Fig. 2 Box plots of the yields of soft white winter wheat in response to all fertilizer in a deep band below the seed and direct-seeded at the indicated locations with (+) and without (-) soil fumigation in rows spaced uniformly (U) at 30 cm apart or in pairs (P) spaced 18 cm apart with 42 cm between paired rows, (A) all treatments, (B) only those treatments with wheat straw on the soil surface, and (C) only those treatments with bare soil. White bars are the yield means and brackets are the yield extremes
