth is being observed across the region. Pastures were fertilized and in several states, hay has been harvested once already.

Wheat - About 60% of the winter wheat has been harvested in Arkansas, 30% in North Carolina, and 13% in Missouri. A sizeable portion of the Arkansas harvested acreage will be doublecrop-planted to soybeans, where irrigation is available.

Cotton - Cotton is developing faster than normal, just as with other crops, because of a greater accumulation of heat units. Yet, in some areas cotton was planted the second time, or later than normal, because of excessive moisture.

Citrus - According to the Florida Ag Statistics Service: "Cultural practices are continuing and include fertilization(s), hedging, and resetting of young trees. Most fresh fruit packinghouses are closed for the season with only a few continuing to pack Valencia oranges. Valencia orange weekly harvest is declining as plants close for the season."

Rice - Rice acreage appears to be up slightly from 2003. Heavy rains in Louisiana have made it challenging to manage pests and also to get the N flown on fields at midseason timing. In Mississippi, Arkansas, and the Missouri bootheel, frequent showers have also saved farmers from the need to flush irrigate early, to get the crop emerged.

The earlier outlook for a good supply of irrigation water dried up during the past few months as a warm, dry spring rapidly melted the snowpack that is relied upon to provide moisture through the summer. The four key components of a good water year include the snowpack, soil moisture, stream flow, and reservoir storage. Parts of Idaho, Montana, Colorado, Oregon, and Utah are currently experiencing various degrees of drought. A nearly decade-long drought in Arizona has resulted in water allocations from the Salt River Project being cut by one-third again this year.

Responding to these water shortages continues to be a challenging proposition, prompting reexamination in crop selection, field management, irrigation methods, fertilization practices, and production decisions required to squeeze out the maximum benefit from every drop of water.