11 September 1998

Bi-cropping lifts protein

BI-CROPPING maize with sunflowers, kale or runner beans could produce higher yields than growing maize alone and forage could be 3-5% higher in crude protein.

Reading Universitys Julian Park said research showed higher crude protein content from bi-cropping. But there had been difficulties with weed control, synchronising harvest dates, and harvesting techniques.

Bi-crops of maize with kale, runner beans and sunflowers harvested last year had crude proteins of 11%, 12% and 13%, respectively, compared with maize alone at 8% CP. He believed harvest difficulties could be overcome using crop varieties which had better matched harvest dates and without expensive changes to harvest machinery.

Digestibilty studies in sheep showed no detrimental effects of feeding bi-crops. However, sunflowers were less digestible and least palatable. But runner beans could have anti-nutritional factors, making them unsuitable for feeding cattle, warned Dr Park.

He advised waiting for further research before trying bi-cropping on a commercial field basis.