THE INFLUENCE OF CROP ROTATION AND TILLAGE METHODS ON THE DISTRIBUTION OF EXTRACTABLE BORON IN NORTHERN IDAHO SOILS1

Publisher Website
Google Scholar
Abstract
Plots were established north of Moscow, Idaho, in 1974 using no-till, minimum tillage and conventional tillage treatments with 3 crop rotations. Rotations included the following: a 2 yr winter wheat (Triticum aestivum L. cv. Nugaines)-spring pea (Pisum sativum cv. Alaska) rotation (1:1 cereal/legume ratio); a 3 yr winter wheat-spring wheat (T. aestivum L. cv. Fieldwin)-spring pea rotation (2:1 cereal/legume ratio); and a 3 yr winter wheat-alfalfa (Medicago sativa L. cv. Ladak), red clover (Trifolium pratense cv. Kenland), pea-alfalfa, red clover rotation (1:2 cereal/legume ratio). B was determined by hot water extraction. Tillage .times. depth and rotation .times. depth interactions characterized extractable B distribution in the soils. When parameters were considered individually, extractable B levels in the sampled soils decreased with increasing depth. Extractable B in the surface (30 cm) of the soil profile was greater in conventional than in minimum and no-till treatments. Lower extractable B levels found in soils with no-till and minimun tillage treatments may be attributed to greater B leaching potential, or greater B tie-up by organic matter, or both. The crop rotation with the greatest cereal/legume ratio (2:1) had highest levels of extractable soil B. The greater demand of B by legumes, more specifically alfalfa, peas and red clover probably resulted in lower extractable soil B levels in rotations with smaller cereal/legume ratios.