[EN] 17. IRRI Agronomy Challenge: Milling the Paddy & Postharvest Issues

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Description:

Achim Dobermann, deputy director general for research at the International Rice Research Institute (IRRI; http://irri.org), and Leigh Vial, head of IRRI's experiment station, are conducting a special project, the IRRI Agronomy Challenge, in which they are demonstrating how to grow a productive rice crop in a 25 x 100-meter field on IRRI's research farm.

Now that the rice has been harvested, Mr. Vial and Martin Gummert, IRRI's postharvest specialist discuss postharvest activities at the IRRI rice mill.

Commentary from Mr. Vial:

While for many, the quantity of paddy rice (with the hull on) seems like the objective of growing a crop, it is the quantity of whole, milled rice that we grow that is the genuine goal.

Ever tried eating paddy rice? It is amusing to see almost everyone referring to the paddy yield as the objective of almost every production and research endeavor, particularly agronomy research.

Paddy rice is made up of the white rice grain, surrounded by the bran layer, which makes brown rice. This is enclosed in a hull, which gets you back to paddy. If the paddy has been harvested too dry, or the variety is prone to cracking, or the mill is not well-adjusted, a larger proportion of the grains crack. This gives us broken rice, which is tolerable in limited quantities, and okay for processing, but not valued as normal rice to eat.

To get the maximum amount of whole rice out of the mill, we need to harvest it at the right moisture. We achieved that. We need to dry it evenly. We got fairly close to that, although as Martin pointed-out we were using a flat-bed dryer, which is not as uniform in its drying as, say, a re-circulating dryer. We need to mill it in a modern, well-adjusted and maintained rice mill. We did that.

To measure the result, we need to mill the rice we produced from our Agronomy Challenge in isolation from the other rice we mill, then measure the weight of the various components to estimate the whole-grain yield. Well, we didn't quite do that...did I mention we dried it well? Hence, although I am confident it was reasonable, we can not furnish a whole milled-rice yield, so let's keep talking about our paddy yield!