Reference

Weed control in reduced tillage corn production systems

Weed control in reduced tillage corn production systems. Moomaw, R. S.; Martin, A. R. (Northeast Stn., Univ. Nebraska, Concord, Nebr., USA). Agron. J., 70(1), 91-4 (English) 1978. CODEN: AGJOAT. ISSN: 0002-1962. DOCUMENT TYPE: Journal CA Section: 5 (Agrochemicals) An investigation in weed control in till-planted and slot-planted corn with preplant translocated and contact herbicides, broadcast or band applications of preemergence herbicides, and a cultivation variable. Field expts. utilized previously undisturbed ridges of old corn rows for till-planting or slot-planting corn. Applications of 2,4-D butoxy EtOH ester [1929-73-3] and paraquat [4685-14-7] were used in combination with preemergence herbicide (atrazine [1912-24-9], cyanazine [21725-46-2], and alachlor [15972-60-8]) treatments that were either row banded or broadcast. One or 2 cultivations were imposed on the 2 tillage systems. Till-planting resulted in more soil surface tillage and less dependence on herbicides than did slot-planting. Max. corn yield was achieved in the till-plant system by row banding several preemergence herbicide treatments, coupled with one cultivation. Slot-planting resulted in less soil disturbance with the planter than did till-planting and required more herbicide usage. With slot-planting, a preplant application of 2,4-D was essential to remove the predominantly broadleaf weed population and maximize corn yields. When preplant 2,4-D was used with slot-planting, corn yields were not different between band and broadcast applications of the preemergence herbicides used. Two cultivations rather than one tended to increase yields of slot-planted corn.

Adsorption, mobility, and degradation of cyanazine and diuron in soils

Adsorption, mobility, and degradation of cyanazine and diuron in soils. Majka, J. T.; Lavy, T. L. (Univ. Nebraska, Lincoln, Nebr., USA). Weed Sci., 25(5), 401-6 (English) 1977. CODEN: WEESA6. DOCUMENT TYPE: Journal CA Section: 5 (Agrochemicals) In the field, surface applied cyanazine (I) [21725-46-2] and diuron [330-54-1] did not move below 5 cm in a Monona silty clay loam (Typic Hapludoll) which received 20 cm of water over a 54-day period. In hand-packed soil columns in the lab., surface-applied diuron and I penetrated to depths of 10 and 20 cm, resp., when leached over a comparable time period and with amts. of water similar to that used in the field. Soil thin-layer chromatog. and adsorption isotherm studies showed that diuron was adsorbed more strongly than was I. In general, both compds. were degraded more rapidly at the higher temps. when incubated at 5, 20, 35, and 50 over a 20-wk period. Degrdn. was slowest at 5° in a Valentine loamy fine sand (Typic Ustipsamment). Diuron appeared to break down most readily at 35°. Cyanazine was usualy decompd. by the 10th week at 5° and the 5th week at higher temps.