After reading this article you will learn about:- 1. Meaning of Site Specific Nutrient Management (SSNM) 2. Concept of Site Specific Nutrient Management 3. Soil Test based Nutrient Management.
Meaning of Site Specific Nutrient Management (SSNM):
Site specific nutrient management is a set of nutrient management principles combined with good crop management practices that will help farmers to attain high yield and achieve high profitability both in the short and medium-term. The principles of SSNM are generic and also applicable to other crops including rice.
SSNM provides an approach for the timely application of fertilizers at optimal rates to fill the deficit between the nutrient needs of a high yielding crops and the nutrient supply from naturally occurring indigenous sources, including soil, crop residues, manures and irrigation water.
Applying the right nutrient source, at the right rate, at the right time, in the right place is essential to nutrient stewardship and is the core of the 4 Rs. Such 4 R nutrient stewardship for fertilizer best management practices is an approach that considers economic, social and environmental dimensions of nutrient management.
Concept of Site Specific Nutrient Management (SSNM):
Nutrient management and recommendation process in India is still based on response data arranged over large domains. The SSNM provides an approach for need based feeding of crops with nutrients while recognizing the inherent spatial variability.
It involves monitoring of all pathways of plant nutrient flows/supply, and calls for judicious combination of fertilizers, bio-fertilizers, organic manures, crop residues and nutrient efficient genotypes to sustain agricultural productivity.
It avoids indiscriminate use of fertilizers and enables the farmer to dynamically adjust the fertilizer use to fill the deficit optimally between nutrient needs of the variety and nutrient supply from natural resources, organic sources, irrigation water etc.
It aims at nutrient supply at optimal rates and times to achieve high yield and efficiency of nutrient use the crop. SSNM approach involves three stepsâ€”establishing attainable yield targets, effectively use existing nutrient sources and application of fertilizers to fill the deficit between demand and supply of nutrients.
Soil nutrient supply potential and its spatial variability, productivity potential and targets for crops and cropping systems, estimation of nutrient requirements, and fertilizer use efficiency besides assessment of resource quality and socio-economic background of the farmers are essential for developing site specific IPNS.
The soil, crop, nutrient and resource related parameters that are essential for suggesting and practicing site specific IPNS include:
i. Soil testing-nutrient supply potential.
ii. Productivity targets of crops and cropping systems and nutrient needsâ€”each ton of grain removes about 82 kg nutrients which do vary with crops and productivity,
iii. Efficiency of nutrient sourcesâ€”fertilizers organic nutrient sources like FYM, green manures.
iv. Composts, bio fertilizers, organic industrial wastes and soil amendments.
v. Nutrient efficient genotypes.
vi. Selection of suitable crops and cropping systems involving N fixing crops and their management.
vii. Correction of soil and nutrient related problems.
Soil Test based Nutrient Management:
Evaluation of soil fertility and making fertilizer prescriptions for sustained crop production is of importance to the farming section. Considerable progress has been made to understand the contribution of soil and fertilizer to crop nutrition and the influence of nutrient levels and management on crop productivity and nutrient use efficiency.
Soil testing to assess the nutrient supply capacity provided an opportunity for practical solutions to nutrient management. Soil test based recommendations will be useful only when it is based on important factors like soil, crop, variety, fertilizer and management interaction for a given soil condition.
The soil test based crop response (STCR) project of ICAR provided the right impetus to understand the variability in the soil and crop with practical solutions to enhance nutrient use efficiencies narrowing down to each farm or field. The on-farm trials provided further need and scope for refinement, and recommendations of fertilizer nutrient use over large domains.
Any deficit application of fertilizers will limit crop yields, facilitate nutrient mining and result in depletion of soil fertility. Excessive or imbalanced application not only wastes limited sources but also has the potential to pollute the environment. An approach towards mitigating such concern is site specific nutrient management (SSNM), which takes into account spatial variations in the landscape.
Use of GPS and GIS Systems:
Wide spread adoption of SSNM technologies based on soil testing require extensive soil sampling and analysis which could be a hindrance considering the available infrastructure. Use of Global Positioning system (GPS) and Geographical Information System (GIS) and mapping can provide the right support as cost effective alternative.