You own two fields and want to grow crops in them. A sample of soil
from each field was sent for a soil test. Results say that only the
second field is fit for growing crops. Why do you think so? What soil
do you think is present in that field?
Answers
Answer:
Divide the field into different homogenous units based on the visual observation and farmer's experience.
Remove the surface litter at the sampling spot.
Drive the auger to a plough depth of 15 cm and draw the soil sample.
Collect at least 10 to 15 samples from each sampling unit and place in a bucket or tray
Explanation:
Soil is a living, breathing, natural entity composed of solids, liquids, and gases. Soil has five major functions:
Provides a habitat for organisms
Recycles waste products
Filters water
Serves as an engineering material
Provides a medium for plant growth1
Our focus will be on the fifth function. In this role, soil provides structural stability for plants and retains and relinquishes water and the nutrients necessary for plant growth.
An ideal soil for plant growth contains 50% pore space and 50% solids, with the pore space filled with equal parts air and water. This distribution rarely occurs because pore space varies with soil texture and soil management. For example, tilling increases pore space, while poor drainage and compaction reduce it.
Soil solids are a blend of mineral materials and organic matter. The mineral materials are typically weathered rock of varying sizes called sand, silt, and clay. The organic matter consists of decaying plant and microbial residues. The relative amounts of pore space and mineral and organic matter vary greatly among different soil types. But for plant growth, most soil scientists agree that 50% pore space, 45% mineral matter, and 5% organic matter make up an ideal ratio (Figure 1–1a). The distribution of soils and pore space in compacted and poorly drained soil is illustrated in Figure 1–1b and Figure 1–1c.