Small growers avocado agronomy
Planting of avocado trees
Selection of trees at nursery
• Tree with healthy roots.
• Flush hardened off. Even tree size(+9months after grafting).Water before going out.
• Handle tree gently (care not to loosen nursery tree medium soil)
• Do not leave tree for long periods in sun before planting.
• Planting holes can be dug with a hoe and spade and needs to be 2ftX2ftX2ft
• Cut plastic away from under container and place in hole.
• Slit sides of plastic midway avoid damaging the roots.
• Pull plastic sleeves upwards over top of tree whilst firming in soil.
• Height of nursery medium soil to be 6cm higher than surrounding soil and tree planted straight.
• When planting bushy part of tree to face the hot western side, so as to protect tree against sunburn.
• Do not compact the soil around the plant.
- Mulch basin of trees but keep mulch away from stem of tree.
- Mulching around the trees will also prevent drying out of the soil and will keep the root system cool and active.
- Water the avocado tree directly after planting. Afterwards regular light irrigation every 2 to 3 days is necessary to keep the root system from drying out.
NOTE it’s important to monitor for any pest that can be damaging your Avocado plants.
Mature trees [old orchard]
Establish orchards needs care to keep them within the production cycle. All management practices have to be adhered to with proper crop management practices like Irrigation, weeding fertilization flower and fruits managements are keeping at the required levels to keep the trees producing.
Periodic additional of inputs to boost production needs to be put at the right timings.
Use a foliar with an NPK formulation plus trace elements LIKE Zinc,Boron,Mg Also do topdressing where possible and maintain a ratio of possible and maintain a ratio of 3;1;3 for nitrogen Phosphorus and Potassium.
• Ideal avocado orchard Fertilization is based on 3 broad facets;
• Leaf and soil sampling
• Crop removal
• Observation Leaf sampling:
• Should be done annually, preferably between Feb-April(6-8 month old leaves)
• Selection of trees that represent the orchard.
Done every year and is used to show the chemical composition of the soil.
It’s most important to do the initial lime applications before planting, basing on pre-plant soil analysis.
• Dolomitic lime-contains both Ca and Mg.
• Gypsum-Contains Ca+S
• Agricultural lime-Contains Ca
Rates of application:
Amount of pre-plant lime application depends on soil pH,exchangeable Al and clay content.
After planting, regular lime application at 1-3Ton/Ha every 2 years following soil analyses
• P is important for development and stimulation of root growth.
• Phosphorous fertilizers
• TSP SSP Rock phosphate
• Apply during the major root-flushes March-May, Sept-Dec).
N is important for growth, flowering and fruit-set of avocado plants.
• CAN, KNO3
• DAP, KNo3 Many NKP FERTILIZERS also supply N besides other nutrients
• N and K fertilizers should be split into applications targeting the active growing period for young and old trees.
• K is important for both yield and fruit quality especially in mature trees.
• K products;
• K2SO4, KNO3, KC1, MOP.
Essential micronutrients include;
• Zinc (Zn)
• Boron (B)
Zinc deficiencies are characterized by chlorosis (yellowing) of young leaves and rounding of the fruits.
Zinc may be applied with ZnSo4 soil application.
• Denotes the amount of nutrient that is removed when fruit crop is harvested. Besides leaf and soil analyses guideline in fertilizer calculation, the expected nutrient removal in the harvested crop should be replenished through fertilizer application.
• The below table indicates the amount of element nutrients removed for every ton of fruit harvested.
• Crop removal.
IRRIGATION OF MATURE TREES
Timing of irrigation
Avocados require 8000-9000 m3 per Ha for the whole year,including water supply from rain.
The avocado trees have varied moisture requirement in amount depending on the prevailing physiological stage.
Aspects/stages directly influenced by optimal water regime on avocadoes include;Flowering,fruit drop sizing and fruit quality.
100-150 liters of water per tree in 2 weeks.
In a week, 50-75 liters being applied per tree will supply adequate moisture to support the tree during peak demands.
Below is a guideline on irrigation calendar for the small farmer
|Period||Plant physiology||Irrigation status||Water volumes and rounds||Comment|
|Dec to March||Fruit set and rapid expansion||Irrigate fully until rains start||25-35 litres per tree twice every week||There must be no stress on trees|
|April to May||Fruit development||Do not irrigate||Rainy season|
|June to August||Harvest||Partially irrigate||5-10 litres per tree once a week||Maintenance only|
|Sept to mid Oct||Dormant period||Do not irrigate||Stress prior to flowering|
|Mid Oct to Rains(Nov)||Flowering and fruit set||Irrigate fully||25-35 litres per tree twice every week||There must be no stress on trees|