Illinois Fertilizer
Conference Proceedings
January 28-30, 1991
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K.A. Kelling and E.E. Schulte1
With the recent increased emphasis on sustainable agriculture and consumer concerns over food safety, some individuals and organizations have been trying to capitalize on this public attention. They are promoting products or programs claiming to be more environmentally compatible, safer for the consumer, or agronomically superior to the more traditional methods of farming. In some cases, these methods are the result of firm convictions that a better way is possible or that the system has worked on their farm. In other cases, a "program" is being promoted because there is a product to be sold.
University scientists are often called upon to provide opinions regarding the usefulness of these types of nonconventional materials or programs. In response to such requests, the North Central Experiment Station Directors established a regional committee (NCR-103) to share available research information and to delineate research needs. Representatives from each of the 12 north central states serve on this committee. Through the committee, coordinated extension and research efforts have been conducted.
Soil and plant additives may be classified under a number of different schemes based on criteria such as intended use or function, method of application, quantity to be applied, or origin of the material. The following system adopted by the NCR-103 committee includes the five primary categories shown in Table 1. Some products by their nature or claims may fall into more than one category. Other categories, which do not fall into existing groups, have been added for those kinds of systems such as "electromagnetic" seed treatments or the use of different soil fertility recommendation systems that are counter to conventional thinking or practice.
Within each of these product category groups, a wide variety of materials or programs have been sold. Development of the NCR-103 committee listing on products, claims, ingredients, and companies (which currently identifies over 315 products) showed that some common trends were evident.
Products are advertised as "natural" "organic" or "work with nature". Many companies appear to be linking themselves to the sustainable agriculture movement.
The same product may be sold under several names. For example, the paper trail of a blue-green algae product shows that it has at' various times since 1973 been sold as Agralife, Agrovita, Genesis II, Planterra, Terra Salvo, Agrispon, Nitro/Max, Reward, Respond, and Soil Inoculant.
Relatively low rates of application are used, although cost of application tends to be about $6-12 per acre, as this is what farmers seem to be willing to spend.
The product mode of action is unspecified or is a "trade secret".
Testimonials are a primary sales technique and sales campaigns usually precede replicated research trials. The decision to buy and use a product is, therefore, often determined by the skill of the salesperson not the efficacy of the product.
To help consolidate available research information on nonconventional additives, the NCR-103 committee published a "Compendium of Research Reports on the Use of Nontraditional Materials for Crop. Production." This compilation contains more than 70 published an unpublished research reports on 73 products. A supplement to this compendium was published in 1983 which contained another 22 reports. As the need arises, it is the intent of the committee to continue to publish supplements on a periodic basis; Supplement 2 is scheduled for publication in 1991. Table 2 gives a summary of all NCR-103 produced documents and how they can be obtained.
A brief examination of the research results in the compendium shows that significant yield responses to application of these "non-traditional" products or programs were rarely obtained. In some instances, the sue of these products in accordance with company recommendations omitted conventional fertilizers and resulted in substantial yield reductions. Tables 3, 4, 5, and 6 show some data for trials conducted in Wisconsin on wetting agents and a "low rate" fertilizer and a soil activator. In all cases, the products tested did not improve crop yield or quality, increase nutrient uptake by the plants or improve measured soil parameters under the conditions of these experiments. In every case, these materials were tested for more than one year.
Tables 5 and 6 show results form recent Wisconsin experiments that included several BioPlus products. BioPlus AP 682 is a "biologically produced poly-coferment liquid complex with vitamins and hormones, auxins and other plant growth regulators as well as root growth stimulants." BioPlus Soil Stabilizer is a "liquid emulsion of soil and water active lignopolymers, polysaccharides, and other polycarbomers. It is an organic complex that holds soil particles in a loose bond aggregate."
Micro 800 is a "uniquely blended natural kelp extract combined with carefully balanced micronutrients and plant growth regulators. "These BioPlus products are produced and/or marketed by Agro Marketing, Inc.. of Hawkins, Texas. Based on various pieces of company correspondence or literature, it appears as if BioPlus was previously sold as AgroPlus and AgroMax. More recently, this product is apparently being marketed by Ag Spectrum Company, Devitt, Iowa as GroZyme. The Wisconsin results show no benefit to corn or alfalfa form the use of BioPlus. Corn growth in 1988 was severely affected by dry weather such that no response to N was seen either. Responses to fertilizer were evident only in the second full hay year due to the relatively high K soil test.
