Investigating the influence of eco-friendly approaches on saline soil traits and growth of common bean plants (Phaseolus vulgaris L.)

Abstract

Soil salinization significantly impacts agricultural lands and crop productivity in the study area. Moreover, freshwater scarcity poses a significant obstacle to soil reclamation and agricultural production. Therefore, eco-friendly strategies must be adopted for agro-ecosystem sustainability under these conditions. A study conducted in 2022 and 2023 examined the interaction effects of various soil mulching materials (unmulched, white plastic, rice straw, and sawdust) and chitosan foliar spray application (control, 250 mg L^-1 of normal chitosan, 125 mg L^-1 of nano chitosan, and 62.5 mg L^-1 of nano chitosan) on the biochemical soil characteristics and productivity of common beans in clay-saline soil. Higher organic matter, available nutrient content, and total bacteria count in soils were found under organic mulching treatments (rice straw and sawdust). In contrast, the white plastic mulching treatment resulted in the lowest values of soil electrical conductivity (EC) and the highest soil water content. Conversely, chitosan foliar spray treatments had the least impact on the chemical properties of the soil. Plants sprayed with 62.5 mg L^-1 of nano chitosan exhibited higher chlorophyll content, plant height, fresh weight of shoots and roots, seed yield, and nutrient content compared to other chitosan foliar spray applications. All treatments studied led to a significant reduction in fungal communities and Na% in plants. The combined effect of organic mulch materials and foliar spray application of 62.5 mg L^-1 nano chitosan appeared to enhance biochemical saline soil properties and common bean productivity.

Keywords: Chitosan; Common bean (Phaseolus vulgaris L.); Microbial community; Mulch materials; Nano chitosan; Saline soil characteristics.

Figure 1. Daily of temperature and rainfall at the cultivation period of common bean crop (2022 and 2023).

Figure 2. Characterization of nano chitosan (A) particle size distribution graph, (B) scanning electron microscope (SEM), and (C) the functional groups.

Figure 3. Soil EC (dS m⁻¹) for the interaction affect of mulching treatment with chitosan foliar spray applications in 2022 and 2023.

UNM, un-mulched; WPM, white plastic mulching; RSM, rice straw mulching; SDM, sawdust mulching, Ch₀, Control (distilled water); Ch₁, 250 mg L⁻¹ of normal chitosan; Ch₂, 125 mg L⁻¹ of nano chitosan; Ch₃, 62.5 mg L⁻¹ of nano chitosan. ‘*’ is significant, and ‘ns’ is insignificant at p < 0.05. Mean value ± standard error.

Figure 4. Bacteria community (log CFU g⁻¹) for the interaction effect of mulching treatment with chitosan foliar spray applications in 2022 and 2023.

UNM, un-mulched; WPM, white plastic mulching; RSM, rice straw mulching; SDM, sawdust mulching; Ch₀, Control (distilled water); Ch₁, 250 mg L⁻¹ of normal chitosan; Ch₂, 125 mg L⁻¹ of nano chitosan; Ch₃, 62.5 mg L⁻¹ of nano chitosan. ‘*’ is significant, and ‘ns’ is insignificant at p < 0.05. Mean value ± standard error.

Figure 5. N, P, N, and Na concentration in common bean plants for the co-application affect of soil mulch treatment with chitosan foliar spray applications in 2022 and 2023.

(A) N concentration in common bean plants; (B) P concentration in common bean plants; (C) K concentration in common bean plants; (D) Na concentration in common bean plants. UNM: un-mulched; WPM, white plastic mulching; RSM, rice straw mulching; SDM, sawdust mulching; Ch₀, Control (distilled water); Ch₁, 250 mg L⁻¹ of normal chitosan; Ch₂, 125 mg L⁻¹ of nano chitosan; Ch₃, 62.5 mg L⁻¹ of nano chitosan. ‘*’ is significant, and ‘ns’ is insignificant at p < 0.05. Mean value ± standard error.

Figure 6. PCA biplot had response to co-application affect of soil mulch treatment with chitosan foliar spray applications on the parameters studied of soil and common bean plants.

* SWC, soil water content; EC, soil salinity; S.O.C, soil organic carbon content; Ava. N, P, and K, available N, P and K content; TBC, total bacteria count and TFC, total fungi count. UNM, un-mulched; WPM, white plastic mulching; RSM, rice straw mulching; SDM, sawdust mulching; Ch₀, Control (distilled water); Ch₁, 250 mg L⁻¹ of normal chitosan, Ch₂, 125 mg L⁻¹ of nano chitosan, Ch₃, 62.5 mg L⁻¹ of nano chitosan.