Introduction
Materials and methods
Labeled synthetic urine-based fertilizer production
Synthetic urine | STR | NH3-N | NO3-N | PO4-P | TIC | SO4
| K | Na | Cl | COD |
---|---|---|---|---|---|---|---|---|---|---|
mM | g L−1
| |||||||||
NaH2PO4·H2O | 17 | – | – | 0.54 | – | – | – | 0.40 | – | – |
NH4-acetate | 104 | 1.45 | – | – | – | – | – | – | – | 6.64 |
15NH4-acetate (98 at.% 15N) | 21 | 0.29 | – | – | – | – | – | – | – | 1.33 |
NH4OH (solution 28% NH3) | 175 | 2.45 | – | – | – | – | – | – | – | – |
NH4HCO3
| 271 | 3.79 | – | – | 3.25 | – | – | – | – | – |
Na2SO4 anhydrous | 16 | – | – | – | – | 1.56 | – | 0.74 | – | – |
NaCl | 62 | – | – | – | – | – | – | 1.43 | 2.21 | – |
KCl | 56 | – | – | – | – | – | 2.19 | – | 1.99 | – |
Total | 7.98 | 0 | 0.54 | 3.25 | 1.56 | 2.19 | 2.58 | 4.19 | 7.97 |
Synthetic nitrified urine | SNUF | NH3-N | NO3-N | PO4-P | TIC | SO4
| K | Na | Cl | COD |
---|---|---|---|---|---|---|---|---|---|---|
mM | g L−1
| |||||||||
NaH2PO4·H2O | 17 | – | – | 0.54 | – | – | – | 0.39 | – | – |
NH4NO3
| 155 | 2.17 | 2.17 | – | – | – | – | – | – | – |
15NH
4
15
NO3 (10 at.% 15N) | 85 | 1.19 | 1.19 | – | – | – | – | – | – | – |
Na2SO4 anhydrous | 16 | – | – | – | – | 1.54 | – | 0.74 | – | – |
NaCl | 62 | – | – | – | – | – | – | 1.43 | 2.20 | – |
KCl | 57 | – | – | – | – | – | 2.23 | – | 2.02 | – |
HCl 37 % | 0.005 | – | – | – | – | – | – | – | <0.001 | – |
Total | 3.36 | 3.36 | 0.54 | 0 | 1.54 | 2.23 | 2.55 | 4.22 | 0 |
Fertilizer | DM content | Total N | Total P |
15N atomic enrich |
SA
| Solubility of elements in H2Oa
| Solubility of elements in H2Oa
|
---|---|---|---|---|---|---|---|
% | mg g−1
| mg g−1
| % 15N | Bq µg−1 P | % of total N | % of total P | |
15NH
4
15
NO3
| – | 340b
| 0 | 0.6 | n.a | 100 | 100 |
KH
2
33
PO4
| – | 0 | 227b
| n.a. | 29.2 | 100 | 100 |
Labeled STR | 90 | 53 | 132 | 3.2 | 35.1 | 3 | 1.8 |
Labeled SNUF | 97 | 218 | 17 | 3.5 | 32.4 | 97 | 88.9 |
Growth experiment
Treatment | Urine-based fertilizer | Water-soluble fertilizer | After cut 1 and 2 | ||
---|---|---|---|---|---|
N dose | P dose | N dose | P dose | N dose | |
mg element kg−1 soil | |||||
Reference fertilizers
c
| |||||
0N0P | 0 | 0 | 0 | 0 | 0 |
0N1Pa
| 0 | 0 | 0 | 50a
| 0 |
1Nb0P | 0 | 0 | 100b
| 0 | 100 |
1Nb1Pa
| 0 | 0 | 60b,d
| 50a
| 100 |
1N1.5Pe
| 0 | 0 | 100 | 75 | 100 |
Urine-based fertilizers
| |||||
STRa,b
| 23b
| 50a
| 77 | 0 | 100 |
SNUFa,b
| 100b
| 8a
| 0 | 42 | 100 |
Fertilizer analyses
Plant analyses
Calculation of P and N uptake from fertilizer
Statistical analyses
Results
Characteristics of processed urine-based fertilizers
Plant dry matter production
Total P and fertilizer P uptake by plants
Treatment | Pdfs | Pdff | FertPrec | Relative effectiveness | Ndfs | Ndff | FertNrec | |||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
All 3 cuts | 1st cut | All 3 cuts | ||||||||||
mg P kg−1 soil | mg P kg−1 soil | % | % | % | mg N kg−1 soil | mg N kg−1 soil | % | % | ||||
1N1P | 30 | 14b | 32b | 28 | n.a. | 82 | 36b | 34b | 59 | 77 | ||
STR | 30 | 13b | 30b | 26 | 97 | n.a. | 13a | 10a | 57 | 72 | ||
SNUF | n.a. | 2a | 5a | 26 | n.a. | 84 | 57c | 42c | 57 | 75 | ||
SEM | 0.4 | 3.3 | 7.6 | 0.7 | n.a. | 1.4 | 5 | 4 | 0.3 | 0.8 | ||
ANOVA source of variation
| ||||||||||||
Treatment | n.s. | *** | *** | n.s. | n.a. | n.s. | *** | *** | n.s. | n.s. |