Agriculture & Soil

Growing systems, soil science and what field trials actually show.

• Sep 22, 20265 min

  A Quarter Less NPK, Same Maize Yield, in One Field for One Season

  A single field trial in Bengkulu, Indonesia tested whether fermented oil palm empty fruit bunch liquid could substitute for mineral NPK on hybrid maize. Replacing 25 percent of the NPK dose held grain yield and nitrogen uptake; replacing 50 percent held yield but cut nitrogen uptake by 13 percent; replacing 75 percent cut yield. The trial ran one season at one site with four replications and reported no cost analysis, so the economics that motivated the study remain untested.

• Sep 21, 20265 min

  Manure Cut Fertilizer Needs in a Shallot Trial. One Season, One Field, One Soil.

  A single-season trial on an acid Ultisol in Bengkulu, Indonesia, tested composted cattle manure at 10 tonnes per hectare combined with 100, 75, 50, 25 or 0 percent of the recommended NPK rate, against a full-NPK reference with no manure. Manure plus 75 percent NPK gave the highest fresh bulb yield, 18.3 percent above the reference, and manure plus 50 percent NPK matched the reference while cutting storage weight loss from 22.2 to 15.1 percent after eight weeks. The trial was not replicated across sites or seasons, and the abstract reports no mechanism for the storage effect.