Abstract
T. Aman rice - Mustard - T. Boro rice pattern has been introduced to replace the existing T. Aman rice Fallow T. Boro rice pattern to increase cropping intensity and farm productivity. The transplanted Boro rice production system is becoming unsustainable due to water scarcity. Dry direct seeding (DDS) is an alternative rice cultivation system that reduces irrigation water by 50-60%. Therefore T. Aman rice - Mustard - DDS Boro rice can be a means for increasing farm productivity with minimum water. The adoption of the T. Aman rice mustard - DDS Boro rice cropping pattern requires adjustment of the planting time and selection of suitable variety of rice for both in Aman and Boro Seasons. Two experiments (Expt. 1 and 3) were conducted at the Agronomy Field Laboratory of Bangladesh Agricultural University, Mymensingh to evaluate the yield performance of rice varieties in response to the date of planting in Aman and Boro Season, respectively. Three experiments were conducted at farmers' field (Expt. 2, 4 and 5) in two drought prone areas viz. Rajshahi and Rangpur districts. Experiment 2 and 4 were conducted to select rice varieties for Aman and Boro seasons, respectively. Experiment 5 was conducted to evaluate the productivity of T. Aman rice - Mustard- DDS Boro rice cropping pattern (Pattern 1) against T. Aman rice – Mustard- T. Boro rice cropping pattern (Pattern 2) and T. Aman rice - Fallow- T. Boro rice cropping pattern (Pattern 3). Experiment 1 included seven rice varieties viz. BRRI dhan33, BRRI dhan39, BRRI dhan49, BRRI dhan56, BRRI dhan57, BRRI hybriddhan4 and Binadhan-7 and three transplanting dates viz.25 July, 4 and 14 August in 2013 while five rice varieties viz. BRRI dhan33, BRRI dhan39, BRRI dhan56, BRRI dhan57 and Binadhan-7 and four transplanting dates viz.15 July, 25 July, 4 and 14 August in 2014. Experiment 2 included seven rice varieties viz. (i) BRRI dhan33, (ii) BRRI dhan39, (iii) BRRI dhan49, (iv) BRRI dhan56, (v) BRRI dhan57, (vi) BRRI hybriddhan4 and (vii) Binadhan-7 in Aman season while Experiment 4 included six rice varieties namely BRRI dhan28, BRRI dhan29, Binadhan-14, Hera hybriddhan-2, SL8 Hybrid Supper and Parija in Boro season. Experiment 5 was done in two locations which included three cropping patterns in RCB design with six disperse replications. Split-plot design was used for experiment 1 and 3 while RCBD was used for experiment 2 and 4 with three replications. The unit plot size for experiments 1-4 were 4m x 3m while that for experiment 5 was 40 m × 33 m. Experiment 1 revealed that rice variety Binadhan-7 and BRRI dhan57 gave the best performance for transplanting on 25 July and 4 August in both the locations. Experiment 3 revealed that BRRI dhan28 and Herahybriddhan- 2 gave better yield for sowing during 8 January to 7 February. These two varieties gave the best performance at both the locations (Expt 4). The crop duration from sowing to panicle initiation (PI) ranged from 54 to 137 days and from 46 to 56 days for PI to maturity. Experiment 5 revealed that Binadhan-7 gave higher (5.11and 5.07t ha-1) yield than Sharna (4.36 and 4.28t ha-1) in both locations and years. The yield of mustard at Rajshahi and Rangpur were 1.47 and 1.49t ha1, respectively. The yield of Boro rice cv. BRRI dhan28 in Pattern 1, 2 and 3 were 5.95, 6.05 and 6.01 t ha1 in Rajshahi and 6.05, 5.61 and 5.83 t ha1 in Rangpur, respectively. The system yield of Pattern1, Pattern2 and Pattern3 were 14.23, 14.17 and 10.37 t ha-1 in Rajshahi and 14.11, 14.16 and 10.11 in Rangpur, respectively. The BCR for Pattern 1, 2 and 3 were 1.63, 1.59 and 1.43 at Rajshahi and 1.62, 1.58 and 1.39 in Rangpur, respectively. The irrigation water saving in Pattern 1 over Pattern2 was 30% in Rajshahi and 58% in Rangpur, respectively. The present study concludes that T. Aman rice - Mustard- DDS Boro rice pattern can give higher productivity and farm income using 45-58% less water than T. Aman rice - Mustard - T. Boro rice pattern.