Teff (Eragrostis tef) dry matter yield, nutrient uptake partitioning, and nitrogen use efficiency indices affected by nitrogen rate under balanced fertilization

Figures & data

Table 1. Effect of N rate yield and yield components and SPAD index on teff. Data shown are means from four replications

N Rate (mg kg^−1)	RW (g pot^−1)	SW (g pot^−1)	GW (g pot^−1)	AGBM (g pot ^−1)	Fertile tiller plant ^−1	Total tillers plant ^−1	Plant height (cm)	Panicle weight (g pot ^−1)	HI (%)	SPAD Index
0	3.4 ± 1.2^b	67 ± 4.0^d	27 ± 1.9^d	95 ± 4.6^d	6.7 ± 0.5^d	7.5 ± 0.1	143 ± 5.3	6.4 ± 0.5	29 ± 1.7^bc	32 ± 2.2^d
25	3.6 ± 1.1^b	77 ± 7.7^d	31 ± 5.9^d	107 ± 13.4^d	7.3 ± 0.9^d	8.0 ± 0.7^d	150 ± 10.5	6.6 ± 0.5	28 ± 2.1^c	33 ± 0.7^cd
50	3.9 ± 0.3^b	92 ± 3.7^c	39 ± 5.2^c	131 ± 8.4^c	9.6 ± 1.8^c	10.7 ± 1.8^c	144 ± 9.9	6.6 ± 1.5	30 ± 2.2^bc	35 ± 1.8^bc
100	6.7 ± 2.1^a	107 ± 5.6^b	49 ± 2.6^b	156 ± 6.9^b	10.9 ± 1.7^bc	12.0 ± 1.6^bc	150 ± 6.8	7.3 ± 0.9	31 ± 1.4^ab	36 ± 1.4^abc
150	8.7 ± 2.4^a	115 ± 7.1^b	57 ± 4.04^a	171 ± 7.9^a	12.1 ± 1.0^ab	13.3 ± 1.1^ab	142.9 ± 2.7	7.4 ± 0.7	33 ± 2.2^a	38.4 ± 2.6^a
200	9.3 ± 2.8^a	127 ± 8.3^a	56 ± 6.3^a	183 ± 13.3^a	12.8 ± 0.9^a	14.5 ± 0.7^a	144.1 ± 2.8	7.2 ± 1.3	31 ± 1.8^abc	38.1 ± 2.1^ab
p values	***	***	***	***	***	***	Ns	Ns	*	***

RW: Root weight; SW: Straw weight; GW: Grain weight; AGBM: Aboveground biomass; HI: Harvest index. Treatment means ± standard deviations within each column and treatment with different letters are significantly different at p < 0.05. Ns, not significant. *p < 0.05; **p < 0.01; ***p < 0.001.

Table 2. Effect of N rate and growth stage on root dry matter and nutrient uptake. Data shown are means from four replications

N Rate (mg kg^−1)	Root N Uptake (mg pot^−1)	Root P Uptake (mg pot^−1)	Root K Uptake (mg pot^−1)	Straw N Uptake (mg pot^−1)	Straw P Uptake (mg pot^−1)	Straw K Uptake (mg pot^−1)	Grain N Uptake (mg pot^−1)	Grain P Uptake (mg pot^−1)	Grain K Uptake (mg pot^−1)
0	16.9 ± 6.4^c	2.2 ± 1.1^b	6.4 ± 4.2^ab	146.6 ± 21.4^e	63.4 ± 9.4^a	837.9 ± 56.3^b	278.6 ± 33.2^d	115.6 ± 7.7^c	165.8 ± 8.0^b
25	18.1 ± 5.3^c	1.9 ± 0.7^b	4.3 ± 2.6^b	181.1 ± 15.9^ed	70.9 ± 18.4^a	894.6 ± 34.5^b	340.9 ± 38.6^d	125.8 ± 18.8^bc	195.3 ± 25.3^b
50	20.6 ± 2.5^bc	1.9 ± 0.5^b	3.7 ± 1.4^b	213.4 ± 21.8^d	53.0 ± 22.7^ab	1680.1 ± 1145.6^a	470.5 ± 88.7^c	147.1 ± 8.2^ab	294.2 ± 73.4^a
100	38.0 ± 12.4^b	2.9 ± 1.1^b	5.8 ± 2.7^b	287.3 ± 35.4^c	39.2 ± 6.1^bc	1001.8 ± 58.5^ab	676.5 ± 89.9^b	157.6 ± 13.2^a	281.6 ± 21.3^a
150	58.9 ± 19.4^a	4.9 ± 1.8^a	11.9 ± 6.5^a	379.1 ± 16.8^b	28.6 ± 3.0^c	996.1 ± 39.0^ab	915.4 ± 50.2^a	155.8 ± 14.2^a	282.7 ± 26.0^a
200	70.7 ± 17.3^a	5.9 ± 1.4^a	9.1 ± 4.0^ab	542.8 ± 83.5^a	41.1 ± 5.1^bc	1188.6 ± 360.4^ab	952.4 ± 86.0^a	154.4 ± 21.9^a	293.4 ± 30.0^a
p values	***	***	Ns	***	**	Ns	***	**	***

Treatment means ± standard deviations within each column and treatment with different letters are significantly different at p < 0.05. Ns, not significant. *p < 0.05; **p < 0.01; ***p < 0.001.

