Effect of grass species and fungal endophyte on soil nitrification potential

Figures & data

Table 1  Grass species and Neotyphodium fungal endophyte strains used in an experiment to assess the effect of grass–endophyte combinations on nitrification potential of soil. All C4 grasses are free of Neotyphodium endophytes, but the status of Acremonium fungal endophyte infection was untested.

Grass species (common name)	Description	Neotyphodium endophyte (infection status and strain)	Photosynthetic pathway
Brachiaria decumbens (Signal grass)		Endophyte-free	C4
Paspalum dilatatum (paspalum)		Endophyte-free	C4
Pennisetum clandestinum (kikuyu)		Endophyte-free	C4
Lolium perenne (perennial ryegrass)	cv. ‘Grasslands Samson’ clone #1	AR1	C3
	cv. ‘Grasslands Samson’ clone #1	AR6	C3
	cv. ‘Grasslands Samson’ clone #1	AR37	C3
	cv. ‘Grasslands Samson’ clone #1	Endophyte-free	C3
Festuca arundinacea (tall fescue)	Parent plant A F. arundinacea subsp. atlantigena (octaploid)	AR501	C3
	Parent plant B F. arundinacea subsp. atlantigena (octaploid)	AR542	C3
	cv. ‘Kentucky 31’ F. arundinacea subsp. arundinacea (hexaploid) ‘Continental’ form	Endophyte-free	C3
Festuca pratensis (meadow fescue)	Parent plant 1	AR1002	C3
	Parent plant 2	AR1006	C3
	J110	Endophyte-free	C3

Table 2  Mean total –N production and mean maximum potential nitrification rate from an –N-amended soil over a 4-week incubation interval. The week that the maximum nitrification was achieved is indicated in parentheses. The soils were sampled from the rhizosphere of different plant species after 6 weeks of growth. Means exclude endophyte infected entries. Least significant difference (LSD) (5%) is for all comparisons within the same column.

Grass species	Total soil –N production (µg/g dry soil)	Maximum potential nitrification rate (µg/g dry soil/week)
Brachiaria	99.7	42.6 (3)
Paspalum	123.1	43.9 (3)
Kikuyu	112.5	46.4 (3)
Perennial ryegrass	111.7	46.0 (3)
Tall fescue	108.9	49.1 (3)
Meadow fescue	95.1	28.9 (2)
LSD (5%)	16.3	9.9

Table 3  Mean total –N production and mean maximum soil nitrification rate from an –N-amended soil over a 4-week incubation interval. The soils were sampled from the rhizosphere of different plant species and species–endophyte strain combinations after 6 weeks of growth. The week that the maximum nitrification was achieved is indicated within the brackets. LSD (5%) is for all comparisons within same column.

Grass species	Endophyte	Total soil –N production (µg/g dry soil)	Maximum soil nitrification rate (µg/g dry soil/week)
Perennial ryegrass	AR1	132.2	48.7 (2)
Perennial ryegrass	AR6	134.6	49.2 (2)
Perennial ryegrass	AR37	126.0	48.9 (2)
Perennial ryegrass	Endophyte-free	111.7	46.0 (3)
Tall fescue	AR501	124.5	44.5 (2)
Tall fescue	AR542	132.7	52.9 (3)
Tall fescue	Endophyte-free	108.9	49.1 (3)
Meadow fescue	AR1002	124.4	52.1 (2)
Meadow fescue	AR1006	127.6	49.9 (2)
Meadow fescue	Endophyte-free	95.1	28.9 (2)
LSD (5%)		13.7	10.5