The Effects of Irrigation Levels and Soil Fertilizers on Yield Components and Quantitative and Quality Yield of Balangu (Lallemantia royleana Benth.) under Torbat-e Jam Climatic Conditions

Balangu (Lallemantia royleana Benth.) is one of the medicinal plants of Lamiaceae family that contains essential oils as well as mucilage. The most important feature of this plant is the mucilage of the seeds which widely used in industrial sectors. On the other hand the seeds are a good source of fiber, oil, and protein and have medicinal and nutritional properties. Medicinal plants are rich in secondary metabolites and are potentially useful to produce natural materials. The biosynthesis of the secondary metabolites, although controlled genetically is affected strongly by environmental and agronomic factors. This plant can be grown under a wide range of agro-climatic conditions, but it is mostly confined to the arid areas due its low water requirement and high water use efficiency. It has been used as medicine since ancient times, but it has been cultivated as a medicinal plant only in recent years. The application of soil organic fertilizers is important for sustainable agriculture, healthy agricultural production of medicinal plants especially in arid and semi-arid regions and resorting soil quality. In this study the effects of irrigation regimes and soil fertilizers on qualitative and quality characteristics of balangu as a medicinal plant were evaluated.

The experiment was done as split plot based on a randomized complete block design with three replications at the Agricultural Research Station, University of Torbat-E-jam, Khorasan-e Razavi, Iran during 2019 growing season. Main factor was four irrigation levels (including 35 (as control), 53, 71, and 89 mm evaporation) and sub factor was four fertilizer types (such as cow manure, municipal solid waste compost and mushroom compost and control). Organic fertilizers were applied equal to 10 t.ha-1.The fertilizers were applied before sowing time. Studied traits were quantitative traits (such as plant height, root length, biological yield, seed numbers per plant, 1000-seed weight, seed yield and harvest index), and quality criteria (including mucilage percentage, swelling factor and mucilage yield). General linear model ANOVA was used for soil fertilizers and irrigation regimes on quality and quantity criteria of balangu. Duncan’s test at p≤0.05 tested the significance of differences among means.

The results revealed that the irrigation regimes and different fertilizers had significant effects on the quantitative and qualitative characteristics of balangu as a medicinal plant. Compared with irrigation regimes, the highest and lowest values for seed yield were observed in 35 and 89 mm evaporation, respectively. The maximum and minimum values of seed yield were recorded for cow manure and control, respectively. Higher seed yield in cow manure+35 mm evaporation is due to number of seeds and 1000-seed weight. Also, the maximum mucilage content as an important factor was related to cow manure+35mm evaporation and the minimum was for 89mm evaporation+ control.

Results of this study indicated that cow manure as organic fertilizer could improve plant height, biological yield, seed yield, 1000-seed weight, seed No. per plant, harvest index, and quality criteria such as mucilage content, swelling factor and mucilage yield of balangu. The importance of cow manure is being realized and its long term adverse effects on soil chemical properties. Besides supplying micronutrients and micronutrients, organic fertilizers also improve the physical and chemical properties of soil. They are also useful in improving the efficiency of fertilizer recovery thereby resulting in higher plant yield. So, to prevent the environmental impact from extensive application of chemical fertilizers, the biological fertilizers could be recommended to insure the society health and a sustainable agriculture. Therefore, 35 mm evaporation and cow manure application is recommended for balangu cultivation under Torbat-e-Jam climatic conditions. Future studies should be conducted to evaluate the influences of different organic fertilizers and irrigation regimes for various climatic conditions.