CONCENTRATED AQUEOUS SUSPENSION OF MICROFIBRILLATED CELLULOSE COMPRISING SALTS FOR PLANT NUTRITION

Abstract

A concentrated aqueous composition of microfibrillated cellulose (MFC) comprising salts for plant nutrition. The concentrated aqueous composition comprises microfibrillated linear polymers of D-glucose molecules (cellulose microfibers), calcium ions, sulfate ions and other elements for plant nutrition. The concentration of calcium ions and sulfate ions exceeds the concentration corresponding to the solubility of calcium sulfate in water. The proportion of MFC is within a range of 1% and 99% w/w of the composition, and the precipitation of salts is prevented in a pH range from 1 to 13.

Claims

1. A concentrated aqueous composition for plant nutrition comprising: microfibrillated cellulose (MFC); calcium ions; sulfate ions; and elements for plant nutrition selected from nitrogen, phosphorus, potassium, magnesium, iron, chlorine, manganese, boron, zinc, copper, cobalt, and molybdenum, wherein a concentration of calcium ions and sulfate ions exceeds a concentration corresponding to the solubility of calcium sulfate in water, and wherein the proportion of MFC is within a range of 1% and 99% w/w of the composition, and wherein all essential elements are available for plant nutrition in a pH range from 1 to 13.

2. The concentrated aqueous composition according to claim 1, further comprising (all percentages correspond to % w/w): between 60% and 90% of water; between 1% and 40% of MFC, between 1% and 55% of calcium nitrate; between 0.01% and 0.5% of magnesium EDTA (ethylenediamine tetraacetic acid); between 0.01% and 0.7% of manganese EDTA; between 0.01% and 0.7% of zinc EDTA; between 0.01% and 0.9% of copper EDTA; between 0.001% and 0.01% sodium molybdate (dihydrate); between 0.0001% and 0.001% of cobalt EDTA; between 1% and 12% of potassium nitrate; between 0.5% and 25% of monopotassium phosphate; between 0.5% and 42% of magnesium sulfate; and between 0.1% and 42% of potassium sulfate.

3. The concentrated aqueous composition according to claim 2, further comprising: 18.6 liters of water (68.2%); 6,000 grams of MFC (22.0%); 1,000 grams of calcium nitrate (3.7%); 12 grams of magnesium EDTA (0.0440%); 20 grams of manganese EDTA (0.0733%); 20 grams of zinc EDTA (0.0733%); 25 grams of iron EDTA (0.0916%); 3 grams of copper EDTA (0.0110%); 0.3 grams of sodium molybdate (dihydrate) (0.0011%); 0.03 grams of cobalt EDTA (0.0001%); 10 grams of boric acid (0.0366%); 300 grams of potassium nitrate (1.10%); 400 grams of monopotassium phosphate (−1.47%); 750 grams of magnesium sulfate (2.75%); and 150 grams of potassium sulfate (0.55%).

4. (canceled)

5. (canceled)

6. (canceled)

7. The use of the concentrated aqueous composition according to claim 1 in hydroponics, fertigation, or direct substrate fertilization.

8. (canceled)

9. The concentrated aqueous composition according to claim 1, further comprising salts of calcium, sulfate, nitrogen, phosphorus, potassium, magnesium, iron, chlorine, manganese, boron, zinc, copper, molybdenum, and cobalt.

10. The concentrated aqueous composition according to claim 9, further comprising salts selected from the group consisting of calcium nitrate, potassium nitrate, ammonium nitrate, potash, potassium chloride, calcium oxide, calcium chloride, iron ethylenediamine tetraacetic acid (iron EDTA), sodium molybdate (dihydrate), ammonium molybdate, ethylenediamine tetraacetic manganese (Mn EDTA), manganese chloride, ethylenediamine tetraacetic zinc (Zn EDTA), zinc chloride, ethylenediamine tetraacetic magnesium (Mg EDTA), magnesium oxide, ethylenediamine tetraacetic copper (Cu EDTA), ethylenediamine tetraacetic cobalt (Co EDTA), boric acid, sodium tetraborate, potassium sulfate, magnesium sulfate, ammonium sulfate, ferrous sulfate, copper sulfate, magnesium sulfate, zinc sulfate, monopotassium phosphate, diammonium phosphate, phosphoric anhydride, and potassium nitrate.

