Drip emitter spacing for banana on alluvial soil, and the hours

Drip emitter spacing for banana on alluvial soil is the easy half of the question: the 40 cm spacing every inline pipe on our listing carries puts four or five drippers under each plant, and on alluvial soil their bulbs merge into one continuous band along the row, which is exactly what a plant with a root spread of a metre wants.

The hard half of drip emitter spacing for banana on alluvial soil is the run time, because banana drinks more than any crop we size for and the line applies water slowly across a wide row.

This guide covers how alluvial soil moves and holds water, why the whole row is wetted rather than two spots per plant, the hours per day from the calculator's figures, and the two mistakes alluvial ground punishes: a lateral laid for a lighter crop, and long runs on a field with the river's water table under it.

How alluvial soil moves water

Alluvial soil is the deep, river-laid ground of the Godavari and Krishna belts: silty to sandy loam, few stones, easy to work, and in most places deep enough that roots never meet rock. Water from a dripper spreads moderately, a bulb of 60 to 90 cm across, and goes down at a steady pace. It holds a fair store, two or three days of crop water in the root zone, so it is forgiving of a missed day in a way red loam is not.

Its fault is the one that comes with its origin. Along the rivers the water table can sit close under the field, and the lower patches drain slowly after a long run or a rain. Banana, which grows a thirty kilogram bunch on a plant that hates wet feet, pays for standing water with root rot and a leaning stem.

• Moderate spread: 60 to 90 cm across under one dripper, so neighbours at 40 cm merge into a band.
• Deep and stone-free: water goes down evenly and the root zone is wherever the plant puts it.
• Fair storage: a missed day is survivable; a missed week is not, on this crop.
• The water table: low patches waterlog after long runs; that is the alluvial risk.

Drip emitter spacing for banana on alluvial soil

Banana stands at 1.8 to 2.1 metres between rows and about 1.8 metres between plants, and one lateral runs along each row. With a 4 litre per hour dripper every 40 cm, each plant sits over four or five drippers, and on alluvial soil those bulbs join into a band 60 cm or more wide along the whole row. The plant's roots spread about a metre from the stem, so the band between plants is not wasted; by the third month the roots have filled it.

That is why the whole-row band is the right pattern here and two emitters at the stem is the wrong one. Two 4 litre drippers wet two small bulbs and a plant that drinks 25 to 30 litres a day in peak season would need them running three or four hours; the band gives it the same water from a wider, shallower wet zone in a third of the time.

The lateral is 16 mm inline from the drip range, and the banana drip guide says which wall to choose for a crop that stands fifteen months.

On the widest rows, 2.1 metres, growers sometimes ask for a lateral on each side of the row. On alluvial soil one lateral laid 20 to 30 cm from the stem line is enough through the first cycle; a second line is a ratoon decision, when the mat has spread, not a planting one. The banana crop page keeps the spacing beside the products.

The run time, in hours

The pipe applies it slowly. A dripper every 40 cm at 4 litres an hour puts 10 litres an hour onto each metre of lateral, and on rows 1.95 metres apart that metre serves nearly two square metres, so the line applies about 5 mm an hour.

Eight millimetres a day is therefore an hour and a half of running, and the lighter months nearer an hour. An acre carries about 2,100 metres of lateral drinking 21,000 litres an hour, which most pumps can hold in two shifts, each getting its hour and a half.

On alluvial soil that hour and a half is given every day in peak season, in one run on the loamier ground and in two runs of forty-five minutes where the soil is sandier or the field is low. Split runs let the first soak away before the second arrives, and keep the band wide rather than deep.

Banana in its peak months uses about 5 to 8 mm a day, which on one acre is roughly 20,000 to 32,000 litres at the root, or about 22,500 to 36,000 litres from the pump once drip's losses are allowed for; the water requirement calculator gives the figure for your own acreage. That is the thirstiest line in the calculator, and the reason a pump sized for cotton comes up short under banana.

The two mistakes alluvium punishes

The first is a lateral chosen for a lighter crop. Growers who moved to banana from cotton or chilli keep the schedule they knew, twenty minutes a day, and the band under the plants never wets more than the top hand's depth. On alluvial soil the symptom is slow: the plants grow, but the bunch is small and the plant leans in its ninth month because the roots stayed shallow. The fix is the hour, every day, from planting.

The second is the opposite and the alluvial one. A grower who runs the line for three hours to be safe, on a low field with the river's water table a metre down, waterlogs the row. Banana roots in standing water rot within days, the leaves yellow from the bottom, and the plant that was pushed hardest falls first in the next wind.

The check is a trowel at a hand's depth beside the stem the morning after a run: moist and crumbling is right, wet and shining is a run too long.

The band hides a blocked dripper better than any other pattern, because its neighbours cover for it until a bunch is short; the blocked-line guide covers flushing, and the filter it depends on is not something we stock.

• Lighter-crop schedule: twenty minutes a day, shallow roots, small bunch, a leaning plant late in the cycle.
• Over-long runs on low ground: standing water in the band, yellowing from the bottom, root rot in the wet months.
• The check: a trowel beside the stem the morning after a run, moist not shining.

The figures are a starting point

The 5 to 8 mm a day and the bulb widths are published agronomic ranges, not measurements from your field, and alluvial ground varies from sandy phases to heavy ones within one village. Treat the hour and a half as the first week's schedule and let the trowel correct it. The same arithmetic on heavier and lighter soils is worked in the black-soil cotton guide and the red-loam chilli guide.

If you want the lateral count, the shifts and the pump checked against your bore, send us the row spacing, the acreage and the bore yield and we will say whether the pump can give a banana acre its hour and a half, and in how many shifts.