Synthesizing Nanoencapsulated Sulfentrazone Herbicide and Optimizing Time and Dose for Season Long Weed Management in Irrigated Blackgram (Vigna mungo L.)

Background: Pulses are nutritious edible seeds of leguminous plants, have become an essential part of the human diet. Among the pulses, blackgram (Vigna mungo L.) is an important legume crop cultivated in tropical and subtropical regions of the world. Even though there are so many factors responsible for the lower yield of blackgram, weeds play a major role. Sulfentrazone is a broad spectrum herbicide belongs to the family of phenyl triazolinone. Sulfentrazone has high persistence and mobility with mean partition coefficient Koc = 43 and sorption coefficient Kd less than 1 and also has high horizontal and vertical leaching potential. Even though generally used herbicides in blackgram like pendimethalin, imazethapyr and quizalofop-ethyl are helpful in managing weeds, they have to apply multiple times or have to integrate with other methods of weed management which is expensive. So as to reduce the usage of multiple herbicides, to avoid manual weeding and to achieve season long weed control without affecting the environment the nano-encapsulated sulfentrazone is the better alternative and it gives better solution for the above constraints besides increasing the productivity.Methods: Laboratory and field experiments were conducted in the Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore during 2019-2020. Laboratory experiment was conducted to prepare nano-encapsulated sulfentrazone herbicide using solvent evaporation method. Screening trial was conducted in field with 17 treatments in randomized block design. Main trial was conducted with nine treatments of randomized block design by selecting the best performing treatments in screening trial. A confirmatory trial was also conducted by using same treatments.Result: The encapsulated sulfentrazone particles were characterized in SEM (Scanning electron microscope) and also analysed with EDAX (Energy dispersive X-ray analysis) for elemental analysis, which is followed by particle size analysis and zeta potential to know the size and stability respectively. All these tests concluded that the sulfentrazone particles were encapsulated correctly and might be useful for slow release of the particle and also for reducing vertical and horizontal leachability. The field trials revealed that sulfentrazone @ 0.30 kg a.i. ha-1 with encapsulation applied at 1 DBS is better alternative for the season long weed management in blackgram without affecting the soil and ground water, as well as increasing the productivity.