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Publication numberUSRE34670 E
Publication typeGrant
Application numberUS 07/818,472
Publication dateJul 26, 1994
Filing dateJan 6, 1992
Priority dateJul 17, 1986
Publication number07818472, 818472, US RE34670 E, US RE34670E, US-E-RE34670, USRE34670 E, USRE34670E
InventorsJohn M. Day, Paul M. Williams
Original AssigneeAgricultural Genetics Company Limited
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Inoculant composition for plants
US RE34670 E
Abstract
The invention relates to an inoculant composition for plants, comprising a carrier medium, at least one species of microorganism having a beneficial effect on the plants, and a copolymer of (1) vinyl pyrrolidone and (2) vinyl acetate or styrene or substituted styrene.
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Claims(2)
    We claim: .[.1. A seed having a coating comprising at least one species of microorganism having a beneficial effect on the seed or resulting plant, and a copolymer of (1) vinyl pyrrolidone and (2) vinyl acetate or styrene or a substituted styrene..]. .[.2. An inoculant composition for plants, comprising a carrier medium, at least one species of microorganism having a beneficial effect on the plants, and a copolymer of (1) vinyl pyrrolidone and (2) vinyl acetate or styrene or a substituted styrene..]. .[.3. The composition of claim 2, wherein the plants are legume crops and said microorganism is Rhizobium bacteria..]. .[.4. The composition of claim 2, wherein said carrier medium is peat..]. .[.5. The composition of claim 3, wherein said carrier medium is peat..]. .[.6. The composition of claim 2, wherein said copolymer is a copolymer of viyl pyrrolidone and vinyl acetate in respective proportions by weight of from 50:50 to 70:30..]. .[.7. The composition of claim 3, wherein said copolymer is a copolymer of vinyl pyrrolidone and vinyl acetate in respective proportions by weight of from 50:50 to 70:30..]. .[.8. The composition of claim 4, wherein said copolymer is a coplymer of vinyl pyrrolidone and vinyl acetate in respective proportions by weight of from 50:50 to 70:30..]. .[.9. The composition of claim 5, wherein said copolymer is a copolymer of vinyl pyrrolidone and vinyl acetate in respective proportions by weight of
  1. from 50:50 to 70:30..]. .Iadd.10. A seed having a coating consisting essentially of at least one species of microorganism selected from the group consisting of bacteria of the genera Rhizobium, Bacillus, Azotobacter, Arthrobacter, Pseudomons, Azospirillium, Cyanobacteria, and mycorrhizal fungi having a beneficial effect in the seed or resulting plant, and a copolymer selected from the group consisting of (1) a copolymer of vinyl pyrrolidone and vinyl acetate in respective proportions by weight of from 50:50 to 70:30, (2) a copolymer of vinyl pyrrolidone and styrene, and (3) a copolymer of vinyl pyrroldione and a substituted
  2. styrene. .Iaddend. .Iadd.11. The seed of claim 10, wherein said seed is the seed of a legume crop plant and said microorganism is a Rhizobium bacteria. .Iaddend. .Iadd.12. The seed of claim 10, wherein said copolymer is a copolymer of vinyl pyrrolidone and vinyl acetate in respective proportions by weight of 50:50 to 70:30. .Iaddend. .Iadd.13. The seed of claim 10, wherein said copolymer is a copolymer of vinyl pyrrolidone and styrene. .Iaddend. .Iadd.14. The seed of claim 10, wherein said copolymer is a copolymer of vinyl pyrrolidone and a substituted styrene. .Iaddend. .Iadd.15. An inoculant composition for plants, consisting essentially of a carrier medium, at least one species of microorganism selected from the group consisting of bacteria of the genera Rhizobium, Bacillus, Azotobacter, Arthrobacter, Pseudomonas, Azospirillum, Cyanobacteria, and mycorrhizal fungi having a beneficial effect on the plants, and a copolymer selected from the group consisting of (1) a copolymer of vinyl pyrroldione and vinyl acetate in respective proportions by weight of from 50:50 to 0:30, (2) a copolymer of vinyl pyrrolidone and styrene, and (3) a copolymer of vinyl pyrrolidone and a substituted styrene. .Iaddend. .Iadd.16. The composition of claim 15, wherein said plants are legume plants and said microorganism is a Rhizobium bacteria. .Iaddend. .Iadd.17. The composition of claim 15, wherein said carrier medium is peat. .Iaddend. .Iadd.18. The composition of claim 16, wherein said carrier medium is peat. .Iaddend. .Iadd.19. The composition of claim 15, wherein said copolymer is a copolymer of vinyl pyrroldione and vinyl acetate in respective proportions by weight of from 50:50 to 70:30. .Iaddend. .Iadd.20. The composition of claim 16, wherein said copolymer is a copolymer of vinyl pyrrolidone and vinyl acetate in respective proportions by weight of from 50:50 to 70:30. .Iaddend. .Iadd.21. The composition of claim 15, wherein said copolymer is a copolymer of vinyl pyrrolidone and styrene. .Iaddend. .Iadd.22. The composition of claim 16, wherein said copolymer is a copolymer of vinyl pyrrolidone and styrene. .Iaddend. .Iadd.23. The composition of claim 15, wherein said copolymer is a copolymer of vinyl pyrrolidone and a substituted styrene. .Iaddend. .Iadd.24. The composition of claim 16, wherein said copolymer is a copolymer of vinyl pyrrolidone and a substituted styrene. .Iaddend.
Description

