Mesic Typic Hapludult Research Articles

Effect of Differential Adsorption of Potassium and Magnesium in Soils on Magnesium Uptake by Corn

AbstractIndices of the differential adsorption of potassium (K) and magnesium (Mg) were used to explain the differences in magnesium uptake by corn seedlings (Zea mays L.) grown on two widely different soils of the Rayne (a fine‐loamy, mixed, mesic Typic Hapludult) and the Hublersburg (a clayey, kaolinic, mesic Typic Hapludult) series. The differential adsorption of potassium was found to be the controlling factor in the uptake of magnesium by corn seedlings in these two soils. The differential adsorption concept may be useful in predicting which soils may or may not respond readily to magnesium fertilization.

Determination of Physiological Maturity in Oat1

AbstractIn studying various ecological and physiological factors affecting the yield of the several small grains, it is important to be able to define the length of the grain fill period, that is the period from anthesis to physiological maturity. Unfortunately, the various small grain crops do not develop a readily recognizable indicator, such as the ‘black layer’ in corn, Zea mays L., and tested methods to evaluate physiological maturity in small grains seem to be lacking. Our objective was to evaluate several techniques for determining when physiological maturity occurs in spring oat, Avena sativa L. In this study, five methods of determining physiological maturity were evaluated. Field grown plants of ‘Astro,’ ‘Noble,’ and ‘Otee’ spring oat were tagged when the spikelets at the second node from the base of the panicle were at anthesis. Plants were grown on a Murrill fine silty loam (a mixed, mesic Typic Hapludults.). Beginning 15 days after anthesis for each cultivar, spikelets at the tagged node were sampled daily, and an evaluation made of color changes in certain panicle parts, the uptake of a red, water‐soluble dye, and the uptake of14C‐sucrose. The groats were then weighed, freeze‐dried, and reweighed to secure dry weight and fresh moisture content. Lack of dry weight changes significant at p ⩽ 0.05 was used as the standard method to define physiological maturity and the other techniques compared to this. When half of the glume tips no longer took up the red dye and approximately 75% of the glume surface was yellow it provided a useful, nondestructive estimation of physiological maturity as defined by the dry weight method. Small amounts of 14C‐sucrose were taken up for a few additional days, but dry weight changes were not significant at p ⩽ 0.05. Groat and grain moisture content did not satisfactorily indicate physiological maturity. Observations of color changes in the glumes and cessation of dye uptake, either alone or in combination, provide a method of comparing the length of the oat fill period under various cultural and environmental conditions and for various genotypes.

Influence of Date of Harvest on Yield and Agronomic Characteristics of Meadowfoam1

AbstractLimnanthes alba Benth. is a winter annual and a potential new oil crop. Effective harvesting techniques are necessary to improve the seed retention of Limnanthes before its acceptance as an agronomic crop. The influence of time of harvest on seed yield, seed weight, and oil content was determined. The use of paraquat, 1,1′‐dimethyl‐4,4′‐bi‐pyridinium ion, as a harvest aid to hasten maturity and reduce shattering was evaluated. Seed yield, seed weight, and oil content were measured in the field on two plant introductions grown on a Matapeake silt loam (fine‐loamy, mixed mesic Typic Hapludults). A 20 to 37% decrease in yield was observed when the harvest was delayed 2 weeks. Harvesting 1 week before maturity resulted in the highest yield (1,461 kg/ha). The highest oil content (26%) and seed weight were obtained by harvesting at maturity. Paraquat was unacceptable as a harvest aid because of its adverse effects on yield and oil content.

Influence of Plant Stage at Initial Harvest and Height of Regrowth at Cutting on Forage Yield and Quality of Timothy and Orchardgrass1

AbstractThe need to obtain the best compromise between yield and quality has been recognized for years. The object of this study was to evaluate the influence of initial harvest at various growth stages and height of regrowth (all cuttings after initial harvest) at cutting on forage yield and quality of ‘Climax’ timothy (Phleum pratense L.) and ‘Pennlate’ orchardgrass (Dactylis glomerata L.). First growth of these grasses was harvested at each of the following stages: (a) transition (changing of apical meristem from vegetative to reproductive growth), (b) boot, and (c) anthesis. Following each initial harvest stage, regrowth was removed throughout the growing season at each of the following plant heights: 10 to 15 cm, 20 to 25 cm, 30 to 36 cm, 41 to 46 cm, and 51 to 56 cm. This field investigation was conducted during 1970 and 1971 on a fine, loamy, mixed, mesic Typic Hapludults (Murrill series) at the Agronomy Research Farm near Rock Springs, Penn.Delaying the first harvest of timothy and orchardgrass from the transition to anthesis stage resulted in increased yield and estimated total digestible nutrients (TDN). However, total seasonal regrowth, total TDN of regrowth, total digestible protein, and total digestible protein of regrowth decreased significantly (P≤0.05). Allowing plants of both species to attain heights of 20 to 36 cm, with few exceptions, produced highest total and regrowth forage yield, TDN, and digestible protein. However, frequent removal of regrowth, at a plant height of 10 to 15 cm, resulted in significantly (P≤0.05) lower yields and encouraged weed encroachment. These data indicate first harvest forage removal at the transition stage, followed by regrowth removal each time plants attain a height of 20 to 36 cm results in highest production of quality forage as measured by total seasonal regrowth, total TDN of regrowth and total digestible protein.