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

Abstract

The impacts of climate change on the planet are increasing and one of the main problems is the occurrence of extreme weather events such as droughts and floods. The effects of climate change are expected to increase cultivation in areas with fewer freshwater resources available and longer periods of water stress limitation (Oki & Kanae, 2006).Water deficiency stands out for being common in tropical ecosystems (Monteiro et al., 2014), and it directly affects pastures that

Silicon Mitigates Nutritional Stress of Nitrogen, Phosphorus, and Calcium Deficiency in Two Forages Plants

“…In grasses, the element concentrates mostly in leaf cell walls 11 , which may improve nutrient use e ciency, thus favoring biomass production. Previous reports show this effect for sugarcane 43 and Brachiaria 'Mavuno' 29 . However, con rmation of this hypothesis depends on speci c studies on the cell walls of U. brizantha cv.…”

“…Notwithstanding, studies evaluating the effect of Si on the mitigation of abiotic stresses in forage plants are still limited. One study indicates a positive effect of this element on the alleviation of water de cit damage in Brachiaria 'Mavuno' 29 . Another study addresses nutritional de ciency in Panicum maximum and in the hybrid Ipyporã (B. ruziziensis × B. brizantha) 30 .…”

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

“…The source of Si was sodium silicate and potassium stabilized with sorbitol (113.4 g L −1 de Si and 18.9 g L −1 of K 2 O), in the concentration of 2.5 mmol L −1 , as indicated by Birchall 43 , simulating a 5 mm irrigation depth every five days. The study of Rocha et al 25 on Brachiaria was used as a reference; Si was applied immediately after the first cycle of forage for a period of 40 days.…”

“…Total microporosity was considered as equivalent to 100% of soil water retention capacity; however, the water condition was considered as 70% of this value, as it corresponds to the usual demand for most crops. The water deficit condition was achieved by maintaining the water level at 40% of the soil water retention capacity, determined on study of Rocha et al 25 . Previous studies suggest that the best benefit of Si occurs in plants with a water level close to 40% and at a water level close to 70% it is sufficient to achieve maximum forage dry mass production.…”

“…Studies have suggested that Si reduces water stress due to less water loss by cuticular transpiration 23 , but the cuticular transpiration rate is very low compared to stomatal transpiration 24 , suggesting that Si also affects other mechanisms that need to be better investigated. Recent research has indicated that Si absorption improves its physiological aspects mainly by modifying elemental stoichiometry and could minimize damage from water deficit 25 – 27 . However, most studies on stoichiometric homeostasis focus mainly on N and P, studies on the Si are incipient 28 , 29 .…”