Stocking Methods and Soil Macronutrient Distributions in Southern Tallgrass Paddocks: Are There Linkages?

Brian K Northup,Patrick J Starks,Kenneth E Turner

doi:10.3390/agronomy9060281

Brian K Northup, Patrick J Starks + Show 1 more

Open Access

https://doi.org/10.3390/agronomy9060281

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Abstract

Broad ranges of factors (parent materials, climate, plant community, landscape position, management) can influence macronutrient availability in rangeland soils. Two important factors in production-scale paddocks are the influences of location in space and land management. This study examined plant-available macronutrients (total mineral and nitrate-N, P, S, K, Ca, and Mg) in soils, with paired sets of probes (anion and cation exchange membranes) that simulate uptake by plant roots. Data were collected from sets of paddocks of southern tallgrass prairie in central Oklahoma, managed by four stocking methods during the 2015 growing season (mid-March, growth initiation by native grasses, and early-August, time of peak living plant biomass). Macronutrient availability in the 0–7.5 cm and 7.5–15 cm depths were determined at locations in close proximity to water (water tanks and 25% of the distance between tanks and paddock mid-points (PMP)), and distances near the mid-points of paddocks (70% of the distance between water and mid-points (0.7 PMP), and PMP). All of the tested stocking methods affected levels of availability of macronutrients at different times of the growing season, and among different locations within paddocks. Such responses indicated stocking methods may not result in uniform distributions of flux in plant-available macronutrients. The overall exposure of landscapes and arrangement of features within paddocks also appeared to influence macronutrient distributions.

Highlights

A diverse range of factors influence the availability of macronutrients in soils of native grasslands, often with a large degree of interaction among factors
Soils in paddocks assigned to continuous stocking had proportions of sand and silt with coefficients of variation (c.v.) that ranged from 16% to 41%, while soils in the rotational and high-density short-duration rotational stocking (HDRG)-stocked paddocks varied from 4% to 14%
Responses during this study provided a mixed result for defining how, or if, seven years of applied stocking methods affected levels and distributions of plant-available macronutrients at contrasting locations within production-scale paddocks

Summary

Introduction

A diverse range of factors influence the availability of macronutrients in soils of native grasslands, often with a large degree of interaction among factors. The availability of macronutrients, and the forms of macronutrients, within soils of native grasslands generally reflects the nature of parent materials from which the soils evolved, and is further affected by plant communities, climate, position within landscapes, and management [1,2,3]. These factors result in variable spatial and temporal distribution patterns for plant-available macronutrients in soils of ecosystems dominated by perennial grasses [1,3].

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