Effect of Water Hyacinth Compost mixtures on
growth attributes of Chilli

Introduction

Water hyacinth (Eichhornia crassipes) is a perennial, herbaceous monocotyledon member of the pickerel weed family which is native aquatic weed of tropical American countries (Gopal, 1987). Further, it can be found as native plant in Amazon Basin in Brazil (Hailu & Degaga, 2019). It is usually found as a floating and invasive aquatic plant with mature roots which can be over 2 m. The spread of this invasive species is difficult to manage by chemical, biological and physical methods and threatens not only the biodiversity of aquatic ecosystems but also economic development and human well-being (Unep, 2012). Water hyacinth leads to environmental pollution due to organic waste which spreads over water bodies rapidly and it difficult to remove without continuous daily base activities (Tubagus et al., 2011).

Despite the adverse effects of water hyacinth, it can be used as significantly benefitted by producing compost (Abdel-Sabour, 2010; Anjanabha and Kumar, 2010) with favorable C/N ratio due to high content of cellulose 20.4 – 42.23% (Tubagus et al., 2011). Further, the plant contains valuable source of macronutrients such as nitrogen, phosphorus and potassium that are essential for plant growth (Center et al., 2002; Sahu et al., 2002; Woomer et al., 2000). Using water hyacinth as compost manure is very profitable due to rapid free production and high nutrient content. Due to the high moisture content of water (>95%) in these plants the output of compost may be less. Thus, mixing with several other organic wastes may increase the quantity as well as the quality of the final product. Further, water hyacinth can be collected effortlessly to produce compost as it is a very common weed in many surface water resources in Sri Lanka.

Chilli (Capsicum annum) is one of the most important cash crops grown in Sri Lanka. It has become an essential ingredient in Sri Lankan meals. In Sri Lanka, the average extent of chilli cultivation in 2014 is about 14,294 ha and the production is about 60,269 Mt of green chilli (Krishanpillai & Silva, 2016). Chilli production is done using inorganic fertilizer nowadays which creates environmental and global issues. Therefore, the best way of producing chilli is using organic fertilizer. In that case, water hyacinth compost can be used as an organic fertilizer to produce chilli in a sustainable manner in Sri Lanka. The objective of this study was to evaluate the effectiveness of various compost mixtures by water hyacinth on the growth performances of chilli (C. annum).

Methodology

Preparation of water hyacinth compost mixtures

The experiment was carried out at the research field, Faculty of Agriculture, University of Ruhuna. Six different compost trial mixtures were prepared (Table 1), using Eichhornia crassipes, cattle manure, spent poultry litter, Eppawala rock phosphate, wood ash and dry leaf litter. Water hyacinth was harvested manually from Moragoda canal, Galle. Then they were air-dried for 2 days and chopped into small pieces of about 5 cm. Compost heaps were designed on a concrete floor allowing aerobic digestion. Moisture content was measured using field method and turn the heap weekly to aerate the mixture.

After 90 days of composting, each mixture was characterized for chemical composition before incorporating with soil (Table 2).

Greenhouse experiment

The surface Ultisols which was classified as Hapludults according to the USDA soil taxonomy (Mapa et al., 1999) were collected from 0 – 15 cm depth from an arable land of the Faculty of Agriculture, University of Ruhuna, Kamburupitiya, Sri Lanka. A subsample was air dried and sieved using 2mm sieve was used for the determination of physico-chemical characteristics of soil (Table 3).

Two kilograms of soil were filled to the polythene pots and supplemented with the basal dressing at the rate of Urea 35 kg/ha (0.047g/pot), Triple super phosphate 100 kg/ha (0.134g/pot), and Murate of potash 75 kg/ha (0.1g/pot). The pots were allowed to stand for 1 week before planting the Capsicum annum (variety MI-2) seedlings. The compost mixtures 1-6 were incorporated at a field application rate of 20 MT/ha (26.87g/pot) at the time of planting accordingly to the soil as Treatment 1-6. A control was taken with only the soil without adding any compost mixture. Each treatment was replicated trice and the experiments were laid out in a Complete Randomized Design in a greenhouse.

Four different growth parameters were used to investigate the effect of each compost trial mixture on the growth performance of C. annum by measuring plant height (cm), root length (cm), and dry weight of roots and shoots (g). The plant height was measured every other day. After terminating the experiment after 45 days of planting, the shoots and the roots of the plants were separated and oven dried at a temperature of 60 ºC to a constant weight and their dry weights measured and recorded (Somasegaran and Hoben, 1994).

