Best Management Practices ( BMP) for Monsoon Agriculture

SAIKAT K BASU

Do crop plants need fertilization during the monsoon season?

Yes, crop plants often do need fertilizer application during the monsoon, but with careful management. Here's why and how:

Why it's needed:

Leaching of nutrients: Heavy monsoon rains can wash away essential nutrients from the soil, especially nitrogen.

Increased growth demand: Plants grow rapidly during the monsoon due to ample water, increasing their nutrient needs.

Key considerations:

Type of fertilizer: Use slow-release or organic fertilizers to reduce leaching.

Split application: Apply fertilizers in split doses—before planting and then at intervals during the growing season—to improve uptake and minimize loss.

Avoid application before heavy rains: Fertilizing just before a downpour can lead to runoff and nutrient waste.

Use of micronutrients: Rain can cause micronutrient deficiencies, so balanced fertilization (NPK + micronutrients) is important.

What kind of fertilizers are mostly needed during the monsoon and why? 

During the monsoon season, crops experience rapid growth due to increased water availability, but heavy rainfall can also lead to nutrient leaching—especially of nitrogen. The types of fertilizers most needed during the monsoon are:

1. Nitrogen-based Fertilizers

Why: Nitrogen is essential for vegetative growth, and it gets easily leached from the soil due to heavy rains.

Examples: Urea, Ammonium Sulfate.

Application Tip: Apply in split doses to reduce loss due to leaching.

2. Phosphorus-based Fertilizers

Why: Phosphorus supports root development and early plant growth. Though it doesn't leach easily, wet conditions can make it less available to plants.

Examples: DAP (Diammonium Phosphate), SSP (Single Super Phosphate).

Application Tip: Apply at the time of sowing for better root uptake.

3. Potassium-based Fertilizers

Why: Potassium improves disease resistance and water regulation in plants. It's moderately leachable and thus may need replenishment.

Examples: MOP (Muriate of Potash), SOP (Sulfate of Potash).

4. Micronutrients (as needed)

Why: High rainfall can deplete micronutrients like zinc, iron, and magnesium.

Examples: Zinc sulfate, Ferrous sulfate.

During monsoon, balanced fertilization with an emphasis on nitrogen (in split doses), along with phosphorus and potassium at sowing, ensures healthy crop.

Do organic fertilizers or compost application work better compared inorganic synthetic chemical fertilizer application during the monsoon?

During the monsoon season, organic fertilizers or compost often perform better than synthetic chemical fertilizers for several key reasons, although the best choice can depend on the specific crop, soil, and farming practices. Here's a comparison based on monsoon conditions:

1. Nutrient Retention

Organic Fertilizers/Compost: Release nutrients slowly, which reduces nutrient leaching due to heavy rainfall. This makes nutrients available over a longer period.

Chemical Fertilizers: Release nutrients quickly, which can be washed away by rain, leading to nutrient loss and groundwater contamination.

2. Soil Structure and Health

Organic: Improve soil structure, increase water-holding capacity, and promote microbial activity — all beneficial during wet conditions.

Inorganic: Do not improve soil structure; repeated use can degrade soil quality over time.

3. Environmental Impact

Organic: Less likely to pollute water sources; environmentally safer.

Inorganic: Higher risk of runoff and eutrophication of nearby water bodies during heavy rain.

4. Immediate Nutrient Needs

Organic: Not ideal for emergency nutrient supplementation, as they release nutrients slowly.

Inorganic: Provide quick nutrient supply — useful if crops show deficiency symptoms that need fast correction.

5. Cost and Labour

Organic: May require more labour and bulk handling; cost varies based on availability.

Inorganic: Easier to apply and manage; more predictable nutrient content.

6. Best Management Practices for Monsoon Farming:

Integrated Nutrient Management (INM): Combine both organic and synthetic fertilizers. Use compost or well-decomposed manure to improve soil health and apply minimal chemical fertilizers based on soil tests to meet immediate nutrient demands. Use slow-release or coated fertilizers if relying on synthetic options during the monsoon. Well-managed organic soils or systems with strong crop rotations and cover crops may need less fertilizer.

Should the use of liquid fertilizer applications, fertigation and use of foliar sprays be restricted or completely haulted during the monsoon ?

The use of liquid fertilizers, fertigation, and foliar sprays during the monsoon season should be approached with caution rather than completely halted. Here's a breakdown:

1. Liquid Fertilizer &Fertigation

Caution: YES | Complete Halt: NO (with conditions)

Challenges: Heavy rains can cause nutrient leaching, washing away fertilizers before plants can absorb them. Risk of waterlogging, especially in poorly drained soils, can lead to nutrient loss and root damage.

Best Management Practices: Apply during dry spells or just before light rains, avoiding periods of heavy or consistent rainfall. Use split applications (smaller, frequent doses) to reduce leaching risks. Employ slow-release or stabilized fertilizers if available. Use soil moisture sensors or weather forecasts to guide timing.

2. Foliar Sprays

Caution: YES | Complete Halt: NO (with timing adjustments)

Challenges: Rain can wash sprays off the leaves, making them ineffective. High humidity can promote foliar diseases and reduce spray drying time.

Best Management Practices: Spray during dry windows (e.g., early morning or late afternoon when rain is unlikely). Use sticking agents or spreader-stickers to improve adhesion and effectiveness. Avoid spraying before or during expected rainfall.

Instead of a full halt, adapt the timing, type, and method of application to the monsoon conditions. Monitoring weather, using protective technologies (like covered fertigation systems), and precision agriculture practices will ensure nutrient efficiency and reduce losses.

(Photo by the author)