Plant N uptake in the periphery of a bovine urine patch: determining the ‘effective area’

Figures & data

Figure 1. Plot layout showing the concentric zones A, B and C and their dimensions and areas.

Figure 2. Mean pasture yields in zones A, B and C for treatments A, urine + fertiliser; B, urine only; C, fertiliser only; D, control. Error bars = LSD (95%), n = 4.

Figure 3. Cumulative pasture yields in zones A, B and C for each treatment. Different letters represent a statistically significant difference between yields within treatments. Error bar = LSD (95%), n = 4.

Figure 4. Mean pasture N content in zones A, B and C for the A, urine + fertiliser; B, urine only; C, fertiliser only; and D, control treatments. Error bars = LSD (95%), n = 4.

Figure 5. Mean pasture N uptake in zones A, B and C for the A, urine + fertiliser; B, urine only; C, fertiliser only; and D, control treatments. Error bars = LSD (95%), n = 4.

Figure 6. Mean cumulative N uptake in zones A, B and C for each treatment. Different letters represent a statistically significant difference within treatments. Error bar = LSD (95%), n = 4.

Figure 7. Pasture ¹⁵N recovery in zones A, B and C for the A, urine + fertiliser; B, urine only; C, fertiliser only; and D, control treatments. Error bars = LSD (95%), n = 4.

Table 1. Cumulative recovery of ¹⁵N in pasture and soil at day 106. There was no effect of fertiliser on ¹⁵N recovery.

Fraction	Zone	Urine + fertiliser (% ^15N recovered)	Urine only (% ^15N recovered)
Cumulative plant ^15N	Zone A	30.6a	29.7a
	Zone B	17.3b	17.3b
	Zone C	4.2c	2.7c
	Subtotal	52.1	49.7
Soil total ^15N 0–7.5 cm depth	Zone A	12.0a	13.5a
	Zone B	2.7b	7.2b
	Zone C	1.8c	2.0c
	Subtotal	16.5	22.7
Soil total ^15N 7.5–20 cm depth	Zone A	3.2a	5.4a
	Zone B	0.7b	3.1b
	Zone C	0.7c	1.6c
	Subtotal	4.1	10.1
Total ^15N recovered	Zone A	45.8a	48.6a
	Zone B	20.7b	27.6b
	Zone C	6.7c	6.3c
	All zones	73.2	82.5

Letters indicate differences between zones (P < 0.05) within a given fraction.

Figure 8. Soil concentration at two depths (0–7.5 and 7.5–20 cm) in zones A, B and C for the A, urine + fertiliser; B, urine only; C, fertiliser only; and D, control treatments. Error bars = LSD (95%), n = 4. Note different scales on the y axes.

Figure 9. Soil concentrations at two depths (0–7.5 and 7.5–20 cm) in zones A, B and C for the A, urine + fertiliser; B, urine only; C, fertiliser only; and D, control treatments. Error bars = LSD (95%), n = 4. Note different scales on the y axes.

Figure 10. Soil inorganic ¹⁵N recovery for the A, urine + fertiliser at 0–7.5 cm depth; B, urine only at 0–7.5 cm depth; C, urine + fertiliser at 7.5–20 cm depth; and D, urine-only treatments at 7.5–20 cm depth. Error bars = LSD (95%), n = 4.