Shattercane and grain sorghum [Sorghum bicolor (L.) Moench] seeds were buried at three depths for various times. Few grain sorghum seeds were viable 4 months after burial regardless of burial depth. None were viable 8 months after burial.Only a few shattercane seeds from compact panicles were viable 4 months after burial, but some remained viable 3 years, mostly at the deeper burial depths (30.5 to 38.0 cm). Light was not a major requirement for germination after seeds were retrieved from burial regardless of time buried.Some shattercane seeds from open panicles germinated after retrieval from all three burial depths even after 3 years. In general, number of viable seeds increased as depth of burial increased regardless of time buried. Germination, light‐dependent in many wild cane seeds from open panicles, increased in light dependence with length of burial.

Effects of soil water and herbicide vapors on the phytotoxicity of eight dinitroaniline herbicides to oats (Avena sativaL. ‘Dal’) were studied. Oat primary root length was inhibited more by the herbicides than was shoot length or shoot fresh weight. All of the herbicides, except oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide), inhibited primary root length through vapor activity. Vapors of dinitramine (N4,N4-diethyl-α,α,α-trifluoro-3,5-dinitrotoluene-2,4-diamine) were most inhibitory. Herbicide vapor inhibition increased with temperature. Soil water affected oryzalin activity more than it did that of the other herbicides. Oryzalin phytotoxicity to the oat primary root was reduced more at the low soil water than was that of the other herbicides. Its low vapor activity apparently reduced its effectiveness in dry soil. Difference in magnitude of herbicide phytotoxicity between two soil moisture levels generally was more pronounced at lower herbicide concentration.

An oat (Avena sativaL. ‘Dal’) primary root bioassay procedure was used to study the persistence of eight dinitroaniline herbicides in soil. Sensitivity of the bioassay to the herbicides depended on the length of time roots were exposed to the herbicide treatments. Root inhibition increased with time of exposure. Herbicide persistence was studied under growth chamber, greenhouse, and field conditions. The herbicides remained biologically active the longest under dry and cool soil conditions. At 5 C, little change in herbicide activity was observed over an 8-month period. Under greenhouse conditions, the herbicides in wet soil dissipated rapidly, as compared with those in dry soil. Soil samples taken from depths of 0 to 7.5 cm and from 7.5 to 15 cm in the field showed that the herbicides were retained primarily in the surface 7.5 cm. Small amounts were found from 7.5 to 15 cm only shortly after the herbicides were applied. Dinitramine (N4,N4-diethyl-α,α,α-trifluoro-3,5-dinitrotoluene-2,4-diamine) was the only herbicide tested of which soil residues from spring field applications were not detected the following fall.

Adsorption of benefin (N-butyl-N-ethyl-α,α,α-trifluoro-2,6-dinitro-p-toluidine), dinitramine (N4,N4-diethyl-α,α,α-trifluoro-3,5-dinitrotoluene-2,4-diamine), fluchloralin [N-(2-chloroethyl)-2,6-dinitro-N-propyl-4-(trifluoromethyl)aniline], oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide), profluralin [N-(cyclopropylmethyl)-α,α,α-tri-fluoro-2,6-dinitro-N-propyl-p-toluidine], and trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) was studied in 10 Wisconsin soils. Ratios of the quantity of each herbicide adsorbed and quantities remaining in the soil solution at equilibrium (Kd value) on a Piano silt loam (Typic Argiudoll fine-silty, mixed, mesic) remained relatively constant over a range of concentrations. Herbicide adsorption by the soils was related more closely to soil organic matter than to the other soil chemical and physical properties. Diffusion of the herbicides in Piano silt loam was affected by soil water. Diffusion of trifluralin, profluralin and benefin decreased as soil water increased. Diffusion of dinitramine and fluchloralin did not change significantly with change in water content. Diffusion of oryzalin increased at the highest soil water content. None of the herbicides moved more than 10 mm in the soil during a 17-day period. In unsaturated Piano silt loam, relative mobility of the herbicides was trifluralin ≥benefin>profluralin>fluchloralin>dinitramine≥oryzalin. Oryzalin reached highest mobility in water-saturated soil.

Eight substituted dinitroaniline herbicides were studied for relative effectiveness in controlling weeds and for tolerance of peas (Pisum sativumL.). Greenhouse trials comparing 10-5M herbicide solutions added to washed silica sand indicated that trifluralin (α,α,α-trifluroro-2,6-dinitro-N,N,-dipropyl-p-toluidine) and dinitramine (N4,N4-diethyl-α,α,α-trifluoro-3,5-dinitrotoluene-2,4-diamine) were the most phytotoxic to peas. Field trials conducted over a 3-yr period using 0.84 and 1.68 kg/ha application rates demonstrated that all eight of the herbicides successfully controlled the weeds present. Use of trifluralin resulted in the lowest shelled pea yields at both rates of application. Significant reductions in yield occurred from the 1.68 kg/ha rate of trifluralin in 1973 and 1975 when compared with the untreated checks. While major differences did not occur between the other chemicals, the greatest average pea yields resulted from the use of oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide), dinitramine, and fluchloralin [N-(2-chloroethyl)-2,6-dinitro-N-propyl-4-(trifluoromethyl)analine].