Soil chemical properties and crop yields response to dryland diversified crop rotations

Abstract

Diversified crop rotations can affect soil water and nutrient uptake and produce variable quality and quantity of crop residue that may alter soil chemical properties and crop yields compared to monocropping. We examined the effects of dryland diversified crop rotations with or without cover crop on soil pH, organic matter (SOM), P, and K contents at 0–15 cm, NO 3 ‐N content at 0–60 cm, and crop yields compared to continuous monocropping from 2014 to 2018 in the US northern Great Plains. Crop rotations were continuous durum ( Triticum turgidum L.) (D), durum‐fallow (DF), durum‐spring cover crop‐pea ( Pisum sativum L.)‐corn ( Zea mays L.)‐safflower ( Carthamus tinctorius L.) (DBPCS), and durum‐winter wheat ( Triticum aestivum L.)/fall cover crop‐pea/fall cover crop‐corn‐safflower (DWP1CS). Cover crops contained a mixture of cereals, legumes, and oilseed crops. Total annualized crop residue returned to the soil from cash and cover crops was 33%–159% greater for DBPCS and DWP1CS than D and DF. Soil pH was 3%–4% greater for DBPCS than DF and DWP1CS. Soil P content was 17%–20% greater for DWP1CS than D and DBPCS. In contrast, SOM was 6%–9% greater for D than DBPCS and DWP1CS. Crop rotation had no effect on soil K content. Annualized grain yield was 28%–85% greater for D and DWP1CS than DF and DBPCS. Crop residue and grain yield were negatively correlated with soil NO 3 ‐N content. Diversified crop rotations increased the amount of crop residue and soil pH and P content but reduced SOM, resulting in different crop yields compared to continuous monocropping.