 |  | | |
 | grid sampling |
| |
|
|  |
  | East Zone India |
| |
   | Eastern Canada & Northeast U.S. |
|  |
  | Great Plains U.S. |
| |
|
|  |
  | North and West Zone India |
| |
|
|  |
  | Northcentral U.S. |
| |
|
|  |
  | Northeast India & Bangladesh |
| |
|
|  |
  | Northwest China |
| |
|
|  |
  | Southeast China |
| |
|
|  |
  | Southern India & Sri Lanka |
| |
 | IPNI-23 | Global Maize Project in India: Dharwad, Karnataka |  |
  | Southwest China |
| |
|
|  |
  | Western U.S. |
| |
|
|  |
 | irrigation |
| |
|
|  |
 | magnesium |
| |
|
|  |
 | manure management |
| |
  | maximum economic yield (MEY) |
|  |
 | micronutrients |
| |
|
|  |