The experiment was started at farmer’s field of Rajbari district during 2017-2018.The study area was under the agro-ecological zone “Low Ganges River Floodplain (AEZ-12). Initial soil properties of the experimental field were determined and information of soil texture, bulk density, soil pH, soil organic matter, total N, exchangeable K, available P, S, Zn, and B contents at 0-15 cm soil depths are presented.
Treatments and design:
The unit experimental plot area was 7.2 m × 2.5 m and the design of the experiment was split-plot with three replications. Two tillage methods such as, T1: minimum tillage (MT)/strip tillage (ST) and T2: conventional tillage (CT) was assigned in main plot and four nutrient management system such as NM1: farmer’s practice (FP), NM2: 100% STB as per FRG, all from chemical fertilizer,NM3: 125% STB as per FRG, all from chemical fertilizer and NM4: 80% from chemical fertilizer + 20% from cow dung was allotted in sub-plot in a split-plot design with three replications.
Land Preparation by tillage methods:
The strip tillage (ST) was accomplished by power tiller operated seeder (PTOS) using rotating blades maintaining 20 cm spacing from row to row for preparing the strip and a narrow furrow opener by one pass around 18-24 hours before transplanting rice seedlings. For sowing jute seeds, ST was done by one pass with power tiller operated seeder (PTOS) using rotating blades maintaining 25 cm spacing from row to row. For onion seedling transplanting, minimum tillage (MT) was done by one pass with power tiller operated seeder (PTOS).
Conventional tillage (CT) was done by power tiller with three passes followed by two laddering for jute and onion seed sowing.In case of rice cultivation under CT method, at first, irrigation was done in the plots up to saturation condition, and then soil was puddled with three passes by the power tiller followed by two times ladderingand then 30-day old rice seedlings were transplanted.
Sowing/transplanting:
Jute seed (cv. Nabin) was sown on 11 May, 2017 maintaining 25 cm × 7-10 cm spacing, T. aman rice seedlings (cv. BRRIdhan 72) were transplanted on 10 August 2017 maintaining 20 cm × 20 cm spacing and onion seedlings (cv. King) were transplanted on23 January 2018 at 15 cm apart from rows to row and 10 cm apart from plant to plant.
Fertilizer dose and application method:
The rates of chemical fertilizers were N153P13K72S12Zn1B0.5 kg ha-1for jute,N100P13K47S9Zn2B0.5kg ha-1for T. aman and N100P46K94S23Zn4B1.5 kg ha-1for onion according to STB followed by FRG-2012. The farmer’s practice regarding fertilizers application was N180P10K45S8 kg ha-1 for jute, N120P10K40S6Zn1 kg ha-1 for T. aman and N140P30K60S16 kg ha-1 for onion.
For jute, full amount of fertilizers except urea was applied as basal whereas urea was applied in two equal splits at 25 and 50 days after sowing (DAS).At farmer’s practice treatment, ½ urea was applied with all other fertilizers during final land preparation and ½ urea was at 30 DAS.
For rice, all other fertilizers except urea, was applied during final land preparation. Urea was applied in three equal splits- the 1/3rd will be applied at 4 DAT, the second split at tillering stage (32 DAT) and the third split at 5-7 days before PI stage (47 DAT).At farmer’s practice treatment, ½ urea was applied with all other fertilizers during final land preparation and ½ urea was at 36 DAT.
In case of onion, all required fertilizers in full dose and ½ urea and MoP was applied as basal dose whereas the rest urea and MoP applied in 2 equal splits at 25 and 50 days after transplanting (DAT).At farmer’s practice treatment, ½ urea was applied with all other fertilizers during final land preparation and ½ urea was at 35 DAT. Organic manure (cow dung) was applied before land preparation.
Crop harvesting and data collection:
Jute was harvested on 31 July 2017, T. aman was harvested on 03 Dec. 2017 and onion was harvested on 08 April 2018. Two m2 area from each plot was selected for data collection. Ten plants of each plot were selected for yield attributes. 1000- seed weight of T. aman was measured plot wise. The plants were cut, then threshed, cleaned, sun-dried and weighed of grain and straw separately from 2.0 m2 area of each plot. Finally, the grain and straw were converted into t ha-1.
Statistical analysis:
All the crop data and soil properties at selected depths were statistically analyzed using a split-plot design. Treatment effects on measured variables were tested by analysis of variance (ANOVA) and comparisons among treatment means were made using the least significant difference (LSD) multiple range test calculated at 5% level of probability (P ≤ 0.05). Statistical procedures were carried out with the software program “Statistix for Windows (1998)”.