Extended Abstract

Introduction: Vinasse is one of the by-products of alcohol and yeast companies that use molasses as a raw material. The production of this substance is very high in the industry and the release of Vinasse in nature has environmental damage due to the large amounts of organic and inorganic materials. Today, the possibility of using this substance in low concentrations as organic fertilizer in agriculture has been proposed. Using Vinasse as an organic fertilizer is a simplest and most practical way to reduce waste.
Materials and methods: In this regard, this experiment was conducted with the aim of investigating the use of Vinasse as fertigation on the growth traits of cucumber (Cucumis sativus L.) in a completely randomized design with four replications. Cucumber seeds of hybrid cultivar (super max F1) with 99% purity were used. In order to seed germination and seedling production, seeds were cultured in cocopeat+perlite (1:1) and placed in the growth chamber. After seven days from seed sowing, experimental treatments were applied. Treatments included 1) hogland fertilizer, 2) diluted Vinasse, 3) hogland fertilizer+diluted Vinasse, 4) ½ hogland fertilizer+½ diluted Vinasse. After 7 weeks, plants were collected and growth parameters were measured. The investigated morphological traits included the number of leaves, fresh and dry weight of leaves, fresh and dry weight of roots, fresh and dry weight of stems, volume of roots, length and diameter of stems, as well as leaf surface. The plant leaf area was measured using ImageJ 1.52v software. Also, physiological traits such as relative water content (Barrs & Weatherley, 1962), electrolyte leakage (Marcum, 1998), pigment content (chlorophyll index, chlorophyll a, b, total chlorophyll and carotenoid) (Dere et al., 1998), protein (Bradford, 1976), proline (Bathes et al., 1973) and leaf nitrogen were measured by kjeldahl method (Page et al., 1982). Statistical analysis of data was done using JMP-8 software and mean comparison was done using LSD test.
Results and discussion: The use of Hoagland nutrient solution alone led to an increase in the number of leaves in the plant compared to other fertilizer treatments and recorded the highest leaf fresh weight (4.52 grams) and leaf dry weight (0.35 grams). Meanwhile, the combined use of Vinasse and Hoagland nutrient solution in full concentration was able to increase the leaf area in the plant and the highest amount of leaf area (29.21 cubic centimeters) was recorded in this treatment. Root fresh weight was affected by the combined treatment of Vinasse and Hoagland nutrient solution in half concentration and it increased significantly (1.89 grams) compared to other treatments. The application of Vinasse alone could only lead to the production of the highest dry weight of the stem (0.23 grams) compared to other experimental treatments. Although the complete Hoagland fertilizer treatment showed good results in the development of the root system, the use of the combination of Hoagland and Vinasse nutrient solution in half concentration showed a more appropriate response. Results showed that plants treated with Vinasse entered the reproductive phase faster than other experimental treatments. Vinasse contains significant amounts of potassium and organic matter (Kusumaningtyas et al., 2017). The rapid flowering of Vinasse-treated plants is probably due to the high potassium content of this organic fertilizer and the reduction in nitrogen content. The use of Vinasse as a fertigation in plants leads to the enrichment of microelements in the substrate (Kogani et al., 2018), and due to the abundance of organic matter in Vinasse, it is an important source of nutrients that is suitable for plant growth (Madejon et al., 2001). However, according to the results of this experiment, it was determined that application of Vinasse alone is not able to meet the nutritional needs of the cucumber plant. The use of hogland fertilizer + diluted Vinasse improves the growth traits of the plant such as leaf number, root fresh weight, root dry weight, leaf dry weight and leaf area. The use of diluted Vinasse reduced the chlorophyll content and increased the proline.
Conclusion: In general, Vinasse is not a complete fertilizer because of the low nitrogen content. So it needs to be combined with other nitrogen fertilizers. However, this fertilizer can be used in the reproductive growth stage when the plant needs lower amounts of nitrogen.