Drought and nutritional stresses are the biggest restraints to crop yields in the southeastern U.S. One of the main underlying causes for the stresses is the inability of roots to penetrate deeply into the soil horizon and efficiently absorb water and nutrients, and crop plants must compete with weed species for the resources. In this series of experiments, we examine the ability of roots of different soybean genotypes and weed species to penetrate soil layers with high bulk densities and to acquire nutrients from subsoil patches. Plants were grown for 4 to 5 weeks in custom-built PVC cylinders (25 cm ht, 12.7 cm id) filled with a silt loam soil. The cylinders were separated into 3 sections, with the middle section of the cylinder packed to a bulk density of 1.6, 1.7, 1.8, 1.9, or 2.0 g/cu cm, and the top and bottom sections were 1.6 g/cu cm. Additionally, in separate experiments, labeled 15N fertilizer was placed in capsules in the bottom section to quantify nutrient retrieval from localized N patches. The experiments have revealed some variation among soybean genotypes in the ability to penetrate high bulk densities. None of the soybean roots, however, could penetrate densities greater than 1.8 g/cu cm. In contrast, Palmer amaranth roots were able to penetrate 1.9 g/cu cm and, to a small extent, 2.0 g/cu cm. Sicklepod roots extensively penetrated 2.0 g/cu cm. Penetration through the compacted layer was associated with fine roots. Yet, penetration was not readily explained by differences in species root morphologies, because sicklepod root diameters generally are only slightly smaller than soybean and neither have roots as small as amaranth. Experiments are continuing to examine root properties that allow root penetration through compacted layers and morphological adjustments associated with proliferation in nutrient patches lower in the soil profile.