Concept of INM :
Primarily INM refers to combining old and modern methods of nutrient management into ecologically sound and economically optimal farming system that uses the benefits from all possible sources of organic, inorganic and biological components/substances in a judicious, efficient and integrated manner. It optimizes all aspects of nutrient cycling including N, P, K and other macro- and micronutrient inputs and outputs, with the aims of synchronizing nutrient demand by the crop and its release in the environment.
A complete set of INM strategy comprises of several key steps which are as follows:
 • Determine soil nutrient availability and nutrient deficiency in crop plants. While soil sampling and laboratory determinations are usually used for assessing soil nutrient availabilities, there are two general ways to detect nutrient deficiencies. First, visual clues can provide indications of specific nutrient deficiencies through plant symptom analysis diagnosis. Second, where symptoms are not visible, post-harvest tissue and soil samples can be analyzed in a laboratory and compared with a reference sample from a healthy plant.
 • Systematically appraise the constraints and opportunities in the current soil fertility management practices, and how these relate to nutrient diagnosis, such as the insufficient or excessive use of N fertilizers.
 • Determine the farming practices and technologies that balance the nutrients which are necessary under different climates and soil types. The soil nutrient budgets for a given area and time can be calculated by the difference between the nutrient input and output as suggested by Fig. 4. Once these factors are understood, then appropriate INM technologies can be selected.
 • Assess the productivity and sustainability of INM practices. INM methods require locally appropriate technologies and farmers' participatory involvement in the testing and analysis.

The main principles of INM
 Below are the main principles of INM which include the following:
 (a) Using all possible sources of nutrients to optimize their input As mentioned earlier, the overall objective of INM is to maximize the use of soil nutrients to improve crop productivity and resource-use efficiency. Increased N fertilizer application rates and an associated increase in environmental pollution have led to greater dependency of crops on soil derived N.
(b) Matching the soil nutrient supply with crop demand spatially and temporally.
(c) Reducing N losses while improving the crop yield

 Strategies for further development of INM

a)Combination of soil and plant analysis
b)fine-tuned to the local environmental conditions
c) Mechanization due to serious labor shortage
d)Conservation tillage and rainwater-harvesting technologies
e)Recycling of organic nutrient flows
f)New technological innovations
g) Appropriate policy interventions

In a nutshell, we can visualize the concept of INM. The key steps in INM are using all possible sources of nutrients to optimize nutrient inputs, spatial and temporal matching of the soil nutrient supply with crop demand and reducing N losses while improving crop yield. Recent field experiments have demonstrated that INM can lead to significant increases in crop yields while substantially reducing reactive N losses and GHG emissions. As there has been a continuous overuse of chemical fertilizers in association with low resource-use efficiency and serious environmental pollution, the use of nutrient inputs from organic fertilizers will be of fundamental importance for plant growth and environmental concerns, which should be a priority for INM practices. In general, the INM method provides a “win–win” opportunities to simultaneously increase crop production and reduce environmental impact. The methodology adapted for INM should also be site-specific and must be tailored to local circumstances, as there is no “one-size-fits-all” solution to the complex problems of smallholder farmers in diverse agricultural systems. Thus, a demand-driven approach to development programs will be crucial for future widespread diffusion of INM.