Effects of environmental factors on the performance of Digitaria eriantha and Medicago sativa in monoculture and mixture

1997 ◽  
Vol 37 (3) ◽  
pp. 323 ◽  
Author(s):  
P. G. Tow ◽  
A. Lazenby ◽  
J. V. Lovett
Keyword(s):  
Medicago Sativa ◽  
Growth Patterns ◽  
North West ◽  
Far North ◽  
Temperature Regimes ◽  
Moisture Regimes ◽  
Digitaria Eriantha ◽  
Summer Temperatures ◽  
Spring Temperatures ◽  
Applied Nitrogen

Summary. A glasshouse experiment was conducted to test hypotheses concerning differences in environmental adaptation of Digitaria eriantha (digitaria) and Medicago sativa cv. Hunter River (lucerne), and advantages of growing them in mixture on a solodic soil on the Far North-West Slopes of New South Wales. The 2 species were grown in monoculture and mixture in simulated solodic soil profiles, at 2 temperature regimes, 2 levels of available nitrogen (0 and 0.25 g/container after each harvest), and 3 moisture levels (drought, adequate, flood), thus providing the range of conditions encountered in the field. The 2 species differed markedly in their response to temperature, which explains the complementary seasonal growth patterns in the field. Summer temperatures favoured digitaria growth while spring temperatures favoured lucerne growth. At summer temperatures, digitaria outyielded lucerne at all moisture regimes with applied nitrogen, as well as the flooded treatment without applied nitrogen. At spring temperatures, lucerne outyielded digitaria without nitrogen applied, as well as in the adequate moisture regimes with nitrogen applied. Yields of each species were reduced by periodic flooding and droughting; at their respective more favoured temperature regimes for growth, the percentage reduction in yield at individual harvests was higher in lucerne than in digitaria, especially for flooding. Flooding at summer temperatures had the worst effect on lucerne but summer droughting was almost as severe, especially with continued application of these treatments. Both species responded to nitrogen, the percentage dry matter increase being higher at summer than at spring temperatures. The species responded to temperature, moisture and nitrogen in the same way in mixture as in monoculture. The yield response of the mixture was dominated by that of the most responsive species at that regime. Monocultures rarely outyielded the mixture. The mixture sometimes significantly outyielded both monocultures, mainly with summer temperature, adequate moisture and low nitrogen. Long-term exploitation of the complementary temperature responses of the 2 species and their overall adaptation to the temperature regime of the Far North-West Slopes may depend on measures to minimise the effects of intermittent flooding and droughting in summer.

Adaptation and complementarity of Digitaria eriantha and Medicago sativa on a solodic soil in a subhumid environment with summer and winter rainfall

1997 ◽  
Vol 37 (3) ◽  
pp. 311 ◽  
Author(s):  
P. G. Tow ◽  
J. V. Lovett ◽  
A. Lazenby
Keyword(s):  
Medicago Sativa ◽  
Dry Matter ◽  
New South ◽  
New South Wales ◽  
North West ◽  
Far North ◽  
South Wales ◽  
Digitaria Eriantha ◽  
High Yields ◽  
Yield Responses

Summary. A cutting experiment was conducted over 4 years on a solodic soil on the Far North-West Slopes of New South Wales to compare the environmental adaptation of Digitaria eriantha ssp. eriantha cv. Premier and Medicago sativa cv. Hunter River. Adaptation was tested by comparing seasonal yield responses of the monocultures and the mixture at high and low levels of nitrogen (N); monoculture yields were also compared with those predicted by a simple climate-based model. When N was non-limiting, digitaria yields were highest in summer while lucerne yields were highest in spring. Lucerne yields in summer were often much lower than those predicted by the model but the plant recovered well during periods of milder temperature, until decimated by flooding. Yields of the mixture were similar to those of digitaria in summer when it was grass dominant, and similar to lucerne in spring when it was legume dominant. Overall, at high N the mixture did not outyield digitaria. In the absence of fertiliser N, digitaria and lucerne monocultures gave similar dry matter yields. However, over the 3 warm seasons, the mixture produced 72% more dry matter than the monocultures and 263% (325 kg/ha) more N than digitaria. The complementary seasonal responses of digitaria and lucerne, and high yields of the mixture suggest a role for the mixture on solodic soils on the Far North-West Slopes of New South Wales provided the effects of irregular flooding on lucerne can be minimised by management or more tolerant cultivars.