Table 3. Effect of nitrogen (N) rate on NUE indices and grain protein content. Data shown are means from four replications

N Rate	NAE	NPFP	NAPE	NUpE	NUE	NUtE (g g-1)	NRE (%)	NHI	Grain Protein
(mg kg^−1)	———————————(g g-1)—————————-						————–(%)—————-
0						63.8 ± 6.3^a		65.5 ± 3.9	6.5 ± 0.7^d
25	24 ± 22.6	159 ± 20.0^a	40 ± 23.6	2.7 ± 0.1^a	159 ± 20.0^a	59 ± 5.4^ab	57 ± 30.1	66 ± 3.2	7.0 ± 0.7^cd
50	29 ± 14.2	97 ± 12.9^b	45 ± 9.0	1.7 ± 0.2^b	97 ± 12.9^b	56 ± 1.5^bc	65 ± 26.9	68 ± 5.4	8.0 ± 0.6^c
100	27 ± 3.2	61 ± 3.3^c	41 ± 3.7	1.2 ± 0.2^c	61 ± 3.3^c	519 ± 4.0^c	67 ± 11.1	70 ± 0.6	9.0 ± 0.7^b
150	25 ± 3.9	47 ± 3.4^cd	34 ± 2.5	1.10.04 ± ^cd	47 ± 3.4^cd	44 ± 2.0^d	72 ± 6.4	71 ± 1.8	10.0 ± 0.3^a
200	18 ± 5.0	35 ± 3.9^d	27 ± 5.9	0.9 ± 0.1^d	35 ± 3.9^d	37 ± 3.5^e	67 ± 5.9	64 ± 4.5	11.0 ± 0.5^a
p values	Ns	***	Ns	***	***	***	Ns	Ns	***

Treatment means + standard deviations within each column and treatment with different letters are significantly different at p < 0.05. Ns, not significant. *p < 0.05; **p < 0.01; ***p < 0.001.NRE: Nitrogen recovery efficiency; NAE: Nitrogen agronomic Efficiency; NPFP: Nitrogen partial factor productivity; NAPE: Nitrogen agrophysiological efficiency, NUpE: Nitrogen uptake efficiency; NUE: Nitrogen use efficiency; NHI: Nitrogen harvest index; NUtE: Nitrogen utilization efficiency.

Table 4. Pearson correlation coefficients for physiology, yield and yield components, composition of teff and nutrient use efficiency indices across nitrogen fertilizer treatments

	SPAD	SW	GW	HI	RW	FTPP	RNU	SNU	GNU	NHI	NUtE	NUpE	NUE	Protein
SPAD	1
SW	0.78	1
GW	0.80	0.94	1
HI	0.57	0.53	0.78	1
RW	0.69	0.80	0.74	0.38	1
FTPP	0.67	0.88	0.87	0.57	0.73	1
RNU	0.69	0.82	0.77	0.41	0.98	0.77	1
SNU	0.69	0.89	0.81	0.40	0.82	0.81	0.89	1
GNU	0.81	0.94	0.97	0.69	0.79	0.89	0.84	0.89	1
NHI	0.30	0.11	0.30	0.56	−0.04	0.19	−0.10	−0.22	0.21	1
NUtE	−0.69	−0.86	−0.78	−0.34	−0.81	−0.82	−0.85	−0.93	−0.89	0.07	1
NUpE	0.04	−0.06	−0.1	−0.1	−0.2	−0.09	−0.2	−0.15	−0.13	0.13	0.07	1
NUE	−0.08	−0.19	−0.20	−0.15	−0.31	−0.22	−0.33	−0.29	−0.27	0.13	0.23	0.98	1
Protein	0.77	0.88	0.85	0.50	0.80	0.87	0.84	0.90	0.94	0.14	−0.97	−0.09	−0.25	1

SW: straw weight; GW: grain weight; HI: harvest index; RW: root weight; FTPP: Fertile tillers per plant; RNU: root N uptake; SNU: straw N uptake; GNU: grain N uptake.

Data availability statement

All the data used and/or analyzed during the study are available from the corresponding author upon reasonable request.