Fodder Yield, Quality and Growth of Chia (Salvia hispanica L.) as Affected by Sowing Density and Top-Dressing Nitrogen Fertilization

Abstract

Chia (Salvia hispanica L.) seeds are considered a superfood, but research on vegetative biomass uses is scarce. We conducted a two-year trial under the hypothesis that short-day flowering black chia would provide quality forage at high latitudes and tested sowing density (D1 = 125, D2 = 25, D3 = 8 and D4 = 4 plants m−2) and top-dressing N fertilization (N = 0, N = 20 kg ha−1) at three stages (EV = early vegetative, LV = late vegetative and EF = early flowering). Forage yield reached 9.0 and 5.64 t ha-1 of total and 2.07 and 1.56 t ha−1 of leaf dry mass at EF in 2013 and 2014, respectively. High plant density corresponded to higher biomass but to lower plant relative growth rate, stem diameter, branching, proportion of leaves and lipid and crude protein content. Crude protein declined from 18% at EV to about 8% at EF and was lower in D1 than in D4. Lipids ranged between 33.83 g kg−1 (D4, EV) and 17.34 g kg−1 (D1, EF) (p < 0.005). N topdressing affected forage quality but not yield. Alpha-linolenic acid was the most abundant fatty acid (FA) (608 g kg−1 FA at EV). The long vegetative growth of short-day flowering chia in southern Europe is favorable to fodder production, and management should be optimized by seeking balance between growth rate and stand density while optimizing vegetative stage growth for the highest forage quality.