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As I said earlier, the national numbers were not unexpected. With soybean prices at nearly record levels, growers are shifting their acreage. Virginia is slowly becoming a full-season soybean state with only 35% to be planted double-crop. This is a big change. Just a few years ago, we planted nearly 2/3 of our soybeans behind wheat.
So, what's going to happen with the soybean market? I honestly have no clue. After seeing the dry weather and rust problems in South America, I suspected that their production would be down. But, I didn't think it would be down as much as the reports are indicating. For example, Argentina crop estimates are now down to 30 to 32 million tons versus previous USDA estimates of 36.5 million tons. In Brazil, crop estimates are down a whopping 7 million tons (52.5 from 59.5). If these estimates are anywhere to being accurate, world ending stocks could drop to 24 million tons, versus 39.27 million tons last year. This paints a much different picture that we had last February when we were thinking that soybeans were way overpriced.
I said this to a number of people and I'll say it here again. I'm not sure that having South America as the largest soybean producing area is all that bad for those who are willing to market their crop. Why do I say this? In the past, the U.S. Corn Belt has generally controlled our prices. Regardless of our production in Virginia, the Mid-Atlantic, or the entire non-Corn Belt producing area, our prices were being controlled by the Mid-West. Now, South America is just as big a player. We now have two weather markets. Yes, this makes for greater volatility. But, with greater volatility comes better pricing opportunities.
While attention will be turning to the new crop situation in the U.S, the situation in South America is still worth watching. Who knows what's really happening down there? But, when reports surface, whether they're accurate or not, the market will move. But, the large increase in intended plantings in the U.S. will temper the market. In the near future, we'll need to begin looking within our own borders. The corn news is bullish. Fundamentals for that crop look very good. Unless record yields are realized, corn stocks will drop. When stocks drop, prices will.... Just some food for though.
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Another reason for not varying seeding rates is the perceived ability for the soybean plant to compensate for poor stands and gaps within a row. This is true, to an extent. I know of few other row crops with soybean's ability to compensate, especially when weather is cooperative. However, soybeans do not compensate as much as we'd like to think. I'd prefer to get it right the first time and not depend on the crop's ability to compensate. By using the appropriate seeding rates for your conditions, you can get the most yield out of the least amount of seed. But, this will requires your willingness to change seeding rates as the season progresses and you move to different soil types. If higher yields, seed savings, and higher profits are of no concern, then here are my suggestions: drop 120,000 seed/acre for full-season plantings and 200,000 seed for double-crop plantings. These are good average seeding rates that will work in most cases. On the other hand, for those of you that wants to obtain higher yields with the least amount of seed possible, read on.
Realize that I'm not talking about solely increasing your seeding rate as you move from full-season to double-crop plantings. It was proven long ago that changing seeding rate as you change cropping systems is beneficial. But instead, I'm talking about varying your seeding rate with soil type and with planting date within the cropping system. Over the last several years, I've conducted soybean leaf area research that used plant population, among other things, to create varying levels of leaf area. In these studies, it was evident that lower-than-recommended seeding rates are needed on our most productive soils, and higher-than-recommended seeding rates were needed on our least productive soils. Sometimes, producers will balk at this notion. And I can understand why. In the words of these producers, "Now let me get this straight. You want me to spend more money on seed for land that will make me the least amount of money?" Yes, believe it or not, that's what I'm saying. Before I give my suggested seeding rates, let's first look into the reasoning for this.
Many of you may be tired of listening to me talk about soybean leaf area, but it does explain much of reasoning behind not only adjusting seeding rates, but row width, insect defoliation thresholds, and other things. Basically, the soybean crop needs a leaf area index, or LAI, of 3.5 to 4.0 by full bloom (R2 stage) in order to maximize yield potential. LAI is the leaf area divided by the land area (a LAI of 4.0 means there is 4 ft2 per ft2 of land). When the crop obtains an LAI of 3.5 to 4.0, it is effectively capturing around 90-95% of the sunlight. Unless the soybean plant builds up it's LAI to this minimum level by the most critical time of crop development (pod and seed fill), it will never fully take advantage of the available sunlight. Note that I'm talking yield potential here and not absolute yield. Just because you obtain an LAI of 4.0 by flowering doesn't mean that you'll yield 50 bushels per acre; you may still only yield 25 bushels. But, if leaf area is adequate, then you'll yield 25 bushels and not 20. Our research indicates that the LAI-yield relationship is pretty stable over 20 to 50 bushel yield levels.
