Water deficit modifies C:N:P stoichiometry affecting sugarcane and energy cane yield and its relationships with silicon supply

Abstract

Climate change has increased the occurrence of water deficit in regions where sugarcane and energy cane are cultivated, jeopardizing dry matter production of stems. It was hypothesized that the reasons behind this fact relate to C:N:P stoichiometric modifications in these species that impair the conversion rates of accumulated nutrients in the stems, which could be attenuated by supplying silicon (Si) to the crops. Thus, the aims of this study were to evaluate the effects of water deficit in sugarcane and energy cane ratoons in the presence and absence of Si, in the C:N:P stoichiometry of stems, in the use efficiency of these nutrients and in the accumulation of dry matter in stems. Two experiments were carried out, using sugarcane (Saccharum officinarum) and energy cane (S. spontaneum), cultivated in pots filled with a Typic Quartzipisamment. The treatments for both experiments were arranged in a factorial scheme 2 × 2, without (70% of the soil’s water retention capacity) and with (30% of the capacity) water deficit, without and with the application of Si via fertirrigation, associated with foliar pulverization, both at a concentration of 2.5 mmol L−1, arranged in randomized blocks. The reduction in dry matter production of stems in both species caused by water deficit was due to modifications of the C, N and P stoichiometric homeostasis, but the benefit of Si in these plants when increasing dry matter production was not a reflection of the change in homeostasis, thus it may be involved in other mechanisms that remain unknown and should be further studied.

New outcomes on how silicon enables the cultivation of Panicum maximum in soil with water restriction

“…3 a,d). Other authors report the same results for different forages, such as sugarcane 53 . Water deficit in the pastures did not change the C:Si ratio, regardless of Si.…”

“…The present study evidenced, especially with Si addition to the crop, that water deficit in the P. maximum pasture, regardless of cultivar, significantly impairs plant growth by changing homeostasis, i.e., decreasing the C:N ratio by reducing plant C content. This induces instability in the metabolism of the crop, especially in terms of physiological processes 31 , 53 . Thus, it was clear that water deficit aggravated physiological stress in the pastures due to an increase in electrolyte leakage, followed by a decrease in Fv/Fm.…”

“…3 c,f). Sugarcane plants under water deficit also showed decreased carbon use efficiency 53 . This increase in C use efficiency (Fig.…”

Impact of Si on C, N, and P stoichiometric homeostasis favors nutrition and stem dry mass accumulation in sugarcane cultivated in tropical soils with different water regimes

“…However, studies on this species and most crops focus on plants grown under abiotic (Verma et al, 2020b;Sousa Junior et al, 2021;Teixeira et al, 2021) and biotic stress conditions (Tomaz et al, 2021). There are indications that the beneficial element modifies the C:N:P stoichiometry, guaranteeing productivity gains, which was observed in forage plants cultivated in Quartzarenic Neosol (Rocha et al, , 2022 and young sugarcane plants cultivated for only 30 days (Teixeira et al, 2020) and 80 days (Oliveira Filho et al, 2021). However, it is unknown whether these effects could reflect in a later growth stage of the crop's stems.…”

New strategy for silicon supply through fertigation in sugarcane integrating the pre-sprouted seedling phase and field cultivation

“…This element can favor crop growth, with or without stress 7,8 due to its physiological bene ts, increasing photosynthetic pigment biosynthesis, strengthening the antioxidant defense system, and favoring photosynthetic e ciency, a fact observed in different species [9][10][11][12] , including sugarcane 13,14 . Furthermore, Si bene ts are favored in sugarcane because the crop has a high root uptake e ciency regarding this element [15][16][17] .…”