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(11) Patent Number: KE 56

(45) Date of grant: 10/03/2005

(51) Int.Cl.6: C 05G 3/00, 5/00

(21) Application Number: 1997/000219

(22) Filing Date: 0909/1997
(73) Owner: MEA LIMITED of, P.O.Box 1018, Nakuru, Kenya


(57) Abstract: The invention relates to the production and use of a blended compound fertilizer derived from the mixture of Ammonium Nitrate, superphosphate and potassium chloride in a granulation process to which magnesium Oxide and Boron is added as a blender. The production is thereafter coated, moisturized to facilitate the combination of the ingredients. The combination is granulated, dehydrated and cooled.

The use of NPK fertilizer blends have been practiced in developed countries and to some extent in Kenya for tea, cereals tobacco, floriculture and horticulture. The idea has however not infiltrated the coffee industry whereby until now a tactful dressing of the soil with macro and micro nutrients as well as ameliorants has been practiced. This has caused undulations in the soil water solute status to levels outside optimum.

Research on coffee nutrition has been carried out by Coffee Research Foundation but the findings on recommendations never addressed evolving a single rationalized fertilizer
recommendation. This has resulted in undulations in soil water solute status relative to known nutrient uptake pattern by coffee plant.

The present invention relates to the production of a compound fertilizer having a NPK +++ configuration. This product is derived from a mixture of Ammonia Nitrate, Superphosphate and Potassium Chloride in a granulation process, to which Magnesium Oxide and Boron is added. The product is coated, moistened to facilitate the combination of the various ingredients.

The compound fertilizer is mixed in the ratios NPK 18-4-12.

This is then blended to take the NPK +++ configuration mentioned herein above in the ratios: NPK (18-4-12) + 2Ca0 + 1Mg0 + 0.1B

This combination is granulated and then dehydrated in drying drum and cooled.
The present invention discloses boron as the major blend. Boron is a nutrient which is essential for fruit setting, water use efficiency and shoots development. Studies conducted in Kenya shows that there's an improvement in production of up to 50 per cent. Many compound fertilizers lacked boron and the soils become exhausted due to prolonged and continuous farming. The blend offers prophyllectic approach to the fertilization practice which would ably manage the deficiency problem before it becomes manifest.

The known macronutrient uptake by the coffee tree to produce a tone of clean coffee/acre has been estimated as 34kg nitrogen (N), 7kg P205 and 59kg K20. Additionally coffee pulp draws out of the soil 40kg K20 and between 20 and 30kg Nitrogen and small quantities of P205 per tone of dry pulp. This amounts to about 34-64kg N, slightly over 7kg P202 and 94kg K20 which has to be replaced by the blend.

In addition to the above macronutrient uptake, coffee also extracts from the soil micronutrients like Boron (B), Zinc (Zn), Iron (Fe). Copper (Cu), Manganese (Mn) and Molybdenum (Mo). Coffee often experiences Baron and Zinc deficiencies which limit coffee production greatly through suppressed flower formation. Ideally, the coffee leaf should contain at least 40ppm boron, and l0ppm Zinc for normal flowering. Boron and Zinc here often been given as foliar feeds where the soil is deficient with good soil fertilization, foliar fertilization will be unnecessary. The trace contents of copper and zinc in NPK fertilizer adequately replace natural uptake of the two by the coffee plant unless soil acidity is suboptimal.

The optimum soil condition for Nutrient Absorption is PH - CACL2 for high coffee production lies between PH 4.4 - 5.4. To keep coffee soils within this range of soil reaction it is essential to build in ameliorating materials in the fertilizer blend at proportions that will fully neutralize any fertilizer-induced acidity and, at the same time replace the cations Calcium and Magnesium taken up by the plant and to lesser extent leaded to deeper soil horizons.

The regularity of application of the blend will even out the current fluctuations of soil water solute status through continued addition of the cations Potassium (K+), Calcium (Ca++), Magnesium (Mg++) and Ammonium (N114+) to the soil. The current cultural by the co-operative and estates sector practice of separate applications of various fertilizer types is the main cause of soil water solute fluctuations. This results from imbalanced nutrient ratios and outright under-nourishment of the coffee tree. For optimum boron and nigro-nitrogen uptake by coffee to take place, Calcium has to be adequately available. To increase and maintain high level of coffee production, nitrogen uptake must be maximized through applying nitrogen alongside an ameliorant. The bled serves this purpose.

The salient features of the suitable blend for maximum coffee production includes:-
(i) High Nitrogen (N).
(ii)  Low Phosphate (P205)
(iii) High potash (K2O)
(iv) Micronutrient (B)
(v) Built in ameliorant (CaO and MgO )

Suitable fertilizer blend as described above should take the place of the summation of all the applications of the compound, straight N, P and K fertilizers and the occasional need in foliar-apply Boron and Zinc besides the blend also takes care of soil amelioration. The blend will take that place when applied under the following regime.

(i) Full split six months prior to the main flowering period.

(ii) This should be followed by two-half splits 30 days apart within the long rains in East and Rift Coffee growing Areas.

(iii) One full split 6 - 7 months prior to flowering followed by three one-third splits spaced one month apart.

It should be noted that a full split is 300g/tree; a half split 150g/tree and a third split is 100g/tree.

The development of a blended fertilizer will fill the existing gap in complete nutrient fertilizer supply and also stimulate higher coffee production at lower costs of purchase and application.

1. The production of compound fertilizer derived from the mixture of Ammonium Nitrate, Superphosphate and Potassium Chloride, blended with Boron and Magnesium to take the form.
NPK (18:4:12) + 2CaO + 1Mg0 + 0.1B

2. The granulation of the nutrient in claim 1 which are dehydrated and cooled.

3. The use of boron as a blend as claimed in 1 for fruit setting.

4. The use of boron as a blend is claimed in 1 for water use efficiency.

5. The use of boron as a blend as claimed in 1 for shoot development.

6. The use of fertilizer blend as claimed in 2,3,4 and 5 where the uptake of both the macro and micronutrients uptake is improved.

7. The use of the fertilizer blend claimed in any of the claims above is neutralizing any fertilizer-included acidity.

8. The use of the fertilizer blend claimed in 7 to replace the micronutrients either taken up by the plant or leached.

9. The use of a compound fertilizer blend claimed in 1 where the soiled water solute fluctuations are reduced.

10. The use of a compound fertilizer blend as claimed in any of the claims above where in balanced nutrient ratios and outright under-nourishment if the coffee plant is avoided.

11. The use of a compound fertilizer blend as claimed in any of the claims.


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