YIELD, SYSTEM PRODUCTIVITY AND PROFITABILITY OF RICE-MAIZE CROPPING SYSTEM ARE INFLUENCED BY TILLAGE OPTIONS IN COMBINATION WITH DIFFERENT LEVELS OF IRRIGATION AND NITROGEN

Abstract

Due to the changing climate, the sustainability of rice-maize cropping systems is fundamental to food security and livelihood of farmer’s community of South Asian countries including Bangladesh also. On the other hand, to meet the food security of the increasing population, the cropping intensity is increasing day by day. As a result, inorganic fertilizers including N and also water demand have been increased at an alarming rate. The current knowledge of N and water management in CA identifies research gaps that need to be addressed to optimize N and water management with the ultimate goal to minimize N and water losses to the environment and reduce farmers´ input costs. Keeping the above issues in mind, a rice-maize cropping system was established in different tillage systems in combination with different levels of irrigation and nitrogen to find out the best option for higher yield, system productivity and profitability of this cropping system. From the rice-maize cropping pattern result, it was found that yield of both rice and maize significantly increased with a full dose of nitrogen and irrigation in combination with traditional tillage operation. The rice equivalent yield (REY) was considered as system productivity. The REY in different treatments significantly differed due to different tillage systems in combination with nitrogen and irrigation. Among these treatments combination, T2×N3 (PTR Rice - Conv. Maize (3 Irrigations: 45, 90 and 120 DAS + Rice: 65.3 kg N ha-1) (1st, 2nd and 3rd doses) and Maize: 173.3 kg N ha-1 (1st and 2nd doses)) produced the maximum REY (16896 kg ha-1), followed by T1×N3 (PTR Rice - Conv. Maize (4 Irrigations: 15-20, 45, 90 and 120 DAS) + Rice: 65.3 kg N ha-1) (1st, 2nd and 3rd doses) and Maize: 173.3 kg N ha-1 (1st and 2nd doses)) (16124.88 kg ha-1) and T3×N3 (13802.03 kg ha-1) (DSR Rice (Irrigated) – Strip-till Maize (4 Irrigations: 15 20, 45, 90 and 120 DAS) + Rice: 65.3 kg N ha-1) (1st, 2nd and 3rd doses) and Maize: 173.3 kg N ha-1 (1st and 2nd doses)). On the other hand, minimum rice equivalent yield (1525.01 kg ha 1 ) was obtained from T4×N1 (DSR Rice (Irrigated up to reaching the reproductive stage) Strip-till Maize (3 Irrigations: 45, 90 and 120 DAS + 0 kg N ha-1)) combination. If we consider the economic benefit of the system, the maximum gross margin was recorded in the treatment combination of T2×N3 (PTR Rice - Conv. Maize (3 Irrigations: 45, 90 and 120 DAS + Rice: 65.3 kg N ha-1) (1st, 2nd and 3rd doses) and Maize: 173.3 kg N ha-1 (1st and 2nd doses)) produced the maximum REY (16896 kg ha-1) (475204 Tk ha-1), followed by T1×N3 (PTR Rice - Conv. Maize (4 Irrigations: 15-20, 45, 90 and 120 DAS) + Rice: 65.3 kg N ha-1) (1st, 2nd and 3rd doses) and Maize: 173.3 kg N ha-1 (1st and 2nd doses)) (452246 Tk ha-1), T2×N2 (PTR Rice - Conv. Maize (3 Irrigations: 45 DAS, 90 DAS and 120 DAS) + Rice: 3.2 kg ha-1) (1st, 2nd and 3rd doses) and Maize: 86.6 kg ha-1) (1st and 2nd doses) (412844 Tk ha-1), T3×N3 (DSR Rice (Irrigated) – Strip-till Maize (4 Irrigations: 15-20, 45, 90 and 120 DAS) + Rice: 65.3 kg N ha-1) (1st, 2nd and 3rd doses) and Maize: 173.3 kg N ha-1 (1st and 2nd doses)) (398110 Tk ha-1). The minimum gross margin was recorded in the treatments combination of T4×N1 (DSR Rice (Irrigated up to reaching the reproductive stage)–Strip-till Maize (3 Irrigations: 45, 90 and 120 DAS) + 0 kg N ha-1 for both crops (35869 Tk ha-1), T6×N1(DSR Rice (Rainfed)–Strip-till Maize (Rainfed) + 0 kg N ha-1 for both crops (42529 Tk ha-1), T5×N1 (DSR Rice ((Irrigated up to the maximum vegetative stage) – Strip-till Maize (2 Irrigations: 50 DAS and 100 DAS) + 0 kg N ha-1) (43644 Tk ha-1). This is a one-year observation, it will be continued next year to make a conclusion.