Abstract
Soil physical and structural degradation may influence crop productivity over time in long-term no-tillage system areas. A field study was conducted at two sites, Palmeira das Missoes and Nao-Me-Toque, in southern Brazil to quantify soil physical/hydraulic and structural changes in zones with different yield potentials. The sites have been managed under no-tillage system without soil disturbance for more than 10 years. Soils were classified as Oxisols (Hapludox). Each site was divided into three zones with low, medium and high yield potentials based on overlapping of yield maps obtained from harvesters with precision agriculture tools. Within each yielding zone soil samples were collected to determine bulk density, porosity and aggregate stability. In addition, water infiltration rate and initial time for starting surface runoff were measured using a sprinkler infiltrometer (Cornell Sprinkler infiltrometer). Our findings showed that soils under low-yielding zones presented higher bulk density, lower macro-aggregate stability and water infiltration rate as well as shorter time for starting surface runoff compared to high-yielding zones. Therefore, these results suggest that soil physical and structural degradations have induced crop yield losses under long-term no-tillage areas. Macro-aggregate stability (>4.76 mm) and water infiltration rate were efficient parameters for distinguishing yielding zones in Oxisols managed under long-term no-tillage system in southern Brazil. Key words: Soil compaction, Cornell Sprinkler Infiltrometer, soil aggregation, water infiltration.
Highlights
The perpetuation of conservationist tillage systems is directly related to the soil and to the adopted crop management practices, which can enable the maintenance and improvement of soil structure quality (Dumanski, 2015) and crop yield (Pittelkow et al, 2015)
Under long-term no-tillage the absent of soil disturbance associated with intensive machinery traffic have induced critical soil compaction (Nunes et al, 2015), that leads to decreasing crop growth and yield, as reported by Pittelkow et al (2015)
We suggest that management strategies including cover crop with tap root system, crop rotation, or even mechanical chiseling should be adopted by farmers, especially under medium- and low-yielding zones, to improve soil physical and structural qualities, and to increase water infiltration rate, water storage and reduce surface runoff, as consistently reported in the literature (Lanzanova et al, 2010; Jemai et al, 2013; Sun et al, 2015)
Summary
The perpetuation of conservationist tillage systems is directly related to the soil and to the adopted crop management practices, which can enable the maintenance and improvement of soil structure quality (Dumanski, 2015) and crop yield (Pittelkow et al, 2015). Soil aggregation is globally used as an indicator of soil structural quality changes induced by land use and management practices (Vezzani and Mielniczuk, 2011; Karlen et al, 2013). Macro-aggregates play crucial role on the stabilization and protection of soil organic matter (Six et al, 2000a), which increase the soil resilience to structural degradation and water dynamics in the soil (Vezzani and Mielniczuk, 2011). Studies have shown that increases of soil aggregation is positively correlated to higher yields of corn (Song et al, 2015), soybean (Corbin et al, 2010) and other cereals (Hou et al, 2012)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