11. A method for preparing a solid fertilizer comprising the step of dehydrating the aqueous concentrated composition according to claim 1 to obtain a product with a solid consistency.

12. The method for preparing a solid fertilizer according to claim 11 wherein the dehydrating step is carried out for approximately 24 hours at 161.6° F.

13. A method for preparing a solid fertilizer comprising the steps of pouring the aqueous concentrated composition according to claim 1 in a mold and dehydrating it to obtain a shaped product with a solid consistency.

14. The method for preparing a solid fertilizer according to claim 13 wherein the dehydrating step is carried out for approximately 24 hours at 161.6° F.

15. The method for preparing a solid fertilizer according to claim 13, wherein the shaped product is a tablet.

16. The solid fertilizer obtained from the method according to claim 11.

17. The solid fertilizer according to claim 16, wherein the solid fertilizer is in the form of a tablet.

18. The solid fertilizer according to claim 17, wherein the tablet includes: 10.00% water; 50.56% MFC; 14.65% calcium nitrate; 0.176% magnesium EDTA; 0.293% manganese EDTA; 0.293% zinc EDTA; 0.366% iron EDTA; 0.044% copper EDTA; 0.044% sodium molybdate (dihydrate); 0.0044% cobalt EDTA; 0.147% boric acid; 4.39% potassium nitrate; 5.86% monopotassium phosphate; 10.99% magnesium sulfate; and 2.19% potassium sulfate.

Description

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

[0027] The formulations for fertilizers vary according to the specific requirements of each crop, its stage of development, and the surrounding climatic conditions.

[0028] The salts that are most commonly used for the formulation of stock A are as follows:

[0029] Calcium nitrate

[0030] Potassium nitrate (optional, since it is also present in stock B)

[0031] Ammonium nitrate

[0032] Potash

[0033] Potassium chloride

[0034] Calcium oxide

[0035] Calcium chloride

[0036] Iron ethylenediamine tetraacetic acid (Fe EDTA)

[0037] Sodium molybdate (dihydrate)

[0038] Ammonium molybdate

[0039] Ethylenediamine tetraacetic manganese (Mn EDTA)

[0040] Manganese chloride

[0041] Ethylenediamine tetraacetic zinc (Zn EDTA)

[0042] Zinc chloride

[0043] Ethylenediamine tetraacetic magnesium (Mg EDTA)

[0044] Magnesium oxide

[0045] Ethylenediamine tetraacetic copper (Cu EDTA)

[0046] Ethylenediamine tetraacetic cobalt (Co EDTA)

[0047] Boric acid

[0048] Sodium tetraborate

[0049] The most common salts to formulate stock B are:

[0050] Potassium sulfate

[0051] Magnesium sulfate

[0052] Ammonium sulfate

[0053] Ferrous sulfate

[0054] Copper sulfate

[0055] Magnesium sulfate

[0056] Zinc sulfate

[0057] Phosphate

[0058] Monopotassium phosphate

[0059] Diammonium phosphate

[0060] Phosphoric anhydride

[0061] Potassium nitrate

[0062] As described above, stock A usually includes the nitrates (calcium, potassium, and ammonium) and the EDTA-chelated microelements. However, another possible common formulation is to incorporate only the nitrates (calcium, potassium, and ammonium) and the iron EDTA in stock A; and to incorporate the microelements in the form of sulfates (magnesium, manganese, copper, zinc, etc.) in stock B, so that sulfates and calcium do not precipitate as calcium sulfate.

[0063] Surprisingly, the inventors found another alternative which involves the use of microfibrillated cellulose (MFC), obtained from a fibrillation process of cellulose in a wet state.

[0064] Microfibrillated cellulose (MFC) is a substance composed of cellulose and water, with a cellulose concentration of less than 15%. It is characterized by being able to store large quantities of water in relation to its mass, obtaining “creamy” or “gel-type” suspensions with very low proportions of microfibrillated cellulose (as low as 2%). Its pH varies in a range from 4 to 8 and its density between 1.2 and 1.6 kg/L.

