Evaluation of yield and nitrogen utilisation with urease and nitrification inhibitors in sweet potato crop (Ipomoea batatas L.)

Figures & Tables

	LAI	No tuber per plant	Marketable yield (Kg·ha⁻¹)	Non-marketable yield (Kg·ha⁻¹)	Percentage of marketable	Tubers (no·ha⁻¹)	Mean fresh weight tuber (Kg)	Yield (Kg·ha⁻¹)	DM upper leaves and stems (Kg·ha⁻¹)	N% tuber	N% upper parts
Year A
Urea	5 ac	5.75 a	20,072 a	7,273 ns	73 ns	184,122 a	0.149 ns	27,346 a	5,150 ac	1.026 a	0.470 a
Urea + UI	5.07 b	6.23 b	22,285 b	7,530 ns	75 ns	201,739 b	0.148 ns	29,815 b	5,406 bc	1.169 b	0.476 b
Urea + NI + UI	5.14 a	6.39 b	23,230 b	7,694 ns	75 ns	204,522 b	0.151 ns	30,923 b	5,411 b	1.330 c	0.490 b
Control	5.05 c	5.50 a	18,412 c	6,866 ns	73 ns	175,304 a	0.144 ns	25,433 c	5,111 a	1.076 ab	0.436 a

Year B
Urea	5.11 ac	5.42 a	19,700 a	7,963 ns	71 ns	173,280 a	0.160 ns	27,663 a	5,288 ac	1.083 a	0.493 a
Urea + UI	5.25 b	5.75 b	20,902 ab	8,103 ns	72 ns	183,760 b	0.158 ns	29,005 b	5,488 bc	1.158 b	0.480 b
Urea + NI + UI	5.35 a	6.08 b	21,273 b	8,518 ns	72 ns	194,800 b	0.152 ns	29,515 b	5,705 b	1.293 c	0.483 b
Control	4.90 c	5.25 a	18,180 c	7,990 ns	74 ns	168,240 a	0.109 ns	18,440 c	5,017 a	0.825 ab	0.325 a
F_{fertilization}	7.88***	35.759***	57.504***	1.615 ns	0.23 ns	35.759***	1.795 ns	40.776***	11.376***	26.702***	3.419*
F_year	5.088*	28.603***	17.664***	12.394**	2.316 ns	28.603***	5.072*	2.653 ns	2.523 ns	0.002 ns	0.163 ns
F_{fertilization×year}	0.917 ns	1.196 ns	3.097*	0.272 ns	0.545 ns	1.196 ns	0.881 ns	1.007 ns	1.47 ns	0.99 ns	0.25 ns

	N% tuber	N% upper parts	Nitrogen uptake in upper parts Kg · ha⁻¹	Nitrogen uptake in tuber Kg · ha⁻¹	Nitrogen total uptake Kg · ha⁻¹	Tuber protein yield Kg · ha⁻¹	NUE	NHI	NAE
LAI	0.530**	0.152 ns	0.309 ns	0.430*	0.446*	0.430*	0.488*	0.269 ns	0.370 ns
No tuber/plant	0.657***	−0.080 ns	0.046 ns	0.693***	0.666***	0.693***	0.631**	0.680***	0.284 ns
Marketable yield Kg · ha⁻¹	0.705***	0.148 ns	0.242 ns	0.819***	0.809***	0.819***	0.774***	0.643**	0.658***
Non-marketable yield Kg · ha⁻¹	0.185 ns	0.470*	0.634**	0.257 ns	0.321 ns	0.257 ns	0.269 ns	−0.133 ns	0.342 ns
% of marketable	0.281 ns	−0.344 ns	−0.386 ns	0.261 ns	0.202 ns	0.261 ns	0.249 ns	0.489*	0.154 ns
Tubers no ha⁻¹	0.657***	−0.080 ns	0.046 ns	0.693***	0.665***	0.693***	0.631**	0.680***	0.284 ns
Mean fresh weight tuber Kg	−0.163 ns	0.472*	0.452*	−0.059 ns	−0.001 ns	−0.058 ns	−0.023 ns	−0.383 ns	0.348 ns
Yield Kg · ha⁻¹	0.702***	0.399 ns	0.546**	0.858***	0.883***	0.858***	0.814***	0.495*	0.727***
DM tuber Kg · ha⁻¹	0.422*	0.433*	0.479*	0.511*	0.545**	0.512*	0.422*	0.199 ns	0.504*
DM upper Kg · ha⁻¹ (leaves and stems)	0.382 ns	0.389 ns	0.756***	0.460*	0.529**	0.460*	0.565**	−0.0143 ns	0.420*

	Nitrogen uptake in upper parts (Kg·ha⁻¹)	Nitrogen uptake in tuber (Kg·ha⁻¹)	Nitrogen total uptake (Kg·ha⁻¹)	NUE	NHI	NAE
Year A
Urea	24.230 a	112 a	136 a	0.016 a	0.822 a	17.237 a
Urea+UI	25.760 b	139 b	165 b	0.276 b	0.844 ab	37.809 b
Urea+NI+UI	26.540 b	165 c	191 c	0.492 c	0.861 b	47.047 b
Control	22.494 a	110 a	132 a	–	0.829 c	–

Year B
Urea	26.055 a	120 a	146 a	0.034 a	0.821 a	23.542 a
Urea+UI	26.435 b	134 b	161 b	0.263 b	0.836 ab	34.729 b
Urea+NI+UI	27.546 b	153 c	180 c	0.425 c	0.847 b	38.979 b
Control	16.112 a	81 a	97 a	–	0.625 c	–
F_{fertilization}	5.888**	68.165***	69.300***	65.327***	6.482**	24.464***
F_year	0.842 ns	1.222 ns	0.571 ns	0.323 ns	1.199 ns	0.103 ns
F_{fertilization ×year}	0.251 ns	2.216 ns	2.117 ns	0.452 ns	0.311 ns	0.658 ns