Allelopathic effects account for the inhibitory effect of field-pea (Pisum sativum L.) shoots on wheat growth in dense clay subsoils

Abstract

The deep-placement of nutrient-rich organic amendments in poorly-structured subsoils can improve subsoil structure and increase grain yields, but its widespread adoption by farmers is limited by the availability and cost of animal manures, the current choice of amendment. Three glasshouse experiments investigated the effectiveness of dried field pea (Pisum sativum L.) shoots (green chop), as green manure, on wheat growth in three subsoils with contrasting soil chemical and physical properties. The growth of wheat plants was greatly suppressed when the green chop was placed in Sodosol and Chromosol subsoils. In contrast, there was a 2-fold increase in shoot biomass in response to the addition of green chop to Vertosol. Three allelopathic compounds, pisatin, anhydropisatin, and maackian, were identified at higher concentrations in the extracts of remaining green chop residues in the Sodosol and Chromosol, compared to the Vertosol, directly supporting phytotoxicity as the cause of observed inhibitory effects of green chop in these soils. The persistence of the phytotoxicity in the Sodosol might be attributed to its poor aeration caused by poor structure or compaction. Nevertheless, pre-incubation led to microbial decomposition of the allelochemicals in the Sodosol, though at a much slower rate than in the Vertosol. Further studies are needed to determine the time period required for the disappearance of the phytotoxic effects in soils with different physico-chemical properties.

An Insight Into the Effect of Organic Amendments on the Transpiration Efficiency of Wheat Plant in a Sodic Duplex Soil

“…Further insights into soil physical conditions that invoked the increase in canopy TE can be gained by comparing the amendment effect in the Vertosol and Sodosol. The Vertosol is characterized by a well-structured subsoil with an air-filled porosity of 26% at field capacity, which was more than twice that in the Sodosol subsoil (12%) (Wang et al, 2019 ). Earlier studies provided evidence that soil structure, such as the proportion of macroaggregates or aeration, is a key driver in shaping the microbial community structure in subsoils (Turner et al, 2017 ; Celestina et al, 2019 ).…”

Autoallelopathic and Allelopathic Influence of Aqueous Winter-Cereal Extracts

“…Allelopathic interactions accounting for the inhibitory effect of shoots on wheat growth in dense clay subsoils have been recorded (Wang et al, 2019). e plant parts showed an inhibitory effect on root and shoot growth.…”

Determining the effect of soil properties on the stability of scopoletin and its toxicity to target plants

“…Despite the fact that allelochemicals are substances with generally lower risk, lower requirements for registration, favorable perception by society, and potential to satisfy the demand of herbicides with new modes of action, the inconsistency in field performance they commonly present under different edaphic-climatic scenarios represents an important limitation for their wider success as pest management products (Wang et al 2019). To face this limitation, studies on the fate of allelochemicals in the soil environment are badly needed, as soil is recognized as a "black box" with respect to understanding the bioactivity of allelochemicals on target organisms (Reigosa et al 1999;Trezzi et al 2016).…”