By Smart Farmer team
Adequate nutrition for your plant is not an issue in question. Without it you cannot expect much from the tree. The coffee plant needs a lot of nutrition, especially nitrogen, to be able to bear enough fruit and carry it.
The tree requires certain elements in large quantities such as nitrogen (N), phosphorous (P), potassium (K) among others, which are referred to as macro-nutrients. Other elements are required in small quantities such as zinc (Zn), boron (B), iron (Fe), manganese, molybdenum, and chlorine among others and are referred to as micro-nutrients.
“Before embarking on any fertiliser programme, it is important that a soil and leaf analysis is done to determine if any soil amelioration is needed depending on the soil pH, or not,” says Mr Martin Ngare the Coffee Management Services (CMS) general manager in an interview with Smart Farmer Magazine.
For the purposes of this article, late crop will refer to the coffee that flowers with the March to April long rains while early crop will refer to the coffee that flowers with the October to November short rains.
Feeding for next year’s late crop starts in September/October
Feeding your coffee tree should start in earnest in October/November for next year’s coffee late crop using compound fertilisers, which have macronutrients that include NPK – nitrogen, phosphorous and potassium. But this will depend on the advice given in the soil and leaf analysis.
This is important as the coffee tree will have started cell differentiation six months prior to flowering. At this point therefore, phosphorous is a critical nutrient. Fertilisers should be applied along the drip line where feeder roots of the coffee trees will be concentrated.
“We always advise coffee farmers to do the right thing, at the right time, at the right place, using the right material, and correct rate or amount. You could be feeding your crop right, but if you feed it at the wrong time, it will be a waste,” says Mr Ngare.
Compound fertilisers consist of mechanical mixtures screened to homogenous granules, each having certain proportions of primary nutrient (NPK) such as 20:10:10 or 17:17:17, says KALRO.
The coffee trees use them slowly and can stay in the soil for some time. They need to be incorporated shallowly into the soil.
Application: Apply 250gms of NPK fertiliser per tree two weeks after the rains begin. Dig a shallow trench around the tree at the drip line, which is about two-to two-and a-half feet from the stem.
(A drip line is formed by rainwater dripping from the outer leaves around the bush that form a circumference of about two-to two-and a-half feet from the stem. This is where most of the water concentrates when it rains and there’s a tendency by the feeder roots to grow along the circle created.)
Macronutrients perform the following functions in the coffee:
- Nitrogen: assists in boosting the coffee bean size, expansion and forage during dry times, and assists in crop bearing capacity
- Phosphorus: Assists in wood maturity and strengthens the tree. It also gives the bean sturdiness/density, and early bean maturity.
- Potassium: promotes mucilage development and better use of water, so that the bean becomes dense and bold. It also helps ripening and boosts the quality of the bean. It is also important in transport of all other nutrients within the plant.
It is important to apply Zinc in November/ December to boost optimal flowering.
January to mid-February
- Boron: This is applied in January/ February to assist the plant avoid flower abortion.
- Manure: As a routine, the application of well-prepared organic manure of one to two debes every two years is recommended, to build the soil organic matter. This in turn improves soil texture and structure. It improves soil aeration and moderates topsoil temperatures, amongst other benefits.
- Lime: Add lime according to soil analysis to prevent acidity. Broadcast between rows.
“Lime is also a fertiliser,” says Mr Ngare. “It’s a macronutrient that contains calcium and magnesium, which are necessary for the tree. Calcium is required for budding. Magnesium ni boda boda (transport), it helps the food to get into the plant,” he adds.
“Apply it when it is dry in January, because when it is wet, it cakes. Phosphorous and potassium compound together but the lime breaks the compounding and allows the plant to take the feed,” he says.
Flowering in March/April
By March/April, the bush is already flowering depending on the onset of the rains and the need for nitrogen rises due to bean formation and expansion, which takes three to four months. At this time apply 300gms of CAN in two splits per tree at the drip line. It is necessary to apply 150gms of NPK to supply K for optimal nutrient uptake.
After four months, expansion stops. Application of fertilizer after the bean expansion has stopped is wasteful as it only makes the tree green but will not result in denser and bold beans.
“If the beans don’t get enough nutrition within the four-and-a-half months of expansion, they will not expand, fatten, or grow after that. Trying to boost their growth after this time will be in vain as they will remain stunted if they were stunted,” says Mr Ngare.
“It is important to note that if the weather is dry and one is not able to apply ground fertiliser, these nutrients can be supplied through application of foliar fertilisers,” says Mr Ngare. “It is, however, important to note that foliar fertilisers only supply limited quantities of these nutrients, given that the plant is not able to absorb huge quantities through the leaves unlike the roots,” he adds.
When it is dry coffee trees are not able to take up food, they require water to go with it. Feeder roots also dry up during this time and cannot take up nutrition.
Nutrient supplementation through foliar feeding can be done throughout the coffee bean expansion to ripening.
“In April, apply CAN or other nutrition one-to-two weeks after it rains. Do not apply it immediately, because feeder roots normally take one to two weeks to get revived. They will, therefore, not be able to uptake the fertiliser and you will waste your nutrient to leaching.”
“Coffee Management Services Ltd, has come up with innovative highly concentrated suspension foliar fertilisers foliar feeds called Biofol that are used in coffee nutrition. These range of these foliar feeds include;
- Biofol Triple Max -23:23:23, which contains essential micronutrients. Use this product during coffee berry expansion between May to July for late crop farms. It will offer the much-needed nitrogen, Phosphorous and Potassium.
In July, it is wet and cold and feeder roots may become dormant. Applying this nutrition is necessary to ensure that there is sufficient nitrogen to avoid overbearing dieback.
- Biofol Boron Max is used in January and February for late crop flowering farms and in August and September for early crop flowering farms to supply Boron.
- Biofol Zinc Xtra Uptake. This product is used between November and December and in an June/July to supply Zinc needed for flower formation initiation.
- Biofol High P Max is used between November and December to promote early bearing wood maturation for late crop farms and March to April for early crop farms
- Biofol High K Max is used in September and October to aid in ripening for late crop farms and also in March to April for early crop farms. This helps the berries to ripen evenly and quickly, and get enough mucilage, so that it gets out of the tree to start preparing for April.