Herbicide and irrigation management options in conventionally-tilled wheat: deciphering water and energy budgeting, and grain and monetary output in north-Indian plains

In South Asia, declining water tables due to increased irrigation and labor shortages for manual weeding pose significant challenges for wheat production. Additionally, herbicide resistance, often resulting from poor management practices, further complicates weed problems. The objective of this study was to assess the impacts of traditional irrigation regimens (IRs) and herbicide application on wheat crops. The findings showed that when irrigation was applied at 100 mm CPE (IR₄), and at 40 mm CPE (IR₁), different combinations of herbicide to weed managment were tested. In comparison to the other treatments, application of irrigation at 40 mm cumulative pan evaporation (IR₁) along with the Pendimethalin₁₀₀₀ g ha^-1 (pre-em) in combination with clodinafop-propargyl 10% + metribuzin 22% + sulfosulfuron 4.2% at a rate of 1125 g ha^-1 at 30 DAS (WM₁) produced the best results in terms of crop yields, economic returns, relative water content, consumptive use, rate of water use, water use efficiency, water productivity, energy input-output, energy returns, energy productivity, energy intensity, specific energy, energy efficiency, maximum field capacity, available soil water, and soil profile moisture extraction pattern. The only exceptions were Pendimethalin₁₀₀₀g ha^-1 (pre-em) combined with carfentrazone ethyl 20% + sulfosulfuron 25%WG), at the rate of 100 g ha^-1 at 30 DAS (WM₂) and the weed-free treatment (WM₅), where the differences were not statistically significant. The yield of wheat grain (14.26 kg ha^-1) and straw (14.41 kg ha^-1) decreased as the unit dry matter production of weeds increased. The study recommends exploring additional weed control strategies and irrigation management options in future improve wheat yields in conventionally-tilled systems.