Fill in the following blanks with suitable words :
Excessive use of chemical fertilisers make the soil……..

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks us to fill in the blank regarding the effect of excessive use of chemical fertilizers on soil.

2. **Identifying Key Terms**: The key term here is "chemical fertilizers." These fertilizers often contain mineral acids.

3. **Effects of Chemical Fertilizers**: When chemical fertilizers are used excessively, they can alter the soil's pH level. Specifically, they can increase the acidity of the soil.

4. **Conclusion**: Therefore, the blank can be filled with the word "acidic." The complete sentence would read: "Excessive use of chemical fertilizers makes the soil acidic."

5. **Implications**: It is important to note that acidic soil can lead to a decrease in organic matter and ultimately reduce the productivity of the soil over time.

**Final Answer**: Excessive use of chemical fertilizers makes the soil **acidic**.

---