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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 yiel
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) | ||
Kisan yield level (kg/ha)1 | Rice crop N content (kg/ha)2 | Total N rate - upper limit (kg/ha)3 |
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 | 129 |
Notes | |||||
1 Maximum farmer yield level achieved in the last three years | |||||
2 Estimated N content in rice plant to support maximum achieved yield (total above ground dry matter at 15% MC, assuming 1.5% concetnration in dry matter) | |||||
3 Upper limit for N application with an N-balance target of + 40 kg/ha | |||||
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 rate to the relevant 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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