[0065] Cellulose microfibrils are very small cellulose fibers obtained from the mechanical disintegration of plant fibers and by a sequence of specific chemical and mechanical treatments (fibrillation process).

[0066] When the cellulose goes through a fibrillation process, the surface area becomes much larger in comparison with the original raw material, thus generating a significant increase in the quantity of hydroxyl groups (OH) available on the surface of the microfibrils. As these hydroxyl groups have a natural negative charge, they will be able to capture ions with a positive charge, such as calcium ions. In this way, the calcium ions are prevented from bonding with the sulfates, avoiding altogether its precipitation as calcium sulfate. Microfibrillated cellulose retains its structure in a pH range from 1 to 13, meaning the number of available hydroxyl groups are not significantly modified by pH. The interaction between hydroxyl groups and ions is therefore highly resistant to external pH modification.

[0067] In the case of compositions with a low proportion of humidity, it is possible to obtain a solid fertilizer with highly beneficial characteristics. One of them is to allow the release of the nutrients on demand of the plant. The solid fertilizer contributes nutrients to the water retained by the substrate by a diffusion process and, as the plant absorbs them, the solid fertilizer contributes new nutrients; in this way the solid fertilizer effectively releases nutrients on demand of the plant. On the other hand, the hydroxyl groups of the MFC compete with the surrounding water for interaction with the nutrient ions, so the degree of leaching of nutrients is reduced, since they are withheld by the MFC in the presence of rain.

[0068] A preferred aqueous composition of the present invention includes (all percentages in the following description and in the examples correspond to % w/w):

[0069] between 60% and 90% of water

[0070] between 1% and 40% of microfibrillated cellulose (MFC)

[0071] between 1% and 55% of calcium nitrate

[0072] between 0.01% and 0.5% of magnesium EDTA

[0073] between 0.01% and 0.7% of manganese EDTA

[0074] between 0.01% and 0.7% of zinc EDTA

[0075] between 0.01% and 0.9% of iron EDTA

[0076] between 0.010% and 0.1% of copper EDTA

[0077] between 0.001% and 0.01% sodium molybdate (dihydrate)

[0078] between 0.0001% and 0.001% of cobalt EDTA

[0079] between 0.01% and 0.4% of boric acid

[0080] between 1% and 12% of potassium nitrate

[0081] between 0.5% and 25% of monopotassium phosphate

[0082] between 0.5% and 42% of magnesium sulfate

[0083] between 0.1% and 11% of potassium sulfate

[0084] A most preferred aqueous composition of the present invention includes.

[0085] 18.6 liters of water (68.2%)

[0086] 6,000 grams of microfibrillated cellulose (22.0%)

[0087] 1,000 grams of calcium nitrate (3.7%)

[0088] 12 grams of magnesium EDTA (0.0440%)

[0089] 20 grams of manganese EDTA (0.0733%)

[0090] 20 grams of zinc EDTA (0.0733%)

[0091] 25 grams of iron EDTA (0.0916%)

[0092] 3 grams of copper EDTA (0.0110%)

[0093] 0.3 grams of sodium molybdate (dihydrate) (0.0011%)

[0094] 0.03 grams of cobalt EDTA (0.0001%)

[0095] 10 grams of boric acid (0.0366%)

[0096] 300 grams of potassium nitrate (1.10%)

[0097] 400 grams of monopotassium phosphate (1.47%)

[0098] 750 grams of magnesium sulfate (2.75%)

[0099] 150 grams of potassium sulfate (0.55%)

[0100] The following examples show the preparation of concentrated formulations that may contain all the necessary components for a plant. The formulations are not intended to specify the required quantities or to restrict the ingredients used. Their main intention is to show the preparation of a concentrated aqueous suspension of this invention. The following examples also demonstrate the effectiveness of concentrated formulations in different crops. The examples are not intended to limit or restrict the crops for which the formulations can be used. Concentrated suspensions or solid fertilizers can be formulated for every and any crop.

