I am fed up with the prescribed watering of areca plants - 170 liters per tree per week. 170 liters per tree is a huge quantity! Are there anyone who has pondered over this matter… especially areca growers? Can you please share your thoughts/experiences?
well, it is understandable that mulching and multicropping can reduce water requirement by reducing soil evaporation, but it won’t have any bearing on the transpiration by the areca tree itself. Is areca really a water thirsty crop? if yes, how does it compares against other horticulture crops like coconut, lemon etc?
Surprisingly, with a rain fall of 3,000 mm (western ghats average annual rainfall), if even 50% of the water falling on one acre of land was harvested, it would have satisfied the requirement of 170 ltrs per tree per week.
Isn’t it a tragedy that we now depend on ground water to satisfy this irrigation requirement? I am quoting western ghats as my plot is located there.
Sadly, water table in hilly area like the one you mentioned, is complex. The valley regions are usually flooded, and hence its water table will be saturated. Hence there is no use in harvesting rain water here. Where as the hilly areas seep the percolated water to valley during dry season, which means they are the best place to harvest rain water. The summary is, the scope of water harvesting is limited to select areas here as compared to plateau regions.
Also it is highly doubtful if it is ever possible to harvest the rain to the extent you mentioned. Other than the thin weathered rock layer and limited rock fractures, there are no place the water can be stored (like huge lakes in the plains)… So I guess it is inevitable that large part of the rain reaches the sea during the rain.
mpneerkaje, so it does appear that you have given rain water harvesting significant thought. Nice to know. My plot is on a slope and I am trying to dig CCTs to at least slow the flow of water if not completely ensure percolation.
Coming to water usage again, I guess green manure (live mulch) like Velvet Beans and Cow Pea significantly increase the moisture holding capability of the soil. I had been to a farm near Gubbi, Tumkur about 2 weeks ago. The owner, Mr. Shankarappa said he irrigates his 8 acre farm from 2 borewells. He switches on the sprinklers for 45 mins, once in 2 days. Assuming he uses 2 HP pumps, and each pump output is about 100 gallons per minute. He pumps a total of 6.2 million litres for the entire 8 acres in a year. That’s a measly 776,000 litres per acre per year.
At your quoted figures of 170 ltr per tree per year, assuming 523 trees per acre, it takes almost 4.2 million litres per acre! almost 6 times what Mr. Shankarappa pumps. He also grows areca (on 1.25 acres), coconut and banana (on teh rest of the plot) which are all crops that are high on water requirement. Looks like his yield is pretty much on par with the best of yields I have heard of.
Interesting calculations indeed… Our current usage is as follows :
We have total 1200 Areca (leaving the side crops for now). We cover them using around 50 sprinkler points. We run sprinklers 1.5 Hrs per week.
The sprinkler that we use sprinkles minimum 1000 liters per hour (jalpari.com/3-4-full-circle- … 13379.html)
Hence total water used per week = 50 X 1.5 X 1000 = 75,000 liters per week
Total water consumed per year (considering 16 weeks of irrigation, which is again minimum) = 75,000 X 16 = whopping 12L liters!
Deducing the per tree watering from the above calculations - 75,000 per week/1200 trees = 62.5 liters per tree per week, which less than half of prescribed 170 liters per week per tree.
The point is, even at 62.5 liters per tree per week, the consumption is 12L liters of water… too much isn’t it?
Coming to your numbers… may be Krishnappa using even less water than you quoted, because borewells yield usually much less than what the pump can pump. Hence 2HP pump may not be pumping to its full capacity as you mentioned. That means it is worth re-considering this magic 170 liters theory as I guess (and many people have witnessed), it can be much much less if proper farming techniques are used. I am looking for all such options.
Thanks for those figures. If it’s not too personal, can we ask you about your areca yield with this watering schedule? How much does your farm produce per acre? Also, what sort of mulching/ manuring techniques do you use? 1.5 hours of irrigation a week does sound a little less compared to what I see in the Malnad region.