IOSR Journal of Agriculture and Veterinary Science (IOSR-JAVS) e-ISSN: 2319-2380, p-ISSN: 2319-2372. Volume 8, Issue 5 Ver. I (May. 2015), PP 45-50 www.iosrjournals.org DOI: 10.9790/2380-08514550 www.iosrjournals.org 45 | Page Mixed Cropping Onion with Different Plant Population of Sweet Gourd A.H.M.M.R. Talukder 1 , J. Rahman 2 , L. Nahar 3 , M. M. Rahman 2 & N.Kaisar 4 1 Scientific Officer, Bangladesh Agricultural Research Institute, Gazipur-1701, Bangladesh. 2 Scientific Officer, Regional Agricultural Research Station, Jamalpur-2000, Bangladesh. 3 Scientific Officer, Bangladesh Rice Research Institute,Gazipur-1701,Bangladesh. 4 MS students department of soil science Bangladesh Agricultural University, Mymensingh- 2202,Bangladesh. Abstract: An experiment was conducted at the Regional Agricultural Research Station, Jamalpur during rabi 2012-2013and 2013-2014 to find out the optimum plant population of sweet gourd in Sweet gourd onion mixed cropping systems(s). The treatments were : T 1 =Sole onion (BARI Peaj-1) (Broadcast), T 2 =Sole sweet gourd (2m × 2m), T 3 = Onion (BARI Peaj-1) (Broadcast) + sweet gourd ( 1 plant plot -1 ) (8m × 8m) (625 number plant population ha -1 ), T 4 = Onion (BARI Peaj-1) (Broadcast) + sweet gourd ( 2 plant plot -1 ) (4m × 4m) (1250 number plant population ha -1 ), T 5 = Onion (BARI Peaj-1) (Broadcast) + sweet gourd ( 3plant plot -1 ) (2.67m × 2.67m) (1875 number plant population ha -1 ), T 6 = Onion (BARI Peaj-1) (Broadcast) + sweet gourd (4 plant plot -1 ) (2m × 2m) (2500 number plant population ha -1 ). The result obtained from the experiment revealed that bulb yield of onion reduced significantly in all combination of onion-sweet gourd mixed cropping system and the bulb yield of onion was drastically reduced when the maximum number of sweet gourd (4 plant plot -1 ) (2m ×2m)(2500 number of plant population ha -1 ) was prevailed with onion. During the both years among the mixed cropping systems100% onion broadcast + 3 plant plot -1 (2.67m × 2.67m) (1875 number plant population ha -1 ) gave the maximum gross margin (Tk. 2,44,596 ha -1 and Tk. 2,92,796 ha -1 ) followed by 100% onion broadcast + 4 plant plot -1 ) (2m × 2m) (2500 number plant population ha -1 ) ( Tk. 2,06,682 ha -1 and Tk. 2,43,482 ha -1 ) respectively. During the both years the maximum onion equivalent yield (16.79 and 19.5) was obtained from the treatment combination of 100% onion broadcast + 3 plant plot -1 (2.67m × 2.67m) (1875 number plant population ha -1 ) followed by 100% onion broadcast + 4 plant plot -1 (2m × 2m) (2500 number plant population ha -1 ) (15.81 and 17.7) respectively. Keywords- mixed cropping, onion, optimum plant population, sweet gourd I. Introduction Intercropping can be explained as a system where two or more crop species are grown in the same field at the same time during a growing season [1]. It is a simple and inexpensive strategy and has been recognized as a potentially befitted technology to increase crop production due to its substantial yield advantage than sole cropping [2]. The purpose of intercropping is to generate beneficial biological interactions between the crops. Intercropping can increase yields, more efficiently use available resources, reduce weed, insect and disease pressures and provide greater biological and economic stability [3]. Intercropping has been an essential production method in tropical regions for hundreds of years [3], and to a lesser extent in temperate regions [4]. Intercropping was once common in temperate regions, but has been largely replaced in the last 150 years by monocultures [5]. Intercropping is the most common practice to the farmers of Bangladesh, because it increases the total productivity per unit area through the maximum utilization of land, labour and growth resources [6]. The most common goal of intercropping is to produce a greater yield on a given piece of land by making use of resources that would other wise not be utilized by a single crop. Better intercrop production could be achieved with the choice of appropriate crops [7], population density and planting geometry of component species/crops [8]. Greater productivity in intercropping system is commonly achieved by minimizing inter-specific competition and maximizing complementary use of growth resources [9]. Among the intercropping practices sweet gourd onion intercropping is a common practice to the farmers of char areas. Sweet gourd is creeper type species that covers the maximum areas of land and good source of vitamin and also used as vegetable. On the other hand, onion is a herb type species and it has a preservative and medicine uses [10]. It has been compared cropping systems over three successive seasons (monsoon, winter and summer) in India [11]. In another study, intercropping of pearl millet with cowpea or groundnut showed their significant effects on soil and crop productivity after either sole or intercrop system [12]. To optimize the planting density, the seedling rate of each crop on the mixture has been suggested to adjust below the full rate to reduce competition from overcrowding. Thus, intercrops yield was found to be increased in the mixture stand compared to sole stand [13]. plant architecture allows one intercrop to capture sunlight that would not otherwise be available to others. This phonological character is particularly important to growth and yield of cereals and legume crops [14], [15].