EXAMPLES

Example 1

[0101] Preparation of Concentrated Aqueous Suspension

[0102] Example to Prepare 10 Liters of Stock A:

[0103] The following elements were mixed into 9.3 liters of water at 77° F. and neutral pH (the reason that 9.3 liters of water are added is to get 10 liters of stock A, as salts provide approximately 700 cc of the volume):

[0104] 1,000 grams of calcium nitrate

[0105] 12 grams of magnesium EDTA

[0106] 20 grams of manganese EDTA

[0107] 20 grams of zinc EDTA

[0108] 25 grams of iron EDTA

[0109] 3 grams of copper EDTA

[0110] 0.3 grams of sodium molybdate (dihydrate)

[0111] 0.03 grams of cobalt EDTA

[0112] 10 grams of boric acid

[0113] The weight of the resulting 10 liters of stock A is 10,390 grams.

[0114] Example to prepare 10 liters of stock B:

[0115] The following elements were mixed into 9.3 liters of water at 77° F. and neutral pH (the reason that 9.3 liters of water are added is to get 10 liters of stock B since salts provide approximately 700 cc of the volume):

[0116] 300 grams of potassium nitrate

[0117] 400 grams of monopotassium phosphate

[0118] 750 grams of magnesium sulfate

[0119] 150 grams of potassium sulfate

[0120] The weight of the resulting 10 liters of stock B is 10,900 grams.

[0121] Example to obtain 27.3 kilos of concentrated aqueous suspension of stock A and B in microfibrillated cellulose:

[0122] The reason that 27.3 kilos are prepared is because the proportions, in this formulation, are 6 parts of microfibrillated cellulose (MFC) for every 10 parts of Stock A (10,390 grams) and 10 parts of Stock B (10,900 grams), which results in the aforementioned quantity.

[0123] Six kilos of microfibrillated cellulose (MFC) were mixed into 10 liters of stock A and stirred manually for 5 minutes. Then, 10 liters of stock B were added to the resulting solution and stirred manually for 5 minutes. The resulting solution has the initial composition of stock A and stock B as well as the microfibrillated cellulose (MFC), with a pH of 3.4. This means:

[0124] 18.6 liters of water (68.2%)

[0125] 6,000 grams of microfibrillated cellulose (22.0%)

[0126] 1,000 grams of calcium nitrate (3.7%)

[0127] 12 grams of magnesium EDTA (0.0440%)

[0128] 20 grams of manganese EDTA (0.0733%)

[0129] 20 grams of zinc EDTA (0.0733%)

[0130] 25 grams of iron EDTA (0.0916%)

[0131] 3 grams of copper EDTA (0.0110%)

[0132] 0.3 grams of sodium molybdate (dihydrate) (0.0011%)

[0133] 0.03 grams of cobalt EDTA (0.0001%)

[0134] 10 grams of boric acid (0.0366%)

[0135] 300 grams of potassium nitrate (1.10%)

[0136] 400 grams of monopotassium phosphate (1.47%)

[0137] 750 grams of magnesium sulfate (2.75%)

[0138] 150 grams of potassium sulfate (0.55%)

[0139] The weight of the suspension is 27,290 grams.

[0140] Examples of mixes with and without precipitates

Example 2

[0141] Stock A and Stock B were Mixed

[0142] One hundred (100) cc of the obtained stock A and 100 cc of the obtained stock B were mixed at 77° F.; the mixture was stirred and after 3 minutes the emergence of a precipitate was observed. Thirty minutes later the mixture was stirred again and 2 minutes after that the precipitate was still present, thus confirming that the precipitate does not re-dissolve.

Example 3

[0143] Stock a and MFC were Mixed, then Stock B was Added

[0144] One hundred (100) cc of the obtained stock A were mixed into 60 grams of microfibrillated cellulose (MFC); the mixture was stirred manually, and then 100 cc of the obtained stock B were immediately added. After 3 minutes, no precipitate emergence was observed. The sample was monitored 24 hours later, 48 hours later, and even 90 days later but no modifications were found in its appearance.

Example 4

[0145] Stock B and MFC were Mixed, and then Stock a was Added.

