Crop Establishment Methods and Weed Management Practices Affect Grain Yield and Weed Dynamics in Temperate Rice

Intikhab Aalum Jehangir,Ashaq Hussain,M Anwar Bhat,Arafat Abdel Hamed Abdel Latef,Waseem Raja,Shabir H Wani,Najeeb R Sofi,Omar M Ali

doi:10.3390/agronomy11112137

Abstract

Higher demand and cost of labor and water shortage have forced the farmers to look for an alternate method of cultivation in rice as a substitute to the existing conventional transplanting. Dry direct seeding and water seeding have emerged as better alternatives over transplanting method. These methods not only result in labor saving, but also result in significant water saving in rice. These are important adaptation strategies to the impending climate change. However, the direct seeding method is confronted with severe weed infestation and yield losses if weeds are not managed well. Against this backdrop, a field study was undertaken during kharif seasons of 2019 and 2020 to evaluate the effect of crop establishment methods and weed management practices on rice and its associated weed flora. The results demonstrated that grain yields obtained under water seeding (WS) were statistically at par with transplanting (CT), but significantly superior to dry direct seeding (DDSR). Yield attributes were significantly superior in WS as compared DDSR, but were at par with CT. Weed density followed the order of DDSR > WS > CT. With the advancement in age of the crop, sedges dominated in DDSR, whereas broad-leafweeds (BLW) dominated in WS and CT methods of establishment. All the herbicides reduced the weed density significantly as compared to weedy check. Penoxulam (PE) reduced the weed density and weed dry matter on an average by 91% and 92% at 30 DAS/DAT over weedy check, respectively. PE proved significantly superior in controlling all the sedges and grasses but was less effective against BLW. Maximum reduction in yield due to weeds was observed in weedy check (WC) (58%) and the lowest was observed in PE (3%). Application of PE @ 22.5 g ha−1 under the WS method of crop establishment resulted in highest average weed control efficiency and grain yield.

Highlights

pyrozulsufuron + pretilachlor (PP) and bispyribac sodium (BS) applied plots were found to be dominated by sedges, PE treated plots were dominated by BLW at 30 DAS
All the herbicides reduced the weed density significantly compared to weedy check ranging from 69% and 80% in PP, 90% and 91% in PE, and 83% and 84% in BS at 30 DAS/DAT and 60 DAS/DAT, averaged over two years, respectively
The highest number of weeds and weed dry matter per unit area was recorded in DDSR across the chemical weed management practices

Summary

Introduction

Rice cultivation methods have been changing from time to time in response to technological developments, water and labor availability, and increased cost of production and higher cropping intensity. In India, rice is mainly cultivated through conventional transplanting method, alternative to this, direct seeding has been practiced successfully in the past two decades with few manipulations, depending on the geographic and agro-climatic conditions. In different forms of direct seeding, reduced yields have been witnessed due to severe weed competition. In India, an economic loss of USD billion has been found to be inflicted by weeds alone in 10 major crops, out of which the share of rice is 21.4% and 13.8% in direct seeded and transplanted rice, respectively [6]

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Conclusion