WO2001049116A1

WO2001049116A1 - A plant promoting composition and method for its application

Info

Publication number: WO2001049116A1
Application number: PCT/NO2000/000421
Authority: WO
Inventors: Nabil Mohamed Mahrous; Marit Laegreid; Aud Berglen Eriksen
Original assignee: Norsk Hydro Asa
Priority date: 1999-12-30
Filing date: 2000-12-08
Publication date: 2001-07-12
Also published as: NO310641B1; AU2238201A; NO996587L; EG23873A; NO996587D0

Abstract

The present invention relates to a plant promoting composition and a method for treatment of C3 plants with said composition. Said composition comprises 15-30 % volume/volume of methanol, 1.5-4 % weight/volume nitrogen and 0.2-0.4 % weight/volume of chelated micronutrients. The plants are treated with 90-180 l/hectare methanol, 9-25 kg/hectare nitrogen and 1.2-2.4 kg/hectare micronutrients. Treatment of plants at atmospheric ground-level ozone content above 40 ppm will especially be useful.

Description

A plant promoting composition and method for its application

The present invention relates to a plant growth promoting composition comprising methanol and a method for treatment of C₃ plants with said composition.

All plant growth stems from taking C0₂ from air, water and nutrients from the soil and converting or fixing it into cellular growth constituents using energy from sunlight, i.e. photosynthesis. However, photorespiration can be a kind of competitor to the photosynthesis process and reduce the potential plant growth. In C₃ plants, photorespiration which increases with increasing temperature, results in lower net photosynthesis. It has been known for a long time that methanol may stimulate the growth of certain C₃ plants, such as cotton, wheat, soybean, potato, tomato, sugar beet, pea plants and the like, especially under some stress conditions. However, the reported results and recommended compositions to be applied vary within very wide ranges. Literature survey shows that the effect is variable, from 0 effect to 50-150% yield increases. The overall effect of methanol is thought to be due to stress reduction in the plant, mainly stress caused by drought and intensive sunlight under dry, arid conditions. However, this hypothesis has not been verified by controlled physiological experiments. C0₂ will be the main limiting factor. Spraying the plants with methanol is believed to generate C0₂ for providing a nutritive mechanism for immediate inhibition of photorespiration. If methanol acts as a carbon nutrient, the result should be a more efficient photosynthesis. Accordingly, the true mechanism for application of methanol is obviously not completely known. The main problem seems to be the total composition of the plant growth stimulant and how it shall be applied in order to get consistent results for various crops. The influence of different stress conditions on consistent yield is also rather unclear. From US Patent No. 4,274,861 it is known a composition for stimulating plant growth and enhancing fruit production in leguminous plants, for instance soybeans. The composition employs a lower aliphatic alcohol such as methanol in combination with a 2,4-D Herbicide, a surfactant and a suitable adherent. The composition is applied and maintained on the plant during the flowering stage of the plant. The amount of methanol is 44,000 ppm by weight, of surfactant 4,000 ppm by weight and of adhering agent 5,000 ppm by weight.

From US Patent No. 3,915,686 a method of stimulating plant growth is described employing 2-15% by weight of lower aliphatic alcohols such as methanol in an aqueous solution. This composition is further diluted prior to its application. The recommended amount of alcohol is 50-600 pounds per acre, depending on types being subjected to treatment. The method comprises placing soil in which plants have grown or plants in the aqueous methanol solution and removing said plants or soil as early as 1 hour after insertion.

Physiological and growth response of C₃ plants to methanol treatment is also described by Songciao Huang and John N. Nishio, Dept. of Botany, Univ. Wyoming, Laramie, WY 82071. Response on soybean, spinach, sugar beet and pea plants was investigated under controlled environmental conditions. Plants were sprayed with different concentrations of methanol, up to 20%. Soybean plants are reported to grow bigger and show more turgidity under 15% methanol treatment.

In US Patent No. 5,597,400 there is described a plant growth stimulant which increases intracellular carbon dioxide. Said stimulant comprises an aqueous solution of methanol or methanol metabolite selected from the group consisting of formaldehyde, formic acid, and methyl formate. The methanol is present in amounts of 10-50% by volume and said solution further comprising a nitrogen nutrient source and a phosphorous nutrient source and an amount of agriculturally acceptable surfactant effective to enhance surface wetting and methanol penetra- tion of the treated plant. During application the plant shall be exposed to a minimum light intensity of 1000 mEin/ 2/sec for at least two hours after application of the growth promoting composition.

Foliar applied methanol and nitrogen for increased productivity on leguminous plants is also described in US Patent No. 5,532,204. Plants to be treated comprise soybeans, peanuts, peas and beans. The method comprises applying to leguminous plant foliage at a seed growth stage within a developed seed pod of the leguminous plant a composition consisting essentially of methanol that is up to 50% by volume in a water based solution, and applying a corresponding unreacted urea fertilizer to the leguminous plant that is in the range of about 25-50 pounds/acre.

