Water stress and warming impact nutrient use efficiency of Mombasa grass (Megathyrsus maximus) in tropical conditions

Abstract

Temperature and other abiotic factors, such water and nutrient availability, play an important role for plants in response to the changing environments. At this regard, both warming and drought might affect the nutrient use efficiency (NUE) and growth of Megathyrsus maximus a C4 forage grass of high interest for cattle feeding. However, the nutrient requirements of this species under climate change are unknown. Therefore, we aimed to evaluate the individual and combined effects of two levels of temperature: ambient and elevated temperature (2°C above ambient temperature), and two levels of soil water availability: irrigated plants and non‐irrigated plants on accumulation of leaf nutrients, NUE and biomass production of M. maximus. Temperature control was performed by a temperature free‐air‐controlled enhancement (T‐FACE) system under field conditions. In general, we observed that warming under well‐irrigated conditions increased the leaf accumulation of most nutrients, improving the NUE of N, P, K, Ca, Mg, Cu, Mn and Zn. Plant growth was also enhanced under warming effects, with higher leaf dry mass accumulation and root development. Meanwhile, drought decreased NUE of K, Ca, B and leaf dry biomass, while root growth was stimulated. The combined effects of warming and drought on nutrient accumulation, NUE and plant growth tended to be greater than the individual effects expected from a single factor; thus, warming mitigated the negative impacts of individual drought. In summary, our findings suggest that warming and drought, both as individual and combined factors, will change the nutrient requirements of M. maximus in tropical ecosystems.

Effects of two water regimes on morphological traits, nutritive value and physiology of three Bituminaria bituminosa varieties from the Canary Islands

“…Leaf ash content increased with WW treatment. This finding is consistent with other research that reported an increase in most leaf nutrient under well‐irrigated condition (Olivera‐Viciedo et al., 2020), especially those nutrients that are passively uptaken (Wu et al., 2012). Furthermore, ash content has been positively correlated with transpiration ratio (ratio of water transpired to carbon fixed) (Masle, Farquhar & Wong, 1992; Merah, Deleens, Souyris & Monneveux, 2001), and an increase in the later can occur under well‐irrigated condition.…”

Si fertigation attenuates water stress in forages by modifying carbon stoichiometry, favouring physiological aspects

“…Olivera Viciedo et al. (2020) studied the impacts of water deficiency on Megathyrsus maximus and found a reduction in plant dry matter under such stress.…”

Nanosilica modulates C:N:P stoichiometry attenuating phosphorus toxicity more than deficiency in Megathyrsus maximus cultivated in an Oxisol and Entisol

“…The efficiency of plants to use absorbed nutrients to compose its tissues has a direct influence on biomass production 61 , 79 . Therefore, P deficiency in relation to P-sufficient plants reduced nutritional homeostasis and the use efficiency of C and N, affecting forage plant growth in both cycles and in the two soils studied, with a decrease in dry matter production dries of 50 and 31% in plants grown in Oxisol and Entisol, respectively.…”