It should be noted, however, that a few instances of positive product performance have been seen, particularly with the plant growth regulators and stimulants. For example, in Wisconsin, potato work using a biological activator, yield increases were not significant for each year, but were significantly increased by 22 cwt/a when examined over the three-year term of the experiment. (Kelling et a1.,1983).
In some cases, the program or product that is being promoted is built in part on some valid theoretical concept. However the specific circumstances of use may be the material or program may be of very limited value in other settings.
Ground rock phosphate has been used in direct applications to supply P for crops for more than 150 years. However, the effectiveness of rock phosphate as a direct application depends on the solubility and fineness of the rock, the time of reaction, and especially the soil pH.
|
Phosphate |
pH 4.6
|
pH 5.6
|
pH 6.6
|
|---|---|---|---|
|
-----------------yield (/pot)-----------------
|
|||
| None |
0.13
|
0.14
|
0.14
|
| Comm. rock phosphate |
1.51
|
0.72
|
0.28
|
| Monocalcium phosphate* |
3.70
|
2.90
|
5.60
|
| * The monocalcium phosphate was applied at 1/4 the rate of total phosphorus supplied as the rock phosphate. Adapted from Joos and Black (1950). | |||
As early as the 1950s, soil pH was recognized as a primary factor controlling P availability from rock phosphate. This is. illustrated by the data of Joos and Black (1950) shown in Table 7. Clearly, availability of the rock phosphate was much better at pH 4.6 and even 5.6, than at 6.6. This means that although rock phosphate may be an acceptable phosphate source for crops grown on very acid soils, it is not an appropriate source at soil pH levels needed for most crops. As noted by Engelstad and Terman (1980), "no rock phosphate source is effective on soils having pH levels above 5.5 to 6.0."
Early work with Ca:Mg:K:H ratios was conducted by W. Albrecht in the 1940s. Albrecht was a professor of soil science at the University of Missouri with a strong interest in the nutritional value of vegetables and field crops in relation to soil fertility. He observed that plants grown in acid soils often took up more Ca than plants grown in limed soils with the H+ neutralized. He was particularly enamored with Ca nutrition and sought to lime and fertilize for maximum Ca content rather than yield. This concept was not shared by most other scientists who recognized that it was far more efficient to increase Ca in the diet with Ca supplements than by soil application.,. Albrecht eventually founded Brookside Laboratories, an organization that has not changed its basic approach in the past 50 years.
Bear and Toth (1948), in giving proportions of different cations on the exchange sites of an "ideal" soil, suggested a Ca:Mg ratio of 6.5:1. This work was done on New Jersey soils that had moderate exchange capacity and were natively low in magnesium. Conversely, Hunter (1943) found that the yield of alfalfa was not influenced by variations from 1:4 to 32:1 in the Ca:Mg ratio of the soil and Halstead et al. (1958) found that a narrow Ca:Mg ratio did not have an adverse effect on yield. Giddens and Toth (1951) obtained low yields of ladino clover on soils when either Mg or K was the dominant exchangeable cation; however with Ca as the dominant cation, no specific cation ratio gave the best yield.
In none of this work has it ever been shown that the 20 to 40 percent exchangeable Mg in many Wisconsin or northern Illinois soils is detrimental. To test this idea, Simson et al., (1979) varied the Ca:Mg ratio of Plainfield loamy sand and Theresa silt loam by wide margins with additions of gypsum (CaS04) and Epsom salt (MgSO4). Although the Ca:Mg ratio of the plant was altered about 50 percent by soil Ca:Mg ratio changes exceeding 200 percent, the yield of corn and alfalfa were not affected significantly.
Conclusion on the usefulness of this concept were clearly stated by E.O. McLean (1982), a graduate student under Albrecht and later a professor at the University of Missouri and Ohio State, when he noted that "since types and relative amounts of each cation exchange bond are so variable in a soil, and plants tolerate -- indeed seem to thrive on -- wide ranges in saturations of basic cations, basic cation saturation ratios per se seem unimportant to the well-being of a crop growing on a give soil." He further suggested that "we look very critically at the Basic Cation Saturation Ratio (BCSR) concept as a basis for making lime and fertilizer recommendations. Since values of BCSR seem to be completely independent of crop yields, perhaps we should instead concentrate on sufficiency levels of each basic cation."
