Changes in the soil quality attributes of continuous no-till farming systems following a strategic tillage

Abstract

The adoption of no-till farming systems has greatly reduced energy and machinery inputs while significantly improving soil health and productivity. However, the control of crop weeds and diseases in no-till (NT) systems has become increasingly difficult for landholders in Australia’s northern grains regions, with occasional strategic tillage (ST) being considered as a potential management option. This study investigated the effects of occasional ST on physical, chemical and biological soil properties, productivity, and weed control on five long-term (7–44 years) NT-managed soils. The study area extended from Biloela (Vertosol, 666 mm annual rainfall), Condamine (Sodosol, 624 mm annual rainfall), Moonie (Dermosol, 636 mm annual rainfall) and Warwick (Vertosol, 675 mm annual rainfall) in Queensland to Wee Waa (Vertosol, 582 mm annual rainfall) in New South Wales. Tillage treatments included chisel, offset disc and prickle–disc chain with various timings and frequencies. Soil samples (0–0.3 m) obtained 3 and 12 months after occasional ST were analysed for total and particulate organic carbon (TOC, POC), available phosphorus (P), bulk density, soil water, and microbial enzymatic activity. In-crop weed density was also recorded. One-time tillage, with chisel tines, offset disc or chain harrows, in long-term NT helped to control winter weeds in the first year, with variable results in the second year. Grain yield overall showed no significant impact in either year, except on the Brown Sodosol (P = 0.08) in the first year. The initial impacts of strategic tillage on soil water were largely restricted to the 0–0.1 m depth range, with slight, non-significant decreases occurring. Available P, TOC, POC and total microbial enzymatic activity were not significantly impacted by either cultivation frequency or implement type. The use of an occasional ST for the purpose of weed control could be utilised as a viable management option for NT systems in the region without impacting on long-term productivity.

Tillage does not increase nitrous oxide emissions under dryland canola (Brassica napus L.) in a semiarid environment of south-eastern Australia

“…However, with increased pressure from soil-and stubble-borne diseases and the development of herbicide-resistant weeds under a strict no-till farming system, farmers are tending to use tillage as a strategic tool to manage problematic weeds and break disease life cycles (Crawford et al 2015). In the current study, the site had been cropped using no-till or minimum tillage for at least 5 years before the experiment commenced.…”

“…The challenge is to find a balance between the negative impacts of tillage on soil structure by tillage and the maintenance of optimum crop agricultural production. In recent years, several field experiments were conducted across northern and southern grain regions in Australia to investigate how much damage is done to soil by occasional tillage, strategically applied, in an otherwise no-till system (Crawford et al 2015;M. K. Conyers, unpubl.…”

Effect of strategic tillage in soil microbial communities in Vertisols from Queensland, Australia

“…The elevated concentration of microorganisms in this particular region is due to an exchange of nutrients between the plant and the different communities surrounding the root, which allows different types of associations ( Figure 1). A number of factors have been shown to influence the quantity and quality of root exudates including plant species [14], soil type [15,16], developmental stage [17], and nutritional status [18]. If specific elements associated to the release of such exudates are better understood, novel approaches to enhance beneficial microbial communities could be proposed.…”

“…However, the main concern among growers is that tillage will cause serious negative long-term impacts to their system (Crawford et al, 2014.…”

“…However, soils with weak A-horizons and contrasting textural properties are more prone to adverse impacts on soil fertility [11,14,15] Soil microbial communities are considered suitable indicators for soil quality due to rapid responses of microorganisms to disturbance events [16]. The degree of soil disturbance can be measured using different biological indicators including enzymatic and microbial metabolic activity as well as genetic fingerprinting profiles.…”