[0146] In this example, the order of the stocks in the preparation of the aqueous suspension was exchanged. One hundred (100) cc of the obtained stock B were mixed into 60 grams of microfibrillated cellulose (MFC); the mixture was manually stirred and then 100 cc of the obtained stock A were added. After 3 minutes no precipitate was seen emerging. The sample was monitored 24 hours later, 48 hours later, and even 90 days later but no modifications were found in its appearance.

[0147] Examples 3 and 4 demonstrate the flexibility of the addition of MFC to the formulations. It is evident to a person skilled in the art, however, that the present formulations may be prepared without the need for initial stock solutions through direct mixing of the essential salts with MFC.

Example 5

[0148] This example aims to demonstrate that there is no evidence of toxicity in the use of microfibrillated cellulose (MFC) when it is used in a nutrient solution. Three identical small hydroponic floating systems were prepared in which two lettuce specimens were grown.

[0149] The hydroponic floating system consisted of 20-liter trays where two seedlings of lettuce were laid in each one. The trays had a flat bar of polystyrene to support the seedlings and each of them had two holes that enabled the roots to reach the water contained in the trays.

[0150] Hydroponic system number 1 was fed with stock A and stock B nutrient solutions, and no microfibrillated cellulose (MFC) was added. Hydroponic system number 2 was fed with a concentrated aqueous suspension of stock A and B in microfibrillated cellulose (MFC) having a microfibrillated cellulose (MFC) concentration of 23%. Hydroponic system number 3 was fed with a concentrated aqueous suspension of stock A and B in microfibrillated cellulose (MFC), having a microfibrillated cellulose (MFC) concentration of 80%.

[0151] The amount of solution and/or aqueous suspension added in the three systems had the same electrical conductivity in each case, ensuring the same provision of salts in each of them (electrical conductivity is a measure of the amount of dissolved solids per unit of volume).

[0152] The targeted electrical conductivity varied from week to week, depending on the requirements of the lettuce plants in their lifecycle, having 350 ppm in week 1, 700 ppm in week 2, 1,050 ppm in week 3, and 1,400 ppm in week 4.

[0153] After week 4 all the lettuce plants had showed equal growth and reached a weight ranging between 270 and 280 grams each.

[0154] Thus, we can conclude that microfibrillated cellulose (MFC) allows for the availability of salts for plants as well as the right absorption of nutrients since the growth of specimens studied did not reveal significant variations.

Example 6

[0155] This example shows how microfibrillated cellulose (MFC) prevents calcium sulfate from precipitating even when solutions of calcium nitrate and sulfates in their highest possible concentration at 77° F. and neutral pH are mixed.

[0156] Two Samples were Tested:

[0157] A control sample where three salt dilutions at its highest possible concentration at 77° F. and neutral pH were mixed, in this order: 180 cc of water*, 100 cc of calcium nitrate solution (1,200 grams in 1 liter of water), 100 cc of potassium sulfate solution (120 grams in 1 liter of water), and 100 cc of manganese sulfate solution (710 grams in 1 liter of water). *One hundred and eighty (180) cc of water was added so as to equate the volumes in the samples (water in the first one and microfibrillated cellulose in the second one).

[0158] After mixing them mechanically, observed was a precipitate of 192 grams of calcium sulfate.

[0159] In the other sample, three salt dilutions at its highest possible concentration at 77° F. and neutral pH, were mixed in microfibrillated cellulose (MFC), following this order: 100 cc of calcium nitrate solution (1,200 grams in 1 liter of water) in 60 grams of microfibrillated cellulose (MFC), 100 cc of potassium sulfate solution (120 grams in 1 liter) in 60 grams of microfibrillated cellulose (MFC), and finally 100 cc of manganese sulfate solution (710 grams in a liter) in 60 grams of microfibrillated cellulose (MFC). The three suspensions were mixed altogether. There were no signs of a precipitate after 48 hours.

Example 7

[0160] This example shows that microfibrillated cellulose (MFC) makes it possible to elaborate suspensions of homogeneously distributed salts that contain solids in a much higher proportion than the quantity of salts that could be contained in a water solution of the same volume.

[0161] Two sample tests were run.

