Agronomy Journal

Mays, D. A.; Terman, G. L.

doi: 10.2134/agronj1969.00021962006100040001xpmid: N/A

Field experiments were carried out during 1965–67 to compare rates, sources and times of N topdressing for ‘Kentucky 31’ fescue (Festuca arundinacea). Uncoated ammonium nitrate (AN), urea, and other readily soluble N fertilizers resulted in higher first‐cutting yields, which were higher in content of total N. Sulfur‐coated urea (SCU) resulted in lower first‐cutting and higher later‐cutting yields than did the soluble N sources. Total annual yields were usually similar with all N sources. Mixtures of AN and SCU or split applications of AN resulted in the most uniform seasonal growth and N content. Lower yields and apparent crop recovery of N from uncoated urea and urea ammonium phosphate (UAP) indicated lower efficiency of these urea‐containing N sources for topdressing, particularly at higher N rates. December, January, February, and March topdressing dates had rather similar effects on forage yields and N contents.

Berry, R. F.; Hoveland, C. S.

doi: 10.2134/agronj1969.00021962006100040002xpmid: N/A

The effect of summer defoliation on autumn‐winter (October—February) growth of koleagrass, hardinggrass, ‘Ky 31’ and ‘Goar’ tall fescue was studied for two years. Clipping in June and July reduced the autumn‐winter forage yield of harding 55% and kolea 47% as compared with that of plots unclipped from May to September. Percent total available carbohydrates (TAC) in July was positively correlated with autumn‐winter production of both Phalaris species. Kolea was more summer dormant than harding.

King, J. W.; Beard, J. B.

doi: 10.2134/agronj1969.00021962006100040003xpmid: N/A

A technique was developed for measuring the rooting of sodded turfs. ‘Merion’ Kentucky bluegrass sod pieces, transplanted from organic and mineral soil, were placed in a frame having a fiberglass screen bottom. The frames containing the sod pieces were placed on a sandy loam soil and allowed to root. After 5 weeks the sod was lifted vertically from the underlying soil with a block and tackle technique. Sod grown on organic soil rooted into the underlying soil better than that produced on mineral soil.

Robinson, Frank E.

doi: 10.2134/agronj1969.00021962006100040004xpmid: N/A

Five plant densities of carrots, Daucus carota L. cultivar ‘Long Imperator #58,’ were studied under sprinkler irrigation in the arid Imperial Valley, California. Carrots on a 10‐cm square grid (870,000 per hectare) produced the least dry matter but the earliest roots of marketable size (35 T/ha). Twenty‐five days later plants in a 5.1‐cm square grid (3,370,000 plants per ha) produced both greater dry matter yields and yields of roots of marketable size (94 T/ha). The three greater densities of 13,590,000, 54,390,000, and 223,050,000 plants per ha produced greater dry matter yields but did not reach marketable size. Root‐to‐top ratios were approximately 1:1 in the two greatest densities and 2:1 in the three lowest densities.

Donnelly, E. D.; Patterson, R. M.

doi: 10.2134/agronj1969.00021962006100040005xpmid: N/A

Seed yield and proportion of chasmogamou seed as affected by irrigation and clipping were determined for 18 lines of sericea, Lespedeza cuneata. Seed yields were increased by irrigation regardless of clipping management; however, irrigation did not increase the percentage of chasmogamous seed. Clipping in June drastically reduced seed yield and percentage chasmogamous seed. Irrigation of clipped sericea further reduced chasmogamous seed percentage below that of nonirrigated clipped sericea. Lines reacted differently to irrigation and clipping both as to proportion of seed types and seed yield.

Colovos, N. F.; Koes, R. M.; Holter, J. B.; Mitchell, J. R.; Davis, H. A.

doi: 10.2134/agronj1969.00021962006100040006xpmid: N/A

The nutritive value of reed canarygrass (Phalaris arundinacea L.) was studied in two experiments. In the first year, effects of stage of growth at harvest and method of preservation on digestibility and nutritive value were studied using cattle. In the following year, effects of degree of maturity at harvest and level of feed intake on digestibility and nutritive value were investigated. Maximum ad libitum intake of each forage was determined with both cattle and sheep. First‐cutting reed canarygrass was harvested the first week of June and conserved as hay. In the first year, it also was stored as haylage in a conventional tower silo. Twelve to 15 days later, a more mature first‐cutting was harvested as hay. Forty days after each first‐cutting, an aftermath (second year only) was harvested and conserved as hay. For uniformity, all hay was artificially dried with heat at a mean temperature of about 44 C.

Foy, C. D.; Fleming, A. L.; Armiger, W. H.

doi: 10.2134/agronj1969.00021962006100040007xpmid: N/A

Differential aluminum tolerance of ‘Perry’ and ‘Chief’ soybean varieties, determined previously from growth on acid Bladen soil, was confirmed in nutrient solutions containing Al as the known growth‐limiting factor. Differences in Al tolerance between the two varieties were steadily increased as the Ca level of the nutrient solution was reduced from 50 to 8 to 2 ppm.

De Roo, H. C.

doi: 10.2134/agronj1969.00021962006100040008xpmid: N/A

The plant moisture stresses (PMS) in leaves, shoots, and roots of tobacco were determined as the negative hydrostatic xylem sap pressure in a pressure bomb.

Parker, M. B.; Harris, H. B.; Morris, H. D.; Perkins, H. F.

doi: 10.2134/agronj1969.00021962006100040009xpmid: N/A

An abnormal leaf characteristic of soybeans [Glycine max (L.) Merrill], described as crinkle leaf, was associated with high levels of water‐soluble soil and leaf manganese (Mn). Symptoms appeared on soybeans in a pot experiment using Hiwassee loam soil but were not evident on plants growing in Tifton loamy sand. An application of MnSO4, induced symptoms in soybeans on Tifton soil, and lime alleviated symptoms on Hiwassee soil. Symptoms included severe crinkling, interveinal chlorosis, necrotic spotting of leaves, and malformation of pods which resulted in more single seeded pods. Heavy rates of commercial fertilizer on a State loam soil in a field experiment caused similar leaf symptoms on soybeans. Symptoms in the field were associated with increased soil acidity, increased water‐soluble soil Mn, and high leaf Mn. Chicken manure applied at rates equivalent to commercial fertilizer N‐P‐K content slightly decreased soil acidity and produced normal plants. In the field, symptoms occurred at the pod‐fill stage during a period of high soil moisture. Yields were not affected by the toxic condition.

Davies, D. B.; Runge, E. C. A.

doi: 10.2134/agronj1969.00021962006100040010xpmid: N/A

Root explorations under oats and soybean growing in cores taken from four commonly occurring soil parent materials in Illinois were compared after 8 weeks growth. Nutrient deficiencies were minimized so that the comparison was between the physical properties of the four materials. Root growth in the silty clay, silty clay loam, and loam tills differed by small amounts and was much less in all three than in the loess parent material. The variation of root weight was significantly correlated with bulk density.