Water stress, nano silica, and digoxin effects on minerals, chlorophyll index, and growth in ryegrass

Document Type: Research Paper


1 Ph.D. Graduate studentconducting thesis research jointly between Department of Horticultural Science and Engineering, University of Tehran, Iran, and University of Idaho, USA.

2 Department of Horticultural Science and Engineering, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran.

3 University of Idaho, Parma Research and Extension Center, 29603 U of I Lane, Parma, ID, USA


Water shortage worldwide mandates minimum use of irrigation water with maximum
efficiency and productivity in all agricultural crops, landscape plants and turf. The objective in
this experiment was to study the effect of two levels of evapotranspiration-based (ETc) drought
in combination with two levels of nanosilicon dioxide (SiO2; NanSi1=1 mM and NanSi=2 mM),
two levels of digoxin (Dig1=0.25 mg.l-1 and Dig2=0.5 mg.l-1) and Dig1 plus NanSi1 on
mineral nutrient concentration, chlorophyll index, visual performance of perennial ryegrass
(loliumperenne) under climatic conditions of the southwest Idaho in the Intermountain West
Regions of the United States. Clippings with 50% ETc had higher percentage dry weight but
lower chlorophyll index and visual rating than those with 75%. Clippings of 75% ETc treatment
had significantly higher concentrations of nitrogen (N), potassium (K), zinc (Zn) and copper
(Cu) but lower sodium (Na), than those of 50% ETc treatment. Considering all mineral nutrient
values, chlorophyll indices and visual performance ratings, we conclude that application of 75%
c is sufficient for maintaining a healthy lawn with satisfactory appearance while we can save
25% water as compared to application of water at 100%. Root growth was not affected by any
of these treatments. Based on the results of this study, applications of NanSi1 or Dig1, either
individually or simultaneously, can slow the process of quality decline in perennial ryegrass turf
under extremely severe drought conditions.