The Distribution of Soil Micro-Nutrients and the Effects on Herbage Micro-Nutrient Uptake and Yield in Three Different Pasture Systems

Cathy L Thomas,Paul Harris,Tegan Darch,Stephan M Haefele,Deborah A Beaumont

doi:10.3390/agronomy11091731

Abstract

Pasture micro-nutrient concentrations are often deficient for herbage productivity and the health of livestock. The aim of this study was to investigate soil and herbage micro-nutrient content and the effects on yield on the three pasture systems of the North Wyke Farm Platform (NWFP): high-sugar grass + legume mix minus nitrogen (N) fertilizer (blue/HSG + L); permanent pasture plus N fertilizer (green/P + N); high-sugar grass plus N fertilizer (red/HSG + N). The locations with high soil total micro-nutrient concentrations had a greater slope and higher soil organic matter (SOM) content. Herbage micro-nutrient concentrations were often greater at the locations with high soil total micro-nutrient concentrations. The concentration and uptake of nearly all micro-nutrients was greatest in the herbage of the green/P + N system, which had the highest SOM content, whereas they were often lowest in the red/HSG + N system, which had the lowest SOM and the highest yield, indicating biomass dilution of micro-nutrients in the herbage. At the locations with high soil micro-nutrient concentrations, yield was higher than at locations with low micro-nutrient concentrations, and was equal across the three pasture systems, regardless of fertilizer N treatment. Variation in micro-nutrient uptake/yield in the blue grass–legume system was predominantly explained by the soil molybdenum (Mo) concentration, possibly relating to the requirement for Mo in biological nitrogen fixation. There was, therefore, a trade-off in ploughing and re-seeding for higher yield, with the maintenance of SOM being important for herbage micro-nutrient content.

Highlights

Pasture, in numerous ways, is a more economic, sustainable, and less environmentally damaging livestock production system compared to intensive indoor systems [1,2]
Some locations in the blue/HSG + L and green/P + N systems but not the red/HSG + N system were in the Denbigh/Cherubeer series, and these were all classed as having high micro-nutrient content
The red/HSG + N system had some locations in the Fladbury soil series, and this soil series corresponded to lower elevation than elsewhere, with locations of both high and low micro-nutrient concentration

Summary

Introduction

In numerous ways, is a more economic, sustainable, and less environmentally damaging livestock production system compared to intensive indoor systems [1,2]. In pasture systems, deficiencies of micro-nutrients are often found in the herbage and livestock. A comparison of organic and conventional farms in Spain found that cobalt (Co), Cu, iodine (I), selenium (Se) and Zn were much higher in the concentrate cereal feed compared to forage, and the hay silage concentrations of these nutrients would be below recommended values. Micro- and secondary-nutrient concentrations in soils are often deficient for pasture productivity; for example, deficiencies of magnesium (Mg) [9] and molybdenum (Mo) [10,11] have been observed

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Conclusion