Demand-driven fertilization. Part I: Nitrogen productivity in four high-maintenance turf grass species

Figures & data

Table I. Amounts of elements in the nutrient solution used in experiments (Wallco 51-10-43 + micro^a).

Element	Amount (g L ^−1 )
Nitrogen (N)^b	51^b
Phosphorus (P)	10
Potassium (K)	43
Sulphur (S)	4
Magnesium (Mg)	4
Calcium (Ca)	3
Manganese (Mn)	0.20
Iron (Fe)	0.17
Boron (B)	0.10
Zinc (Zn)	0.03
Copper (Cu)	0.015
Molybdenum (Mo)	0.0004
^aCederroth International AB, Falun, Sweden.
^b NH4-N and NO3-N ratio of 4:6.

Figure 1.  Shoot and root biomass per pot (g dry matter, DM) of the different grass varieties (F_cr=red fescue var. ‘Cezanne’, F_ch=red fescue var. ‘Center’, B_ve=velvet bentgrass var. ‘Legendary’, B_cr=creeping bentgrass var. ‘Independence’), at different fertilization regimes (N1, N2, N4, N16 = 12.5, 25, 50, and 200 mg N L⁻¹ respectively in the irrigation water) for (a) cut and (b) uncut grass. Different small letters show significant differences in root and shoot biomass, respectively, between different N fertilization regimes within the four grass species (α = 0.05). ns = not significant.

Figure 2.  Biomass partitioning (% shoot and root of total biomass) and shoot:root ratio (values on top of each bar) of (a) cut and (b) uncut turf grass species at the different N fertilization levels. Abbreviations as in Figure 1.

Figure 3.  Nitrogen concentrations in leaves (%) of the (a) cut and (b) uncut turf grass species at the different N fertilization levels. Vertical bars show LSD at α = 0.05. Abbreviations as in Figure 1.

Figure 4.  Correlation between leaf N concentration and leaf biomass production after 3 weeks at the different N fertilization rates for the cut turf grass species (a) F_cr, (b) F_ch, (c) B_ve and (d) B_cr and the N concentration at the lowest growth rate showing no pronounced deficiency symptoms (growth minimum) and highest growth rate achieved in this experiment (growth maximum). Abbreviations as in Figure 1. Symbols show means of six replicates for the cut and four replicates for the uncut treatment.

Table II. Content of carbohydrates (% of DM) in clippings (pooled samples) from creeping bentgrass, B_cr, and slender creeping red fescue, F_cr, at different N fertilization levels, 12.5 (N1), 25 (N2), 50 (N4) and 200 (N16) mg N L⁻¹ irrigation water.

	Bcr			Fcr
N fertilization rate	Glucose	Fructose	Fructans	Glucose	Fructose	Fructans
N1	0.9	3.1	11.9	0.6	2.5	14.5
N2	0.8	2.4	10.2	0.7	2.3	11.4
N4	1.1	2.8	11.9	0.7	1.9	7.4
N16	0.5	1.1	3.1	0.1	0.6	2.1

Figure 5.  Correlations between leaf N concentration of the grasses (%N in DM) and their relative aboveground biomass growth (growth at N1, N2, N4, and N16 in relation to N1) for the cut and uncut (a) fescue species (F_ch and F_cr) and (b) bentgrass species (B_cr and B_ve). Abbreviations as in Figure 1. Symbols show means of six replicates for the cut and four replicates for the uncut treatment.