|CASSOL, GUILHERME - Universidade Federal De Santa Maria|
|MARCHESAN, ENIO - Universidade Federal De Santa Maria|
|ROBAINA, ADROALDO - Universidade Federal De Santa Maria|
|TRIVISIOL, VINICIUS - Universidade Federal De Santa Maria|
|WERLE, ISABEL - Universidade Federal De Santa Maria|
|GOLLO, ELISA - Universidade Federal De Santa Maria|
|GIACOMELI, ROBSON - Universidade Federal De Santa Maria|
Submitted to: Pesquisa Agropecuaria Brasileira
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/21/2020
Publication Date: 8/17/2020
Citation: Cassol, G.V., Marchesan, E., Massey, J., Robaina, A.D., Trivisiol, V.S., Werle, I., Gollo, E., Giacomeli, R. 2020. Raised seedbeds and irrigation increase the yield of soybean rotated with rice in lowland of Southern Brazil. Pesquisa Agropecuaria Brasileira. 55. https://doi.org/10.1590/s1678-3921.pab2020.v55.01398.
Interpretive Summary: Irrigated rice is the main crop grown in lowland areas of Santa Catarina and Rio Grande do Sul states in southern Brazil. The combined rice area across both states is over 3 million acres every year, representing more than 70% of total Brazilian rice production. In this region, rice has been historically grown using a continuous rice cropping system or in rotation with cattle. However, the development of weed resistance to herbicides has become a major issue for producers. To overcome this issue, production of soybean in rotation with rice is becoming more common. However, soybean yields are relatively low owing to poorly-drained soils common to the lowland, rice-growing regions of south Brazil. This study tested practices that reduce water-logging and, therefore, improve soybean yields. Flat-planted soybean were compared to soybean grown on raised beds. Average yields of soybeans planted on raised seedbeds were about 10% higher than those that were flat planted. Moreover, properly-timed irrigation improved yields by about 5% when compared to non-irrigated treatments. These results indicate that when soybean are planted on raised seedbeds in combination with properly-timed irrigation, soybean yields are improved. This helps refine the production practices for soybean grown in rotation with rice in lowland conditions of southern Brazil.
Technical Abstract: The adoption of raised seedbeds and 26 irrigation have improved yields in lowland crop rotation systems worldwide. However, research is limited for southern Brazil. Thus, field experiments were conducted in the 2014/15 and 2015/16 growing seasons to determine the effects of planting systems (raised seedbed and flat planting) and irrigation (irrigated and non-irrigated) on yield of soybean rotated with rice. Water use, crop growth and nitrogen fixation were also evaluated. Water savings for raised seedbeds ranged from 14% (151 m3 ha-1) in 2014/15 to 27% (163 m3 ha-133 ) in 2015/16 compared to flat planting system. The numbers and viability of nodules were not affected by planting 35 systems in either years of study. However, irrigation increased nodule number per plant, dry weight of nodules and nitrogen fixation regardless of planting system. Average grain yields of raised seedbeds were 10% (529 kg ha-137 ) and 9% (362 kg ha-138 ) higher than flat planting in 2014/15 and 2015/16, respectively. Irrigation improved yields by 5% (203 kg ha-1) in 2014/15 and 7% (265 kg ha-139 ) in 2015/16 compared to non-irrigated treatments. These results indicate that raised seedbeds and irrigation improve yields of soybean grown in rotation with rice in lowland conditions of southern Brazil.