.Iadd.This application is a continuation of application Ser. No. 07/516,738, filed Apr. 30, 1990, now abandoned, which is a reissue of Ser. No. 07/074,543, filed Jul. 17, 1987, now U.S. Pat. No. 4,849,005.

DETAILED DESCRIPTION OF THE PREFERERD EMBODIMENTS

The present invention thus provides an inoculant composition for plants, comprising a carrier medium, at least one species of microorganism having a beneficial effect on the plants, and a copolymer of (1) vinyl pyrrolidone and (2) vinyl acetate of styrene or a substituted styrene (e.g. methyl styrene).

Preferably, the plants are legume crops and the microorganism is Rhizobium bacteria.

The carrier medium is preferably peat, in particular irradiated sedge peat.

A preferred copolymer for use in the present invention contains vinyl pyrrolidone and vinyl acetate in respective proportions by weight of from 50:50 to 70:30, most preferably about 60:40.

The invention also provides a seed having a coating comprising at least one species of microorganism having a beneficial effect on the seed or resulting plant, and a copolymer of (1) vinyl pyrroldione and (2) vinyl acetate or styrene or a substituted styrene.

The invention further provides a method of sowing seeds, in which the seeds are sown together with an inoculant composition as defined above. The inoculant composition may be applied either to the seeds or to the soil at the time of sowing.

The inoculant compositions according to this invention may be used for the inoculation of dry seeds or they may be slurried with water when this type of inoculation is desired.

The invention is illustrated by the following Examples.

EXAMPLE 1

Inoculant compositions were prepared by mixing samples of peat with various polymers to make a total weight of 150 g in each case, followed by injecting with 110 ml of Rhizobium broth and curing for seven days prior to use, 0.5 g of each inoculant composition was then mixed dry with 100 g of legume (soya) seeds. The seeds were then separated from excess inoculant, and the weight of inoculant adhering to the seeds was measured. The results are shown in Table 1 below.

              TABLE 1______________________________________               Wt. of inoculantAdditive            adhering to 100 g seed(additive - peat 150 g)               (mg)______________________________________Control (no additive)               1215 g PVP (M.W. 10,000)               1725 g PVP (44,000)    2485 g PVP (700,000)   1045 g PVP VA-S-630    2975 g Antara 430      1855 g PVP/VA-S-630 after storage*               230Control after storage*               112______________________________________ *Storage for 14 months at laboratory temperature

PCP/VA S-630 is a 60:40 vinyl pyrrolidone/vinyl acetate copolymer which is obtainable from GAF (Great Britain) Co., Limited, Manchester. It is a spray-dried, high molecular weight powder which can form stable emulsions in water.

