Mulches enhanced growth and yield of onion

Available online at www.banglajol.info Bangladesh J. Sci. Ind. Res. 53(4), 305-310, 2018 Mulches enhanced growth and yield of onion M. G. Rachel1, M. M. A. Mondal2*, M. H. R. Pramanik1 and M. A. Awal1 1 Department of Crop Botany, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh 2 Crop Physiology Division, Bangladesh Institute of Nuclear Agriculture, Mymensingh-2202, Bangladesh Abstract Accepted: 23 May 2018 The experiment was conducted to investigate the effect of mulches on soil nutrients and microclimate status, growth and bulb yield of onion cv. Taherpuri. The experiment was comprised of six mulches viz., i) Control (no mulch), ii) Black polythene sheet, iii) White polythene sheet, iv) Rice straw, v) Water hyacinth and vi) Saw dust. Application of different mulches improved soil microclimates, increased plant growth and bulb yield over control. Among the mulches, black polythene mulch showed superiority in growth and yield contributing characters compared to other mulches, resulting the highest bulb yield. DOI: http://dx.doi.org/10.3329/bjsir.v53i4.39195 Keywords: Mulch; Soil micro-climate; Growth; Yield; Onion Received: 10 October 2017 Revised: 04 February 2018 Introduction Onion (Allium cepa L.) is by far the most important of the bulb crops and is one of the important popular vegetable crops in the world (FAO, 2016). But in Bangladesh, it is extensively used as a spice for cooking purposes. An edible portion of 100 g onion bulb contains 1.4 g protein, 11.2 g carbohydrate, 12 mg ascorbic acid, 32 mg calcium and 49 calories (Encyclopedia, 2017). Recently, research has suggested that onions in the diet play a vital role in preventing heart diseases and other ailments (Encyclopedia, 2017). Onion is known to contain substances having antibiotic properties. Among the spices grown in Bangladesh, onion ranks second in respect of production and area (MOA, 2016). With the increase of population, the demand as well as the import of onion is increasing day by day. But due to limitation of land it is not possible to raise the production of the crop horizontally. The expansion of onion cultivation will hamper the cultivation of other profitable crops particularly rice, the staple food grain of Bangladesh. The only way to solve the problem is to increase per hectare yield. The average yield per hectare is about 6.82 tons which is much lower than other developed countries where average production is over 17.5 t ha-1 (FAO, 2016). Successful onion cultivation largely depends on the optimum cultural management practices. This includes judicious *Corresponding author e-mail: application of manures and fertilizers, efficient use of available soil moisture, spacing and time of planting. Out of these, efficient use of soil moisture is very important, because rainfall is scanty during Rabi season in Bangladesh when farmers grow this valued crop. Onions are rather sensitive to drought stress (Zayton, 2007). One single most important factor that influences seed yield is soil moisture therefore, onions require frequent irrigations. The crop requires 350-500mm of water over the growing season (FAO, 2013) hence adequate moisture possibly through irrigation is important in the production of onions. Onion root system is shallow so it extracts very little water from depths beyond 60 cm. Further, growers have to depend either on natural precipitation or supplemental irrigation for growing onion. On the other hand, irrigation feasibilities are not sufficient in all the regions of the country. Sometimes pump cannot lift water in dry season due to lowering of water layer. As a result, the production of onion is hampered to a great extent. Soil moisture is lost through two main processes: i) Evaporation from soil; and ii) Transpiration through plant leaves. Conservation of soil moisture may help in preventing the loss of water through evaporation permitting maximum utilization of moisture by plants. 306 Mulches enhanced growth and yield of onion Mulching is an important technology which decreases the loss of soil water through evaporation and conserve soil moisture thus reduces the irrigation requirements, increasing root development, promoting faster crop development, reducing weed attack and inducing earlier harvest of crop (Mahajan et al., 2007). In soil management relationships, mulch has been reported to influence organic matter content, activity of microorganisms, availability of soil nutrients, control of erosion and soil compaction and regulating soil temperature (Stowell, 2000). These results suggest that mulch improves the soil environment for increasing crop growth, development and yield However, onion growth and development is greatly influenced by mulching and irrigation (Rahman et al., 2013). Rhee et al. (1990) showed that mulch increases the efficiency of applied N fertilizer by reducing leaching and evaporation loss of nutrients. Use of various mulches like black polythene, transparent polythene, rice straw, saw dust, water hyacinth reported to conserve soil moisture efficiently in garlic and onion as reported by many workers (Jamil et al., 2005; Anisuzzaman et al., 2009; Islam et al., 2010; Inusah et al., 2013). Again, Islam et al. (2002) reported that different types of mulches including rice straw and polythene significantly increased the growth and yield of onion. Under these circumstances mulching is an effective cultural practice to ensure crop production especially in dry season. It also helps in better utilization of all the nutrients in the soil (Streck et al., 1995). In view of the above facts, the present study was undertaken to evaluate the changes in temperature and soil moisture and to evaluate the growth and yield of onion under sub-tropical conditions grown with plastic and indigenous natural mulches. Materials and methods The experiment was carried out at the Field Laboratory, Department of Crop Botany, Bangladesh Agricultural University, Mymensingh, during the period from December 2014 to April 2015. The popular onion variety, Taherpuri was used as planting material in the experiment. The experiment consists of five different mulches. These are i) Black polythene sheet, ii) White polythene, iii) Rice straw, iv) Water hyacinth and v) Saw dust along with control (no mulch). The experiment was laid out in a Randomized Complete Block Design where each treatment replicated thrice. The size of the unit plot was 3 m x 2 m. Distance between plant to plant was 10 cm and row to row was 20 cm. Urea (180 kg ha-1), triple super phosphate (200 kg ha-1)), muriate of potash (170 kg ha-1)) and gypsum (120 kg ha-1) were used as source of nitrogen, phosphorus, potassium and sulphur, respectively. Well decomposed cowdung (5000 kg 53(4) 2018 ha-1) was also applied to the field before final land preparation. Thirty five day old healthy and uniform seedlings of onion were transplanted in the afternoon on 10 January 2015. The different mulches were placed on the respect (...truncated)