What if you have more leaf area than you need, say an LAI of 6.0? That's OK. It will not give you higher yields, but it's generally not helping much either. As mentioned earlier, if lodging occurs due to too much growth, then yields could decrease with higher leaf areas.
There are several things that affect leaf area. Some of the most important are soil moisture, crop rotation, planting date, row spacing, plant population, variety, and insect defoliators. The plant-available water-holding capacity of the soil definitely affects leaf area and yield. In our Mid-Atlantic Cropping Systems study in Caroline County, we showed soil type and planting date most affected the ability of the soybean crop to obtain adequate leaf area. The highly-productive Wickham soil allowed adequate production of leaf area while the less productive Bojac 2A soil rarely obtained enough leaf area to maximize yield potential. In this same study, double-crop soybeans following full-season soybeans had less leaf area than double-crop soybeans following corn. So, rotation matters. Other experiments on the same farm showed significant yield increases with increasing seeding rates on the Bojac soil, but less of an effect of seeding rate with yield on the Wickham soil.
Increasing seeding rate or decreasing row spacing will increase leaf area. Therefore, on less productive soils, these strategies can be very effective. Variety selection, as related to maturity group is also important. A maturity group III soybean will not produce the same amount of leaf area that a group V will. Therefore, higher seeding rates are needed for earlier-maturing varieties. Figure 7.2.1 illustrates this point. Note that yield maximized for the group V soybeans at plant populations of around 150,000 plants per acre. But, the group III soybeans required 200,000 plants per acre. We were able to relate this response to leaf area. The group III soybean only obtained adequate leaf area in 2001 and only at the two highest populations tested. That's why yield continued to increase with this variety.
So, higher plant populations are needed on soils of lower productivity and lower populations are needed on soils of higher productivity. We should vary seeding rate with maturity group. And as we delay planting date, higher seeding rates should be used. Table 7.2.1 lists my suggested final plant populations that should maximize yield under different yield environments.
Fig. 7.2.1. Yield response of two soybean varieties to plant population. The maturity group (MG) III variety is represented by Southern States brand RT-3975 and the MG V variety is represented by Southern States brand RT-557N. Soybeans were planted after wheat harvest in late June to early July at the Tidewater AREC in Suffolk, VA. Vertical bars represent ± standard error of mean. Suffolk.
Table 7.2.1. Suggested final plant populations for soybeans in Virginia. Plant populations must be adjusted for expected percent emergence to obtain seeding rate.
| Avg. Yield Potential* | Maturity Group | May 1-31 | June 1-15 | June 16-30 | July 1-15 |
| (bu/acre) | (Final Plant Population Needed to Maximize Yield) | ||||
|---|---|---|---|---|---|
| 20-30 | III | 140 | 160 | ----** . | ---- |
| IV | 130 | 150 | 200 | 220 | |
| V | 120 | 140 | 180 | 200 | |
| 30-40 | III | 120 | 140 | 200 | ----- |
| IV | 110 | 130 | 180 | 200 | |
| V | 100 | 120 | 160 | 180 | |
| >40 | III | 120 | 120 | 180 | ----- |
| IV | 100 | 110 | 160 | 180 | |
| V | 100 | 100 | 140 | 180 | |
**Maturity group III soybeans are not recommended on these soils and planting dates
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Slides courtesy of BASF
This disease is hard to detect when it's in its early stages; a windshield check will not do. It can spread and progress very rapidly. Fungicides, while effective need to be applied at first sign of detection (first photograph). If you wait until you really notice it (second photo), it's too late to avoid significant yield losses.
Therefore, Ames Herbert, Extension Entomologist, and I were entrusted by your Soybean Board to make sure that this disease, if it moves into the U.S., will not get out of hand and result in significant yield losses in Virginia. We don't just want to detect the disease; we want to prevent yield loss. Therefore, we will conduct an intensive monitoring program here in Virginia in 2004.
