Methods of fertilizer application include scattering and mixing with the soil before planting; application with a drill below the surface of the soil at the time of planting; row application before or at planting time; and row application during plant growth, also called side-dressing.
The Prophet (SAW) says "Search for your livelihood much below the soil - at every layer of the earth surface".
Genotypes were sown in pots either free-drained (control) or waterlogged to 10 mm below the soil surface at the start of the experiment.
The sor1 mutant has relatively thick roots (data not shown) that elongate above and just below the soil surface beginning at the seedling stage.
After 2.5 months, in mid-July, the water level in half of the replicate mesocosms was allowed to fall through evapotranspiration to 5 cm below the soil surface and was maintained at this level for rest of the experiment; in the remaining mesocosms the water level was maintained at the soil surface.
Corresponding changes occur in herbaceous plants, in which the preparation for winter may involve the dying back of aerial parts altogether, leaving protected organs at or below the soil surface.
Species were kept at a constant water level with saturation at 15 cm below the soil surface.
Many scrubland shrubs develop a swollen stem base or an underground woody organ called a lignotuber, which, because it is at or just below the soil surface, is protected from damage even during fires that completely remove the shrub's crown.
The three soil moisture regimes in three replicates each were: (A) drip-irrigation at −50 kPa of soil matric potential (IR50); (B) drip-irrigation at −80 kPa of soil matric potential (IR80); and (C) constant shallow water table at 0.45 m below the soil surface (WT45).
In one soil column the water table remained constant at −20 cm below the soil surface, while in the other the water table oscillated between the soil surface and the bottom of the column, at a rate of 4.8 cm d−1.
After 10 days, when the native seedlings had successfully established, we planted one 8-to 10-cm piece of knotweed rhizome, with two intact nodes, in the centre of each pot, at 5 cm below the soil surface.
