Controlled traffic farming effects on productivity of grain sorghum, rainfall and fertiliser nitrogen use efficiency

Controlled traffic farming (CTF) is a mechanisation system in which all machinery has the same (or modular) working and track width so that field can be confined to least possible area of permanent lanes. CTF enables productivity non-compacted crop beds optimised for given energy, fertiliser water (rainfall) inputs. This study investigated agronomic response economic return grain sorghum grown compacted soils represent conditions non-CTF systems, respectively. Yield-to-nitrogen (N) responses were derived following application urea, 3,4-dimethyl pyrazole phosphate-treated urea (DMPP), ammonium nitrate (UAN, 32% N) at rates between 0 300 kg ha−1 N. Selected soil properties measured guide parametrisation Agricultural Production Systems Simulator (APSIM), was used assess long-term (55 years) effects on productivity, rainfall use efficiency (RUE) develop rainfall-runoff relationships. Grain yield components (harvest Index, thousand-grain weight, number grains) significantly higher compared with non-CTF. On average, most N rates, corresponding yields, 144 3428 ha−1, 100 1796 non-CTF, When inputs optimised, calculations showed 18% increase Nitrogen (NUE) 1.75 times than Rainfall-use about 65% CTF, concurrently reduced amount runoff Average season (330–450 mm in-crop) 30% lower CTF. For subtropical Australia, APSIM simulations increased inter-season stability gross margin by AUD74 or greater depending adopted tillage in-crop rainfall. In improvements NUE RUE are constrained compaction. Enhanced fertilisers, such as DMPP-treated cannot compensate other stresses caused compaction therefore achieve system. Adoption delivers improved resource-use profitability rainfall-limited environments.