Initial growth of cassava plants cv. Mossoró under different water regimes

The sprouting phase of cassava is critical for the establishment of the plant, with this phase being dependent on soil moisture. As such, this study evaluated the effect of different irrigation levels on the initial growth of cassava cv. Mossoró in semi-arid conditions. The experiment was conducted under completely randomized design conditions with 5 replications. The treatments in pots containing one plant per experimental unit consisted of 5 irrigation levels, 0, 25, 50, 75 and 100% of the reference evapotranspiration (ETo, mm day-1), which corresponded to totals for the experimental period of 11.20; 42.15; 73.09; 104.03 and 134.97 mm, respectively. At 30 days after planting, the number of leaves and stems, as well as the dry mass of the shoot and the root had increased sharply for irrigation levels up to 73.09 mm. For higher irrigation levels there was a tendency for plant growth stabilization; however, above 104.03 mm there was a decrease. Shoot and root dry mass ratio showed severe water stress at the 11.20 mm level, being more damaging to root growth. Plant height showed a positive linear trend as the level of irrigation was increased, as opposed to water use efficiency. Therefore, irrigation with 50% replacement of ETo (73.09 mm) provided the best conditions for early growth of cassava

Initial growth of cassava plants cv. Mossoró under different water regimes = Crescimento inicial de plantas de mandioca cv. Mossoró sob diferentes regimes hídricos

The sprouting phase of cassava is critical for the establishment of the plant, with this phase being dependent on soil moisture. As such, this study evaluated the effect of different irrigation levels on the initial growth of cassava cv. Mossoró in semi-arid conditions. The experiment was conducted under completely randomized design conditions with 5 replications. The treatments in pots containing one plant per experimental unit consisted of 5 irrigation levels, 0, 25, 50, 75 and 100% of the reference evapotranspiration (ETo, mm day-1), which corresponded to totals for the experimental period of 11.20; 42.15; 73.09; 104.03 and 134.97 mm, respectively. At 30 days after planting, the number of leaves and stems, as well as the dry mass of the shoot and the root had increased sharply for irrigation levels up to 73.09 mm. For higher irrigation levels there was a tendency for plant growth stabilization; however, above 104.03 mm there was a decrease. Shoot and root dry mass ratio showed severe water stress at the 11.20 mm level, being more damaging to root growth. Plant height showed a positive linear trend as the level of irrigation was increased, as opposed to water use efficiency. Therefore, irrigation with 50% replacement of ETo (73.09 mm) provided the best conditions for early growth of cassava. = A fase de brotação da mandioca é crítica para o estabelecimento da cultura, sendo esta fase dependente da umidade do solo. Assim, esse estudo teve como objetivo avaliar a influência de diferentes lâminas de irrigação no crescimento inicial de mandioca cv. Mossoró em condições de semiárido. O experimento foi conduzido em delineamento inteiramente casualisado, com 5 repetições. Os tratamentos consistiram de 5 lâminas de irrigação, sendo 0, 25, 50, 75 e 100% da evapotranspiração de referência (ETo, mm dia-1), que corresponderam a um total de 11,20; 42,15; 73,09; 104,03 e 134,97 mm durante o período experimental, em vasos contendo uma planta por unidade experimental. Aos 30 dias após o plantio, verificouse que o número de folhas e de hastes, assim como a massa seca da parte aérea e da raiz, aumentaram acentuadamente até a lâmina de 73,09 mm, com tendência a estabilização a partir desse ponto, e posterior queda a partir de 104,03 mm. A relação entre a massa seca da parte aérea e a massa seca da raiz demonstrou estresse hídrico severo na lâmina de 11,20 mm, sendo mais danoso ao crescimento das raízes. A altura das plantas apresentou comportamento linear positivo à medida que se aumentou a lâmina, ao contrário da eficiência do uso da água. Portanto, a lâmina com reposição de 50% da ETo, (73,09 mm), proporciona um crescimento inicial adequado para mandioca