Abstract
Three experiments were conducted at the Bangladesh Agricultural Research Institute, Burirhat, Rangpur, Bangladesh during 2009-10, 2010-11 and 2011-12. Different spacing of maize in intercropping with potato was examined in the first experiment to assess the competitive ability and productivity. The treatments comprised combination of two row spacings 60 and 120 cm and three plant to plant spacing 25, 30 and 35 cm of maize in between potato rows. Two sole cropping potato and maize were also tested. Thus, the experiment consisted of eight treatments and these were investigated in randomized complete block design with three replications. Experiment 2 was undertaken to see the effect of mungbean cultivation as green brown manure after potato + maize intercropping on the performance of transplant Aman rice. The experiment was laid out in a split-plot design with three replications considering the eight treatments of previous experiment as main plot and three mungbean treatments as subplot assigned into main plot. In experiment 3, four combinations (cultural management) comprising two intercropping systems of potato+maize from experiment 1, and two mungbean biomass from experiment 2 under Potato+Maize-Mungbean-T. Aman rice cropping pattern were tested against five integrated use of organic and inorganic fertilizers. The experiment aimed at higher productivity and economic performance of the pattern and was laid out in randomized complete block design with three replications in two successive years. Fertilizer nutrients were determined based on soil test values according to Fertilizer Recommendation Guide (BARC, 2005). Growth parameters, yield and yield contributing characters, intercropping indices and economic performance were studied. The result revealed that plant height, dry matter accumulation and crop growth rate (CGR) were higher in sole crops. But among the intercropping treatments maize spacing 60 cm x 30 cm and 60 cm x 35 cm into potato field were similar. Highest potato equivalent yield (33.60 t ha-1) and economic return (Tk. 276483.05 ha-1) were also calculated in maize spacing and 60 cm x 35 cm into potato field. Intercropping potato+maize with maize spacing 60 cm x 35 cm was better in terms of potato equivalent yield (43% over sole potato, 100% over sole maize) LER (61-74%), ATER (09-21%), RY (60-73%) and gross margin (46-64% over sole potato, 84% over sole maize). Both potato and maize had a good competitive ability in association up to the closer maize spacing 60 cm x 30 cm less than which was inferior. Potato dominated maize to some extent in association especially when maize was in closer spacing but after harvest of potato, maize grown sharply and compensated yield. Intercropping potato+maize at 30-35 cm plant spacing of maize in 60 cm apart row was advantageous regarding productivity and economic benefit. In second experiment, mungbean green manure and brown manure incorporation into soil after the potato+maize intercropping enhanced the following T. Aman production but mungbean brown manure treatment increased system productivity due to value addition of mungbean grain it produced in addition. In third experiment, maize spacing 60 cm x 35 cm in Potato+Maize-Mungbean-T. Aman cropping pattern gave the highest total productivity (PEY 50.47 t ha-1), monetary return (Tk. 230000) and benefit cost ratio (2.32). Poultry litter slurry application on the above pattern exhibited the highest system productivity (PEY 51.27 t ha-1) and improved soil fertility status which was identically followed by cowdung slurry (PEY 45.26 t ha-1). A marked increase of soil organic matter and NPKS after two crop cycle was observed compared to initial soil in the organic fertilizer treated plots. Thus, maize intercropping with potato at 60 cm x 35 cm spacing sequentially followed by mungbean brown manure and T. Aman rice along with poultry litter slurry or cowdung slurry is more productive and profitable technology in respect of agro- economic productivity and soil fertility maintenance.