WO2021118426A1

WO2021118426A1 - Method for increasing the starch content in agricultural crops

Info

Publication number: WO2021118426A1
Application number: PCT/SE2020/051085
Authority: WO
Inventors: Hugo HJELM; Sławomir MICHAŁEK; Martina HÅKANSSON
Original assignee: Perstorp Ab
Priority date: 2019-12-11
Filing date: 2020-11-12
Publication date: 2021-06-17
Also published as: SE545216C2; SE1930398A1

Abstract

The present invention refers to a method for increasing the starch content in agricultural crops, said method comprising the step of applying a solution comprising 0.2 – 4.0 % by weight of potassium formate to said crops, wherein said solution is applied to said crops by foliar application.

Description

Method for increasing the starch content in agricultural crops

FIELD OF THE INVENTION

The present invention refers to a method for increasing the starch content in agricultural crops, said method comprising the step of applying an aqueous solution comprising 0.2 - 4.0 % by weight of potassium formate to said crops, wherein said solution is applied to said crops by foliar application.

BACKGROUND OF THE INVENTION

Starch provides almost three-quarters of the nutritional energy consumed by mankind. It is also widely used in pharmaceuticals, textiles, the paper industry, drilling fluids, biodegradable plastics and gypsum binders.

Starch is extracted from a wide range of agricultural crops. These include maize, wheat, potato and cassava (also known as manioc in some regions) and to a lesser extent from rice, barley and sorghum. Colder climates favor potato growing and cassava is cultivated in the tropics, while grain varieties are grown all over the world.

Potato starch is extracted from the tubers of Solarium tuberosum, which was first cultivated around ad 200 in Peru. Potato starch is mainly produced in Europe. Many types of potatoes are grown; for the production of potato starch, potato varieties with high starch content and high starch yields are selected. The cultivation of potatoes for starch mainly takes place in Germany, the Netherlands, China, Japan, France, Denmark, and Poland, but also in Sweden, Finland, Austria, the Czech Republic, Ukraine, Canada, and India. Starch is typically isolated from cull potatoes, surplus potatoes, and waste streams from potato processing. However, there are special cultivars developed for starch manufacture. These starch cultivars contain roughly about 20 % per weight of starch.

The cells of the root tubers of the potato plant contain starch grains (leucoplasts). To extract the starch, the potatoes are crushed and the starch grains are released from the destroyed cells. The starch is then washed out and dried to powder. Potato starch is a very refined starch, containing minimal protein and fat. This gives the powder a clear white colour, and the cooked starch typical characteristics of neutral taste, good clarity, high binding strength, long texture and a minimal tendency to foaming or yellowing of the solution. Potato starch contains approximately 800 ppm phosphate bound to the starch; this increases the viscosity and gives the solution a slightly anionic character, a low gelatinisation temperature of approximately 60 °C, and high swelling power. These typical properties are used in food and technical applications.

With a growing population in the world, the demand of agricultural crops and the products manufactured therefrom, such as starch, is expected to increase in the future. Therefore it is desirable to increase the efficiency of starch production by developing a method for increasing the starch content of agricultural crops.

Fertilizers are commonly used for growing all crops, with application rates depending on the soil fertility, usually as measured by a soil test and according to the need of the particular crop. Many sources of fertilizers exist, both natural and industrially produced. Fertilizers in general provide (in varying proportions) three macronutrients; nitrogen, phosphorous and potassium, three secondary nutrients; calcium, magnesium and sulfur and micronutrients like copper, iron, molybdenum, zinc and boron.

Fertilizers are classified in several ways, they are classified according to whether they provide a single nutrient or if they provide two or more nutrients (multinutrient fertilizers). A very common type of multinutrient fertilizers are the NPK fertilizers, providing a mixture of the macronutrients nitrogen, phosphorous and potassium. There are also organic fertilizers, which are usually recycled plant- or animal-derived matter.

Potassium is one of the major nutrients required by all crops and is present in large quantities in the plant in the form of the cation K+. Potassium is considered second only to nitrogen, when it comes to nutrients needed by plants and it affects the plant shape, size, color, taste and other measurements attributed to healthy produce. Potassium increases crop yield and improves quality. It is required for numerous plant growth processes, as potassium is fundamental to many metabolic processes through the activation of a large number of enzymes required for chemical reactions in plants. The potassium changes the physical shape of the enzyme molecule, exposing the appropriate chemical active sites for reaction. Potassium also neutralizes various organic anions and other compounds within the plant, helping to stabilize the pH-value between 7 and 8, which is an optimum for most enzyme reactions.

