SELECTIVITY OF BENTAZON AND NICOSULFURON IN Crotalaria spectabilis INTERCROPPED WITH MAIZE CULTURE

Abstract

Corn intercropped with showy crotalaria allows better use of the agricultural year, having in the same period, economic return from grain yield and the benefits of the legume. The objective was to study the selectivity of the herbicides bentazon and nicosulfuron to C. spectabilis, the weed control and the corn development intercropping system. Two experiments were conducted in the field, one in late-season and the other one in regular growing season. The experimental design was the randomized block, with fourteen treatments and four replicates. Eight treatments with herbicides were studied: bentazon (720 e 960 g a.i. ha -1 ), nicosulfuron (16 e 48 g a.i. ha -1 ) and bentazon + nicosulfuron (720 + 16; 720 + 48; 960 + 16; 960 + 48 g a.i. ha -1 ). Moreover, six controls were maintained: sole corn and sole showy crotalaria (with and without weeds), corn and sunn hemp intercropped (with and without weeds). The herbicide bentazon isolated, in both dosages tested, was selective to C. spectabilis. Nicosulfuron in 48 g a.i. ha -1 , isolated or in mixture with bentazon, promoved the best weed control. Corn affected the recoverability of showy crotalaria plants treated with herbicides. In intercrop of corn and C. spectabilis, both late and regular season had good results in corn yield, legume mass accumulation without the necessity of herbicides pulverization. SELETIVIDADE DE BENTAZON E NICOSULFURON PARACrotalaria spectabilis EM CONSÓRCIO COM A CULTURA DO MILHO RESUMO -O consórcio de milho com crotalária possibilita o melhor aproveitamento do ano agrícola, tendo no mesmo período o retorno econômico com a produção de grãos e os benefícios da leguminosa. Objetivou-se com esse trabalho, estudar a seletividade dos herbicidas bentazon e nicosulfuron para Crotalaria spectabilis, o controle de plantas daninhas e o desenvolvimento do milho no sistema de consórcio. Dois experimentos foram desenvolvidos em campo, um no período de safrinha e outro no período de safra. O delineamento experimental foi em blocos ao acaso, com 14 tratamentos e quatro repetições. Foram estudados oito tratamentos com herbicidas: bentazon (720 e 960 g i.a. ha -1 ), nicosulfuron (16 e 48 g i.a. ha -1 ) e bentazon + nicosulfuron (720 + 16; 720 + 48; 960 + 16; 960 + 48 g i.a. ha -1 ). Além disso, foram mantidas seis testemunhas: milho e crotalária solteiros (com e sem plantas daninhas), milho e crotalária em consórcio (com e sem plantas daninhas). O herbicida bentazon isolado, nas duas dosagens testadas, foi seletivo para C. spectabilis. Nicosulfuron a 48 g i.a. ha -1 , isolado ou em mistura com bentazon, promoveu o melhor controle das plantas daninhas. O milho afetou a capacidade de recuperação das plantas de crotalária tratadas com herbicidas. No consórcio de milho com C. spectabilis, tanto na safrinha como na safra, houve bons resultados de produtividade do milho e acúmulo de massa pela leguminosa sem a necessidade de aplicação de herbicidas. Palavras-chave: Adubo verde. Crotalária. Fitointoxicação. Interferência. Semeadura simultânea.

Seletividade De Herbicidas Residuais Usados Em Cana-De-Açúcar Para Espécies De Crotalária

“…In the case of C. ochroleuca, the dose of 3 g/ha of metsulfuron-methyl promoted a mortality of 80% (Figure 5). The Nicossulfuron, classified in the chemical group of ALS inhibitors (Acetolactate Synthase Enzyme), just like the Methyl Metsulfuron analyzed in this study, was selective for C. spectabilis in a post-emergence application study using the herbicides nicossulfuron and bentazon (24) . Thus, the dose of 0.75 g/ha, below that recommended by the manufacturer, is the most advisable for application in the desiccation of C. ochroleuca, aiming at the establishment of the species.…”

Selectivity of herbicides used in corn on Crotalaria ochroleuca G. Don

“…The authors also report that due to these characteristics, atrazine and mesotrione should not be placed in the crotalaria culture because they were not selective. Nogueira et al (2019) concluded that a dose of 48 g ha -1 of nicosulfuron resulted in high weed control in C. spectabilis; however, this dose resulted in a phytotoxic effect of 81.3% at 42 DAA, significantly reducing its biomass. In this sense, the authors emphasize that C. spectabilis is a plant with C3 photosynthetic metabolism, with slow initial growth and that the application of nicosulfuron slows down this vegetative development even more, a fact that can significantly reduce the biomass of this crop in competition with maize and/or weeds.…”

Physiological Response of Seeds of Crotalaria spectabilis under Drought and Heat Stress

“…Crotalaria spectabilis is a species of the legume family, originally from the Indo-Malay region, with an annual cycle and distributed around the world [1]. It is a plant widely used in the agricultural production system, whether in the succession of crops or intercropped with other crops [2].…”