Donald W. Trotter Ph.D.
ABSTRACT. As the beneficial effects of fossilized marine algae continue to be proven in the areas of plant growth, yield, and quality several questions have arisen regarding how this mineral affects soil microflora. Effects of fossilized marine algae as a soil conditioner for alleviating certain chemical, physical, and microbiological are continuing to be studied. In the study reported here, Kelzyme fossilized marine algae inoculated into test soils on a one acre plot of citrus and tomato in southern California was conducted with controls to determine increases in microbiological activity of target species of both beneficial and pathogenic species. Test results indicate increased numbers of Enterobacter spp. And starch digesting bacteria in soil. Additionally marked suppression of Verticillium, Thielaviopsis, and Fusarium fungal species that are destructive soil borne plant pathogens. Tests showed increases in the population of Trichoderma and Penicillium species that are known to suppress plant pathogenic fungi in soils. Soil physical properties, including cultivation depth and porosity was also generally improved by Kelzyme treatment.
Introduction:
Soil microorganisms can have both positive and negative effects on plant growth. They can facilitate nutrient absorption by plants (Bowen and Rovira, 1966); promote plant growth or stimulate seedling development by producing hormone-like substances (Rubenchick, 1963; Mishustin 1970; Brown 1974); that suppress and control plant pathogens and diseases through various antagonistic activities (Marois et al., 1981); or adversely affect plant growth through their pathogenic behavior (Elad, 1985).
A principle goal of farming is to produce abundant and healthy crops with a minimum of input. A vigorous soil microflora has been found to minimize the necessity for extensive chemical fertilizer and pesticide additions (Higa, 1986; 1988). The purpose of this study was to investigate the effects of Kelzyme on soil microflora, the effects of Kelzyme on soil physical and chemical properties, and how this material can be successfully applied to modern agriculture.
Materials and Methods:
The Kelzyme mineral was obtained from the deposit and transported to the test site in Encinitas, California in San Diego County, USA. Testing was done on a total of 36 three year old Satsuma Mandarin Orange trees. At the site of each tree four tomato plants were planted of the Roma cultivar. Each site consisted of four citrus trees and sixteen tomato plants. Each site was randomly placed to ensure equal opportunity in soil variation. The soil was tested at twelve random locations and an aggregate pH of 7.8 and was classified as primarily decomposed granite. Soil actual P and K levels were moderately high yet unavailable. It was decided that no additional application of these nutrients would be added to determine increases in available P and K from elevated microbial activity.
The control site (A) was left alone. Site (B) received an application of 1Kg actual nitrogen from Ammonium nitrate. Site (C) received 1Kg actual nitrogen from Ammonium nitrate and 5Kg of Kelzyme. Site (D) received 1Kg actual nitrogen from composted poultry guano and 5Kg of Kelzyme. Site (E) received 1Kg actual nitrogen from ground alfalfa meal and 5Kg of Kelzyme. Site (F) received 1 Kg actual nitrogen from composted feedlot and 5Kg Kelzyme. Site (G) received 1Kg actual nitrogen from fossilized seabird guano and 5Kg Kelzyme. Site (H) received 1Kg actual nitrogen from aged, ground feather meal and 5Kg Kelzyme. Site (I) received 1Kg actual nitrogen from cold process fish emulsion and 5Kg Kelzyme.
Testing began on March 30, 1998. Tomato tests were concluded on September 21, 1998 which allowed for two successive plantings. The tests on citrus were concluded on March 30, 1999.
Total microorganisms were estimated by the plate count method. Bacteria and actinomycete populations were counted on egg albumin agar (Tadao, 1984). Total fungi were counted on rose bengal agar (Martin, 1950). Azotobacter were isolated on nitrogen-free mannitol broth agar (Harrigan and Margaret, 1966). Clostridia were isolated on media described by Sheldon (1970). Lactobacillus spp. were counted on Rogosa agar (Harrigan and Margaret, 1966). Enterobacter was counted on MacConkey agar (Harrigan and Margaret, 1966). Starch digesting bacteria were counted using the method of Sheldon (1970). Agrobacterium, Erwinia, Pseudomonas, and Xanthomonas spp. were counted on D1, D3, D4, and D5 selective media, respectively (Kado and Heskett, 1970). Fusarium was counted on Komadas medium (Tadao, 1984); Verticillium on alcohol agar medium (Mathew and Chester, 1959); and Thievalopsis on RBM2 medium (Tsao, 1964).
