Which soil conditions impede seedbed establishment for introduced grasses?

• A. Crusting alone limits seedbed establishment
• B. Crusting, compaction, and salinity impede establishment
• C. Gentle slope and high organic matter promote establishment
• D. High soil fertility guarantees establishment

Answer: (B)

The main idea is that several soil constraints can interact to block seedbed establishment for introduced grasses. Crusting creates a hard surface after rain, which reduces water infiltration, limits seed–soil contact, and makes it hard for seedlings to emerge. Compaction squeezes the pore space in the soil, slowing infiltration, restricting root and shoot growth, and reducing the oxygen available to germinating seeds. Salinity adds osmotic stress, making water uptake by seeds and young roots more difficult and, at high levels, can be toxic. When crusting, compaction, and salinity occur together, they present multiple barriers from the surface down into the rooting zone, making establishment much less likely than with any single factor alone. By contrast, gentle slope and high organic matter support establishment, and high soil fertility does not by itself guarantee establishment because these other problems can still impede growth.