The general fertilizer recommendation for potato production is 120 kg/ha N, 240 kg/ha P2Os, and 240 kg/ha K20. However, proper fertilization should be based on soil analysis. Apply chicken manure during land preparation at a rate of 5 t/ha to contribute 60-100 kg NPK and micronutrients. Also apply 14-14-14 at 3-5 bags/ha as basal fertilizer. Apply the remaining N and K requirements during hilling up. Excess nitrogen delays maturity, promotes skinning, and blackspot bruising. In areas where bacterial wilt is a problem, early hilling up is necessary to prevent root injury.
Irrigation is very important as potatoes have a shallow and sparse root system. Initial light irrigation is appropriate at 5-7 days after planting. Subsequent irrigation is given at 7-15 days interval depending upon the climatic condition and soil type.
Weeding and Hilling Up
The potato crop develops a canopy in about 4 weeks after planting. Weeds must be controlled by this time to gain competitive advantage for the crop. Perform weeding, hilling up, and sidedressing simultaneously 1 month after planting. Subsequent weeding can be done sparingly depending on weed population.
Pest and Disease Management
The major pests of potatoes include cutworms, thrips, aphids, mites, leafminers, and potato tuber moth. Encourage the presence of natural enemies such as braconids and predaceous ground beetles.
Pests and Recommendations
Spray biological insecticides such as Bacillus thuringiensis and Nuclear Polyhedrosis Virus (NPV). Collect NPV-infected cutworm larvae and store in the freezer for later use. These can be macerated then diluted at 12 infected larvae/6 L water. Fully-grown larvae killed due to NPV infection hang with their head down, holding on with the abdominal pro-legs. Pheromones are also effective. If needed, spray with insecticides such as fipronil, fenvalerate, MIPC, and permethrin following the recommended rates.
Spray with soap solution (4 tbsp soap/16 L water). If needed, spray with oxamyl, cypermethrin, or fipronil following the recommended rates.
Spray with hot pepper (100 g macerated hot pepper per 16 L water) and soap solution. If needed, spray with cypermethrin, fenvalerate, deltamethrin, or other recommended chemicals following product labels.
Spray with soap solution. Use appropriate miticides such as methiocarb following the recommended rates.
e. Leaf Miner
Intercrop with beans, onions, or other vegetables and maintain low weed population along alleys. If needed, spray with cyromazine, cartap hydrochloride following the recommended rates. Alternate different products of recommended pesticides to prevent development of pesticide resistance.
f. Tuber Moth
Hill up adequately to cover the tubers. For seed pieces, dust with fine wood ash or carbaryl.
Diseases and Recommendations
a. Late blight
Use mancozeb, chlorothalonil, and metalaxyl, following the recommended rates, in rotation. Compost tea showed good activity against late blight when enriched with selected microbial antagonists. To prepare compost tea, soak V2 sack (15 kg) of mature compost in a % drum (200-L capacity) of water for 5-7 days. Dilute the tea to 20 parts water and spray on the plants. Avoid too much nitrogen fertilization.
b. Bacterial wilt
Use clean planting materials. Plant potato in well-drained soils. Practice crop rotation.
Rogue infected plants. Control aphids which are insect vectors of viruses.
Harvest at full maturity for longer storability. Most potatoes mature at 75-90 days after planting or when 80% of the leaves of the total plant population become yellow. Dehaulm or vine-kill to reduce skinning and bruising during harvest, and shrinkage during storage. Cut the foliage (dehaulm) at 5-10 cm from the ground level 5-7 days before harvest to harden the skin of tubers. Harvesting is done by manual digging of the tubers using a spading fork or any pointed instruments. Do not expose tubers in sunlight to prevent greening.
Classify potato according to size based on diameter anc weight as follows:
|7.5 and above
4.0 – 7.4
3.0 – 3.9
|301 and above
181 – 300
90 – 180
Cost and Return Analysis per Hectare
1. Variable Cost
a. Labor (P220/man-day [MD]):
- Clearing (20 MD) – 4,400
- Bed preparation (20 MD) – 4,400
- Manure application (10 MD) – 2,200
- Seed preparation (2 MD) – 440
- Planting (6 MD) – 1,320
- Sidedressing (2x) (4 MD) – 880
- Weeding/hilling up (12 MD) -2,640
- Irrigation (10 MD) – 2,200
- Spraying (1 Ox) (20 MD) – 4,400
- Vine killing (2 MD) – 440
- Harvesting/hauling (20 MD) – 4,400
- Cleaning/sorting (20 MD) – 4,400
- Miscellaneous (e.g., hauling, repairs, etc.) (10MD) – 2,200
- Seeds (1,500 kg) – 37,500
- Manure (100 sacks) – 12,000
- 14-14-14 (3 bags) – 2,469
- 0-0-60 (4 bags) – 3,412
- Fungicides – 9,600
- Insecticides – 2,500
- Fuel and oil – 4,000
- Packaging materials – 3,000
- Miscellaneous (e.g., paild, gloves, etc.) – 2,200
- Interest on Production Loans at 21 % p. a. – 10,500
- Total (Variable Costs) – 121,301
2. Fixed Cost
- Land rental – 10,000
- Knap sack sprayer (1 unit) – 500
- Hoe (5 pes) – 417
- Shovel (3 pes) – 250
- Plastic drum (2 pes) – 533
- Total (Fixed Costs) – 11,700
3. Total Costs- 133,001
4. Gross Income –
- Regular season (at P10/kg with 25 t/ha yield) – 250,000
- Off-season (at P20/kg with 15 t/ha yield) – 300,000
5. Net Income
- Regular season – 116,999
- Off-season – 166,999
For more information on plant and planting materials, contact:
Philippine Council for Agriculture, Forestry and Natural Resources Research and Development (PCCARD), Los Banos, Laguna
Phone: (049) 536-0015 to 20
Baguio National Crop Research Development Center
Guisad Valley, Baguio City
source: PCCARD, FNRI-DOST, PNS, DA-BAFPS, BAS, photo from freedigitalphotos.net