Hardwood cover crops:can they enhance loblolly pine seedling production
It has been extremely difficult to obtain more than two loblolly pine (Pinus taeda L.) crops following even effective soil fumigation with methyl bromide in southern forest tree nurseries. The traditional agronomic cover crops such as sorghum and sudex, unless followed by fumigation, do not normally produce satisfactory loblolly pine seedling crops. Various species of hardwoods appear to stimulate the following pine crop even in the absence of fumigation. In the present study, we fumigated immediately before the hardwood and sudex cover crop sequences because no effective herbicide was available to control weeds in the hardwood nursery beds. Heights and root collar diameters (RCD) of loblolly pine seedlings from all cover types were comparable. Stem weights were generally greater for seedlings in the hardwood-pine rotation. Also, the needles were longer and thicker in pine seedlings grown after hardwoods as compared to those following the sudex cover crop.