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100kg of fertilizer, estimates plant uptake is 80, N balance = +20
Target +30kg balance which provides a safe buffer; farmer unlikely to see yield reduction
There is opportunity to reduce N fertilizer by 20 kg per hectare without impacting the yielyield
FRAME strategy for addressing excess N use in rice to enhance farm profitability and to reduce GHGs | ||||||||
A.J. McDonald (ajm9@cornell.edu), S.Sherpa (s.sherpa@cgiar.org) | ||||||||
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Kisan yield level (kg/ha)1 | Rice crop N content (kg/ha)2 | Total N rate - upper limit (kg/ha)3 | DAP (kg/ha)4 | Urea (kg/ha) | DAP (kg/acre) | Urea (kg/acre) | DAP (kg/kattha) | Urea (kg/kattha) |
1500 | ||||||||
19.1
59
1750
22.3
62
2000
25.5
66
2250
28.7
69
2500
31.9
72
2750
35.1
75
3000
38.3
78
3250
41.4
81
3500
44.6
85
3750
47.8
88
4000
51.0
91
4250
54.2
94
4500
57.4
97
4750
60.6
101
5000
63.8
104
5250
66.9
107
5500
70.1
110
5750
73.3
113
6000
76.5
117
6250
79.7
120
6500
82.9
123
6750
86.1
126
7000
89.3
36 | 66 | 21 | 135 | 9 | 55 | 0.27 | 1.71 | |
1750 | 42 | 72 | 25 | 147 | 10 | 59 | 0.31 | 1.86 |
2000 | 48 | 78 | 28 | 158 | 12 | 64 | 0.36 | 2.00 |
2250 | 54 | 84 | 32 | 170 | 13 | 69 | 0.40 | 2.15 |
2500 | 60 | 90 | 36 | 182 | 14 | 74 | 0.45 | 2.30 |
2750 | 66 | 96 | 39 | 193 | 16 | 78 | 0.49 | 2.45 |
3000 | 72 | 102 | 43 | 205 | 17 | 83 | 0.54 | 2.59 |
3250 | 78 | 108 | 46 | 217 | 19 | 88 | 0.58 | 2.74 |
3500 | 84 | 114 | 50 | 228 | 20 | 92 | 0.63 | 2.89 |
3750 | 90 | 120 | 53 | 240 | 22 | 97 | 0.67 | 3.04 |
4000 | 96 | 126 | 57 | 252 | 23 | 102 | 0.72 | 3.18 |
4250 | 102 | 132 | 60 | 263 | 24 | 107 | 0.76 | 3.33 |
4500 | 108 | 138 | 64 | 275 | 26 | 111 | 0.81 | 3.48 |
4750 | 114 | 144 | 68 | 287 | 27 | 116 | 0.85 | 3.63 |
5000 | 120 | 150 | 71 | 298 | 29 | 121 | 0.90 | 3.77 |
5250 | 126 | 156 | 75 | 310 | 30 | 125 | 0.94 | 3.92 |
5500 | 132 | 162 | 78 | 322 | 32 | 130 | 0.99 | 4.07 |
5750 | 138 | 168 | 82 | 333 | 33 | 135 | 1.03 | 4.22 |
6000 | 144 | 174 | 85 | 345 | 35 | 140 | 1.08 | 4.36 |
6250 | 150 | 180 | 89 | 357 | 36 | 144 | 1.12 | 4.51 |
6500 | 156 | 186 | 92 | 368 | 37 | 149 | 1.17 | 4.66 |
6750 | 162 | 192 | 96 | 380 | 39 | 154 | 1.21 | 4.81 |
7000 | 168 | 198 | 100 | 391 | 40 | 158 | 1.26 | 4.95 |
Notes | |||||||||||
1 Maximum farmer yield level achieved in the last three years | |||||||||||
2 Estimated N content in rice plant to support maximum achieved yield ( |
above |
-ground DM estimated by assuming a HI of 50% and 20% MC); assumes an N concentration of 1.5% |
concentration in dry matter |
per IRRI knowledge bank | |||||||||||
3 Upper limit for N application with an N-balance target of + |
30 kg/ha with N inputs based solely on inorganic fertilizer and outputs estimated for grain and straw w/ complete removal | |||||||||||
4 DAP rate determined by crop P requirement at full replacement levels for crop removal; assumes a P2O5 concentration of 0.64% in rice above-ground dry matter per IRRI knowledge bank |
Key messages: | |||||||||||||||||||||||||
If farmers are applying more N than the upper limit for their maximum achieved yield level, reductions in N rate are possible without reducing yields. These farmer should be encouraged to reduce their N |
usage to the |
corresponding upper limit rate. | |||||||||||||||||||||||||
If farmers are applying less N than the upper limit for their maximum achieved yield level, they should maintain their current rate unless they are interested in increasing yields. For famers who wish to increase yields, they can be encouraged to experiment with a moderately higher N rate (i.e. add an additional 25 kg/ha) to determine if there is a yield gain that can be achieved with additional N. |
2: Usage and utility of leaf color chart
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