Spatial–temporal variability of soil moisture, nitrogen availability indices and other chemical properties in hoop pine (Araucaria cunninghamii) plantations of subtropical Australia

AbstractA branchlet-mining scolytid beetle, Hylurdrectonus araucariae Schedl, has invaded the hoop pine (Araucaria cunninghamii) plantations at Bulolo and Wau in Papua New Guinea. A study of the infestation pattern in a plot of 184 young (5–6 year-old) trees at Bulolo from February 1968–August 1972 revealed four major phases: (i), a relatively prolonged but small build-up of the population on most trees over a period of 12–18 months following the first attack; (ii), a dramatic upsurge in the infestation over the following 12–18 months, reaching a peak infestation with the severe attack of nearly all trees in the plot; (iii), a sharp decline in the number of attacks and population over the next 12–18 months due to a lack of nest sites and food and (iv), a slow decline over a protracted period. The variation (313 to 6220) in the maximum number of infested branchlets on the trees in the plot at peak attack was great, due to the differing amounts of foliage and size of the trees, but it usually represented an estimated 85–95% of the foliage.A comparative study of seedling resistance of the two major plantation species, hoop pine and klinkii pine (Araucaria hunsteinii) was carried out at Bulolo in 1967 using seedlings from the local nursery and placing them in cages with large quantities of infested foliage. Over a two-month period, no colonies of H. araucariae were established in the klinkii pine seedlings and only three of 32 attacks recorded in the hoop pine seedlings had produced brood. Infestation of seedlings was extremely rare in the plantations and natural stands. On the other hand, most trees aged 2·5 to 12 years in the plantations at Bulolo and Wau were susceptible to severe infestation. Older trees were seldom severely attacked. Klinkii pine has proved non-susceptible to attack. In studies of impact in three plots of 1000 trees at Bulolo from 1967–1971, least growth increment and highest mortality was recorded in the plot that had been initially severely affected by the scolytid. In contrast, good growth and low mortality was recorded in the plot of healthy trees. They were later exposed to severe infestation from the adjacent plantation of young 3–4 year-old trees, but escaped relatively unscathed. In another study of impact at Bulolo from 1967–1972, the effect of two levels of pruning on subsequent growth and re-infestation was examined. The results indicated that site also strongly affected the situation, with little growth and high mortality evident on poor sites. Secondary insects, notably the weevil Vanapa oberthueri Pouillaude, were an important factor contributing to mortality among the stressed trees.

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Spatial and Temporal Variability of Soil Moisture

International Journal of Geosciences ◽

10.4236/ijg.2010.12012 ◽

2010 ◽

Vol 01 (02) ◽

pp. 87-98 ◽

Cited By ~ 23

Author(s):

Vanita Pandey ◽

Pankaj K. Pandey

Keyword(s):

Soil Moisture ◽

Temporal Variability ◽

Spatial And Temporal Variability

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Responses of two hybrid Populus clones to flooding, drought, and nitrogen availability. I. Morphology and growth

Canadian Journal of Botany ◽

10.1139/b92-281 ◽

1992 ◽

Vol 70 (11) ◽

pp. 2265-2270 ◽

Cited By ~ 43

Author(s):

Zhijun Liu ◽

Donald I. Dickmann

Keyword(s):

Soil Moisture ◽

Water Stress ◽

Nitrogen Availability ◽

Carbon Allocation ◽

Hybrid Poplar ◽

Leaf Expansion ◽

Root Production ◽

Leaf Initiation ◽

Stem Biomass ◽

Nitrogen Levels

Repeated progressive drought and flooding stress were imposed on hybrid poplar clones Populus × euramericana 'Eugenei', and Populus tristis × Populus balsamifera ‘Tristis’ grown in pots in a greenhouse under two nitrogen levels. In both clones the rate of leaf initiation was promoted only in high-N plants subjected to minimum water stress. Water stress alone did not retard the rate of leaf initiation, but it significantly reduced leaf expansion of 'Eugenei', whereas only flooding led to smaller leaves in 'Tristis'. The addition of N stimulated leaf expansion, leaf chlorophyll and N concentrations, and leaf and stem biomass production across soil moisture levels, but the greatest effect of N was associated with minimum water stress. High N altered carbon allocation towards the aboveground portions, leading to lower root to shoot ratios. High N also appeared to stimulate initiation of fine roots. Soil moisture determined the amount of biomass that accumulated in roots, with highest root production in well-watered pots and lowest in flooded pots, with the droughted treatment in between. Leaves became thinner as soil moisture decreased from flooding. Stem biomass of 'Tristis' declined more under flooding than under drought, whereas 'Eugenei' displayed a greater reduction of stem biomass in droughty than in flooded soil. Key words: water stress, nitrogen, leaf and root morphology, root to shoot ratio, biomass, Populus, flooding.

