Straw Baling Brings Big Bucks, But Don't Forget Nutrient Replenishment

Farmers who baled their straw this harvest are earning significant additional revenue, but they must not forget to replenish nutrients removed by the process. According to the British Hay and Straw Association, merchants are paying around £80/t ex-farm for wheat straw, with barley straw as high as £113/t in the South West. This can deliver an extra £320/ha of income, but considering baling costs, growers may only net £220-£270/ha.

However, experts warn that failing to replenish potassium (K) and phosphorus (P) nutrients removed by straw baling is a false economy. 'At about £30/ha to replace both the P and K removed from baling straw, it's a false economy to take shortcuts, as both nutrients are yield-limiting,' says Origin Soil Nutrition agronomist Toby Ward.

Growers have several options for replenishing these nutrients, including manures and digestates, but these should be analysed for nutrient content. Individual straights such as triple superphosphate or muriate of potash can also be used, although combining P and K fertilisers may be more effective in some cases.

A free online calculator from the Potash Development Association (PDA) can help growers keep on top of P and K requirements. According to the calculator, a 10t/ha wheat crop without straw baled requires 65kg P2O5/ha and 55kg K2O/ha to maintain soils at the recommended soil indices.