Soil bulk density and porosity were determined according to methods described by Henry (1984), using 2 and 4 cm diameter cores from each plot taken to a depth of 10 cm. Soil porosity was calculated from the ratio of pore space and soil volume. Soil aggregation was determined by the pipette method described by Martin and Waksman (1940). Soil phosphorus content was determined by the method of Hormers and Parker (1961).
Results:
Change in Soil Microflora:
In most cases, the numbers of bacteria, fungi, and actinomycetes increased after the soil was treated with Kelzyme fossilized marine algae, although the numbers of actinomycetes were lower in site (G) than the unfertilized control (Table 1). It was interesting that the lowest number of actinomycetes occurred when the soil was treated with conventional fertilizer only (site B).
Generic analysis of the bacterial flora in the soil due to Kelzyme treatment is shown in Tale 2. In most cases the Kelzyme treatment markedly increased the number of Enterobacter spp. and starch digesting bacteria over that of the unfertilized control (A), but had little effect on enhancing the numbers of Lactobacillus spp. The highest numbers of Azotobacter and Clostridium species were attained with the fertilized control (B), while the lowest number of each occurred with the unfertilized, untreated control (A). The highest number of Xanthomonas and Erwinia species were found in the fertilized control (B), the highest number of Agrobacterium from the combination of cold process fish emulsion and Kelzyme (I), and the highest number of Pseudomonas from composted feedlot and Kelzyme (F).
The number of fungal species after Kelzyme treatment of this soil are shown in Table 3. The highest number of Trichoderma species was found after treatment with composted feedlot and Kelzyme (F) and the highest number of Penicillium with composted poultry guano and Kelzyme. However, the lowest number of specimens in these genera resulted from the ammonium nitrate only treatment (B). The highest number of Verticillium species was observed in the fertilized control (B) and with alfalfa meal and Kelzyme (E). But the combination of cold process fish emulsion and Kelzyme appeared to suppress the numbers of this soil borne plant pathogen. The highest number of Fusarium species resulted from treatment with the fertilized control (B), while the combination of cold process fish emulsion and Kelzyme markedly suppressed the numbers of this particularly destructive plant pathogen.
Change in Soil Physical and Chemical Properties:
Soil physical properties were determined one year after treatment with the Kelzyme mineral and are shown in Table 4. Cultivation depth and porosity were significantly higher with most Kelzyme treatments than with the controls, (A) and (B). Soil hardness was significantly higher for the unfertilized control, although it was also high for the ammonium nitrate and Kelzyme treatment (C). There was little difference in soil bulk density among all treatments.
Soil aggregation was significantly higher for all Kelzyme treatments than either the control (A) or the fertilized control (B). Soil aggregation actually decreased in the fertilized control (B).
There was little difference in the effect of Kelzyme treatment or the unfertilized controls on soil pH. The fertilized control showed a change in pH from 7.8 to 7.3, which seemed fairly dramatic. However humus content was markedly increased which is assumed to be caused from the organic matter in many of the treatments (D through I). Nitrate levels were slightly higher in treatments (D through I); ammonium levels were unremarkably higher in the Kelzyme treatments. Potassium was also slightly increased by an average of 7% by the Kelzyme treatments. The most dramatic effects on the Kelzyme treatments were the elevated levels of calcium, Ca and the increased levels of inorganic (plant available) phosphorus which was higher than the unfertilized control in all cases. (Figure1).
Tomato and Citrus Production:
Tomato yields for the first crop showed significant difference between the Kelzyme treatments and the unfertilized control. However yields were much higher in the fertilized control and the ammonium nitrate and Kelzyme (B and C) sites. The fertilized control (B) declined significantly in the second planting yet the decline in production in the ammonium nitrate and Kelzyme (C) site appeared to remain viable suggesting an extended viability of the nitrogen source in the presence of Kelzyme (Horst and Fenn, 1985) Figure 2 and Table 5. The number of nematode galls on tomato plants grown in the control sites, both fertilized and unfertilized (A and B) were higher than each of the Kelzyme treatments (D through I). Sites C, D and H were particularly effective at suppressing nematode damage.
