Evaluation and Characterization of Different Potting Media for Improving Growth and Yield of Melon (Cucumis melo L. )

Abstract

The demand for soilless media in vegetables transplants production is increasing. Muskmelon (Cucumis melo L), an important member of Cucurbitaceae family, was for exploring the potting media. It regulates the human body heat, relieves from constipation, acidity and stomach problems. Peat moss is typically used in potting mix for muskmelon transplants production, however, it is a non-renewable resource and can be expensive. In tropical climate areas, there is shortage of peat or no peat and needs to be transported from remote temperate regions of availability and transportation adds to carbon emissions. The barriers of transportation, marketing and supply chain problems are major hurdles for the farmers to use peat. Moreover, as the peat is heterogeneous in nature depending upon the source, nature of materials and factors affecting the peatlands. It is required to process the peat prior to use it for specific plants growth. The higher processing costs, increasing transportation charges and interference of middle man in the business chain causes increases in price. Also there are concerns about purity of peat, its negative characteristics and timely supply to farmers in remote areas. Moreover, harvesting of peat has environmental concerns and human safety risks. The continuous harvesting of peat with the passage of time will deplete peat reservoirs. Hence, peat alternatives, such as composts could improve input use-efficiency and reduce peat imports. The potting media for optimal muskmelon plant growth is always demanded by farmers because muskmelon has high nutritional requirements. The main aim of this study was to develop complete or partial substitutes of peat from composts. It was hypothesized that composted guar (Cyammopsis tetragonoloba L.), jantar (Sesbania aculeata L.), wheat straw (Triticum aestivum L.) and rice hull (Oryza sativa L.) with suitable physicochemical properties; especially having suitable percent air-filled porosity (AFP) ranges and NPK fertilizer, would be a possible solution to substitute the peat moss partially or completely for growing muskmelon transplants. The materials for processing of guar and jantar composts were collected at flowering stage of crop growth. Wheat straw was collected from after wheat harvest and rice hull were collected from rice processing industry after thrashing the paddy. All the collected material was undergone the process of composting. For objective i) finished composts were grinded, sieved through nest of five sieves with openings (0.5, 1, 2.0, 3.3, and 5.0 mm) to get the particle sizes < 0.5, 0.5-1, 1-2, < 2 mm, 2-3.3 and 3.3-5 and > 5 mm. These particle sizes were systematically mixed in different proportions for achieving 5-10, 11-15 and 16-20 % AFPs. Three levels of AFP 10, 15 and 20 % for guar, jantar and wheat straw composts, and only 10 % AFP for rice hull compost were achieved. To address objective ii) physiochemical properties of composts of 10, 15 and 20 % AFP levels, and peat, were compared to answer the question, Could the experimental composts of 10, 15 and 20 % AFP levels either without or with NPK fertilizers produce acceptable physicochemical properties? The same compost-AFP-fertilizer combinations were used in a trail to evaluate muskmelon transplants growth as compared to control (10, 15 and 20 % AFP levels of composts without applied NPK). For objective iii) the 10 % AFPs of composts that were identified as superior among all tested AFP levels in previous study, and the peat moss control were treated with steam-heating and formalin-fumigation, plus as an unsanitized control and were used to grow muskmelon seedlings in plug trays under greenhouse conditions. These potting media were evaluated for muskmelon seed germination and seedlings out of various potting media were compared for various muskmelon seedlings growth parameters. After 30 days of seedlings growth, the seedlings were transplanted into the field for comparative efficiency of seedlings in the field and compared the transplanted seedlings for, success rate, transplant shock, growth rate and yield. For the final objective; iv) the composts adjusted at 10 % AFP were blended @ 10-50 % with peat to get potting media. They were compared with peat moss for various physical and chemical properties, germination, plant growth parameters and mineral nutrients supply. The seedlings out of various media were transplanted in the field in order to compare the seedlings for their comparative performance in the field for their success rate, transplants shock, growth rate and yield. The smaller particle sizes produced lower levels of AFP. The increasing the proportions of particle sizes of 2-3.3 mm with fractions < 2 mm increased the AFP although showed some variability. The next study showed that composts of guar, jantar, wheat straw and rice hull adjusted at 10 % AFP have nutrients in acceptable ranges to support the muskmelon seed germination and different stages of seedlings growth as compared to peat moss and could support the seedlings growth to acceptable level. These could be used as a substitute of peat moss for growing muskmelon transplants. However, NPK fertilizer supply could additionally support the seedlings growth for better seedlings. In the study of using sanitation, the performance of all composts adjusted at 10 % AFP persisted and sanitation improved the growth of seedlings out of sanitized guar, jantar, and wheat straw composts and their post transplanting performance. Seedlings grown in unsanitized rice hull compost produced statistically similar leaf areas to those grown in unsanitized peat. The fresh weight of seedlings from steam-sanitized rice hull compost would be 5 to 17 % higher than seedlings grown in unsanitized peat moss, and higher than unsanitized rice hull compost. The sanitation experiment showed that sanitation of rice hull compost is not mandatory to produce acceptable transplants growth. The steaming is economical to use and environmental friendly to use. In the final study, all composts and blends produced plants of acceptable size, with the blends containing 30-50 % rice hull compost producing the best seed germination, seedlings growth and superior performance after transplanting in the field giving better per plant yields. The combined results of this study showed that all of the experimental composts adjusted at 10 % AFPs and their mixes and up to 50 % in the peat as media could serve as acceptable replacements for muskmelon transplants production. The outstanding growth observed in plants grown in the 30-50 % rice hull compost media, pair with the natural sanitation of rice hull compost, suggested that rice hull compost as 30-50 % peat replacement can serve as an excellent media component for muskmelon transplants production. The composts and their amendments with peat could be compared for other crops and other stages of crops. They can be tested for their capacity to continuous optimal supply of nutrients for acceptable growth of seedlings and for improving the post planting performance. These media could be compared for their comparative efficiency of providing biologically favorable and sustainable environment, ecotoxic effects and their capacity to keep away from the media borne pathogens over whole crop growth period and to test whether the media could positively influence the growth after transplanting to find more efficient media.