Introduction to sitespecific nutrient management SSNM Need for

Introduction to site-specific nutrient management (SSNM)

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

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

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

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

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)

Source of nutrients taken up by rice • • • Soil Crop residues and manures Irrigation water Biological N 2 fixation Fertilizers

Source of nutrients taken up by rice Nitrogen Potassium Nutrient needed for yield target Biological N 2 fixation Irrigation water Crop residues & manures Soil

Source of nutrients taken up by rice Nitrogen Potassium Nutrient needed for yield target gap Biological N 2 fixation Irrigation water Crop residues & manures Soil Indigenous nutrient supply

Source of nutrients taken up by rice Nitrogen Nutrient needed for yield target Fertilizer Biological N 2 fixation Irrigation water Crop residues & manures Soil Potassium

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

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.

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