Controlled traffic farming effects on soil emissions of nitrous oxide and methane

Soil compaction affects soil aeration and gas diffusivity, and thus has a major impact on the release of greenhouse gases (GHGs) from fertilised soils. Controlled traffic farming (CTF) systems reduce the area of compacted soil by confining all field traffic to permanent traffic lanes, and a pilot trial at one long-term CTF site provided evidence of reduced soil emissions. We investigated the effect of CTF on soil emissions of nitrous oxide (N2O) and methane (CH4) using replicate manual chamber measurements in 3 traffic treatments;namely:non-trafficked CTF beds, permanent CTF lanes,and a single traffic pass on CTF beds to simulate the random traffic tracks of non-controlled traffic farming. Emissions of N2O and CH 4 were monitored from these treatments in 15 crops over 3 years on 6 grain farms in Queensland, Victoria and Western Australia.Thus, the major objective was to determine the emissions of N2O and CH4 from random trafficked and permanent traffic lane soil, relative to those from non-trafficked CTF beds. These emission ratios are referred to here as traffic impact factors.

土壤压实会影响土壤通气性和气体扩散率，进而对施肥土壤的温室气体（GHGs）释放产生重大影响。可控交通耕作（CTF）系统通过将所有田间交通限制在固定行车道上来减少压实土壤的面积，而在一个长期CTF试验点的试点研究提供了土壤排放减少的证据。我们采用重复手动箱式测量法，在三种交通处理方式下研究了CTF对土壤氧化亚氮（N₂O）和甲烷（CH₄）排放的影响；具体包括：未受交通碾压的CTF床、固定CTF行车道，以及在CTF床上单次通行以模拟非可控交通耕作的随机行车轨迹。在昆士兰、维多利亚和西澳大利亚的6个谷物农场，对这三种处理方式下15种作物在3年内的N₂O和CH₄排放进行了监测。因此，主要目标是确定随机碾压土壤和固定行车道土壤的N₂O和CH₄排放量，与未受交通碾压的CTF床土壤排放量的相对关系。这些排放比率在此被称为交通影响因子。