1. Introduction to site-specific nutrient management (SSNM)

2. Need for an improved approach to nutrient management for rice
The need of rice for nutrients:
Can differ from field to field
Can differ year-to-year because of varying climate and growing-season conditions
Fertilizer rates and timing should be adjusted to location and season-specific needs and conditions

3. SSNM: A plant-based approach
SSNM provides an approach for ‘feeding’ rice with nutrients as needed
Make optimal use of existing nutrients, such as from soil, residues, and manures
Apply N fertilizer at the time and amount required by the rice crop
Apply P and K fertilizers based on crop need, as determined through the omission plot technique

4. Site-specific nutrient management (SSNM)
Feeding
crop
needs!
1. Establish a yield target – the crop’s total needs
3. Fill deficit between total needs and indigenous supply
2. Effectively use existing nutrients

5. SSNM: A plant-based approach
Feed the plant’s need for additional nutrients
Establish a yield target (plant’s need for nutrients)
Effectively use the indigenous supply of nutrients (soil, water, crop residues, and manures)
Apply fertilizer to fill the gap between crop need and indigenous supply
Firmly based on scientific principles of nutrient requirements of the crop to achieve high yields

6. Nutrient management for rice: “Match supply to need”
1. Apply only a moderate amount of fertilizer N within 2 weeks after transplanting or 21 days after sowing
2. Use the LCC to distribute N from 2 weeks after transplanting
Select an N dose and critical LCC value to achieve high yield and 18 to 25 kg grain yield increase per kg N applied
Achieve 1 ton yield increase with 40 to 55 kg N/ha
3. Apply sufficient P and K to overcome deficiency and replace nutrient removed with crop harvest
Apply P basal
Split apply K (50% basal and 50% at panicle initiation)

7. Source of nutrients taken up by rice
Soil
Crop residues and manures
Irrigation water
Biological N2 fixation
Fertilizers

8. Source of nutrients taken up by rice
Nitrogen
Potassium
Nutrient needed for
yield target
Irrigation water
Biological N2 fixation
Crop residues & manures
Soil

9. Source of nutrients taken up by rice
Nitrogen
Potassium
Nutrient needed for
yield target
gap
Irrigation water
Indigenous nutrient supply
Biological N2 fixation
Crop residues & manures
Soil

10. Source of nutrients taken up by rice
Nitrogen
Potassium
Nutrient needed for
yield target
Fertilizer
Irrigation water
Biological N2 fixation
Crop residues & manures
Soil

11. SSNM aims to increase profit for rice farmers through
High yield
High efficiency of fertilizer use

12. Implementing SSNM
Match early application of N with low initial demand of rice for N.
Dynamically apply N based on leaf color, as a measure of plant need for N.
Determine P and K needs based on crop growth to overcome deficiency and replace nutrient removed with crop harvest.
Use existing recommendations for micronutrients.
Provide principles and guidelines to assist decision making by extension and farmers.

13. Development and evaluation of site-specific nutrient management (SSNM) for rice
GBPUAT
TRRI
SWMRI
IIRR
PhilRice ZU
MAS
CLRRI
NISF
PTRRC
GAAS
HAU YU
HZAU
BRRI
HUAF
Member from 1994 or 1997
Member from 2001
Affiliated member
PPI/PPIC
IFA
SDC
IPI