Fuel consumption-derived CO 2 emissions under conventional and reduced tillage cropping systems in northern Japan

Abstract

In the context of their role in net global warming, CO 2 emissions were calculated for fuel-consuming processes associated with arable land crop production in Hokkaido, northern Japan. Fuel-consuming processes included tractor-based field operations, transportation of products and materials and grain drying. In conventional tillage (CT) systems, total CO 2 emissions from fuel consumption were 826.2, 605.4, 424.2 and 738.7 kg CO 2 ha −1 for winter wheat ( Triticum aestivum L.), sugar beet ( Beta vulgaris L.), adzuki bean ( Vigna angularis (Willd.) Ohwi and Ohashi) and potato ( Solanum tuberosum L.) production, respectively. In winter wheat production, 55% of total CO 2 emission were released from kerosene and electricity use for grain drying, the remainder from tractor-based field operations. In contrast, for sugar beet, adzuki bean and potato production, field operations were the main contributors to CO 2 emissions. Of the field operations, tillage and harvesting required the largest amounts of fuels. Under reduced tillage (RT) systems in which soil preparation in early spring was reduced and plowing after harvesting was omitted, 47.5 l ha −1 of diesel oil equivalent to 125.4 kg CO 2 ha −1 could be saved, regardless of crop species. Consequently, total CO 2 emissions could be reduced by 15–29%, respectively, in winter wheat and adzuki bean production. In the Tokachi region of Hokkaido, a primary arable crop production region in Japan, annual CO 2 emissions under CT and RT for the four crops produced were estimated at 82.7 Gg CO 2 per year and 67.4 Gg CO 2 per year, respectively. Besides reduced fuel costs, the use of RT production systems could significantly reduce the large quantities of CO 2 released as a result of arable land crop production in northern Japan.