📖 Lesson 6: Soil Nutrients & Deficiencies

👩🏽‍🏫 Introduction

Hello soil scientist! 🌱🔬

Have you ever wondered why some crops grow strong and green while others are weak and yellow? The secret lies beneath the surface—in the nutrients found in soil.

Just like your body needs vitamins and minerals to stay healthy, plants need nutrients from the soil to grow, flower, and produce food. In this lesson, you’ll learn the types of soil nutrients, their functions in plant growth, and what happens when they are missing.

📘 Core Concepts

🔹 What Are Soil Nutrients?

Soil nutrients are chemical elements in the soil that plants absorb through their roots. These nutrients help with:

• Growth 🌿

• Photosynthesis 🌞

• Root and fruit development 🍎

They are grouped into two main types:

1. Macronutrients (Major Nutrients)

Plants need these in large amounts.

2. Micronutrients (Minor Nutrients)

Needed in small amounts, but still essential.

📌 Too much or too little of these nutrients can harm plants.

🔍 How Do Plants Get Nutrients?

Plants absorb nutrients through their roots from the soil water (called soil solution). That’s why:

• The type of soil,

• Its pH, and

• Its moisture content
  all affect how well nutrients are absorbed.

🧪 Identifying Nutrient Deficiencies

Farmers and gardeners look for signs like:

• Yellowing leaves

• Stunted growth

• Poor root development

• Low fruit yield

🧠 These symptoms help identify which nutrient is missing!

🧩 Sample Problem Walkthrough

🧠 Problem:
A maize plant has yellow leaves and poor growth. What nutrient is likely deficient, and how can it be corrected?

✅ Step-by-Step Solution:

• Yellow leaves and stunted growth are signs of nitrogen deficiency.

• This can be corrected by applying nitrogen-rich fertilizer (like urea or ammonium nitrate).

✔️ Answer: Nitrogen is deficient. Apply a nitrogen fertilizer.

✍🏽 Practice Exercises

1. Fill in the blanks

(a) _______ helps in root development and flowering.
(b) _______ gives leaves their green colour through chlorophyll.
(c) _______ is a micronutrient that helps with flower development.

Answers:
(a) Phosphorus
(b) Magnesium
(c) Boron

2. Match the Nutrient to Its Deficiency Symptom

Answers:
(i) → B, (ii) → C, (iii) → A

3. Short Answer

Q: What is the difference between macronutrients and micronutrients?

Sample Answer:
Macronutrients are needed in large amounts (like nitrogen and potassium), while micronutrients are needed in smaller amounts (like iron and zinc), but both are essential for plant growth.

🌀 Recap

Today, you learned:

• Soil nutrients are vital for healthy plant growth.

• Macronutrients include nitrogen, phosphorus, and potassium.

• Micronutrients include iron, zinc, and boron.

• Deficiency of any nutrient leads to poor plant health and lower yields.

• Farmers use symptoms to diagnose deficiencies and apply the right fertilizer.

💭 Reflection Prompt

Imagine you are a farmer and your crop’s leaves are turning yellow. What steps would you take to figure out what’s wrong—and how would you fix it?