Influence of Sowing Time and Weed Management Practices on the Performance and Weed Dynamics of Direct Drum Seeded Rice

Abstract

Direct drum seeding has emerged as a viable and alternate substitute to the current transplanted rice to address constraints of labor and water scarcity as well as rising cultivation costs. However, heavy weed infestation is the main biological factor leading to immense yield loss, which requires immediate attention. Therefore, adoption of efficient weed management practice is critical for the success and widespread adoption of direct seeded rice. In this regard, an experiment was laid out at the Faculty of Agriculture, Wadura, SKUAST of Kashmir, India, in Kharif seasons of 2018 and 2019 to assess the efficiency of direct seeded rice (DSR) under two sowing dates (D1: 10th May and D2: 3rd June) and six weed management strategies (W1: weedy check (untreated check), W2: four mechanized conoweedings at 15, 30, 45, and 60 DAS (days after sowing), equivalent to weed free (four conoweedings, equivalent to weed free), W3: bensulfuron-methyl + pretilachlor @ 60 and 600 g a.i. ha–1 as pre-emergence (BSM + pretilachlor, PE), W4: oxyfluorfen @ 750 g a.i. ha–1 as pre-emergence (oxyfluorfen, PE), W5: bensulfuron-methyl + pretilachlor @ 60 and 600 g a.i. ha–1 as pre-emergence followed by 2,4-D @ 0.75 kg a.i. ha–1 as post-emergence (30–35 DAS) (BSM + pretilachlor PE fb 2,4-D PoE), and W6: oxyfluorfen @ 750 g a.i. ha–1 as pre-emergence followed by 2,4-D @ 0.75 kg a.i. ha–1 as post-emergence (30–35 DAS) (oxyfluorfen PE fb 2,4-D PoE) on growth characteristics, productivity, weed infestation, and nutrient dynamics. The pooled results showed that 10th May sowing recorded significantly higher values of growth characteristics viz. plant height, dry matter production, tiller count, and yield characteristics, including panicle weight, panicle length, filled grains per panicle, and test weight, as compared to delayed sowing (3rd June). Earlier sowing (10th May) produced significantly higher grain yield (7.33 t ha–1) and straw yield (8.99 t ha–1) when compared to the delayed sowing (3rd June) which produced a grain yield of 6.08 t ha–1 and straw yield of 7.93 t ha–1. Among weed management strategies, four mechanized conoweeding at 15, 30, 45, and 60 DAS resulted in enhanced growth, yield characteristics, and yield but was statistically similar to bensulfuron-methyl (BSM) + pretilachlor PE fb 2,4-D post-emergence (PoE). Delayed sowing (3rd June; D2) recorded significantly higher weed density and dry-weed biomass as compared to earlier sowing (10th May; D1). Among the herbicides tested, sequential application of BSM + pretilachlor PE fb 2,4-D PoE proved an efficient weed management practice with a significantly reduced population and dry weight of weeds. Therefore, it was concluded that 10th May sowing with four mechanized conoweedings or sequential application of BSM + pretilachlor PE fb 2,4-D PoE is promising for improving productivity and efficient weed control in direct drum seeded rice under temperate Kashmir conditions.

Assessment of induced allelopathy in crop-weed co-culture with rye-pigweed model

“…This contrasts with the increased root biomass observed in the rye, particularly in AARRafter and AARRemoval (Fig. 1 d), further suggesting the concept of induced allelopathy 23 . At the 4 week stage, the biomass allocation results mirrored those of the 2 week stage, with pigweed’s root biomass reduced in all modalities except AARRafter, while shoot biomass did not show any decline when compared to control, aligning with the 2 week results (Fig.…”

“…Interestingly, the AARRafter modality shows improved growth in pigweed, especially in shoot length, highlighting the nuanced influence of timing in seed sowing on crop-weed interactions. The influence of seed-sowing timing on crop-weed interactions is a well-explored area in agricultural research 23 . On the contrary, rye shows more or less improved SL in all modalities when compared with the control (RR) (Fig.…”