The majority of the plant’s total potassium requirement is needed for the essential role of maintaining the water content of plant cells. Plants depend upon potassium to regulate the opening and closing of stomata, the pores through which leaves exchange carbon dioxide, water vapor and oxygen with the atmosphere. Proper functioning of stomata are essential for photosynthesis, water and nutrient transport, and plant cooling. If potassium supply is inadequate, the stomata become sluggish - slow to respond - and water vapor is lost. As a result, plants with an insufficient supply of potassium are much more susceptible to water stress.

Potassium has a complex role in photosynthesis, the critical process for plants to convert energy from the sun into chemical energy, in the form of sugars, required for growth and ultimately yield. These sugars contain carbon derived from carbon dioxide from the atmosphere that enters the plant through the stomata. So, the role of potassium in the regulation of stomatal opening is also important for efficient photosynthesis by controlling the movement of carbon dioxide into the leaves. Potassium also has an impact on the production of ATP (adenosine triphosphate), which is the plant’s initial high-energy product from the photosynthesis. When plants are deficient in potassium the rate of photosynthesis is reduced and hence the rate of ATP production is also reduced, slowing down all the processes dependent on ATP in the plant.

Potassium is also important for the transport of sugars, water and nutrients in the plant, for helping plants to resist lodging, for plant disease and pest resistance and for the plant’s frost tolerance. Potassium is required for every major step in protein synthesis. Where potassium levels in the plant are low, protein synthesis can be reduced despite an abundance of available nitrogen.

The enzyme responsible for synthesis of starch (starch synthetase) is activated by potassium. Thus, with inadequate potassium, the level of starch declines while soluble carbohydrates and nitrogen compounds accumulate. Photosynthetic activity also affects the rate of sugar formation for ultimate starch production. Under high potassium levels, starch is efficiently moved from sites of production to storage organs.

Field crops normally absorb the majority of nutrients from the soil through root absorption, but above ground plant structures, especially leaves, are capable of absorbing limited amounts of some nutrients. Because of this, most supplemental nutrients supplied to crops as fertilizer are applied to the soil, and soluble nutrients in the soil contact root hair surfaces, where they are absorbed into the roots and transferred to other parts of the growing plant for metabolic use.

However, leaves and also to a lesser degree stems, and flowering plant tissues, can absorb limited amounts of nutrients. Foliar fertilization is the application of foliar sprays of one or more mineral nutrients to plants to supplement traditional soil applications of fertilizers. The fertilizer is sprayed directly onto the leaves of the plant and the plant absorbs essential elements through their leaves. Foliar feeding of a plant does not replace traditional soil fertilization, it rather complements traditional fertilization.

If only very small amounts of a micronutrient are required by a crop, foliar application may be more effective than traditional soil application. Also, if it is noted that a crop suffers from a deficiency of a particular nutrient, foliar application is a fast and effective way to try to treat that particular deficiency.

The present invention has revealed a new situation where a small foliar application of potassium formate quite unexpectedly gives an increase in the starch content of agricultural crops, despite the fact that soil fertilization, including enough potassium according to recommendations, has already been applied.

DETAILED DESCRIPTION OF THE INVENTION

With a constantly growing population in the world, we need to improve at all stages of the value chain for food production around the world. A more sustainable and yet more efficient agriculture is one part of this complex picture. One way to accomplish this is to develop methods for how to increase the content of specific nutrients in crops.

The present invention refers to a method for increasing the starch content in agricultural crops, said method comprising the step of applying a solution comprising 0.2 - 4.0 % by weight, preferably 0.5 - 3.0 % by weight, even more preferably 0.8 - 2.2 % by weight, of potassium formate to said crops, wherein said solution is applied to said crops by foliar application. Comprehensive field trials have revealed that a relatively small addition of potassium, in the form of potassium formate and applied by foliar application, gives both a higher content of starch and a higher yield in different cultivars of potato.

According to a preferred embodiment of the present invention the agricultural crops is selected from the group consisting of potato, wheat, com, barley, rye, rice, sorghum, cassava and/or sweet potato.

According to a particularly preferred embodiment of the present invention, the agricultural crops is potato.

