Salt stress and BD preps

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Mitigating the adverse effects of salinity stress on lavender using biodynamic preparations and bio-fertilizers

Seyed Ahmad Khatami, Pourang Kasraie, Meysam Oveysi, Hamid Reza Tohidi Moghadam, Farshad Ghooshchi,

Abstract

Sustainable agriculture involves different environmental methods of farming that cause the production of crops by conserving natural resources and preserving biodiversity. The present study aimed to investigate the effects of biological fertilizers and biodynamics on some characters of lavender under salinity stress. The experiment was performed as a factorial in a completely randomized design with three factors including four levels of biological fertilizers (i.e., control, Azotobacter, Azospirillum, and a combination of Azotobacter and Azospirillum), three levels of biodynamic (BD; i.e., control, BD compost, and BD preparations), and three concentrations of salinity stress (i.e., 0, 50, and 100 mM). The results showed that plant height (PH), stem length (SL), root length (RL), fresh weight (FW), dry weight (DW), relative water content (RWC), chlorophyll a (Chla), chlorophyll b (Chlb), total chlorophyll (TChl), and essential oil yield (EOY) were significantly decreased by salinity stress (P < 0.01). According to the results, the interaction effect of the BD preparations with Azotobacter bacteria was the most effective treatment for significant enhancement of FW, DW, RWC, and EOY under salinity stress. Also, the interaction effect of BD preparations with Azospirillum was the best treatment to enhance the PH, SL, and RL under salinity stress. Based on the results, it is suggested that the interaction of the BD preparations and bio-fertilizers could be applied as a salt alleviator to enhance the EOY.

Introduction
Medicinal plants such as lavender play an important role in human health via the pharmaceutical and food industries due to their different chemical constituents (Li et al., 2020). The plants are also used for landscape and aromatic garden design. Iran is rich in different medicinal plants due to various ecological conditions (Farajpour et al., 2017).

Lavender (Lavandula officinalis L.) is an important multidisciplinary aromatic plant, it is indigenous to Southern Europe and the Mediterranean area (Ciocarlan et al., 2021). The flowers of lavender are popular in folk medicine such as carminative, antispasmodic, antidepressant, antirheumatic, antiseptic, and tonic properties (Srivastava et al., 2019).

Climatic changes such as global warming cause to water shortage, which results a reduction in yield and crop quality (Ramezanpour et al., 2022). Sustainable agriculture involves different environmental methods of farming that cause the production of crops by conserving natural resources and preserving biodiversity (Jhariya et al., 2021).

Salinity stress is one of the main challenges to achieving agricultural sustainability in Iran, which results in decreasing the yield and quality of crops as well as the reduction in cultivated land area (Akbari et al., 2020, Habibi et al., 2021, Hazbavi and Silabi, 2021).

In fact, salinity causes disorders in respiration, photosynthesis, mineral uptake, and oxidative stress in the plants, resulting a reduction in both yield and quality of the plants (Sheikh-Mohamadi et al., 2017). In addition, salinity has various effects on soils such as increasing the osmotic pressure of it resulted in decreasing of water potential, the toxicity of specific ion, and imbalance of nutrient ion due to increasing of Na+ and, or Cl- leads to reduced uptake of some ions such as K+, Ca2+, NO3 or P (Omer, 2021).

Bio-fertilization is a new method to become for the development of salt-affected lands, it is a substance that contains living microorganisms. Rhizobacteria, endophytes, and arbuscular mycorrhizal fungi are the main microorganisms used as Bio-fertilizers. The microorganisms, especially the beneficial bacteria, can mitigate the adverse effects of salt stress by different mechanisms, which can stimulate the plant growth under salt stress by stimulating the plant immune system, improving the micronutrient uptake and phytohormone (Kerbab et al., 2021).

One of the essential factors in achieving high yield and optimal quality of medicinal plants is evaluating different plant nutrition systems. Excessive use of chemical fertilizers reduces crop yields due to reduction in acidity and biological activities of soil (Ramezanpour and Farajpour, 2022). Beluhova-Uzunova and Atanasov (2017) showed that biodynamic systems generally have better soil and product quality than conventional farms.

