Feb19

IRRI agronomy challenge: scruffy but growing

Author // Dr. Leigh Vial Categories // Achim Dobermann's blog

February 11: The scruffiness of life... 

There was a priceless moment at the field on Monday morning last week. Achim and I both arrived to topdress the field, and dropped the fertilizer and implements. Achim put his hands on his hips, shuffled from side-to-side, furrowed his brow and scowled at the crop. “It looks so...so...so SCRUFFY!”.

Nancy Castilla and Leigh Vial talk about how to assess the severity of biotic stresses - such as weeds and diseases.  

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Thinking about it, we have faced a fair share of ‘factors’ - as economists would like to put it - knee-deep soil, rain, poor judgment on leveling, birds, imperfect fertilizer spreading, some problems with perennial grass emerging from rhizomes, and now the rats have moved in! At least it is not typhoon season. All of the research programs here at IRRI spend a lot of resources and employ a lot of people to counter such things. In particular, we transplant to ensure we get the desired plant population. Even better, if you can, stay in your office and simulate or assume a yield.

In my 15 year Australian rice growing career, I grew somewhere north of 50 crops. How many got the perfect 10? Two of them, in the same field interestingly enough. Whilst starting with a helpful guide - variety, yield target, field leveling, desired plant population, weed control, fertilizer rates, water regime, etc - the whole exercise is conducted in real life. Real life contains variable weather, pests, weeds, soil variation, communication breakdowns, public holidays, bad judgments and the odd idiot random event. Real life is scruffy. One of the best antidotes for scruffiness is experience within a system, something most farmers have plenty of. Combine that experience with the basic guidelines, or checks as many call them, and you get a lot further. That was Peter Jennings’ point when he urged a revolution in agronomy: get as much scruffiness out of the system as you can.

But woe betide you if you think you can eliminate scruffiness completely…

Nancy Castilla and Leigh Vial discuss how to measuer abiotic stress.

Nancy Castilla and Leigh Vial discuss how to measure biotic stresses.

February 16

We are at the satisfying stage, where the rice is into its last week or so of tillering and is really stretching its legs. The crop has really responded to last week’s topdressing…and our manual application was not too uneven, it seems. Many of the previously worryingly thin areas are filling in nicely…if anything, the thickest areas may present more worries with lodging in another month. Weeds are yesterday’s news.

The rats do seemed to have eased, thanks to the IRRI rat control program that is at full speed at the moment. The bare patches they have created are annoying, but yet again we might be surprised at how the surrounding rice responds to fill in the gap.

Nancy Castilla will help us quantify everything biotic in association with the crop, such as insects, rats, weeds, fungal, and viral disease. Even to the untrained observer, there are plenty of beneficial insects getting around in the crop now, which is great to see. She did spot a bit of tungro in the crop this week, which is a concern, so I hope our variety will do its best to counter it.

Top-dressing next week, as the crop reaches panicle initiation. This will be our last chance to get the nutrition right.

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About the Author

Dr. Leigh Vial

Dr. Leigh Vial

Dr. Leigh Vial is former head of IRRI's Experiment Station. Read more.