Dry Matter Accumulation and Growth Response of Zero Tilled Direct Seeded Fine Rice to Different Weed Competition Durations and Sowing Times

作者：Matloob Amar^*; Khaliq Abdul; Tanveer Asif; Wahid Abdul

来源：International Journal of Agriculture and Biology, 2015, 17(1): 41-50.

• Crop growth rate
• Cultural practices
• Rice direct seeding
• Dry matter
• Weed competition duration
• Weed biomass

Weeds are stringent biological constraint to direct seeded rice (DSR) growth and yield. Cultural practices alter patterns of crop growth and can modify dynamics of weed-crop competition, and hence need to be investigated as a tool for sustainable weed management in DSR. Field studies were carried out during summer 2010 and 2011 to explore the growth response of DSR to different tillage systems, sowing times and durations of weed competition. A commonly grown rice cultivar, Super Basmati was sown on 15th June and 7th July under zero (ZT) and conventional tillage (CT) and was subjected to different durations of weed competition (10, 20, 30, 40, 50 DAS and season long competition). Weed free plots were maintained under each tillage system and sowing time for comparison. Crop growth rate and dry matter accumulation by DSR varied significantly under tillage systems, sowing times, duration of weed competitions, and their interactive effect. During 2010, season long weed free plots sown under CT on 15th June recorded significantly higher CGR that was statistically similar with ZT under same sowing time and 7th July under CT. Under weed competition beyond 20 DAS, June planted crop had a distinct competitive advantage by maintaining higher CGR than July sowing in 2011. Increasing duration of weed duration diminished CGR and under season long weed competition, CGR did not vary significantly between sowing times. Crop growth rate showed temporal differences among treatments and maximum CGR under both tillage systems was observed between 80-95 DAS for crop sown in June whereas DSR crop sown in July achieved maximum crop growth 65-80 DAS-a period coinciding with anthesis. Season long weed free plots sown on 15th June had 9 and 13% more dry matter under ZT and CT, respectively than July sowing. ZT plots subjected to season long weed competition had 81 and 69% less dry matter when sown on 15th June and 7th July, respectively. Corresponding reduction in dry matter under CT was 66 and 76%. A DSR crop should preferably be sown under CT in June and weeds must be controlled before 20 DAS to avoid growth reduction.

• 出版日期2015