Antara 430 is a vinyl pyrrolidone/sytrene copolymer emulsion, also obtainable from GAF.

The results in Table 1 show the improved effect of the vinyl pyrrolidone/vinyl acetate and vinyl pyrrolidone/styrene coplymers in promoting adhesion in comparison with polyvinyl pyrrolidone (PVP). It is also shown that the former copolymer retains its adhesive characteristics during long term storage.

EXAMPLE 2

Tests were carried out to show that the vinyl pyrrolidone/vinyl acetate copolymer promoted peat adhesion to a wide range of legume seeds. Adhesion was measured in the same way as in Example 1. The results are shown in Table 2 below.

              TABLE 2______________________________________                Wt. of inoculant adhering                to 100 g seed (mg)Legume seed Control  PVP VA-S-630______________________________________Soya        121      297Lupin       144      265Phaseolus   165      382vulgarisWhite clover        94      215Lucerne     284      416Chickpea    148      259Lentil      140      240Pea          73      286______________________________________
EXAMPLE 3

Similar experiments were carried out as in Example 1, except that the weight of vinyl pyrrolidone/vinyl acetate copolymer added to the peat was varied. The results are shown in Table 3 below, and indicate that the addition of between 5 and 7.5 g of the copolymer per 150 g of peat provides maximum adhesion.

              TABLE 3______________________________________Wt. of PVP VA-S-630           Wt. of peat adheringadded to peat (g)           to 100 g seed (mg)______________________________________0 (control)     1282               2353.5             2775               3217.5             31710              239______________________________________

The copolymer may be added as a powder to dry peat prior to its sterilisation by gamma radiation, or added as an autoclaved 10% suspension during injection of the peat with a liquid bacterial suspension.

EXAMPLE 4

Rhizobial numbers were counted in inoculant compositions containing the vinyl pyrrolidone/vinyl acetate copolymer and in control compositions not containing the copolymer but otherwise identical. The results are shown in Table 4 below, and indicate that the number of bacteria in inoculants containing the copolymer are not adversely affected by its addition (i.e. it is not toxic). This applies both to fast (3622) and slow (3407) growing rhizobial strains. A similar result, also shown in Table 4, was obtained using the 3407 strain and Antara 430.

              TABLE 4______________________________________             No. of Rhizobia g.sup.-1Bacterial strain  of peat______________________________________             Control   PVP VA-S-630Rhizobium phaseoli 3622             1.22                        1.50 Rhizobium japonicum 3407             1.35                        2.33              Control   Antara 430Rhizobium japonicum 3407             1.8                        1.7 ______________________________________
EXAMPLE 5

The follwing work was carried out to determine the effect of the copolymer on rhizobial numbers during long term storage of inoculants. The experimental procedure was as follows:

Selected sedge peat (Fisons) was adjusted to pH 6.5 using calcium hydroxide and calcium carbonate. This was oven dried at 60 a hammer mill to pass through a 0.4 mm sieve, 5 g aliquots of PVP VA-S-630 were added to 150 g lots of peat and the mixture sealed into 300 gauge polythene bags and sterilized by gamma radiation (50 kGy). These bags were subsequently injected with 57.5 ml of a grown culture of Rhizobium japonicum (3407) plus 57.5 ml of sterile distilled water. Controls (without the copolymer) were similarly prepared. Other irradiated peat packs were injected with 57.5 ml of grown culture plus 57.5 ml of an autoclaved 10% aqueous suspension of the copolymer. All packs were thoroughly mixed, cured at 26 laboratory temperature. At periodic intervals the numbers of viable rhizobial cells in the inoculants were determined (Table 5).

              TABLE 5______________________________________   No. R. g.sup.-1 peatTime after            Copolymer Copolymercuring (months)     Control     (powder)  (suspension)______________________________________0         1.4                  2.1                            2.3 2         4.3                  5.8                            5.5 5         9.6                  1.9                            2.2 9         2.9                  3.0                            2.4 14        1.6                  3.2                            2.9 ______________________________________

Rhizobial numbers in control inoculants (-PVP VAS-630) peaked after approximately nine months of storage and a slight decline was observed after a further five months. Although rhizobial numbers in inoculants containing the copolymer were similar to the controls after nine months storge, numbers were maintained during the subsequent five months. This demonstrated that the addition of the copolymer to peat based inoculants has no detrimental effect on rhizobial numbers.