The BBCH-scale is used to identify the phenological development stages of plants. BBCH-scales have been developed for a range of crop species where similar growth stages of each plant are given the same code. The BBCH-scale for potato thus identifies the phenological growth stages of a potato ( Solarium tuberosum). The scale starts with stage 0, which is sprouting/germination, continues with stage 1: leaf development, stage 2: formation of basal side shoots below and above soil surface (main stem), stage 3: main stem elongation (crop cover), stage 4: tuber formation, stage 5: inflorescence (cyme) emergence, stage 6: flowering, stage 7: development of fruit, stage 8: ripening of fruit and seed and finally stage 9: senescence. The first digit of the scale refers to the principal growth stage and the second digit refers to the secondary growth stage. In the context of the present invention, phenological growth stages are equal to phenological development stages according to the BBCH-scale for potato. According to one embodiment of the present invention, the solution comprising potassium formate is applied to the potato crops during phenological growth stages 1-4. According to a preferred embodiment of the present invention, said solution is applied to said potato crops during phenological growth stages 21-48.

During the work leading to the present invention, foliar application of potassium in three different forms has been tested, besides potassium formate both potassium nitrate and potassium chloride were tested and evaluated (see Embodiment Example 1). These tests clearly show that it is specifically the foliar application of potassium formate that gives the increased starch content in the potato crops. The other two forms of potassium give varying results, sometimes performing worse than the control sample.

The solution applied by foliar application to the crops may in addition to potassium formate comprise other substances that are beneficial for the growth and development of the crop. Such substances can for example be urea, phosphorus, magnesium, calcium, manganese and/or zinc.

The foliar application of the potassium formate solution is preferably performed with a field crop sprayer and at an application rate of 50 - 500 liters/ha (1 ha = 10000 m²).

The solution comprising potassium formate is applied to the crops at one single occasion or at several occasions, preferably at 1-3 separate occasions and with at least 3 days between each occasion.

The present invention is illustrated in the below Embodiment Examples, which are to be construed as merely illustrative and not limiting in any way.

EMBODIMENT EXAMPLES

Example 1: Effect of foliar application of different forms of potassium on starch concentration and fresh tuber yield in two different potato cultivars

Field experiments were conducted at three fields in the Lublin area in Poland during two separate growing seasons (2017 and 2018). Two different potato cultivars, Jelly and Bellarosa, were used. The tubers were planted with a row space of 63 cm and with 48000 plants per hectare. The plot area was 15 m² and with four replicates for each treatment. The sizes of the seed tubers were between 30-40 mm. The in-row seed spacing was 30 cm. The experimental field was ploughed in autumn and tilted two times before planting in spring. Mineral fertilizers - ammonium nitrate (N), and Polifoska® (N, P, K) were spread in spring prior to potato planting and were incorporated into the soil by a harrow. The total amount of fertilizer applied to all fields was 196 kg N, 63 kg P, 168 kg K, 30 kg Mg and 47 kg S per hectare.

Three different forms of potassium were applied at a concentration of 1% by weight, by foliar application: potassium nitrate (KNO3), potassium chloride (KC1) and potassium formate (P0F0). Both potato cultivars were treated at the same time, using 250 liters/ha (250 liters for 10000 m²) of liquid spray (readymade solution). All treatments were sprayed three times. At spraying the later cultivar (Jelly) was on stage II (vegetative growth) and the early cultivar (Bellarosa) was on stage ΙII (tuber initiation). Control fields were sprayed with only water. The pH value of the water used for spraying and preparing solution was 6.8-7.2. The application was done using a 5- liter sprayer . The temperature of the solution was below 20°C and it was applied after sunset.

Chemical plant protection agents against weeds and Colorado beetle were applied according to Table 1 below.

Table 1.

Measurements

When all plants reached physiological maturity the total yield of potato tubers and the content of starch in the potato tubers were determined. Starch content was determined by the gravimetric method proposed by Reimann and Parow from 10 randomly selected plants in each plot. The method according to Reimann and Parow was used among others in research of Taulbert and Smith (1975), Affleck et al. (2012), Brazinskiene et al. (2014), Pszcólkowski et al. (2014) and described by International Starch Institute in Denmark. Total fresh tuber yield was recorded for each treatment in all the replications and data was presented as ton per hectare.

