Which of the following are indicators of soil salinity?

The presence of high electrical conductivity and a white crust on the surface are indeed strong indicators of soil salinity. High electrical conductivity in soil typically indicates the concentration of soluble salts, which is a direct consequence of salinity. When water evaporates from the soil surface, salts can accumulate and form a crust, visible as white deposits. This crust is primarily made up of salts such as sodium, calcium, and magnesium, which can impair plant growth by affecting water uptake and nutrient availability.

The other options do not directly indicate soil salinity. Low organic matter and compacted layers may relate to soil structure and fertility but do not specifically point to salinity issues. High moisture content and looseness in the soil might suggest healthy soil conditions but do not necessarily reflect salinity levels. High nutrient levels and soil color variation might indicate different soil types or nutrient availability but are not definitive indicators of salinity.