The main object of the invention was to arrive at a plant growth promoting composition being customized for giving consistent yields for various crops.

Another object was to arrive at an economical and optimal method for applying the growth promoting composition to the plants.

Based on the reported yield increases for certain crops upon treatment with various methanol containing compositions there should be potential for improvements provided that the plant growth promoting composition contained the right components in optimal amounts and that the treatment of the plants was performed optimally. The teachings of the above patents and other literature on the subject are rather confusing with regard to optimal amounts of methanol and other necessary components necessary for obtaining consistent yield results. In order to further investigate the mechanism of methanol treatment of plants extensive experiments were conducted on various crops under different conditions. From these experiments it was surprisingly found that presence of surfactant in the composition was not as important as stated previously. In fact the conducted experiments revealed that excellent yields could be obtained without using surfactant. It was further found that intensive sunlight was not as critical a factor as stated in US Patent No. 5,597,400. On the contrary, it was found that presence of sufficient and optimal amount of nutrient, first of all nitrogen, and micronutrients combined with optimal amount of methanol in the composition was far more critical for obtaining increased yields.

Urea was found to be the preferred nitrogen source though nitrates like ammonium-, calcium- and magnesium nitrate could also be applied. Micronutrients to be included in the composition should comprise boron, copper, iron, manganese molybdate and calcium. Though these elements can be applied as various salts such as sulphates, it was found that chelated micronutrients would be most effective. Preferred raw materials for the micronutrient mixture would be: boric acid, copper EDTA, iron EDTA/DTPA, manganese EDTA, ammonium hepta- molybdate, zinc EDTA and calcium EDTA. One reason for this selection was that the chelates were found to be soft to leaf tissue (neutral) and not as harsh as salts as their split into ions can cause scorch.

Based on the experiences from the field trials it was found that the aqueous growth promoting composition should contain 15-30% volume/volume methanol, 1.5-4% weight/volume nitrogen and 0.2-0.4% weight/volume of chelated micronutrients.

Preferred amounts of methanol were found to be 20-30% vol/vol, and about 25% vol/vol gave optimal results provided the two other components also were optimalized.

It will be within the scope of the invention to add minor amounts of conventional additives such as standard fertilizers, amino acids etc.

The method for treatment of C₃ plants with the growth promoting composition in order to attain optimal yields was also found to have some critical parameters. Thus it was found that the composition should be applied in amounts being within the following ranges: Methanol 90-180 l/hectare

Nitrogen 9-25 kg/hectare

Chelated micronutrients 1.2-2.4 kg/hectare

Experiments were performed for a period of 2-3 years on a number of crops, and the consistent results for trials on sugar beet and soybean are shown in Examples 1 and 2. Similar trials were performed on other crops such us tomato, cantaloup, onion, rice, grapes and wheat, and the results were equally consistent with regard to increased growth and quality of the crops.

During the experiments there were indications that the ozone level at ground-level could be of importance. This was then further investigated both in the laboratory under controlled environmental conditions in a phytotron and in open top chambers in the field. Methanol is considered a natural metabolite in plants, and methanol can be produced in the plant and emitted into the environment and will be part of the methanol cycle between biosphere and atmosphere. Increased concentrations of ground-level ozone was found to create an additional stress to plants with documented yield reductions at concentrations slightly above natural background levels. The question then was how this methanol can be used under stress conditions, for instance the oxidative stress at high ozone levels at ground- level. It was found that high ozone levels had a very negative effect on plant growth, but surprisingly this seemed possible to compensate by spraying the plants with a composition containing methanol. Experiments proved this to be true. Expected yield reduction was in fact in some of the experiments completely eliminated by treatment of the plants by the above defined composition. Methanol seemed to be the real active component, while the content of nitrogen and micronutrients under the controlled laboratory conditions seemed to be of minor importance. Based on the results from the above investigations, it was found that the C₃ plants should especially be treated with a composition according to the invention at atmospheric ground-level ozone content close to the critical load level above 40 ppm. The invention will be further explained and elucidated in the following examples:

Example 1

This example shows the results of experiments carried out on two varieties (Kawemira and Sifha) of sugar beat grown on new land and old land in Egypt. Standard fertilization according to common practice for the area had been applied to the fields. The sugar beets were treated with compositions containing various amounts of methanol (M) and urea (U) corresponding to 24.7 kg N/hectare and chelated micronutrients (MN) in amounts corresponding to 1.85 kg/hectare. The results of these experiments are shown in Tables 1 -4.

Table 1 shows the results for Kawemira sugar beet on new land.

Table 2 shows the results for Kawemira sugar beet on old land.

Table 3 shows the results for Sifha sugar beet on new land.

Table 4 shows the results for Sifha sugar beet on old land.

As can be seen from Tables 1 -4, the best results are obtained for the composition according to the invention, containing 25% methanol and the above stated amounts of nitrogen and micronutrients. The results for this composition is most consistent for both varieties, whether they are grown on new land or old land, with regard to both yield and quality, i.e. root quality and suger% in sugar beet.

