Wood Distillate Increases Yield and Nutritional Quality of Chickpeas, Lentils, and Beans

Introduction

Agricultural sustainability is increasingly dependent on alternatives to chemical fertilizers and pesticides. Pyroligneous acid, also known as wood distillate (WD), has emerged as a promising biostimulant with the potential to improve crop yield and quality. While its effects on horticultural and cereal crops have been extensively studied, its impact on leguminous crops remains relatively unexplored. A recent study investigated the effects of WD application on chickpea (Cicer arietinum), lentil (Lens culinaris), and bean (Phaseolus vulgaris) plants under field conditions.

Experimental Design and Application

The experiment was conducted in Tuscany, Italy, using seeds of the three leguminous species. The WD used was derived from chestnut wood (Castanea sativa), with a pH of 3.5–4.5, acetic acid content of 2–2.3%, and a polyphenol concentration of 22–25 g/L. Two separate treatment groups were established to compare application methods: one group received WD via foliar spray, while the other received it through fertigation.

  • Foliar spray: 0.2% (v/v) WD applied weekly.
  • Fertigation: 0.3% (v/v) WD applied biweekly.

Control plants received only water. Each legume species was cultivated in separate plots, and yield parameters such as plant biomass, pod and seed weight, protein content, and mineral composition were assessed after four months of growth.

Key Findings

Yield Enhancement

Lentils
  • Fertigation: Plant biomass increased by 63%, pod count per plant rose from 23.5 (control) to 37.4, seed count increased from 29.6 to 50.6, and total seed weight more than doubled from 0.9 g to 2.11 g per plant.
  • Foliar Spray: Pod count rose to 30.2, seed count reached 38.7 per plant, and total seed weight increased from 0.9 g to 1.65 g per plant.
Beans
  • Both fertigation and foliar spray resulted in a 44% increase in pod number. However, fertigation resulted in a 27% increase in total bean weight per plant, whereas foliar spray produced a more modest 15% increase compared to the control.
Chickpeas
  • No significant changes were recorded in any yield parameters, suggesting that WD may be less effective for this species under the tested conditions.

Protein and Mineral Composition

  • Lentil seeds from WD-treated plants showed a 13% increase in total protein content.
  • Iron (Fe) increased by 20%–28%.
  • Calcium (Ca) increased significantly in chickpeas (+66%).
  • Magnesium (Mg) increased in chickpeas and beans.
  • Potassium (K) increased only in lentils.
  • Interestingly, zinc (Zn) levels declined by 8% in beans.

Implications

The results highlight the potential of WD as a sustainable biostimulant that can enhance both yield and nutritional quality in legumes, particularly lentils. Given the increasing demand for plant-based proteins and mineral-rich foods, WD could play a significant role in improving global food security. However, species-specific responses suggest that optimal WD concentrations and application methods should be tailored for different crops. Further studies should explore long-term effects, potential interactions with soil microbiota, and the underlying mechanisms of WD's biostimulatory action.

Article based on: Carril et al., 2023