Macronutrients Absorption and Dry Matter Accumulation in Grain Sorghum

Abstract

-The present study aimed to determine the curves of macronutrients and dry matter accumulation in grain sorghum DKB 599, grown in a semiarid region. A field experiment was conducted on a sandy loam eutrophic red Latosol (Oxisol) in Janaúba, State of Minas Gerais (MG), Brazil, in a randomized block design with four replications.As statistical method, a nonlinear regression, sigmoidal function with three parameters was used. After drying, the plants were weighed and ground to determine N, P, K, Ca, Mg and S concentration. Grain sorghum plants accumulate nutrients in their shoots in the following order: N> K> Ca> P> Mg> S. The highest concentrations of K and N were observed in stems and grains, respectively. In the conditions of this experiment, the most favorable time to perform nitrogen and potassium topdressing fertilization is when the plants present seven fully expanded leaves or 24 days after the emergency (DAE).Keywords: fertilization, growth, nutrition, Sorghum bicolor. ABSORÇÃO DE MACRONUTRIENTES E ACÚMULO DE MATÉRIA SECA NO SORGO GRANÍFERORESUMO -Este trabalho teve como objetivo determinar as curvas de acúmulo de matéria seca e macronutrientes no sorgo DKB 599 cultivado em região semiárida. O experimento foi conduzido em campo sobre um Latossolo Vermelho eutrófico, de textura franco-argilosa, no município de Janaúba-MG, Brasil, em delineamento experimental de blocos casualizados, com quatro repetições. Utilizou-se o modelo de regressão não linear, função sigmoidal com três parâmetros como método estatístico. Após secagem, cada parte da planta foi pesada e moída para, em seguida, determinarem-se os teores de N, P, K, Ca, Mg e S. As plantas de sorgo granífero acumulam nutrientes em sua parte aérea na seguinte ordem: N > K > Ca > P > Mg > S. As maiores concentrações de K e N foram observadas, respectivamente, nos caules e nos grãos. Nas condições de condução do experimento, a época mais propícia para realizar a adubação nitrogenada e potássica em cobertura é quando as plantas apresentam sete folhas totalmente expandidas ou 24 dias após a emergência (DAE).Palavras-chave: fertilização, crescimento, nutrição, Sorghum bicolor.

Intercropping sorghum and grasses during off-season in Brazilian Cerrado

“…In the Brazilian Cerrado region, the practice of cultivating sorghum after the main crop at the end of the rainy season is increasing among farmers, mainly due to its better adaptability to irregular rainfall regimes in comparison to other crops, such as maize (Sodré-Filho et al, 2014;Cordeiro et al, 2015). Compared to other crops, sorghum's advantages include drought tolerance and adaptability to low-fertility and acid soils, common characteristics of the Cerrado region (Borges et al, 2018). The hypothesis that the presence of grasses would not affect sorghum performance was confirmed in the present study, although a number of authors concluded the opposite (Silva et al, 2017;Nakao et al, 2019) and observed losses in grain yield or dry matter production.…”

“…Reduced row spacing also increases the distance between plants in the row, and may reduce the competition between plants over water, light and nutrients (Borges et al, 2018;Francisquini-Junior et al, 2020). There were no differences between systems intercropped with sorghum, neither in the interactions of the species, nor in row spacing (p > 0.05), in terms of sorghum plants' height, weight of 1,000 grains and yield (Table 2).…”

“…During the assessment period, sorghum's accurate assimilation ratio showed an ascending patterneither when sole or intercropped with grasses -with constant development and growth until 60 DAE (Figure 5). Sorghum's growth is directly related to the plants' ability to accumulate sugar, as a response of the accurate assimilation ratio, which results in greater amounts of tissue for its physical structures (Borges et al, 2018) and, consequently, for dry matter production. It is associated with leaf growth area as well, as some intercropping systems may lead to stronger competition between plants over space, light and other resources (Santos et al, 2018a).…”

“…No significant effects of competition were observed between the intercropped species, since there were no differences between systems in terms of sorghum grain yield or forage dry matter production (Table 2). The right combination of crops in intercropping systems does not affect these parameters (Borges et al, 2018;Santos et al, 2018b). Furthermore, even when certain Urochloa species may compete and become weeds to crops due to their high regrowth ability (Nakao et al, 2019), the use of an herbicide at the desiccation operation is effective to control palisade and Congo grasses before the summer crop (Sodré-Filho et al, 2014).…”

Decomposition of sorghum, grass, and sorghum intercropped with grass and soybean performance in integrated systems in the Cerrado

“…Sorghum (Sorghum bicolor L. Moench) shows good perspectives for plant residue production prior to soybean (Glycine max L.) as the summer crop because of its higher accumulated biomass and tolerance to water stress (Borges et al, 2018). It can also be intercropped as an alternative to grazing during low pasture availability (Santos et al, 2018a).…”