Effect of Wheat Straw as a Cover Crop on the Chlorophyll, Seed, and Oilseed Yield of Trigonella foeunm graecum L under Water Deficiency and Weed Competition.

Nabil Raheem Lahmod,Jesús Rodrigo-Comino,Ahmed Abed Gatea Alshammary,Jawadayn Talib Alkooranee

doi:10.3390/plants8110503

Nabil Raheem Lahmod, Jesús Rodrigo-Comino + Show 2 more

Open Access

https://doi.org/10.3390/plants8110503

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Abstract

The effects of water stress on fenugreek crops are well documented. However, little is known about how these plants respond to water deficits under a soil-mulching system when the surface is protected. Therefore, the current research aims to demonstrate the possibility of reducing the impact of water stress and weed competition on the fenugreek crop through the use of wheat residues as a cover crop on the soil surface. A field experiment was carried out during the winter season (2016–2017) using a split-plot design arrangement with three replicates. The experiments included four levels of water deficit, which consisted of a 40% depletion treatment as a control plot, and 50%, 60%, and 70% depletion from the field capacity (DFC) for the other studied fields. The subplot division consisted of mulching the soil with wheat residues. The results demonstrated that soil-mulching systems and a water deficit are able to impact the fenugreek yield of seed and oil. Additionally, soil mulching led to a decrease in weed density and biomass, chlorophyll content, and biological yield. Although high water deficit (70% DFC) led to yield and growth reduction, the use of wheat residue as a cover crop moderated the effect of a strong water deficit on plants and showed clear reduction of weed growth. Therefore, the results suggest that soil mulching can mitigate the adverse effects of water deficit by conserving soil moisture and decreasing weeds, which can be considered an acclimation mechanism under water-deficit conditions to avoid yield loss. Moreover, the allelopathic effects of wheat residue were observed on fenugreek crops subjected to irrigation after depleting 40% soil water moisture, but these effects disappeared within 90 days of sowing. We conclude that these results can help future agricultural planning and systems in order to increase productivity, reduce irrigation costs, and conserve soil quality.

Highlights

Fenugreek (Trigonella foeunm graecum L) is a legume originally from Western Europe, Mediterranean countries, and Northwest Asia [1]
Wheat-crop-residue mulching showed a significant reduction of weed density and dry biomass, while no significant effects of water stress on it were noted (Table 1)
Interaction between mulching treatment and water stress showed a clear suppuration of weed density and biomass with all levels of depletion compared with the non-mulching treatment (Figure 1)

Summary

Introduction

Fenugreek (Trigonella foeunm graecum L) is a legume originally from Western Europe, Mediterranean countries, and Northwest Asia [1]. The traditional importance of fenugreek in these. Fenugreek contains vitamins [4], and many effective medical and pharmaceutical compounds, including trigonelline and choline [5]. This plant has been used for decades to treat diabetes and blood cholesterol [6], for its antioxidant and antibacterial properties [7], and for its potential inhibition of malignant tumors [8]. Fenugreek is one of the most important globally distributed medicinal plants, growing in such locations as Iraq, Lebanon, Egypt, France, and India. Arid and semiarid environmental conditions are suitable for the growth of this medicinal crop, many problems surrounding its productivity have been detected, such as lack of water, a high degree of soil salinity, growth of weeds, and insects and other pests

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