Micronutrient Concentrations in Soil and Wheat Decline by Long-Term Tillage and Winter Wheat–Pea Rotation

• Main Authors: Santosh Shiwakoti, Valtcho D. Zheljazkov, Hero T. Gollany, Baoshan Xing, Markus Kleber
• Format: Article
• Language: English
• Published: MDPI AG 2019-07-01
• Series: Agronomy
• Subjects: boron; dryland; iron; manganese; soil pH; zinc
• Online Access: https://www.mdpi.com/2073-4395/9/7/359

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 (<i>Triticum aestivum</i> L.) under dryland winter wheat&#8722;pea (<i>Pisum sativum</i> 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^&#8722;1 vs. GP: 6.0 mg kg^&#8722;1). In the upper 10 cm soil surface, NT (123 mg kg^&#8722;1) maintained the extractable manganese concentration with GP (175 mg kg^&#8722;1) whereas FT (97 mg kg^&#8722;1), ST (92 mg kg^&#8722;1), and DT (113 mg kg^&#8722;1) 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.