Question

Why does a farmer put lime (calcium oxide) on the soil?
(A) Act as a fertilizer
(B) To kill pests
(C) To make the soil less acidic
(D) To make the soil less alkaline

Answer 1

Hint: Agricultural lime is a powdered limestone or chalk-based soil supplement. Calcium carbonate is the main active ingredient. Calcium oxide is one of the additional compounds that may be present depending on the mineral source. Powdered limestone, unlike quicklime (calcium oxide) and slaked lime (calcium hydroxide), does not require lime to be burned in a kiln; it just requires grinding.

Complete answer:
All of these forms of lime are occasionally employed as soil conditioners, with the general theme of supplying a base to rectify acidity, although crushed limestone is most commonly used in farm fields today. Historically, burnt lime was often used to lime agricultural fields; the discrepancy may be explained in part by the fact that inexpensive mass-production-scale fine milling of stone and ore relies on technology established since the mid-nineteenth century.
The following are some of the impacts of agricultural lime on soil:
It raises the pH of acidic soils, lowering acidity and raising alkalinity.
It serves as a calcium supply for plants.
For acidic soils, it enhances water penetration.
It enhances plant absorption of key plant nutrients (nitrogen, phosphorus, and potassium) in acidic soils.
Dolomitic lime and hydrated lime are two more types of lime that are commonly used in agriculture and gardening. Dolomitic lime can be used as a soil amendment to give comparable benefits as agricultural lime while also providing magnesium.
Hydrated lime can be used as a disinfectant in animal husbandry, creating a dry, alkaline environment in which bacteria cannot easily grow. It can be used as an insect repellent in horticulture farming without harming the pest or the plant. Agricultural lime is often dispersed on fields with spinner-style lime spreaders.
If the farm is acidic, lime is applied to the soil to reduce the acidity and attain the required pH range for farming.
Hence option C Is correct.

Note:
Soils can become acidic for a variety of reasons. Leaching causes acidification in areas where there is a lot of rain. Crop- and livestock-grazed land loses minerals over time and becomes acidic as a result of crop removal. The reaction of plant nutrients in the soil caused by the use of modern chemical fertilisers is a key contributor to soil acidity.