Effects of Small Grain Stubble Height and Mulch on No‐Tillage Soybean Production 1

Little data are available on the increasing popular practice of no‐tillage planting soybeans ( Glycine max L. Merr.) in small grain stubble. To determine the effects of three small grain stubble heights and three straw mulch rates in branching height, plant height, lodging, population, and yield of no‐till planted soybeans, field studies were conducted at Warsaw and Suffolk, Va. for 3 years. Straw mulch treatments were normal amount (✕), twice the normal amount (2✕), and all straw removed (0). The three stubble heights were “Low” (10.2 cm), “Medium” (20.3 cm), and “High” (35.6 cm at Warsaw and 40.6 cm at Suffolk). Neither mulch rate nor stubble height affected final plant stand significantly, but there was a tendency toward fewer plants in the heaviest mulch rate. Mature plants at Warsaw were tallest in the high stubble with no difference between the low and medium stubble; the same trend was shown at Suffolk. Soybean plants grown in the ✕ and 2✕ mulch at Warsaw and the ✕ mulch at Suffolk were taller than those grown in the other mulch treatments. Lodging and pod height followed the same trend as plant height. Seed yield was highest in the medium stubble and ✕ mulch rate. It is concluded that harvesting small grain to leave a 20‐cm stubble produces optimum soybean yields and the addition of mulch shows no benefit.