Northern farming systems – Narrabri site report, 2015–2020

Abstract

Key findings • The three systems (higher nutrient, higher legume and higher intensity) had similar productivity and gross margins (GM) compared with the baseline system, which represents the typical grower’s cropping rotation for the local area. • The systems with lower cropping frequency (lower intensity) and those aimed at growing more diverse crops (higher diversity) had lower grain production compared with the baseline system. • In 2016, nematode numbers (Pratylenchus thornei (Pt)) numbers were higher after chickpea compared with faba bean and field pea, while canola and cotton reduced Pt numbers that year. The higher Pt numbers after chickpea in 2016 continued through to December 2017, after that year’s wheat crop. • High yielding legumes exported more nitrogen (N) and potassium (K) from the farming systems (baseline, higher nutrient, and higher legume) compared with the systems that contained no legumes or lower yielding legumes (higher diversity, high intensity, and lower intensity). • The high cropping diversity (higher diversity) system reduced soil pathogen levels over the five years compared with the baseline system.