Dale Smith

Varietal chemical differences associated with freezing resistance in forage plants

Summary The data presented show that many chemical changes occur in the overwintering parts of plants during the development of frost hardiness and that differences exist among species. However, there is still a question as to whether these alterations in plant metabolism are intimately involved in the development of frost hardiness or whether they are merely associated changes. Of the chemical constituents studied in the work reviewed, only the overwinter trends of total free sugars and water-soluble protein nitrogen were consistently correlated with the overwinter trends of frost hardiness.

Trends of nonstructural carbohydrates in the stem bases of switchgrass.

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Changes in elemental concentrations in alfalfa herbage at two soil fertility levels with advance in maturity

Abstract A two‐year‐old stand of Vernal alfalfa (Medicago sativa L.) established in 45‐cm rows was used to study changes in elemental composition in fertilized (F) and nonfertilized (NF) herbage at different growth stages. Herbage was harvested weekly for eight weeks with the final stage at 85% flower. Herbage yields, as well as concentrations and accumulations of fourteen elements, were compared in F and NF alfalfa. Herbage yields increased from earliest vegetative stage to 60% flower in NF treatment and to 10% flower in F treatment with no yield increases thereafter. Yield of herbage at all growth stages was not increased significantly by fertilization. Concentrations of K, S, P, Mg, Zn, Mn, B, N, Fe, and Al in herbage from both fertility levels, and Cl in NF herbage, generally decreased with advance in maturity. Concentrations of Ca at both fertility levels, and Cl in F herbage increased during early stages of growth and then decreased. Concentrations of Na and Cu showed no significant changes. Concent...

Chlorine concentrations in alfalfa herbage and soil with KCl topdressing of a low fertility silt loam soil

Abstract The purpose of this study was to determine the amount of Cl in plants and soil following topdressing of alfalfa with increasing amounts of KCl (0–0–60). The study was conducted with Ranger alfalfa on a low K Piano silt loam soil that had been topdressed twice during three years with a total of zero, 203, 406, 1220, and 2034 kg/ha of Cl as KCl (0, 224, 448, 1334, and 2240 kg/ha of K). Herbage was harvested annually three times at first flower plus an early October cut (4 cuts). The 3‐year average herbage yields were highest with 1220 kg/ha of topdressed Cl. Herbage yields decreased with 2034 kg/ha of Cl, but not significantly below that at 1220 kg/ha. Weakened and yellowed plants were noted in the spring of the second harvest year after 2034 kg/ha of Cl had been applied, and the first‐flower herbage contained 1.90% Cl. It was concluded that the weakened condition of the alfalfa was due to excess Cl. Movement of Cl through the silt loam soil was rapid. The largest concentrations of Cl in the soil t...

Diurnal variations of nonstructural carbohydrates in the individual parts of switchgrass shoots at anthesis

Highlight: Switchgrass (Panicum virgatum L.) was harvested at early anthesis in the field at Madison, Wisconsin, during 19 72. Shoots were separated into the inflorescence, individual green leaf blades, green leaf sheaths, and internodes at 6 am, 12 noon, 4 pm, and 12 midnight during 3 days: All tissues were analyzed for percentages (dry wt) of reducing and nonreducing sugars, total sugars, starch, and total nonstructural carbohydrates (TNC). Diurnal trends were clearest in the inflorescence, leaf blades, and the upper sheaths and internodes, but they were not always statistically significant. The trend was an increase of nonreducing sugar, total sugar, and starch percentages from 6 am to 6 pm and then a decrease to 12 midnight. Diurnal change in reducing sugar percentage was small in all plant parts. Basal sheaths and internodes tended to increase in percentage of starch and TNC from 6 am to 12 midnight. These are storage parts, and presumably carbohydrates were being translocated continuously from upper parts to these lower sinks for storage, especially after 6 pm. These data indicate that pasturing in the evening might provide advantages insofar as energy concentration in herbage is concerned. The highest content of energy occurred in the inflorescence of all the individual shoot parts. Diurnal trends of elemental concentrations in the shoot parts also were determined and were found to be largely nonsignificant.

Distribution of chemical constituents among shoot parts of timothy and switchgrass at anthesis

Abstract Switchgrass (Panicum virgatum L.) and timothy (Phleum pratense L.) shoots were harvested at 12 noon during three days at Madison, Wisconsin. Shoots were separated into the inflorescence, individual green leaf blades, green leaf sheaths, and internodes. Switchgrass shoots, inflorescences, and leaves were greater in dry weight than those of timothy. Switchgrass shoots had higher concentrations of all macro‐ and microelements measured than timothy, except for K. Most shoot parts of switchgrass were low in K percentage, indicating that switchgrass possibly may have a lower critical K level than timothy for maximum herbage production. Switchgrass shoots contained a concentration of Mg that was three times higher than timothy. This difference is worthy of note since one problem associated with grazing is hypomagnesemia. Fructosans were found only in timothy, but both grasses contained starch. Percentage of total nonstructural carbohydrates (TNC) was nearly three times higher in the shoot of timothy tha...