I won't go into all the details of our plans, but will just say that we will have an individual checking soybean fields throughout Virginia for the entire summer and into the fall. Working with Virginia Tech Plant Pathologists Eric Stromberg and Pat Phipps, we will bring any suspect samples back to our diagnostic clinics for identification. We are also working closely with USDA-APHIS to insure that correct and appropriate measures are taken to report any findings. In addition, we'll be April-planting some maturity group III varieties in 1-acre plots throughout the state in order to put these "trap plots" into the most susceptible reproductive stages early in the year. It's generally thought that the rust will not progress and spread rapidly until photosynthate is beginning to be transferred from the leaves to the pods and seed. If rust moves in, we think that it will show up on these early-planted early maturing varieties first. Some of you may have already been contacted concerning these plots. Several seed companies are providing varieties. If you are interested in planting one of these plots, please contact me.
How alarmed should we be for 2004? We should not necessarily be alarmed. Dr. Stromberg seems to think that even if rust moves in, it won't explode to the extent that we'll see any major yield losses. The photos above were from Brazil and the disease levels in that country are extraordinarily high. I doubt if we will see the problem to that extent, at least in year 1. Still, we'll be on guard and let everyone know if rust has been identified.
I plan on publishing a special rust issue of Soybean Update. In that issue, we'll try to address most, if not all of your concerns.
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Will such a system work here? Well, yes and no. It will work. We can grow soybeans in this manner. But, no, there is little or no advantage. Why? The Mid-Atlantic region doesn't experience a consistent August drought. Instead, we have intermittent drought throughout the season. In other words, June is just as likely to experience drought conditions as July as is August. We can't predict when a drought will occur. Actually, instead of pushing soybean development up into the growing season, I think it's better to delay it until late August when temperatures tend to moderate and rainfall is more likely. This is part of the reason for claims that soybeans following barley sometimes yield better than soybeans planted in May. By delaying planting 2 to 3 weeks, you're delaying development approximately 5-7 days. That week delay in flowering, pod formation, and seed fill can sometimes be very beneficial from the drought avoidance standpoint. So, ESPS will not help us in Virginia avoid drought; it may even may it more likely that we insure that drought affects our crop. I'll explain the reasons in this article.
Still, one dollar per bushel sounds like a pretty good premium. But is it really such a good idea? I conducted research several years ago looking at the ESPS. In that research, we looked at two maturity group III and two maturity group IV varieties planted in mid-April. We were able to test these varieties on a Pamunkey loam in Henrico County and on a much less productive Nansemond fine sandy loam in Suffolk from 1997 to 1999. The Nansemond soil had only about 2/3 of the plant-available water-holding capacity as the Pamunkey soil. We also researched the effect of row spacing and plant population on the system. So, it was a thorough study.
What did we learn? First, we could produce a pretty good yield with this system in Virginia. Averaged over all varieties, row spacing, and plant populations, yield ranged from 30 to 50 bushels. The maturity group III varieties matured by end of the second week of September; the group IV varieties matured about 10 days later. So, if you're trying to capture a September market, the group III soybeans will mature and can be harvested in time. While the group IV soybeans will be mature in September, logistics, weather, or other factors that might delay harvest could make this a little risky. If group IV's are used, then an early IV should be selected. Sound good so far? The details of the experiment could change your mind and give us an indication of why the ESPS is not necessarily beneficial to us.
Keep in mind that planting a maturity group III variety places the most critical times of plant development into July. In our research, flowering occurred by mid-June, pods developed in July, and seed began to form in late July. Late July and August is usually our hottest and driest time of the year. So, this is a major risk. Our yields reflected this risk. On the Nansemond soil in Suffolk, yields for the group III's yielded 6.5 bushels less than the IV's. On the Pamunkey soil, the III's yields were equal to the IV's in a good rainfall year (1998) which produced average yields of 50 bushels per acre. But the group III varieties yielded 2.3 bushels lower in 1999 when yields averaged 40 bushels. Although I did not test a group V nor May plantings in this study, I have little doubt that later plantings or a maturity group V variety would have yielded higher due to the rainfall distribution in those years. Plant populations of over 150,000 plants were required to maximize yield on the Nansemond soil, but less than 100,000 plants were needed on the Pamunkey soil. Therefore, you not only lost more yield on the Nansemond soil, but you had to spend more money for seed. In one year (1999), 9-inch rows increased yields over 18-inch rows by 1.67 and 5 bushels on the Nansemond and Pamunkey soil, respectively.
