Actualizado: 13 de ago de 2020
In May we renovated the first of our coffee lots following successional agroforestry guidelines. To our knowledge this is the first commercial coffee production system based on Syntropic agricultural guidelines in Colombia
Note: After planting the seeds I have into the degraded pasture and seeing that they are not adapted to grow with and out compete the grass cover in bracharia dominated systems, I decided to move to another part of the farm where the ecological system is a step further in succession and there is very little bracharia. If the seeds grow well then it will confirm what I believe about their consortium and I will move forward with replanting the coffee systems on the farm and work on selective pruning in the pasture systems.
I started by cleaning the lower ⅔ of the lot of coffee. I started here because it is considerably flatter than the upper slope and more fertile. The coffee in some places grew to 4 meters and in the lower part of the lot the coffee has shaded out completely (or due to the settling fertility) any early secondary growth and is just the coffee trees with more advanced species growing in the understory. On the upper slopes the coffee is completely taken over by ferns, climbing vines, and bracharia, as well as some clumping grasses and bambusa. I am not sure if this is due to the shape of the lot creating more shade in the middle at the “key point” or because of the settling fertility but it is a trend that is worth investigating. There are many secondary growth species that are not present in the secondary growth in the abandoned cow pastures and I believe that these are the native species belonging to a later “accumulation consortium”. There are very few individuals from the early accumulation consortium except the bracharia which has invaded from the neighboring lot of arazá.
There are 6 year old guamos (inga edulis) at around 10x10, some are dying but some still have vigorous growth. The coffee is planted at 1.5m x 1.5m.
The coffee lot in the process of delimbing and cleaning getting it ready to plant.
Underneath the coffee there is an abundance of cauchos (ficus spp.), and other secondary trees as well as some individuals that have grown above the coffee and secondary growth to reach the light at 4 or 5 meters. This growth has been over the past 2 years because 2 years ago I cleaned the coffee lot and applied a liquid organic fertilizer.
Abundance and diversity of secondary growth under the abandoned coffee. This coffee has almost no aggressive early secondary growth as in the upper slopes. This part of the coffee lot had the most vigorous coffee trees. It is worth noting that because of the density of the coffee that the lower branches lose their leaves and obviously their production because of the lack of sunlight penetration and put all of their energy in growing up. This does create a perfect understory for germination and growth of native secondary species.
I saw just 1 earthworm during all planting and cleaning of the coffee, and very, very few insects and animals during cleaning. Apart from the bot fly that got me in several places and just 1 ant colony in all 1.500m2, which is unusual for a system that has been accumulating biomass for so long.
Bracken Fern The domination of ferns in several places of the system would seem to confirm my suspicion that in this context the ferns are indicators of a mineral imbalance in the soil that has to do with the potasium that they accumulate in their biomass, and calcium in the soil. By taking out potassium and storing it in biomass that resists decomposition the ferns effectively remove the potassium from the system and restore the soil mineral balance potassium:calcium. This imbalance is caused by chemical fertilizer, Urea (CH4N2O) I believe. I postulate that as the urea releases h+ and acidifies the soil, calcium is lixiviated at the lower pH and creates the imbalance between potassium and calcium necessitating the ferns to hold the extra potassium above the soil in plants that are very slow to break down until the the system can accumulate enough calcium to normalize the ratio. This is why when agricultural lime is introduced to the system at 100g/m2 the ferns almost disappear but remain at background levels until the ph and organic matter content of the soils increase. This amount of lime is not enough to raise the ph in any measurable amount (agronomists recommend adding double or triple this amount every year to effect ph) but it is enough to add calcium back into the system and restore a favorable potassium:calcium balance and take away the ecological trigger for the germination and domination of the ferns.
I delimbed the existing coffee (1.5mx1.5m) and left as much naturally regenerated secondary growth as possible. I pollarded the inga (aprox at 10mx10m) and cut up the big branches with the chainsaw procuring that as much of the wood as possible would be in contact with the ground. The natural regeneration species that belong to the earlier pioneer consortium I coppiced and the species that belong to the later accumulation consortium (caucho, aguacatillo, some unidentified tree species, and arrayan blanco) I raised the skirt of the later succession species to 2 meters where possible to encourage stratification and open up lower space for the germinating plants.
The lower right corner of the system has lived under several large pines for the past 15 years and the soil and natural regeneration is significantly different than the rest of the system, also appearing to be drier and have less organic matter and less biomass. I cut the two pines, one fell onto the system and I cut up the branches to encourage decomposition and contact with the soil. Otherwise I planted this area the same as the rest of the system.
The planting will have 2 phases: the first is a cover crop of canavalia, crotalaria, cow pea, and cajanus cajun broadcast along the lines of coffee. At the same time I planted 10 to 15 seeds of acacia magnium, gliricidia sepium, and martin galvis (senna reticulata) 10 cm to the left of each coffee tree. The proportion of the mix was 2:1:2 by weight. I made a hole with a stick and to the best of my ability the seeds were dropped in the hole and then the dirt compressed over them. The first phase of planting was finishing 14/5/2020.
The second phase will include the later succession biomass species and production species that will go in their definitive location, chontaduro 9x12, coffee (Tipica) 2.5x6, inga 3x6, hardwood 21x24, banana (Varied Musa family) 9x6 (x2 the first years banana will accompany the chontaduro). There will be alternating lines at 3m of A) Coffee + Overstory hardwood and B) Musa + Chontaduro + Medium strata fruit tree (Arazá for this system) all spaced at 3m + inga interplanted with 1.5m between each. This will simplify harvesting because the same species will produce at approximately the same time and there will be no searching or missing trees, which will save time and labor and maximize profit of the system.
To see how they would fare and to expand our pup production, I planted 12 musa spp. (banana, plantain, guineo) of all our varieties in lines 9 and 5 along with some achira and pumpkin. The musa is mixed without giving importance to the variety or size, the idea being to have cross pollination over all of the genetic variety and maximize diversity to discourage the propagation of pests and diseases.
Native Accumulation Consortium species
I have not seen these species at their full size and do not have enough information about them to classify into strata.
Unknown Secondary tree species
Caucho (Ficus spp.)
Also present are: Aguacatillo (Persea spp.), Yarumo (Cecropia spp.), Tumbamaco (Didymoanax Morototoni) and several others I have not yet identified