Yield of alfalfa as influenced by levels of P and K fertilization

Abstract This study was conducted to ascertain further the need for P and K fertilizers to obtain maximum herbage yields from alfalfa (Medicago sativa L.). Vernal alfalfa was established on a low K Piano silt loam (Typic Argiudoll) soil and topdressed with zero, 22.4, and 44.8 kg/ha of P in autumn of seeding year and with zero, 224, and 672 kg/ha of K as KC1 each autumn. The harvest schedule was three cuts annually at first flower; a schedule widely recommended in the North Lake states. No statistical significance was found for P levels nor for the P x K interaction; significance was found only for K levels. Maximum herbage yield was obtained with 224 kg/ha of K in the first harvest year, but with the 672 kg/ha of K rate in the second harvest year. Herbage K and Cl percentages and amounts removed from the soil increased significantly each year with each increase in K applied. Herbage P and N percentages were decreased significantly with the first increment of K. Residual herbage yields showed dramatically...

Changes in herbage chemical composition due to proportion of species in alfalfa‐orchardgrass mixtures

Abstract Legumes and grasses are widely grown in mixtures throughout the United States and Canada. This study was conducted to determine the changes in chemical composition of herbage that occur as proportion of legume and grass change in the mixture. Composition of mixtures of alfalfa (Medicago sativa L.) and orchardgrass (Dactylis glomerata L.) were studied after their herbage had been mixed by weight into seven different proportions: 100% alfalfa ‐ 0% orchardgrass, 80% ‐ 20%, 65% ‐ 35%, 50% ‐ 50%, 35% ‐ 65%, 20% ‐ 80%, and 0% ‐ 100%, respectively. The forages were grown in rows of pure alfalfa or pure orchardgrass spaced 45 cm apart on fertilized Dodge silt loam (Typic Hapludalf). Alfalfa was at late bud and orchardgrass was a few days from the appearance of the first anthers when harvested on May 29, 1975. Four replications of each of the mixtures were prepared, and the mixtures were made after tissues had been ground to 40‐mesh size. No significant differences among mixtures were found for S, Cu, tot...

Vegetative responses of silage cats fertilized in the growth chamber with various levels of N and K

Abstract Oats (Avena sativa L.) are often harvested for silage in the Great Lakes states. The objective of this research was to obtain additional information on the response of oats to N and K fertilization. ‘Froker’ spring oats were grown from seed under 27 C day/21 C night temperatures in a growth chamber. The soil was a 4:1 mixture of Dodge silt loam soil (Typic Argiudoll) and sand that contained low levels of N and K. The potted plants were fertilized with 0, 50, 100, and 200 kg/ha of N as NH4NO3 in all combinations with 0, 200, and 400 kg/ha of K as KC1. Plants were harvested at early inflorescence emergence (43 days after seeding). Fertilization with N significantly increased the dry matter yields (g/pot) of the herbage and total plant, the number of axillary tillers/pot, and herbage N percentage. Root yields were increased only with the first increment of N. Nitrogen fertilization had no significant effect on height of the primary shoots and herbage K percentage. The first increment of K (200 kg K/...

Influence of temperature during the preceding growth period of lucerne on its regrowth at different temperatures

One-year-old lucerne (Medicago sativa L. cv. ‘Vernal’) plants were grown to first flower through three cuttings in three temperature regimes, H (33°C day/24°C night), W (27718°C) and C (21712°C), to ascertain the influence of temperature preceding defoliation on subsequent growth. At first and second harvests, some pots were retained in the same temperature regime and the remainder were moved to the other regimes. The following temperature treatments were selected: H in the first, second and third cuttings (H-H-H), H-W-C, H-C-W, W-H-C, W-W-W, W-C-H, C-H-W, C-W-H and C-C-C. Foliage from all plants was harvested at first flower, but only six replications of each temperature treatment were harvested destructively at the end of each growth cycle. When plants were retained at the same temperature for the three cycles, the mass of plant parts and total non-structural carbohydrate (TNC) percentage in roots at each harvest increased with a decrease in temperature. Herbage yields were not influenced greatly by the...