Table 1

Table 2

Table 3

00

Table 4

Example 2

This example shows the results of soybean trials in Egypt at new land and old land of treatment with various compositions, including compositions according to the invention. Standard fertilization according to common practice for the area had been applied to the fields prior to these trials. The treatment compositions contained in some cases calcium nitrate (CN) as nitrogen source. The nitrogen applied, stated as kg per hectare, is stated in the following tables. Some of the compositions also contained chelated micronutrients and then in amounts corresponding to 1.85 kg per hectare.

The results from the trials on new land are given in Table 5. From these results it can be seen that when the treatment composition according to the invention was applied, the pod yield per plant was at its highest. Similar results are recorded for No. of Branches, Seed weight and Seed yield.

The results from the trials on old land are shown in Table 6. Also for these trials it can be seen that for plants treated with compositions according to the invention the results are significantly better than for treatment compositions outside the invention.

The results for soybean are accordingly as consistently positive as shown above for sugar beet.

Table 6

Example 3

This example shows the results from experiments with clover (Trillium subterraneum) and wheat (Dragon, a high-yielding modern variety and Lantvete, an old low-yielding variety) exposed to varying ozone levels and also sprayed with a methanol containing composition. The experiments were performed in open top chambers located in Ostad, Sweden in 1997 (clover) and in 1998 and 1999 (wheat). The chambers had a diameter of 3.3 m and a height of 3.0 m. Each chamber was ventilated, and the level of ozone of the chamber air was controlled and regulated by a controlled ozone analyzer/generator system. The temperature and ozone level in the ambient air and in the chamber air were measured every hour during the growing season. The ozone level in the chambers followed the ambient air level with an additional amount of 30 ppb. Average ozone level in 1998 was 41 ppb and in 1999 60 ppb.

The plants were grown in individual barrels (1201) filled with sand in 1997 and 1998, with clay-loam soil in 1999. There were 56 plants in each barrel and 18 barrels in each chamber. Fertilization of the plants was in 1998 performed by fertigation with daily water and nutrient input using a computer controlled automatic drip irrigation system. In 1999 a base application of 180 kg N/hectare was applied.

A 25% vol/vol solution of methanol was applied as foliar spray 3 times during the growing period, from tillering, flowering and grain filling stage. Charcoal filtered air where ozone was removed was used as control. The average ozone level in the control was 7 ppb. The following results were recorded:

The visible leaf injury caused by elevated levels of ground-near ozone was substantially reduced for clover. This leaf damage was repeatedly shown by experiments in the phytotron to be reduced by treatment of compositions containing relatively low amounts of methanol. In wheat the methanol treatment increased the grain yield, the number of ears and the grain dry weight per ear in both cultivars. Increased ozone levels reduced the plant growth and the yield. The Dragon wheat seemed to be more sensitive to ozone than the Lantvete wheat. The methanol treatment reduced and nullified the negative effect on the plant growth and the yield with a 65% increase for the methanol treated plants compared to the untreated plants in the ozone exposed chambers.

In 1999 only Dragon wheat was tested. The ozone level this year in the area where the tests were performed was higher than in 1998, and a higher yield reduction was observed between the controls in the charcoal filtered air and ozone exposed chambers. Also this year methanol application reduced the negative effect of ozone, with a 16% higher yield for the treated compared to the untreated plants exposed to ozone, but the damaging effect of ozone was not completely eliminated as in 1998.

The results from these experiments clearly show that a methanol containing treatment composition consistently reduces the negative impact caused by elevated ozone levels. Accordingly, the plants should be treated with such a composition when the ground-level ozone level is high, i.e. above 40 ppm.

By the present invention the inventors have succeeded in arriving at a treatment composition with selected amounts of methanol, nitrogen and micronutrients that when applied to C₃ plants according to the method of the invention gives consistent results with regard to increased growth and quality. Said positive and consistent results were obtained under different conditions such as new land and old land in Egypt which have quite different natural nutrient content in the soil. Also with regard to type of crops the increased growth was substantial and consistent for all the types of crops tested, when the plants were treated according to the invention.

Claims

1. A plant promoting composition comprising methanol, characterised in that said composition comprises 15-30% volume/volume methanol, 1.5-4% weight/volume nitrogen and 0.2-0.4% weight/volume chelated micronutrients.

2. A plant promoting composition according to claim 1 , characterized in that said composition contains 20-30% volume/volume methanol.

3. A plant promoting composition according to claim 1 , characterized in that the micronutrients of the composition comprise boron, copper, iron, manganese, molybdate and calcium.

4. Method for treatment of C₃ plants with the plant promoting composition according to claim 1 , characterized in that the C₃ plants are treated with 90-180 l/hectare methanol, 9-25 kg/hectare nitrogen and 1.2-2.4 kg/hectare chelated micronutrients.

5. Method for treatment of C₃ plants according to claim 4, characterized in that the plants are treated with the plant promoting composition at atmospheric ground-level ozone content above 40 ppm.