Morfologia radicular de cultivares de café arábica submetidas a diferentes arranjos espaciais

Abstract

Resumo -O objetivo deste trabalho foi avaliar as respostas morfológicas do sistema radicular de quatro cultivares de café arábica submetidas a diferentes arranjos espaciais. Os espaçamentos adotados foram os de 0,40, 0,50, 0,60, 0,70 e 0,80 m entre plantas na linha, tendo-se mantido fixo 3,8 m na entrelinha. Aos 27, 35 e 39 meses após o transplantio, foram coletadas amostras de solo+raízes em três posições em relação aos caules das plantas e três profundidades. As raízes foram lavadas, coloridas, digitalizadas e processadas com o programa Safira. A cultivar Tupi RN IAC 1669-13 apresentou sistema radicular com características morfológicas relacionadas à absorção de nutrientes e de água superiores às das cultivares Catuaí Vermelho IAC 144, Catuaí Amarelo IAC 62 e Catuaí Amarelo IAC 32, para todos os arranjos espaciais testados. A redução no espaçamento aumenta a abundância de raízes por volume de solo, sem alterar a qualidade morfológica do sistema radicular, nem aprofundá-lo. Os sistemas radiculares das cultivares avaliadas são mais abundantes e apresentam superfície e comprimento específico maiores entre plantas adjacentes, seguidas das posições afastadas a 0,25 e 0,50 m do caule. A proporção de raízes na camada de 0,1 m de profundidade é maior que a na de 0,4 m, para todos os espaçamentos. A variação no espaçamento entre plantas na linha altera a morfologia do sistema radicular do café arábica.Termos para indexação: Coffea arabica, adensamento, programa Safira, sistema radicular. Root morphology of Arabica coffee cultivars subjected to different spatial arrangementsAbstract -The objective of this work was to evaluate the morphological responses of the root system of four Arabica coffee cultivars subjected to different spatial arrangements. The adopted plant spacings were 0.40, 0.50, 0.60, 0.70, and 0.80 m between plants within rows, maintaining 3.8 m constant between rows. At 27, 35, and 39 months after transplanting, samples of soil+roots were collected at three surface positions in relation to plant stems and at three depths. Roots were washed, colored, digitalized, and processed with the Safira software. The Tupi RN IAC 1669-13 cultivar showed a root system with superior morphological traits related to the absorption of nutrients and water, in comparison to those of the Catuaí Vermelho IAC 144, Catuaí Amarelo IAC 62, and Catuaí Amarelo IAC 32 cultivars, for all tested spatial arrangements. The reduction in spacing increases the amount of total root per soil volume unit, without affecting the morphological quality of the root system, nor deepening it. The root systems of the evaluated cultivars are more abundant and show higher surface and specific length between adjacent plants, followed by the 0.25 and 0.50 m positions away from the coffee stem. The proportion of roots at the 0.1 m layer is higher than at the 0.4 m layer, for all plant spacings. Changes in spacings between plants within lines affect the morphology of Arabica coffee root system.

Morphophysiological plasticity of plagiotropic branches in response to change in the coffee plant spacing within rows

“…The cultivar IAC 1669-13 presented the best morphological attributes related to absorption of water and nutrients from the root system in comparison to the other cultivars, especially IAC 144 (RONCHI et al, 2015b). This associated with the likely absence or low autonomy of the plagiotropic branch (CHAVES et al, 2012), can offset, in part, this slight imbalance in the source: sink ratio of the branch, ensuring full fruit filling in this cultivar.…”

“…These cultivars were selected because they are widely used in mechanized coffee areas (IAC 144) and have high potential in the Cerrado region due to the yellow color of fruits and high adaptability (IAC 62 and IAC 32), resistance to rust and nematodes (Tupi RN) and high quality drink (CARVALHO, 2008). Seedlings with four pairs of leaves were transplanted in furrows, in accordance with the planting methods prevalent in the Cerrado region (SANTINATO et al, 2008), with spacing of 3.80 m between rows. The spacing between plants was confined within the extreme limits for mechanized cultivation, since spacing between plants of less than 0.5 m or greater than 0.7 m are rarely used in the region for small sized varieties (MATIELLO et al, 2010).…”

“…In this region, the crops are planted in open rows to allow mechanized cultivation and harvesting and to facilitate cultural practices (MATIELLO et al, 2010;FERNANDES et al, 2012). Thus, for small sized varieties like Catuaí, which are widely grown in the Cerrado region, the spacing commonly practiced is 4.0 m × 0.5 m (CARVALHO, 2008;SANTINATO et al, 2008;MATIELLO et al, 2010).…”

“…Although the definition of the best plant spacing depends on variables such as cultivar, plant size, topography and management conditions, the proper distribution of plants within and between rows may significantly increase the productivity per area (SANTINATO et al, 2008;MATIELLO et al, 2010).…”

Characterization of the Transverse Distribution of Fertilizer in Coffee Plantations

“…Knowledge of root morphology of coffee plants is, therefore, a useful reference. Studies on root distributions in the soil recommend that fertilizer should be applied under the coffee canopy, close to the orthotropic stem [15], where the root concentration and absorption capacity are higher [16].…”