The Impact of Irrigation Intervals and NPK/Yeast on the Vegetative Growth Characteristics and Essential Oil Content of Lemongrass

Abstract

The growth and quality of medicinal plants are greatly affected by environmental stress, with over half of the world’s agricultural land facing water shortages. This research was conducted over two seasons in 2018 and 2019 and aimed to investigate the influence of varying irrigation intervals and partial replacement of mineral fertilizers with biofertilizer (yeast) on the growth, yield, and essential oil content of lemongrass. The study also looked at the effect of the partial substitution of NPK fertilizer with yeast on lemongrass’s ability to withstand water deficit stress. The results showed that water deficit and reducing NPK levels led to a decline in growth characteristics and relative leaf greenness, which was accompanied by an increase in proline content and essential oil percentage. These findings suggest that lemongrass is sensitive to drought and requires adequate nitrogen fertilization. However, extending the irrigation intervals led to an improvement in essential oil content. To achieve high essential oil yield and maintain productivity while considering environmental factors, it is recommended to reduce mineral fertilizer to 50–75% NPK combined with biofertilizer, and space irrigation intervals every 10–15 days. Further research is needed to improve the growth of lemongrass in water-deficient conditions, particularly on newly reclaimed soils.

Lemongrass (Cymbopogon flexuosus) growth rate, essential oil yield and composition as influenced by different soil conditioners under two watering regimes

“…Shahi et al [ 46 ] revealed a PHT range of 35.7–166.7 cm and 16.0–90.0 NOT of C. flexuosus under different organic and inorganic soil amendments in India. Mahmoud et al [ 47 ] reported between 11.5 and 173.8 NOL of C. citratus due to various water intervals and NPK fertilizer application in Egypt. However, the inconsistency among these studies might depend on different harvesting times, soil conditioners and plant species.…”

“…4 ). A study by Mahmoud et al [ 47 ] associated a high number of leaves per hill of C. citratus with irrigation after every five days and 100 % NPK input.…”

“…Altering the frequency of irrigation as well as the NPK fertilization levels can influence the plant's metabolic processes, potentially leading to an elevation in metabolite levels, especially carbohydrates. These carbohydrates serve as the building blocks for oil production, a phenomenon that has also been observed in the case of lemongrass [ 47 ]. The average essential oil content from herbage harvested at 120 and at 180 days after transplanting (DAT) and recovered from the herbage using the steam distillation method is depicted in Fig.…”

Effect of Different Macronutrient Supply Levels on the Drought Tolerance of Rainfed Grass Based on Biomass Production, Water Use Efficiency and Macroelement Content

“…Numerous elements have been shown to alleviate the negative effects of drought stress. In addition to the macroelements N, P and K [5][6][7], B, Mn [8], Ca [9], Se [10], Si [11,12] and Zn [13] have also been reported to mitigate the negative effects of water deficit.…”

“…If sufficient water is available to plants, the limiting factor is usually primarily N; although, depending on the properties of the soil, P and K are also important, so their adequate supply in the soil is crucial [28,29]. Most studies have evaluated the individual effects of N, P or K on the development and biomass production of plants during drought, while studies on the combined effects of these nutrients are scant [7,30]. To the best of our knowledge, the role of these three macroelements in grass biomass production, dry matter content and WUE has not yet been investigated in a factorial field experiment with four nutrient levels and three rainfall levels, thus enabling their effects to be compared and optimal supply levels to be determined.…”