Soil properties and barley yield under a twenty-years experiment of tillage, straw management and nitrogen application rate in the sub-arctic area of Alaska

Abstract

A tillage and straw management study was started near Delta Junction Alaska (64°49'N, 147°52'W) USA in 1983 to determine the impact of tillage, straw management, and nitrogen fertilizer application rate on soil properties and barley (Hordeum vulgare L.) grain yield. In October 2003, soil samples were collected from the 0-5, 5-10, 10-25 cm depths in the treatments: no tillage (NT); disked once each spring (DO); disked twice (each for spring and fall, respectively) (DT); straw and stubble retention (SS); straw and stubble removal (NSS); and 11 and 131 kg N ha-1 nitrogen fertilizer application rates, to determine soil total nitrogen and carbon concentration, cation exchange capacity, mineral N, Mehlich-3 extractable phosphorus, exchangeable potassium, pH, electrical conductivity and bulk density. From 1983 to 2003 grain yield was measured from each treatment except in those years in which yield was lost due to birds, weeds, or chemical fallow. The no-tillage treatment tended to increase soil total organic C and N concentrations at 0-5 cm depths. Soil bulk density (0-5 cm) was lower with NT (p=0.05) than with DT. Retaining straw (SS) on the soil surface increased soil organic C concentration at 5-10 cm depth (p=0.06). Mineral N concentration in soil was higher with NT at 0-5 cm depth (p=0.05). Barley grain yield of NT was better than that of DT but varied with time. Rate of N application increased grain yield up to 91 kg N ha-1. Overall, the no-tillage and straw management had impact on some surface soil properties in sub-arctic Alaska, and no-tillage and minimum tillage increased barley crop yield. © 2007 Taylor & Francis.