[0162] A control sample was run where potassium sulfate was added in an amount that exceeded twice its solubility in water at 77° F. and neutral pH (111 g/L). More specifically, mixed were 28.8 grams of potassium sulfate in 130 cc of water at 77° F. It was stirred manually and immediately after that a precipitate of potassium sulfate was noted.

[0163] Sample number 2 consisted of the same amount of potassium sulfate contained in the control sample (that is, 28.8 grams) that was added into a suspension of the same volume (130 cc) with microfibrillated cellulose (MFC) at 23% (30 grams of microfibrillated cellulose in 100 cc of water). It was stirred manually and after 5 minutes no decantation of potassium sulfate was observed. The sample was monitored 24 hours later, 48 hours later, and even 90 days after without having observable modifications in its appearance.

Example 8

[0164] Preparation of a Solid-Consistency Fertilizer

[0165] An aqueous suspension prepared as described in example 1 is the starting point.

[0166] Taken were 1,000 grams of the concentrated aqueous suspension of stock A and B in microfibrillated cellulose (MFC) as described in example 1. This suspension was poured into granular-shaped molds of 10 cm.sup.3, each of them containing 12 grams of suspension, and were placed in a dehydrator oven at 161.6° F. for 24 hours. The final result of this process was a product with solid consistency. In each cast, a 3 gram tablet was obtained, which implies a loss of 8 grams of water. Assuming that the microfibrillated cellulose (MFC) lost 50% of its humidity and knowing that its fiber ratio is 15%, the resulting composition of each tablet is.

[0167] 10.00% water

[0168] 50.56% microfibrillated cellulose

[0169] 14.65% calcium nitrate

[0170] 0.176% magnesium EDTA

[0171] 0.293% manganese EDTA

[0172] 0.293% zinc EDTA

[0173] 0.366% iron EDTA

[0174] 0.044% copper EDTA

[0175] 0.044% sodium molybdate (dihydrate)

[0176] 0.0044% cobalt EDTA

[0177] 0.147% boric acid

[0178] 4.39% potassium nitrate

[0179] 5.86% monopotassium phosphate

[0180] 10.99% magnesium sulfate

[0181] 2.19% potassium sulfate

Example 9

[0182] Nutrition of a tomato specimen using the concentrated aqueous suspension in its solid form.

[0183] A tomato specimen was grown using for its nutrition only the concentrated aqueous suspension in its solid from, obtained as described in example 8.

[0184] A thin layer of leca was first placed in an 11 liter pot to facilitate the drainage, and then filled with an inert, nutrient-free substrate (peat). Then, 12 tablets obtained as described in example 8 were placed evenly distributed throughout the pot. The pot was watered according to its demand, water being the only input added during the whole cycle. In a 105-day cycle, the plant produced 43 tomatoes with a total weight of 4.9 kilos. The plant showed a normal size with a suitable growth speed and the presence of healthy leaves, particularly in the upper part of its stem.

[0185] This experiment suggests that the nutrients were effectively released at the plant's request throughout the cycle.

[0186] According to the examples provided in the present description, it is possible to conclude that the present invention has the following advantages over the prior art:

[0187] The aqueous suspension with MFC allows for the combination of salts whose concentration would naturally lead to precipitates.

[0188] The elaboration of complete formulations that are totally balanced for each type of crop in only one suspension is possible, which results in higher yields as the crop suffers from no nutritional deficiencies in all its lifecycle as shown in example 9. In its solid version, the nutrients are released on plant demand and there is a reduction in leaching.

[0189] Simplification of the use of fertilizers, since there is no longer a need to handle several solutions such as stock A and stock B.

[0190] Lower transportation costs and carbon footprint reduction due to the possibility to transport a greater amount of salts in the same volume.

[0191] Reduction in packaging as a result of the fewer wrappings needed to deliver the complete formulations.

[0192] Product shelf-life: the product shelf-life increases due to the stability of the suspension.

[0193] Lower storage costs and convenient stock management.

[0194] No pH controls to ensure plant nutrient availability.

[0195] The same suspension can be used in all agricultural applications: hydroponics, fertigation, and direct substrate fertilization.