Impact of nutrients and bio-stimulants on growth and yield of Aloe vera plants

Abstract

Although Aloe vera L. is an indigenous plant of Sudan with numerous applications in health, cosmetics and food industries in global markets, agricultural research to exploit its potential is almost lacking. This study aimed to investigate the impact of the chemical fertilizers nitrogen, phosphorus, sulfur and compound fertilizer NPK applications, besides foliar application of 6-benzyl adenine and different types and forms of bio-stimulants mainly Argel (Solenostemma argel Del. Hayne) and Hazza (Haplophyllum tuberculatum L.) at various rates on the growth attributes and quality of Aloe vera plants under nursery conditions. Experiments were conducted in Sudan University of Science and Technology, College of Agricultural Studies, Shambat, Khartoum North, Sudan. The study was composed of seven independent trials as illustrated sequentially: Five levels of; urea 0.0, 1.5, 3, 4.5 and 6 g/plant, triple super phosphate 46% P2O5) 0.0, 2.5, 5, 7.5 and 10 g/plant, commercial N15P10K15 0.0, 2.5, 5, 7.5 and 10 g/plant) and elemental sulfur 0.0, 0.5, 1.0, 2.0 and 4.0 g/plant were tested as soil applications to the potting media (Gureira) in 25X30 cm plastic bags. In addition 6-Benzyl adenine (BA) at concentrations of 0.0, 75,150, 300 and 600 ppm were tested. Argel foliar and soil treatments were also evaluated. The foliar treatments were cold, hot and boiled water extracts of 15 g dry leaves of Argel per litre while the soil dressing test was for 0.0, 2.5, 5, 7.5 and 10 g/plant dry Argel leaves per plant. The Haza foliar and soil treatments; the foliar treatments were for cold, hot and boiled water extracts of 15 g dry shoots of Haza per litre and the soil application test were for 0.0, 2.5, 5, 7.5 and 10 g/ plant dry Haza shoot treatments. The treatments were arranged in a completely randomized design where each treatment was replicated eight times. Data were collected after 12 months from treatments, analyzed and the results obtained indicated that: The 1.5 g urea treatment enhanced growth, leaf gel and chlorophyll contents, whereas the higher levels of urea were suppressive. The encouraging results obtained from urea treatments in this study elucidated an economical potential for possible large scale production of the plant under Sudan conditions. A general increase was obtained in growth parameters in phosphorus treated plants compared to the control. Except for the peel weight, the highest values of all growth parameters were obtained from the 10 g/plant treatment. The improvements in growth and gel content are indicators of the benefit of Phosphorus applications. The results showed no significant differences in parameters of number of leaf and root length, while limited enhancement was observed in other parameters in NPK-treated plants compared to the control. Except for the number of leaves and the root length, the highest values of growth parameters were obtained from the 2.5 g NPK treatment. The improvements in growth and gel content at the low rates of the fertilizer are indicators of the benefit of low cost of NPK required for unit number of plants grown. The result revealed a general increase in growth parameters in sulfur treated plants compared to the control. Except for the peel weight and chlorophyll content, the highest values of measured parameters were obtained from the 4.0 g/ plant sulfur treatment. Under the conditions of the study, these results elucidated the benefit of sulfur fertilizer as a tool for enhanced production of Aloe vera. The data showed a general increase in growth and yield parameters in BA-treated plants compared to the control. Except for the root fresh weight, the highest values of all growth parameters were obtained from the 600 ppm BA treatment. The enhanced growth attributes and gel yield obtained from BA applications in this study, might put this growth regulator among essential factors for large scale production of the plant under Sudan conditions. Also, there was a general increase in growth parameters in the Argel treated plants compared to the control. Except for the root fresh and dry weights, the highest values of all growth parameters were obtained from the boiled Argel water extract and the 7.5 and 10 g/plant soil dressing treatments. The significant improvements in growth and gel content are indicatives to the possibility of commercial organic production of this plant under Sudan conditions. Relatively, there was a general increase in growth parameters in Haza treated plants compared to the control. Except for the root fresh and dry weights, the highest values of all growth parameters were obtained from the boiled Haza water extract and the 7.5 and 10 g soil dressing treatments. The improvements in growth and gel content are indicators of the agronomic benefit of Haza applications; a step towards organic farming.