EXAMPLE 6

This demonstrates the beneficial effect of the copolymer on rhizobial survival on the seed surface. The experimental details are as follows:

Rhizobial inoculants (without the copolymer) were prepared as described in Example 5. Inoculants containing PVP VA-S-630 were prepared by its addition as an autoclaved suspension. The control and copolymer containing inoculants contained 6 g.sup.-1 respectively at use. The control inoculants were used to inoculate soybean seeds in three ways:

1. Dry dusting--300 g of seed were mixed with 1 gm of inoculant

2. Water slurry--1 gm of inoculant was slurried with 2 ml of water and then mixed with 300 g of seed

3. Gum Arabic slurry--1 gm of inoculant was slurred with 2 ml of a 40% aqueous solution of gum arabic (Sigma) and then mixed with 300 g of seed

In all treatments, inoculated seeds were held at room temperature for 30 min. prior to the removal of unadhered inoculant by sieving.

The inoculants containing PVP VA-S-630 were used in the following way:

1. Dry--1 g of inoculant was mixed with 300 g of seed

2. Moist--g of seed were slightly moistened with 0.3 ml of water, prior to mixing with 1 g of inoculant.

Inoculated seed was dried and sieved as before. The seed lots were then held in air or air dried soil at 25 rhizobial numbers seed .sup.-1 determined during an 8 day period. The results are shown in Table 6.

              TABLE 6______________________________________Time after No. R. seed.sup.-1inoculation      Soil              Air(days)     25              35                        25                               35______________________________________Control InoculantDry Dusting0-26001           140      0        240     02           100      0         0      04            0       0         0      08            0       0         0      0Water Slurry0-20,6001           1200    350      3000     02           1000    60       2000     04            0       0         0      08            0       0         0      0Gum Arabic Slurry0-73,0001          13000   5200      31000  13002           9000   1300      2700    804           5600    200      1000      08           600      0        10      0Inoculant containing PVP-VA-S-630Dry0-34,0001          10000   1700      16000  14002           7500    860      9500   11004           5000    100      7500    2008           830      0        900    10Moist0-79,0001          50000   8000      43000  100002          11000   3400      32000  43004          11000   1000      8000   36008           4000    400      6300    700______________________________________

From the results, it can be seen that rhizobial numbers declined rapidly in all treatments when control inoculants were used for dry dusting or water slurry inoculation. Gum arabic (a conventional sticker) offered protection to the rhizobial cells, thus extending their survival time, but this protection was inferior to that provided by the copolymer.

This superiority of the copolymer over gum arabic in promotion of rhizobial survival on the seed surface becomes plainly obvious when the data obtained with the conventional sticker is compared to moist inoculation using the copolymer--i.e. both treatments providing similar initial rhizobial numbers seed.sup.-1.

EXAMPLE 7

Slurry inoculation of seeds was carried out using a conventional inoculant composition as a control, a conventional composition with gum arabic as a sticker, and a composition according to the invention without a sticker. The results are shown in Table 7 below, and indicate that the copolymer increases inoculant adhesion during slurry inoculation of seeds, thus eliminating the need for an additional sticker.

              TABLE 7______________________________________Treatment       Increase in seed wt. (g)______________________________________Slurry with water           0.62Slurry with 40% soln.           1.10of gum arabicSlurry PVP VA-S-630           1.05containing inoculantwith water______________________________________

This invention relates to an inoculant composition for plants.

TITLE OF THE INVENTION

The term "plants" includes all agricultural crop plants, horticultural plants, trees and bushes.