Statistical analysis

Repeated measures were treated with analysis of variance (ANOVA) using MINI TAB 17 software and significant differences in growth attributes were observed between the trials at P ≤ 0.05 significant level using the Tukey pairwise comparison test.

Resuls & Discussion

The results of ANOVA indicated that the mean shoot dry weight has significantly (p ≤ 0.05) influenced by the various treatments and continued with the Tukey test. According to the results, the potted chilli in treatment 5 recorded the highest mean shoot dry weight of 1.28g on the 41st day which was the soil amended with compost mixture 5. Thus, compost mixture 5 has increased the biomass of the shoot significantly (p ≤ 0.05) from all other treatments and the control (Table 4). This may be due to the release of substantial amounts of nutrients, especially N, P and K during mineralization which were taken by the plants. The nutrients are mostly used in chlorophyll production in photosynthesis process later attributed to plant development (Kamanu et al., 2012).

According to the ANOVA, soil compost amendments had a significant effect (p≤ 0.05) on shoot length (Table 5).

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The potted chilli plant in soil mixed with compost mixture 5 (treatment 5) had the highest mean shoot length of 23.57 cm. The results of the mean separation using Tukey pairwise comparison reveals that the shoot length of the chilli plant potted in soil amended with compost mixture 5 was significantly high compared to the control which only contains soil and other treatments (Table 6).

Further, according to the graph (Figure 1) it was clearly found that the plant height has rapidly increased in treatment 5 after day 13. The compost mixture 5 which consists of N, P, K sources and desirable C:N ratio may have enhanced the plant growth. The treatment 4 and 6 have shown a high growth rate compared to treatment 2, 3 and the control. This indicated that even the compost mixture is lack of other N, P, K sources the water hyacinth has supplied a reliable amount of nutrients to the plants. Even though the compost mixture 1 had cattle manure, the final compost indicated less amount of total N% which may be reduced due to ammonium volatilization. Thus, the treatment 1 with soil incorporated by compost mixture 1 showed less increase of the plant height. Even the compost mixtures 2 and 3 had wood ash and ERP respectively, the treatments with these mixtures did not show any significant increase of the plant height. This may be due to less solubility of these amendments and low C:N ratios of the respective compost mixtures.

No significant differences were recorded on the root dry weight and the root length of chilli grown under different soil amendments (p = 0.911 and p=0.226 on the 42nd day after uprooting).

Conclusion

Water hyacinth compost mixtures incorporated with soil have significantly increased the growth of Capsium annum. Among the treatments, the soil amended with compost mixture having 50% water hyacinth, 25% dry leaf litter, 5% Eppawala rock phosphate, 5% wood ash, and 15% spent poultry litter gave the highest growth of C. annum. Farmers could use to produce compost from water hyacinth which is can be easily obtained and amend with other organic amendments to improve the C. annum production.

Therefore, water hyacinth can be used to produce compost effectively by mixing various other organic amendments to increase the quality of final compost. The problems encountered by this invasive aquatic plant in water bodies (tanks, canals etc.) could be solved by producing compost and it will eventually eradicate these problems. Furthermore, this will serve as a high quality organic fertilizer and could be effective in crop production which may promote organic cultivation as well.

Reference

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Hailu, A., & Degaga, E. (2019). Water Hyacinth (Eichhornia crassipes) Biology and Its Impacts on Ecosystem, Biodiversity, Economy and Human Well-being. Journal of Natural Sciences Research, March. https://doi.org/10.7176/jnsr/9-12-04

Krishanpillai, A., & Silva, C. S. De. (2016). Growth and Yield Performance of Newly Introduced Chilli Variety ( Capsicum annum L . var . MI 1 ) Grown under Basin Irrigation System in Jaffna District of Sri Lanka. September, 471–475.

Tubagus, K., Achmad, B., Hidayati, Y. A., Fitriani, D., & Imanudin, O. (2011). The effect of C/N ratios of a mixture of beef cattle feces and water hyacinth (Eichornia crassipes) on the quality of biogas and sludge. Lucrari Stiintifice. Seria Zootehnie - Universitatea de Stiinte Agricole Si Medicina Veterinara Ion Ionescu de La Brad, 55(16), 117–120.

Anjanabha B., Kumar P., 2010. Water hyacinth as a potential biofuel crop. Electronic Journal of Environmental, Agriculture and Food Chemistry 9(1), 112-122.

Center T.D, Hill M.P, Cordo H. Julien M.H., 2002. Water hyacinth. In Van Driesche, R (ed.). Biological control of invasive plants in Eastern U.S. USDA Forest Service Publication FHTET, pp 41-64.