Ideal Moisture Research Articles

Growth and yield studies of Lupinus angustifolius and L. albus in Victoria

The effect of serial planting on dry matter production, leaf area, grain yield and yield components cf Lupinus angustifoiius (cvv. Uniwhite, Uniharvest and Unicrop) and L. albus (cv. Ultra) was investigated in field plots at Rutherglen in 1973 and 1974. Delayed planting reduced dry matter production of all cultivars, and leaf area for Ultra. Differences in dry matter partitioning were observed between the late flowering Uniharvest, and the early flowering Unicrop and Ultra. In Uniharvest, delayed plantings resulted in a greater proportion of total dry matter being produced during the flowering phase, whereas the reverse was true for Unicrop and Ultra. The later flowering cultivars showed marked grain yield and yield component reduction with later sowing. Yields were reduced by 160.6 kg/ha and 222.5 kg/ha for each week's delay in sowing Uniharvest and Uniwhite, respectively. This effect was offset in the early flowering cultivars by greater development of lateral branches. In addition, when Unicrop and Ultra were planted in April, pod and flower abortion on the main stem resulted from low temperatures at flowering time. Optimum sowing time was early April for Uniwhite and Uniharvest, and early May for Unicrop and Ultra. Excellent vegetative growth under ideal moisture conditions highlighted the poor harvest indices of lupins and the scope for genetic improvement in the genus.

The influence of a severe drought on net photosynthesis of white oak (Quercus alba)

A prolonged and intense drought during the summer of 1976 caused soil water potential in the upper 45 cm of the soil profile to decrease below −2.5 MPa. Predawn xylem pressure potential (P) frequently was less than −1.8 MPa. Under conditions of high soil moisture, net photosynthesis averaged more than 8.0 mg CO2∙dm−2∙h−1 between 0500 and 1800 hours, and maximum rates of net photosynthesis were above 14.0 mg CO2∙dm−2∙h−1. Average and daily maximum net photosynthesis decreased to less than 1.0 and 8.0 mg CO2∙dm−2∙h−1, respectively, during the peak of the drought. Maximum rates of net photosynthesis observed under controlled light and temperature conditions remained above or near 14.0 mg CO2∙dm−2∙h−1 even when predawn P equalled −1.83 MPa. Net photosynthesis seldom decreased below zero if quantum flux densities were greater than the compensation point during this period of record low soil moisture. Environmental conditions, such as fog and clouds, which reduced leaf temperatures and atmospheric evaporative demand, increased net photosynthesis although predawn P was less than −1.8 MPa. During cloudy days, rates of net photosynthesis were within 80% of those observed under ideal soil moisture conditions. The photosynthetic characteristics of white oak noted during this drought are coupled with other physiological traits of white oak to explain its relative success in the oak–hickory forest type.

Survey of the Results of Four Years Experiments On the Chemical Control of the Potato Root Eelworm

A large number of experiments were carried out with several nematicides or compounds thought to influence the development of the potato root eelworm. They include dichloropropane-dichloropropene, chloropicrin, ethylene dibromide, chloro-bromopropene, demeton, schradan and calciumcyanamide. It has been shown, especially using DD-mixture, that the moisture condition of the cysts at the time of treatment largely determines the nematicidal effect of the chemical. Soil moisture at the time of treatment should be considered in this respect, and not merely be taken into consideration when waterlogging prevents the distribution of the fumigant into the soil. In dune-sand soil, 100% kill was obtained in laboratory experiments at a concentration of 8 l/are between 4,2 and 11,8% water content of the soil, working at room temperature. The optimum for this soil type lies between 10 and 12%. Although in experiments where the temperature ranged between +8°C and - 8°C, it was not possible to obtain a 100% kill, it is thought that in practical working conditions for soil fumigation, the influence of soil temperature is of little importance. Field experiments confirmed these results. Treatment under ideal moisture conditions in the summer gave a 100 % control when based on soil sample examination and 99,6% when based on counting new cysts on the roots. Under dry conditions these figures were respectively 53,6% and 74,6%. Treatment during the winter gave no appreciable difference, except for the fact that nowhere was a 100% kill obtained. Yields per plant under ideal conditions varied from 1700 gr per plant to 96 gr per plant in the controls. It is thought that these considerations might prove helpful to explain certain discrepancies in the results of various published experiments on the control of the potato root eelworm.

Kansas Mycological Notes: 1952

The 1952 season was not particularly favorable for the development of fructifications of fungi as compared with the season of 1951 which had almost ideal moisture conditions. A deficiency of rainfall occurred throughout most of the season with drought conditions existing from the latter half of August through the remainder of the year. The saprophytic flora was curtailed and the collections of fleshy fungi were few. Several of the plant pathogenic fungi which in 1951 threatened to build up to epiphytotic proportions were completely checked by the dry conditions of 1952. For example, Dothistroma pini Hulbary, which is believed to be the cause of the serious needle-blight disease of pines, was not observed on any of the new needles produced in 1952 although abundant fruitbodies and spores were present on the 1950-51 meedles. Apparently the dry conditions, especially during May and June (3 inches of rainfall in 1952 compared with 17 inches for the two months in 1951), prevented infection of the developing needles. Fruitbodies of Dothistroma pini were found on two additional species of pine which were formerly thought to be resistant. On white pine (Pinus strobus L.) needle-blight symptoms were similar to those on the other susceptible pines (Austrian, western yellow, lodgepole and Swiss mountain pines), but on table mountain pine (Pinus pungens Lamb.) yellowish spots on only a few needles were noted. This is the first report in the United States of Dothistroma pini on these two species. Perhaps the most interesting fungus record new for Kansas was Ascoidea rubescens Brefeld & Lindau, a primitive ascomycete found in the slime flux of American elm (Ulmus americana L.). A brownish feltlike mat of mycelium was developed on the moist slime flux in which broad hyphae bore terminal cells (the asci) containing many hat-shaped ascospores similar to those produced in some yeast fungi. Single-celled, hyaline conidia were also produced on stout, erect conidiophores. The fungus was first collected in October on an old elm tree along Wildcat Creek. Later the fungus was found by S. M. Pady to be fairly common on elm trees on the Kansas State College campus and along the streets of Manhattan. Dr. Pady was able to culture the organism but only the

How Dry Should Wood Be for Various Industrial Uses?

Abstract The testing of wood for industrial uses is stated to be best made on its moisture content. Much wastage in manufacture is declared to be due to lack of knowledge of this fact, and the consequent antiquated test methods in use in the wood-goods manufacturing industries. The effect of climate on the ideal moisture content is said to count for little. Furniture, flooring, and other products are dried to about 6 per cent, wherever manufactured. A table is given of the equilibrium moisture content of wood at various atmospheric conditions and also a table of the dryness requirements for a wide variety of wood products.