| Summary: | A two-year research was conducted to investigate the effect of different
tillage methods on some soil physical characteristics and crop yield in
rapeseed cultivation after rice harvesting. Five tillage treatments
including: (i) using rotavator, once to depth of 10-15 cm (T1), (ii) using
rotavator, twice to depth of 10-15 cm (T2), (iii) using moldboard plow to
depth of 25 cm + rotavator, once to depth of 10-15 cm (T3), (iv) no-till
planting through removing rice stubbles from plots (T4), and (v) no-till
planting without removing rice stubbles from plots (T5), were evaluated under
randomized complete block design (RCBD) in three replications. The biannual
results revealed that the effect of tillage methods was significant (p<0.01)
on soil bulk density, surface residues after tillage, dry mass of weeds, seed
germination, and grain yield. T2 and T3 made considerable reduction in soil
bulk density compared to other treatments for the 15- to 30-cm tillage
depths. In T1, T2, T3, and T4, surface residues after tillage decreased in
comparison with T5 by up to 35.37, 50.71, 69.92, and 75.75%, respectively.
Having 71.48 g m-2, T5 had the maximum dry mass of weeds while T3 had the
minimum one with 37.50 g m-2. Means comparison represented that in T2 and T3,
seed germination reached the shortest length of 6.4 days in average. The
highest and lowest grain yields were acquired in T3 (1,571 kg ha-1) and T5
(1,339 kg ha-1), respectively. Statistically, there was no significant
difference between T1 (1,432 kg ha-1) and T2 (1,537 kg ha-1) compared with T3
in terms of grain yield.
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