Q. I plan to grow Soy Beans this season. I will grow two (2) hectors in the field, and crops will be watered by rainfall. I live in the tropics with lots of rainfall and sunshine.
What is the appropriate fertilizer combination for growing Soy Beans and the best Cultural practices, including seed rates per hole and per hector in a tropical setting.
A. The ideal fertilizer combination for soy beans is the same as for other vegetables – The Pre-Plant mix before you plant, and The Weekly Feed mix during the growing season. Amounts are as follows: Pre-Plant – 2 tons per hectare, one time before planting, along with 300 kg of Weekly Feed. Weekly Feed should then be applied at the rate of 300 kg per hectare twice more during the growth cycle – first after your plants emerge and the first weeding has been done, and second – 4 weeks later. Be sure you measure and apply accurately. Figure how many rows per hectare, and divide your fertilizers into kg’s per row, then apply, so that all plants are fed evenly.
A plant population of approximately 400,000 plants per hectare is desirable. One kg of medium sized soybean will contain about 6,000 seeds (quantities of seed per kg range from 4800 to 7500). At that rate, two and a half bushels of soybeans will produce about 375,000 plants per hectare assuming 90 percent germination. This would give plants about 4 cm apart within the row at a 75 cm row spacing. Seeding rates should be increased 5 to 7% to compensate for unavoidable plant thinning during weed control, and seeds can be planted as close as 2 cm apart if desired. Finish your seedbed preparation just prior to planting the crop to kill germinating weeds and give your plants an even chance.
After good cultural practices such as thorough seedbed preparation and proper fertilizing, control of early weeds is the next most important element of a profitable soybean growing operation. Early weed control – during the first 2 to 4 weeks of the growing season – is essential to maximize yield. Cultivate after emergence and before weeds are 1 cm tall, with a tractor and cultivator if they are available. Otherwise do weeding with hand tools (the two-way hoe is best). Follow-up with manual weeding of everything missed by the cultivator. And cultivate a second time as soon as weeds appear again.
Because harvesting with a combine is difficult in high rainfall areas, and may not be available, following are instructions for manual harvesting. When leaves start turning yellow, your beans are trying to ripen. With a Japanese Spade cut the roots about 2 cm under the ground, leaving the plants standing. Leave until the stems are dry and the leaves easily shatter off. The pods will be dry also. Bring a trailer with sides into the field close to a row of plants. Take a handful of plants, bang against the inside of the trailer box, and the beans will come off into the trailer. Throw the plant material back onto the ground and till in as a soil amendment.
Take soy beans to a covered area with good circulation, spread 2-3 cm deep, and rake occasionally until thoroughly dry.
Where others were producing 45-58 bushels per hectare in the USA, Dr. Mittleider has grown soy beans with yields as high as 135 bushels per hectare using these methods.