The field experiment was carried out at Shamgonj, Netrakona and Langrabazar, Muktagacha, Mymensingh district of Bangladesh during Rabi season of 2013-2014 and 2014-2015. Four intercrop combinations viz., 100% bottle gourd + red amaranth (T1), 100% bottle gourd + coriander (leaf) (T2), 100% bottle gourd+ radish (leaf) (T3) and Sole bottle gourd (T4) were used. The trial was set up in a randomized complete block design with six replications. The unit plot size was 6 m × 2.5 m. Seeds of bottle gourd (Lagenaria siceraria var. BARI Lau 3), red amaranth (Amaranthus gangeticus var. BARI Lalshak 1), coriander (Coriandrum sativum var. BARI Dhania 1) and radish (Raphanus sativus var. BARI Mula 1) were sown on same day i.e. 20 October, 2013 at Netrakona and 2 November 2014 at Mymensingh. Bottle gourd seeds were sown in pits whereas companion crops seeds were sown following broadcasting method. Distance between two pits was 2 m. Seed rate of bottle gourd, red amaranth, and radish were 5 kgha-1, 2.5 kgha-1 , and 2.5 kgha-1, respectively (BARI, 2006) and coriander seed rate for broadcasting method was 15 kg ha-1 (Mallik, 2010). Intercrops were sown in the whole plot excluding pit areas and therefore the approximate intercrop areas were 95%.
The soil of the experimental sites belongs to AEZ-9. Both the soils of the experimental site were acidic in nature and sandy loam in texture. Soil sample were collected and analyzed following standard method in the laboratory of Soil Science Division of BARI. The crop was fertilized with N80 P35K75S18Zn4B2 kg ha -1 + cowdung @ 10 t ha-1. The sources of N, P, K, S, Zn and B were urea, TSP, MoP, gypsum, zinc sulphate and boric acid, respectively. Entire cowdung, TSP, gypsum, zinc sulphate, boric acid and 2/6 of K were applied during pit making. Total amount of Urea and rest of MoP were applied in four equal installments at 15, 35, 55, and 75 days after transplanting. In 2013-2014 at Netrakona, farmers used additional compost manures and water hyacinth mulch different times at different growing stage of bottle gourd. They gave furrow irrigation as and when required. In 2014-2015 at Muktagacha, farmers gave mainly drip irrigation. All intercultural operations were done timely in both of the locations. Sex pheromone trap was used in both the year to control pest. Leaves of red amaranth, coriander and radish were harvested at 29, 35 and 38 days after sowing (DAS) in 2013-2014 and 32, 35 and 37 DAS in 2014-2015. In 2013-2014, first harvest of bottle gourd was on 21 January, 2014 and continued up to 17 April, 2014. In case of second year cultivation, first bottle gourd was harvested on 26 January, 2015 and it was continued up to 15 April, 2015. Data on yield and yield contributing characters were recorded plot wise and converted into tha-1. Collected data were analyzed statistically with the help of MSTAT-C program and mean separation was done as per Least Significant Difference (LSD) test at 5% level of significance. Economic analyses were done to assess the economic productivity of the intercropping systems.
BEY (t/ha) = Ybg + Yint × Pin / Pbg
Ybg = Yield of main crop (bottle gourd), Yint =Yield of intercrop vegetables, Pint = Market price of intercrop vegetables, Pbg = Market price of bottle gourd.