Introduction:
Crops require a steady supply of nutrients to grow and thrive. These nutrients can be obtained from various sources, both natural and artificial. Understanding the main sources of nutrient supply to crops is essential for effective agricultural practices.

1. Soil:
The soil is the primary source of nutrients for crops. It contains a wide range of essential elements required for plant growth, including macronutrients (nitrogen, phosphorus, and potassium) and micronutrients (iron, zinc, copper, etc.). These nutrients are present in the soil in varying amounts and availability, which influence crop productivity.

2. Organic Matter:
Organic matter, such as decomposed plant and animal residues, is an important source of nutrients for crops. As organic matter decomposes, it releases essential nutrients into the soil, making them available for plant uptake. Organic matter also improves soil structure, water-holding capacity, and nutrient retention, contributing to overall crop health.

3. Fertilizers:
Fertilizers are artificial sources of nutrients that are used to supplement the soil's nutrient content. They come in various forms, including synthetic fertilizers (manufactured industrially) and organic fertilizers (derived from natural sources like animal manure or compost). Fertilizers are applied to the soil or foliage to provide specific nutrients that may be deficient in the soil, thereby enhancing crop growth and yield.

4. Irrigation Water:
Water used for irrigation can also be a source of nutrients for crops. Some essential elements like calcium, magnesium, and sulfur are present in water sources and can contribute to plant nutrition. However, the nutrient content in irrigation water varies greatly depending on the source, location, and treatment processes.

5. Atmospheric Deposition:
Plants can also acquire nutrients from the atmosphere through various processes. Rainfall can wash nutrients from the air and deposit them onto the soil surface, where they become available for plant uptake. Additionally, certain plants can directly absorb nutrients, such as nitrogen, from the air through their leaves.

Conclusion:
The main sources of nutrient supply to crops include the soil, organic matter, fertilizers, irrigation water, and atmospheric deposition. Understanding these sources and their contributions to plant nutrition is crucial for maintaining healthy crop growth and maximizing agricultural productivity. By effectively managing these nutrient sources, farmers can ensure optimal nutrient availability for their crops, leading to improved yields and overall agricultural sustainability.