Jim Beuerlein, Don Myers and Jay W. Johnson
1. How should I choose what variety of alfalfa/corn hybrid, etc. to use?
Variety or hybrid choices should be based on crop performance data generated under conditions (i.e. soil type, environment, etc.) similar to the ones that the farmer is working with. In addition to yield potential, parameters such as standability, insect resistance, disease resistance, winter hardiness, and maturity should be considered. Ohio State annually conducts performance trials on most agronomic crops at various locations throughout the state. The results of these performance trials can be obtained from your local county agent.
2. What information is available regarding corn hybrid and/or soybean varietal selection based upon soil type and soil fertility levels?
There is a limited amount of research that seems to indicate that there is a need to separate corn hybrids or soybean varieties on the basis of fertility levels and soil types.
Work conducted by Dr. Charles Tsai of Purdue University has shown that there is a differential in N uptake for various corn hybrids. This research, however, is in its early stages, and no recommendations are yet available based on it.
The success of various corn hybrids or soybean varieties on different soil types is often related to how droughty particular soils are. Many seed companies do indicate how drought susceptible their hybrids or varieties tend to be. On droughty soils, choose hybrids or varieties that will perform well under water stress conditions.
Reference: Tsai, C.Y., et. al. 1984. Relationship of N Deposition to Grain Yield and N Response of Three Maize Hybrids. Crop Science 24:272-281.
3. How early can we plant corn? How late?
When you are deciding how early to plant corn, one important factor to consider is the condition of the soil; is the soil dry enough to avoid compaction problems? In addition, one needs to evaluate the long term weather patterns for the area. Corn seed will normally have adequate vigor to emerge for at least 3 weeks; therefore, planting 3 weeks prior to expected emergence is usually safe for corn. It takes approximately 150 heat units for corn to emerge. In central Ohio, we usually accumulate this number of heat units by the last week of April or the first week of May. Thus, the earliest recommended time to plant corn in central and southern Ohio would be the first week of April. In northern Ohio, the earliest planting time for corn would be mid April.
Farmers should strive to have their corn planted by early May whenever possible. In most years yields will decline and grain moisture at harvest will increase if corn is planted after this time.
Therefore, the recommended time for planting corn in northern Ohio is April 15 - May 10 and in southern Ohio, April 10 - May 10.
4. What should you do in the spring when its early and the ground is dry? Plant deep or shallow? Work fine or leave coarse? Cultipack or not? Plant or wait?
If it is after the earliest recommended planting date and if the soil is sufficiently dry, crops can be planted early in the spring. An early planting (before May 1st) gives a higher probability for adequate moisture for emergence. Normally, we recommend a slightly shallower planting (1/4-1/2 inch shallower) early in the season.
How fine the soil should be worked really depends on the soil texture. As a general rule of thumb, however, we recommend a coarser seed bed early in the season because coarse seed beds tend to improve water infiltration. Later in the season, a finer seed bed is desirable. A fine seed bed improves seed/soil contact and decreases evaporative losses of water. Cultipacking is normally recommended when we want a fine seed bed.
Planting should be delayed if it is prior to the earliest recommended planting date. You should also postpone planting if the soil has enough water for seeds to sprout but not enough water to allow emergence.
5. With the newer corn hybrids, is it necessary to worry about soil temperature when planting corn early?
There is relatively little data to support the need for more concern about soil temperature with the new hybrids as compared to the old ones. Refer to the current 'Ohio Corn Performance Test" for ratings of the emergence of various corn hybrids.
6. How can I determine whether I should replant or leave a stand of corn? How to compare date of first planting, replanting, and % stand loss?
In determining whether or not to replant corn, three factors should be considered: the population of the current stand, the distribution of the current stand, and the date of replanting. If the current distribution is relatively uniform, you can expect to lose approximately 1-1.5 bushels of corn/day for any planting that is delayed beyond the first week in May in central Ohio. For established populations, you can expect approximately a 4 bushel decrease per 1,000 stand loss. Thus, for every 1,000 plants lost (assuming no replanting costs), you could delay planting approximately 3 days after the first week of May with equal yields expected.
For example, if you lose 5,000 plants/A, you would expect a total yield decrease of 20 bushels. A 20 bushel decrease in yield is equivalent to a full stand planted 17 days after the first week in May (i.e., approximately May 24). Therefore, if you could accomplish replanting prior to May 24, it might be to your advantage to replant, but after May 24 there would be no benefit gained from replanting.
If the plants are well distributed, 15,000 corn plants seeded before May 10, would be expected to yield in the range of 125 to 140 bu/a.
7. How early can I plant soybeans?
If soil conditions are satisfactory, anytime after April 20, 25 and 30 for southern, central and northern Ohio respectively. Yield loss due to delayed planting ranges from one-third bushel to more than 1 bushel per acre per day, depending on the row width, plant type, and actual date of planting.
8. Is there an ideal row width to use for soybeans?
Any row width is satisfactory as long as a closed canopy (row middles filled in) develops prior to flowering. In general, the earlier you plant, the wider the rows can be and still meet this requirement. Although growing conditions will influence the actual time that it takes for a soybean crop to form a complete canopy, an average time frame is 30 days for 7 inch rows, 45 days for 15 inch rows, and 70 days for 30 inch rows. Therefore, for an early May planting, soybean rows usually need to be 15 inches or less.
9. What seeding rates should be used for small grains and forages?
Information concerning the appropriate seeding rates for a number of small grains is given on page 35, Table 8-1 of the Ohio Agronomy Guide, 13th ed. In this same publication on page 63, you will find a table listing the seeding rates of various forage crops.