Another thing about this research needs to be mentioned. We always tried to harvest within a week after the crop was mature. Seed quality will decline rapidly under the warm and humid September environment. One year, we harvested half of the plot, and then were rained out. We came back a week later and the seed had degraded to an un-saleable product. In another year, there were still green leaves on the plant. The crop didn't look mature from the road, but the seed moisture was 13%. We harvested with some trouble, pushing the green vines through our plot combine.
So, what does all this mean? On most of the soils in Virginia, ESPS will not likely pay. In our research, a 6.5 bushel loss at $6.30 (Nov 05) and $7.50 (Nov. 04) per bushel would result in a $40-50 loss. So, at $1 per bushel, you have to produce 40 to 50 bushels to come out even. I wouldn't count on 40 to 50 bushels on a sandy coastal plain soil. Keep in mind that I'm comparing the yield loss to maturity group IV soybeans planted in April. As I said earlier, I suspect a group IV or V soybean planted in May would have yielded even better.
But, let's consider the Pamunkey soil. Yes, it's probably our best soybean soil. But, there are others that are similar. If there is no yield loss, then the $1 per bushel premium would be mostly profit (there are added costs). But, let's assume that we'd lose 3 bushels. In this case, our income could be reduced $19-23. Can we yield at least 20 bushels on these soil types? Yes, in most instances.
Will the ESPS work on a productive soil? With a $1 premium (This was 88¢ on March 31), the ESPS would probably be beneficial on productive soil with a high plant-available water-holding capacity. Remember, we have to have enough stored soil moisture to get the soybeans past the late-July early-August dry spell. On most of our soils, I see no benefit and a lot of risks.
If you have a good soil and are still considering the ESPS, I'll offer these suggestions:
A final point is worth mentioning. I have spoke only about yield potential and costs of producing soybeans in this system. I have not even mentioned whether or not you can sell your crop in September. I know there are some areas of Virginia that will not take soybeans in that month. So, don't just start planting, do your marketing homework first.
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I would suggest that a fungicide seed treatment be used when soybean are planted in late April or early May or when cool soil temperatures are expected. The fungal organisms that will harm our emergence are usually present in the soil. But the length of time that the seed remain in the soil will determine whether or not they will infect the plant and inhibit emergence. If the soils are warm (>65o F), then a fungicide seed treatment may not help. That's why I don't recommend this for double-crop plantings; double-crop soybeans can emerge within 3 days. But, for May plantings, emergence can be delayed for 10 days or more.
People generally want a cutoff date. I usually say May 15, you shouldn't hold tight to this date. Some of the worst emergence I ever saw was with soybeans planted the last week of May. During that year, a cold rain and several days of low temperatures followed planting. So, if the weather forecasts cold weather, you may want to have a hopper-box seed treatment on hand.
We don't always see a yield response to seed treatments. More common is an improvement in the stand. But, even when stands are reduced, the ability of the soybean plant to compensate for gaps masks the seed treatment's benefits. A lot happens between planting and harvest. A good year can cover up a lot of mistakes; but a poor year can bring them out.
Last year, we conducted several small-plot and on-farm tests. Keep in mind that seed quality was lower than average. We did sometimes see a good response to the seed treatment. In the County Agent-lead plots, a statistically significant increase in yield was found at 2 of 5 locations. At the two locations where a benefit was found, the yield increase was 3 and 9 bushels per acre. I conducted 2 trials with seed that contained Phomopsis seed decay and varying levels of purple seed stain. We saw a yield response in 1 of the 2 locations. For the seed with no purple seed stain, yield was increased 5 to 9 bushels with a seed treatment.
So, seed treatments can be beneficial. If considering a seed treatment and if the seed are not pre-treated, then chose a product with either thiram or captain as base product. Carboxin is usually added to one or both of these. Metalaxyl is sometimes added to certain products. Plus, there is some newer chemistry out there that has been very effective. Our results over the last few years basically indicate that the least inexpensive product will usually do the job. Phomopsis and rhizoctonia are the disease most prevalent in Virginia. Most seed treatments will handle these OK. Only in areas where Essex disease (fusarium/pythium damping off) would I suggest using one of the more high-powered products.
For more information on seedling disease, refer to Soybean Update Vol. 6 No. 2 (April 2003) at http://www.vaes.vt.edu/tidewater/soybean/soybeanup/0304/0304.html
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Sincerely,
David L. Holshouser
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