Citrus harvests and plant growth data will be published in February 2000.
Table 6 shows the indirect effect of Kelzyme treatments on yield quality. While the Kelzyme treatments with organic matter nitrogen sources were considerably lower than the ammonium nitrate sites, the number of marketable tomatoes was considerably higher for these Kelzyme treatments than for the fertilized control (B).
Discussion:
The lowest number of actinomycetes occurred in soil treated with ammonium nitrate (B) suggesting that these microorganisms may somehow have been suppressed, either directly or indirectly, by the fertilizer components. Beliaev (1958) found that continuous application of ammonium fertilizer without calcium can suppress the actinomycetes since the ammonium is oxidized to nitric acid by microbial action. The resultant decrease in soil pH can cause unfavorable growth conditions.
The generic analysis of the bacterial flora (Table 2) showed that fermentative bacteria such as Enterobacter, starch digesting bacteria, Azotobacter, and Clostridia, are present in soil treated with Kelzyme and the fertilized control (B), but to a lesser extent in the unfertilized control. This may have been due to the effect of some specific nutrient requirement for the growth of fermentative bacteria. Gyllenberg (1956) reported seasonal variations in which the relative abundance of Aa grouping bacteria increased with a decrease in the abundance of Ba grouping bacteria. It remains unexplained whether the increase in the relative abundance of the Aa grouping bacteria was accompanied by the accumulation of specific nutrients such as amino acids.
At present there is no clear relationship between Kelzyme treatments and the number of soil disease bacteria, e.g., Xanthomonas, Erwinia, Agrobacterium, and Pseudomonas, as shown in Table 2. But in the preliminary experiment it appeared that treatment of soils along with certain organically based nitrogen source (site E) is associated with a rather low population of disease bacteria.
The effect of Kelzyme on fungal populations is soil (Table 3), indicated that soil treated with only fertilizer had low numbers of Penicillium and Trichoderma. These beneficial fungi can play an important role in inhibiting or suppressing soil borne microbial plant pathogens through their antagonistic activities. Large numbers of plant disease pathogens were found in both of the control treatments.
The effect of Kelzyme on soil physical properties suggests that Kelzyme can induce plant roots to penetrate soil more effectively. Soil treated with Kelzyme becomes more friable and porous, less compact, and promotes deeper cultivation. Microorganisms, particularly fungi, can bind soil particles into more stable aggregates. Bacteria can synthesize cementing agents in the form of gums and polysaccharides that also help to promote good aggregation. Lynch (1981) found that Azotobacter chroococcum , Lipomyces starkeyi, and Pseudomonas spp. can promote the stabilization of soil aggregates.
Insoluble soil phosphorus compounds (both organic and inorganic) are largely unavailable to plants, however many microorganisms can solubilize these compounds and make them available for uptake. Martin (1961) found that one-tenth to one-half of the bacterial isolates he tested were capable of solubilizing calcium and phosphorus. Fungal species of the genera Pseudomonas, Myobacter, Micrococcus, Flavobacterium, Penicillium, Sclerotium, Aspergillus, and others are also known to solubilize insoluble phosphates to plant-available forms.
Kelzyme treatment has an indirect effect on covering or healing tomato fruit injuries cause by the Green June bug (figeater). Fruit damage was greatest for the controls and slightly higher for the ammonium nitrate and Kelzyme treatment. However fruit damage was considerably less with the other Kelzyme treatments compared with the controls. These results may be soil specific. Soils that do not have a good fermentation potential can produce malodors that attract harmful insects that prefer to lay their eggs in areas where plant stress or rapid growth is evident. It is noteworthy that three of the Kelzyme treatments, (sites D, E, and F) produced yields that were comparable to, though less than, the ammonium nitrate fertilized sites. These three Kelzyme sites also produced a greater amount of marketable fruit than the ammonium nitrate sites indicating a beneficial effect from Kelzyme on fruit quality. The actual role of Kelzyme in covering tomato fruit injuries needs further investigation to determine what relationships and mechanisms are involved in this process.
References:
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