Biodynamic (BD) farming as an organic system, could achieve agricultural sustainability. Biodynamic composts are essential components of the BD system that contribute to the cycle of manure and other organic residues, nitrogen fixation, humus production, and improved soil health. They are prepared with the help of 502–507 biodynamic preparations, which have a high value. Therefore, composts and biodynamic preparations can be considered as the foundation of the BD system, as their dynamic and biological quality are complementary. The BD preparations have different beneficial effects on plants, such as the formation of deep roots, increasing water holding capacity in the soil during periods of drought, increasing healthy plant production and reducing pest and weed infestation. Lowenfield et al. (2019) studied a different aspects of compost, including production, microbial composition, and physicochemical components in different systems such as BD preparation 500, vermicomposting, biodung, and tank composting on tomatoes. The authors reported that the biofertilizers were more beneficial for the fruit yield of the plant than the chemical fertilizers. A combination of various organic farming systems can produce high-quality agricultural foods (Le Campion et al., 2020). Therefore, in the present study, the effects of biological fertilizers and biodynamic preparations on some characters of lavender (Lavandula Officinalis L.) under salinity stress, were investigated.


Experimental conditions
The experimental part of this research was carried out in a greenhouse, Faculty of Agriculture and Natural Resources, Varamin Branch, Varamin, Iran. The pots were used for planting, and the experiment was performed as a factorial in a completely randomized design with three replications. The experiment was consisted of three factors as treatment applications. The first factor comprised biodynamic compost at three levels, i.e., the control group, biodynamic compost without preparations, and

Results and discussion
According to the results of ANOVA, there were significant differences (P < 0.01) among the three levels of salt stress and the BD and four levels of the BF for all measured characters (Table 2). However, the main effect of the BF was not statistically significant for total chlorophyll and chlorophyll a. According to the results, none of the interaction effects, including double and triple interactions, were not statistically significant for the chlorophyll characters. Also, the interaction

Conclusions
In the present study, an environmentally friendly approach for alleviating the adverse effects of salinity on different characters of lavender by the BD and the BF was investigated. According to the results, the interaction effects of the BD preparations with Azotobacter and, or Azospirillum, were the best treatments to mitigate the adverse effect of salinity stress. These alleviation effects of the two factors could be due to 1) the nutrition value of the BD preparations and many bacterial

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Follow up paper ...

Impacts of plant growth-promoting bacteria, compost and biodynamic compost preparations for alleviating the harmful effects of salinity on essential oil characteristics of lavender

Khatami SA, Kasraie P, Oveysi M, Moghadam HRT, Ghooshchi F, (2023)


Abstract
Background
Biodynamic agriculture and the use of plant growth-promoting bacteria (PGPBs) have been demonstrated to offer various benefits for achieving agricultural sustainability. The aim of this study was to evaluate the effects of PGPBs Azotobacter and Azospirillum, compost, and compost with biodynamic preparations (BD) on the essential oil (EO) characteristics of lavender under salinity stress.

Research methods
The experiment was carried out in a greenhouse for 2 years and involved three factors: four PGPBs, three types of compost, and three levels of salinity stress.

Results
The results indicated that the essential oil (EO) characteristics increased with 50 mM NaCl but decreased with 100 mM NaCl. Salt stress reduced the cell membrane stability (CMS) and auxin content, while increasing proline contents. However, the application of PGPBs, compost, and compost with biodynamic preparations had an opposite effect on CMS, auxin, and proline parameters compared to salt stress. Based on the results, the treatment that combined compost + BD with Azotobacter was found to be the most effective in enhancing the EO characteristics under both mild and severe salinity stress conditions.

Conclusions
The results of this study suggest that compost, biodynamic compost preparations, and PGPBs could be useful in enhancing the EO in medicinal plants and alleviating the adverse effects of salt stress on plants.