Micronutrient concentrations in soil and wheat decline by long-term tillage and winter wheat-pea rotation

Authors: SHIWAKOTIA, SANTOSH - Oregon State University; ZHELJAZKOV, VALTCHO - Oregon State University; Gollany, Hero; XING, BAOSHAN - University Of Massachusetts; KLEBER, MARKUS - Oregon State University

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/3/2019
Publication Date: 7/8/2019
Citation: Shiwakotia, S., Zheljazkov, V.D., Gollany, H.T., Xing, B., Kleber, M. 2019. Micronutrient concentrations in soil and wheat decline by long-term tillage and winter wheat-pea rotation. Agronomy. 9(7):359. https://doi.org/10.3390/agronomy9070359.
DOI: https://doi.org/10.3390/agronomy9070359

Interpretive Summary: Tillage plays a major role in nutrient dynamics under dryland cropping systems, but there remains uncertainty regarding the long-term impacts of tillage on nutrient availability. The objective of this study was to examine the influence of tillage intensity and timing on micronutrient concentration of soils and winter wheat under dryland winter wheat-pea rotation. The treatments included moldboard tillage in fall and spring, disk/chisel tillage, and no-tillage. The concentrations of extractable boron, manganese, zinc, copper, and iron in soil were unaffected by the tillage methods; however, a significant decline in extractable zinc in the top 4 inches of soil was observed compared to an adjacent undisturbed grass pasture. In the upper 4 inches soil surface, no-tillage maintained the extractable manganese concentration like grass pasture while disk/chisel, fall and spring moldboard plow tillage had lower manganese than grass pasture. Soil pH declined in the upper 4 inches under no-tillage more than in the rest of the WW-P treatments. The results suggest no-tillage can play a major role in sustaining micronutrient availability due to decreased soil acidity and the greater amount of organic matter within the surface soil of no-tillage compared to other tillage methods.

Technical Abstract: Tillage plays a major role in nutrient dynamics under dryland cropping systems, but there remains uncertainty regarding the long-term impacts of tillage on nutrient availability. The objective of this study was to examine the influence of tillage intensity and timing on micronutrient concentration of soils and winter wheat (Triticum aestivum L.) under dryland winter wheat-pea (Pisum sativum L.) or WW-P rotation. The treatments included moldboard tillage in fall (FT) and spring (ST), disk/chisel tillage (DT), and no-tillage (NT). The concentrations of Mehlich III extractable boron, manganese, zinc, copper, and iron in soil were unaffected by the tillage methods; however, a significant decline in extractable zinc in the top 10 cm soil was observed compared to an adjacent undisturbed grass pasture (GP) (NT: 2.3 mg/kg vs. GP: 6.0 mg/kg). In the upper 10 cm soil surface, NT (123 mg/kg) maintained the extractable manganese concentration with GP (175 mg/kg) whereas FT (97 mg/kg), ST (92 mg/kg), and DT (113 mg/ kg) had lower manganese than GP. Soil pH declined in the upper 10 cm under NT more than in the rest of the WW-P treatments. The results suggest NT can play a vital role in sustaining micronutrient availability due to decreased soil pH and the greater amount of organic matter within the surface soil of NT compared to other tillage methods.