Results

The starch content in the two different potato cultivars (Jelly and Bellarosa), with potassium supplied in different forms, are shown in Figure 1 below (data from growing seasons 2017 and 2018):

c) d)

Figure 1: Starch content in potato cultivars Jelly and Bellarosa, potassium supplied in three different forms, growing seasons 2017 and 2018. The Fresh tuber yield in the two different potato cultivars (Jelly and Bellarosa) with potassium supplied in different forms, are shown in Figure 2 below (data from growing seasons 2017 and 2018):

a) b)

c) d)

Figure 2: Fresh tuber yield in potato cultivars Jelly and Bellarosa, potassium supplied in three different forms, growing seasons 2017 and 2018. Example 2: Effect of foliar application with potassium formate on starch concentration and fresh tuber yield in 12 different potato cultivars

Field experiments were conducted in the same way as described in Experiment 1, but with potassium formate (1% by weight) as the only treatment tested. 12 different potato cultivars were tested and the tests were conducted during the growing season 2018, in the Lublin area in Poland. Five of the cultivars were special cultivars developed for starch manufacture. Controls were sprayed with only water.

Results

The starch content in 12 different potato cultivars from growing season 2018 are shown in Figure 3 below:

Figure 3. Starch content in 12 different potato cultivars, treated according to the method of the present invention vs. control plants. The fresh tuber yield in 12 different potato cultivars from growing season 2018 are shown in Figure 4 below:

Figure 4. Fresh tuber yield in 12 different potato cultivars, treated according to the method of the present invention vs. control plants.

It is clear from Example 1 that it is the specific application of potassium formate that gives an increased starch content in the crops. For the potato cultivar Jelly, the starch content is on average more than 1 percent point higher where potassium formate is applied, compared to both the control and to the cases where potassium is applied in other forms. It can also be seen in Example 1 that the fresh tuber yield is highest where potassium formate has been applied (both potato cultivars, both seasons). Addition of potassium in all three forms (KNO₃, KC1 and PoFo) gives an increase in fresh tuber yield. However, it is only the specific application of potassium formate that gives an increased starch content compared to the control in all cases. In Example 2, the method of the present invention is tested on a wide range of potato cultivars, both starch cultivars and potato for consumption. In all cases does the method according to the present invention give an increase both in starch content and in fresh tuber yield, compared to the control.

An increase in starch content of about 1 percent point may sound like a modest increase. However, if the actual increase in starch/ha, considering both the increase in starch content and the increase in fresh tuber yield is calculated, it becomes apparent that the gain for the individual potato farmer can become considerable.

For example, by applying the method according to the present invention, the average starch increase (calculated for the five starch cultivars in Example 2) is about 960 kg extra starch/ha, or an increase of 11.4 % in starch content, compared to the control. For an individual farmer, growing starch potato on 20 ha land, this will mean an increased yield of about 19.2 tons of starch/harvest. This implies that the method according to the present invention has a great potential of contributing to a more efficient starch production in the future.

Claims

1. A method for increasing the starch content in agricultural crops, said method comprising the step of applying a solution comprising 0.2 - 4.0 % by weight of potassium formate to said crops, wherein said solution is applied to said crops by foliar application.

2. A method according to claim 1 characterized in, that said solution comprises 0.5 - 3.0 % by weight of potassium formate.

3. A method according to claim 1 or 2 characterized in, that said solution comprises 0.8 - 2.2 % by weight of potassium formate.

4. A method according to any of the claims 1-3 characterized in, that said agricultural crops is selected from the group consisting of potato, wheat, com, barley, rye, rice, sorghum, cassava and/or sweet potato.

5. A method according to claim 4 characterized in, that said agricultural crops is potato.

6. A method according to claim 5 characterized in , that said solution is applied to said potato crops during phenological growth stages 1-4.

7. A method according to claim 6 characterized in, that said solution is applied to said potato crops during phenological growth stages 21-48.

8. A method according to any of the claims 1-7 characterized in that, said solution is applied to said crops at an application rate of 50-500 liters/ha.

9. A method according to any of the claims 1-8 characterized in, that said solution is applied to said crops with a field crop sprayer.

10. A method according to any of the claims 1-9 characterized in, that said solution is applied to said crops at 1-3 separate occasions and that there is at least 3 days between each occasion.

11. A method according to any of the claims 1-10 characterized in, that said solution comprises at least one additional substance, wherein said additional substance is selected from the group consisting of urea, phosphorous, magnesium, calcium, manganese and/or zinc.