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Influence of spatial and temporal variability of subsurface soil moisture and temperature on vapour intrusion

Atmospheric Environment ◽

10.1016/j.atmosenv.2014.01.053 ◽

2014 ◽

Vol 88 ◽

pp. 14-22 ◽

Cited By ~ 9

Author(s):

Dawit N. Bekele ◽

Ravi Naidu ◽

Sreenivasulu Chadalavada

Keyword(s):

Soil Moisture ◽

Temporal Variability ◽

Spatial And Temporal Variability ◽

Subsurface Soil

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A Scanning and Transmission Electron Microscope Study of Leaf Axil Structure in Araucaria cunninghamii

Australian Journal of Botany ◽

10.1071/bt9910067 ◽

1991 ◽

Vol 39 (1) ◽

pp. 67 ◽

Cited By ~ 1

Author(s):

GE Burrows

Keyword(s):

Smooth Endoplasmic Reticulum ◽

Leaf Axil ◽

Thin Walls ◽

Hoop Pine ◽

Axillary Meristems ◽

Full Complement ◽

Plasmodesmatal Frequency ◽

Transmission Electron Microscope Study ◽

Storage Products ◽

Araucaria Cunninghamii

The cells of active plant meristems are characterised by their small size, thin walls and a full complement of organelles, most noticeably a large nucleus surrounded by densely staining, little-vacuolated cytoplasm. The axillary meristems of Araucaria cunninghamii Aiton ex D. Don (hoop pine) possess a similar ultrastructure, even though they quickly assume a near complete, potentially permanent quiescence following their detachment from the flanks of the actively dividing apical meristem. However, they differ from metabolically active cells in that those organelles and structures associated with cytokinesis and cell wall formation are either absent (microtubules) or infrequent and in an apparently inactive state (smooth endoplasmic reticulum, non-vesiculating dictyosomes, nuclei with a low heterochromatin to euchromatin ratio). In addition, storage products (starch, lipid globules), usually not present in metabolically active cells, are well developed. In addition to not developing a bud-like organisation, the meristems are also unlike typical axillary buds in that they have no vascular or provascular connections with the axial vascular tissues and are bounded adaxially by a group of thick-walled cells. While these cells constitute a physical barrier around the axillary meristems, they are nucleated and possess numerous simple pits that have a high plasmodesmatal frequency. Thus it appears that the meristems are not physiologically isolated, but are in cytoplasmic continuity with the remainder of the plant.

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Experimental Evaluation for the Impacts of Conservation Agriculture with Drip Irrigation on Crop Coefficient and Soil Properties in the Sub-Humid Ethiopian Highlands

Water ◽

10.3390/w12040947 ◽

2020 ◽

Vol 12 (4) ◽

pp. 947 ◽

Cited By ~ 3

Author(s):

Abdu Y. Yimam ◽

Tewodros T. Assefa ◽

Nigus F. Adane ◽

Seifu A. Tilahun ◽

Manoj K. Jha ◽

...

Keyword(s):

Soil Moisture ◽

Soil Properties ◽

Irrigation Water ◽

Drip Irrigation ◽

Irrigation System ◽

Chemical Properties ◽

Crop Coefficient ◽

Conservation Agriculture ◽

Ethiopian Highlands ◽

Irrigation Water Use

A field experiment consists of conservation agriculture (CA) and conventional tillage (CT) practices were set up in two areas, Robit and Dangishta, in sub-humid Ethiopian highlands. Irrigation water use, soil moisture, and agronomic data were monitored, and laboratory testing was conducted for soil samples, which were collected from 0 to 40 cm depth before planting and after harvest during the study period of 2015–2017. Calculation of crop coefficient (Kc) revealed a significant decrease in Kc values under CA as compared to CT. The result depicted that CA with a drip irrigation system significantly (α = 0.05) reduced Kc values of crops as compared to CT. Specifically, 20% reductions were observed for onion, cabbage, and garlic under CA whereas 10% reductions were observed for pepper throughout the crop base period. Consequently, irrigation water measurement showed that about 18% to 28% of a significant irrigation water savings were observed for the range of vegetables under CA as compared to CT. On the other hand, the results of soil measurement showed the CA practice significantly (α = 0.05) increased soil moisture (4%, 7%, 8%, and 10% increment for onion, cabbage, garlic, pepper) than CT practice even if irrigation input was small in CA practice. In addition, CA was found to improve the soil physico-chemical properties with significant improvement on organic matter (10%), field capacity (4%), and total nitrogen (10%) in the Dangishta experimental site. CA with drip irrigation is evidenced to be an efficient water-saving technology while improving soil properties to support sustainable intensification in the region.

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