BACKGROUND OF THE INVENTION

Various microorganisms are known to have a beneficial effect on plants, e.g. bacteria of the general Rhizobium. Bacillus, Azotobacter, Arthrobacter, Pseudomonas, Azospirillum and Cyanobacteria (blue-green algae), and mycorrhizal fungae. Such microorganisms are introduced to the plants by the use of inoculant compositions. Although the following description is mainly concerned with Rhizobium inoculant compositions, it will be appreciated that similar principles apply to the use of other microorganisms.

FIELD OF THE INVENTION

It is well known that legume crops can fix atmospheric nitrogen when in association with Rhizobium bacteria which reside within nodules on the plant roots. There are many different species and strains of Rhizobium bacteria. There are specific beneficial strains for each crop, and these will not necessarily effectively nodulate a different crop. Most soils do contain a natural rhizobial population, but wild strains are often ineffective. Successful nodulation depends on the presence of an effective rhizobial strain in the soil, and moreover this strain needs to be sufficiently competitive within the soil environment to enable it to compete successfully with the wild population. The only way to ensure that an effective strain of Rhizobium will associate with the crop is to inoculate the seed, or the soil, at the time of sowing.

Rhizobium inoculant compositions are known which contain appropriate rhizobial strains together with a suitable carrier medium. A preferred carrier medium is peat. The inoculant is placed in intimate contact with the seed to ensure rapid and effective nodulation of the young crop plants. This may be achieved by two general methods, slurry inoculation and dry inoculation. In slurry inoculation, the inoculant is mixed with water and generally a "sticker", e.g. gum arabic or methyl cellulose, to improve adhesion to the seed. This suspension is then mixed thoroughly with the seeds to ensure that all the seeds are coated before sowing. In dry inoculation, the inoculant composition is simply mixed with the seeds in the drill hopper immediately before sowing.

Slurry inoculation is often disliked by farmers as they fear seeds may become partially imbibed during the process and, if subsequently sown into dry soils, their viability may be adversely affected. The procedure is also very dirty, usually involving hand mixing of a thick black suspension prior to seed application. Therefore, considerable interest exists in dry inoculation methods, but unfortunately only low bacterial numbers can be achieved owing to poor adhesion of the peat particles to the seed coat.

SUMMARY OF THE INVENTION

GB-A-2 080 669 proposes the use of a water-soluble polyvinyl pyrrolidone in Rhizobium inoculants. The water-soluble polyvinyl pyrrolidone is stated to promote the survival of the microorganism.

SUMMARY OF THE INVENTION

Although water-soluble polyvinyl pyrrolidone has been found to promote the adhesion of inoculant compositions to legume seeds to a certain extent, the effect is not as great as may be desired. We have surprisingly found that the use of a copolymer of vinyl pyrrolidone and vinyl acetate, in which the proportion of vinyl acetate tends to decrease the water solubility of the copolymer, has an unexpectedly great effect in increasing the adhesion of the inoculant composition to a wide range of legume seeds.

We have found similar effects with the use of a copolymer of vinyl pyrrolidone and styrene or a substituted styrene.

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Referenced by
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US5688727 *Jun 17, 1996Nov 18, 1997Ppg Industries, Inc.Infrared and ultraviolet radiation absorbing blue glass composition
US5916029 *Jun 26, 1996Jun 29, 1999Liphatech, Inc.Process for producing seeds coated with a microbial composition
US6228136Feb 4, 1999May 8, 2001Engineering Technology, IncorporatedCyanobacterial inoculants for land reclamation
US8466087Sep 3, 2010Jun 18, 2013Fbsciences Holdings, Inc.Seed treatment compositions and methods
US8597395Sep 28, 2010Dec 3, 2013Floratine Biosciences, Inc.Methods of reducing plant abiotic stress by applying a composition comprising lignins, tannins, and hydrocarbons
US8614165Jul 15, 2011Dec 24, 2013Brian B. GoodwinMicroorganism compositions and methods
Classifications
U.S. Classification71/7, 71/27, 71/904, 71/23
International ClassificationA01C1/06, C05F11/08
Cooperative ClassificationA01C1/06, C05F11/08
European ClassificationC05F11/08, A01C1/06