4. IRRI Agronomy Challenge 2: Topdressing Urea in Chilly Weather (18 January 2013)

Also see blog at https://irri.org/index.php?option=com_k2&view=item&id=12428:fertilizer-basics&lang=en and still photos on flickr at https://www.flickr.com/photos/ricephotos/sets/72157632409026656/with/8336124832/ Revisit Agronomy Challenge 1: https://www.youtube.com/playlist?list=PL59BE77F7B94D2BA3 and see the growing playlist for AG2 at https://www.youtube.com/playlist?list=PLNowyW0S1hI-KtFPult89oGQ5FIecQpaz Achim Dobermann, deputy director general for research at the International Rice Research Institute (IRRI; https://irri.org), and Leigh Vial, head of IRRI’s experiment station, begin IRRI Agronomy Challenge II. It is the continuation of a special project in which they demonstrate how to grow a productive rice crop in a 25 x 100-meter field on IRRI’s research farm. Here, Leigh applies urea topdressing at 29 days after transplanting and inspects the crop’s progress during abnormally cool weather for the Philippiines. Leigh’s commentary: 18 January: Fertilizing far-apart plants in chilly weather Now 29 days after transplanting, the plants are safe from harm by snails and relatively weed-free. There is the odd ugly patch. The weather has not been good in the last 10 days � rainy, cloudy, and relatively cool � and the plants show it. They have commenced tillering, but are not yet thriving. There is really no cure for unfavorable weather, but a timely topdressing will allow the plants to take full advantage of any future improvement. We applied 100 kg/ha of urea, which equates to 46 kg N/ha, onto dryish soil and irrigated within hours after this. I would give myself a 7 out of 10 for the uniformity of my topdressing. The dry soil does make it easier to see the density of granules on the ground and to adjust the application rate a little as you go. At this time, I do regret the mechanical transplanter’s 30-cm spacing between rows. Around 20, or at most 25 cm, would have been better. Currently, the 30-cm spacing looks to be a wide expanse, ready to be occupied by things other than rice, especially where we have the odd vacant site (or ‘hill’ to the purists), vacant from an imperfect transplanting process. Mother Nature hates an empty space so we will definitely need a second herbicide application. Please help us pray for sunny weather, or can you only pray for rain?


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