While many farmers may be trying to reduce expenses and improve profitability, it should be recognized that a "quick fix" solution may be shortsighted. Nonconventional additives have been with agriculture for many years, and to date, most have not demonstrated an economic benefit to farmers. As with all farm products, it is important that farmers: (1) understand the soil, crop, and cropping circumstances for which the product is recommended and ensure that those conditions exist on their farms: (2) be given specific directions for product use including precautions; (3) obtain an adequate description of what the product does including its mode of action and expected nature of the crop response; and (4) be provided the results of research findings preferably under the same conditions that exist locally. We are recommending that a great deal of caution be used. To the best of our knowledge, there is no product we have included in the nonconventional group currently promoted for agronomic crops which has consistently provided economic responses.
Considering this past record, it is apparent that following such programs in lieu of proven practices adds substantial risk to an already risk-burdened situation. Farmers can ill afford to not get the most efficient use as possible out of the dollars available for nutrient or other crop management programs. Cutting costs per unit of land should not be the goal; the key is cutting costs per unit of production.
Sustainability of agriculture implies that several components of the system including land stewardship, environmental concern, consumer safety, sensitivity to farm structure, and farm profitability must be satisfied. The use of unproven practices or products, while perhaps meeting one or more of the goals, cannot ultimately be sustainable.
Table 1. Nonconventional product categories, materials and typical claims.
Table 3. Effect of several wetting agents on corn grain yields at several N rates.
Table 5. Effect of BioPlus program on corn grain yields at Arlington, WI, 1987-1988.
Table 6. Effect of BioPlus program on alfalfa yields at Hancock, WI, 1981-1989.
Table 7. Yield of sudangrass as affected by phosphate source and pH
Bear, F.E., and S.J. Toth. 1948. Influence of calcium on availability of other soil cations. Soil Sci. 65:67.
Engelstad, O.P., and G.L. Terman. 1980. Agronomic effectiveness of phosphate fertilizers. p. 311-332. In F.E. Khasawneh et al. (ed.) The role of phosphorus in agriculture. ASA, CSSA, SSSA, Madison, WI.
Giddens, J., and S.J. Toth. 1951. Growth and nutrient uptake of ladino clover grown on Red and Yellow and Grey-Brown Podzolic soils containing varying ratios of cations. Agron. J. 43:209-214.
Halstead, R.L., A.J. McLean, and K.F. Nielsen. 1958. Ca:Mg ratios in soil and the yield and composition of alfalfa. Can. J. Soil Sci. 38:85-93.
Hunter, A.S., S.J. Toth, and F.E. Bear. 1943. Calcium-potassium ratios for alfalfa. -Soil Sci. 55:61-72.
Joos, L.L., and C.A. Black. 1950. The availability of rock phosphate as affected by particle size and contact with bentonite and soil of different pH values. Soil Sci. Soc. Am. Proc. 15:69-75.
Kelling, K.A., R.P.- Wolkowski, and G.G. Weis. 1983. Use of non-conventional soil and plant additives on potatoes. Proc. of the Idaho Potato Schools 15:167-172/
McLean, E.O. 1982. Approaches to soil testing: Double equilibration with soil buffer system for assessing nutrients sufficiency versus basic cation saturation. Proc. 1982 Wis. Fert., Aglime & Pest Mgmt. Conf. 21:88-107.
Simson, C.R., R.B. Corey, and M.E. Sumner. 1979. Effect of varying Ca:Mg ratios on yield and composition of corn and alfalfa. Commun. Soil Sci. Plant Anal. 10:153-162.
Walsh, L.M. 1972. Profitable management of Wisconsin soils. American Printing and Publishing, Madison, WI.
Wolkowski, R.P., and K.A. Kelling. 1985. Evaluation of low-rate starter fertilizer applications for corn production. J. Fert. Issues 2:1-4.
Wolkowski, R.P., K.A. Kelling, and E.S. Oplinger. 1985. Field evaluation of Cytozyme for improving crop yield and nutrient content. Commun. Soil Sci. Plant Anal. 16:11991209.
