Photocopy of typescript. / Digitized by Kansas Correctional Industries

An alternative to herbicides in dwarf apple orchards (Malus pumila Mill.) is the use of mulches. Research objectives were to compare several mulch systems (Festuca rubra L., Lupinus albus L. plus Daucus carota L.; straw, manure compost, geotextile) with soil cultivation as to soil physical properties and plant nutrient levels in soils, leaves and fruit. Studies carried out in 1992 and 1993 on three dwarf apple orchards on the Macdonald Campus of McGill University showed that straw mulch increased soil water contents and exchangeable K, but reduced exchangeable Mg compared to Festuca mulch. Straw mulch reduced soil temperatures in summer relative to geotextile or cultivation. Festuca reduced leaf N contents but increased leaf P contents-elative to geotextile treatments. Soil nitrate N contents were correlated with soil water contents, and the ratios N/Ca and K/Ca in the fruit were unaffected by treatment. Straw and geotextile mulches increased soil water content and nitrate-N levels during peak sowing periods and thus were the superior treatments.

No description available.

One potential alternative to chemical weed control is the use of microwave radiation, a particular form of indirect thermal weeding. Absorption of microwave radiation causes water molecules within the tissue to oscillate, thereby converting electromagnetic energy into heat. This technique is rapid, versatile and effective, as the electromagnetic waves heat the plant tissue and destroy cellular integrity. The objective of this research was to evaluate the potential use of dielectric heating for weed management. Ten weed species representing monocots and dicots were selected for this study: southern crabgrass, dallisgrass, yellow nutsedge, fragrant flatsedge, false green kyllinga, common ragweed, field bindweed, henbit, white clover, and pitted morningglory. There was a lag or warm up period between energizing the magnetron and actual microwave radiation production. To eliminate the gap between electric power supplied to magnetron and actual microwave radiation produced, a conveyer was used. Overall injury to grasses, sedges and broadleaf weeds was higher at each dose when weeds were treated by microwave radiation while moving on a conveyer in comparison to being stationary. Grasses showed slightly more tolerance to microwave treatments in comparison to broadleaf weeds. Older weeds (8 to 10 weeks old) showed more tolerance to microwave treatments in comparison to younger weed plants (4 to 6 weeks old). Microwave radiation was able to control a range of weed species, although larger weeds were more likely to regrow after treatment. Ambient temperature had a significant effect on injuries caused by microwave radiation to target weeds, with control increasing as the air temperature increased. Weed control using microwave radiation required more energy when weeds were treated at 13 C compared to 35 C. More energy was needed at lower air temperatures to raise the plant canopy temperature from ambient levels to beyond the biological limit. Microwave radiation at lower doses caused greater injury to common chickweed and yellow woodsorrel than bermudagrass, suggesting the potential for selective weed control in certain situations. A custom built microwave applicator provided similar control of emerged weeds as the contact herbicides diquat and acetic acid. / Ph. D.

Call number: LD2668 .T4 1963 F55 / Master of Science

Call number: LD2668 .T4 1983 C43 / Master of Science

This study determined whether variation in clone, weed control treatment, or stem dimensions, could have an impact upon outerwood stiffness in 17 year old Pinus radiata stems. An experiment located south west of the Dunsandel township in Canterbury, New Zealand, was used to collect measures of acoustic velocity (windward and downward sides) from each of the 278 trees. Diameter at breast height, tree height, and height to live crown were also recorded for each tree. Findings from this research were compared with previous research carried out when the trees were ages eight and eleven. Assuming a green density of 1,000 kg/m3, Young’s Modulus equation was used to convert acoustic velocity to wood stiffness, or, Modulus of Elasticity (MOE). The effect of wind direction upon mean wood stiffness was not significant (α = 0.05). Consequently, one measure of wood stiffness was calculated per tree. Mean stem slenderness and mean wood stiffness values were calculated by block, weed control treatment, and clone. Weed control treatments had a significant impact upon mean wood stiffness in comparison to the control treatment (0.03 m2 area of weed control). Significant differences did not exist between different levels of weed control, ie., 0.75 m2, 3.14 m2 and 9 m2 chemical spot spray area. Clonal variation and stem slenderness significantly affected mean wood stiffness measures. Stem slenderness appeared to be correlated with clonal variation (interaction between clone and slenderness was not significant), however, according to Dr. Euan Mason, this finding is not corroborated by findings from other research on the wood quality of clones in Canterbury (personal communication, September 16, 2013). An analysis of covariance (ANCOVA) determined that mean height to the live crown was not a significant predictor of wood stiffness. Comparison with earlier research showed no change in the ranking of wood stiffness values by clone or treatment.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project. / From "Progressive Agriculture", January, 1965