| Abstrakt: |
Sorghum and sunflower have been reported to contain several allelochemicals. Utilization of these allelochemicals is considered low-cost and natural sources for weed suppression. Field trials were undertaken at Cotton Section, Agriculture Research Institute, Tandojam Pakistan during summer 2010 and repeated during summer 2011 for validating the previous results. The experiments were laid out in three replicated randomized complete block design. The seed of cotton variety "Sindh-1" was sown through drilling in the 1st week of May each year. The treatments consisted of: weedy check (no weeding), interculturing twice (30+60 DAS), Dual Gold 960-EC (S-metolachlor) @ 2.50 L ha-1, sorghum water extracts @ 15 L ha-1 (twice) and 25 L ha-1 (once and twice) and sunflower water extracts @ 15 L ha-1 (twice) and 25 L ha-1 (once and twice), sorghum water extract @ 15 L ha-1+1.25 L ha-1 Dual Gold and sunflower water extract @ 15 L ha-1+1.25 L ha-1 Dual Gold. In interculturing the land space in between two rows of crop plants was pulverized with the help of local tool spade. The statistical analysis of data showed that interculturing, Dual Gold, and sorghum and sunflower water extracts caused significant reduction of weeds and increased seedcotton yield as compared to weedy check. The combined application of sorghum @ 15 L ha-1+ Dual Gold @ 1.25 L ha-1 resulted in weeds mortality upto 66.6%, produced seedcotton yield of 3961.4 kg ha-1 and gave net benefit of Rs. 2,20,029. Sunflower applied @ 15 L ha-1 in integration with Dual Gold @ 1.25 L ha-1 showed weeds mortality of 65.5 %, resulted in seedcotton yield of 3949.7 kg ha-1 and net monetary benefit of Rs. 2,19,821. Sole application of Dual Gold @ 2.5 L ha-1 reduced weeds by 55.9%, produced seedcotton yield of 3212.7 kg ha-1 and net resulted in net benefit of Rs. 1,77,414. It is noteworthy that interculturing twice (30+60 DAS) caused maximum (67.7%) suppression of weeds, produced maximum plant height (117.0 cm) and seedcotton yield (3977.8 kg ha-1) but conferred less (Rs. 2,14,151) net monetary benefits as compared to obtained in sorghum + Dual Gold and sunflower + Dual Gold. Overall results suggested that maximum net income was recorded when sorghum water extract was applied in integration with Dual Gold. The combined application of sunflower with Dual Gold ranked second in monetary benefits. Interculturing twice was found less economical due to higher costs of labour. Hence, it can be inferred from the above results that Dual Gold dose can be reduced up to 50% in combination with sorghum or sunflower water extracts for effective and environment friendly weed management and enhancing cotton yield. [ABSTRACT FROM AUTHOR] |
