21 February 1997

Ridge injection boost for yield

INJECTING liquid fertiliser into potato ridges at planting time can boost income even when prices are low. That is because the technique lifts overall yield, as well as significantly increasing the proportion of baker sized tubers, claims a leading fertiliser supplier.

Field scale trials commissioned by Hydro Chafer and conducted at Harper Adams Agricultural College show that injecting liquid fertiliser into the seed-bed, or using a combination of injection and foliar application, can give significant yield advantages over broadcasting fertiliser.

When the work was completed in 1995/96, potato prices were high and the financial advantage was over £2000/ha (£810/acre). But even now, with ware potatoes averaging £55/t and bakers £75/t, the technique still offers an income boost of £535/ha (£217/acre), says Dr Jim Lewis, head of agronomy for Hydro.

Seven tonnes extra

Injecting an 8:4:12 liquid compound in the seed-bed gave the highest yield at 47.6t/ha (19.3t/acre) – including 19.2t/ha (7.8t/acre) of bakers. A combination of injected 6:4:12 compound and five applications of foliar N, the first two weeks after tuber initiation, and then at 10-day intervals, achieved 46.7t/ha (18.9t/acre). Broadcasting an equivalent compound gave 40.7t/ha (16.5t/acre).

Hydro Chafer has helped develop the technique through its manufacture of Potato Injection Kits, which it offers on a free trial for the first season. Cost of the kit is £3950, including installation and calibration by Hydro Chafer.n