Persistence and water use efficiency of a tropical grass and lucerne on a solodic soil on the Far North-West Slopes of New South Wales

1993 ◽  
Vol 33 (2) ◽  
pp. 245 ◽  
Author(s):  
PG Tow
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Dry Matter ◽  
New South ◽  
New South Wales ◽  
North West ◽  
South Wales ◽  
Summer Temperatures ◽  
Spring Temperatures ◽  
Use Efficiency

The persistence and water use efficiency of Digitaria eriantha spp. eriantha and Hunter river lucerne were compared on red solodic soil with a hardsetting surface and poor internal drainage, on the North- West Slopes of New South Wales. After prolonged watering, the profile was wet to a depth of 48 � 1.5 cm, with an available moisture store of 90 mm. Over 3 years, persistence of digitaria was excellent. The population of lucerne was reduced following flooding at summer temperatures, Dry matter production of nitrogen (N) fertilised digitaria per mm warm season rainfall was similar to that of tropical grasses adapted to comparable rainfall environments in subtropical Queensland. Lucerne dry matter per mm rainfall was only about half that of digitaria (3.2 v. 6.3 kg). Lucerne grew well in mixture with digitaria except under prolonged wet soil conditions in summer. Artificial solodic profiles were constructed in the glasshouse to compare digitaria and lucerne in monoculture and mixture under varying temperature, moisture, and N regimes. Lucerne showed sensitivity to both high and low moisture levels at summer temperatures but performed very well at spring temperatures and moderate moisture levels where the mean evapotranspiration ratio was 400 g water per g dry matter. Water use efficiency was higher in digitaria than in lucerne, except at spring temperatures without added N. Water use efficiency of the mixture was always similar to that of the most efficient monoculture of the particular treatment.

Polytechnic of Central London Spitsbergen Manhaul Expedition, 1976

Polar Record ◽  
1977 ◽  
Vol 18 (115) ◽  
pp. 378-378
Author(s):  
Roger Daynes
Keyword(s):  
Field Work ◽  
Botanical Survey ◽  
Fishing Vessel ◽  
Sleep Patterns ◽  
North West ◽  
Far North ◽  
Human Sleep ◽  
West Spitsbergen ◽  
Support Facility

A seven-man party from the Polytechnic of Central London spent from 25 July to 26 August in north-west Spitsbergen. Field work included botanical survey and sampling, recording of human sleep patterns, and the making of a 16 mm colour film. The party had the support facility of a former Scottish fishing vessel, the Copious, which it shared with the Cambridge Spitsbergen Expedition. The group landed in the far north of Vasahalvøya on Makarovbreen. Overland glacier journeys were made from Makarovbreen south to Liefdef jorden and Bockf jorden, and from the lower end of Woodf jorden across to Kongsf jorden via Blomstrandbreen—roughly 160 km in all.

Contemporary landscape burning patterns in the far North Kimberley region of north-west Australia: human influences and environmental determinants

2004 ◽  
Vol 31 (8) ◽  
pp. 1317-1333 ◽  
Author(s):  
T. Vigilante ◽  
D. M. J. S. Bowman ◽  
R. Fisher ◽  
J. Russell-Smith ◽  
C. Yates
Keyword(s):  
Environmental Determinants ◽  
North West ◽  
Far North

scholarly journals Eastern white pine and eastern hemlock growth: possible tradeoffs in response of canopy trees to climate

2021 ◽  
Author(s):  
Rebecca L. Stern ◽  
Paul Schaberg ◽  
Shelly A Rayback ◽  
Paula F. Murakami ◽  
Christopher Hansen ◽  
...  
Keyword(s):  
Maximum Growth ◽  
Eastern Hemlock ◽  
Competitive Advantages ◽  
White Pine ◽  
Eastern White Pine ◽  
Canopy Trees ◽  
Pollutant Deposition ◽  
Summer Temperatures ◽  
Spring Temperatures ◽  
Over Time

A warming climate and extended growing season may confer competitive advantages to temperate conifers that can photosynthesize across seasons. Whether this potential translates into increased growth is unclear, as is whether pollution could constrain growth. We examined two temperate conifers - eastern white pine (Pinus strobus L.) and eastern hemlock (Tsuga canadensis (L.) Carrière) - and analyzed associations between growth (476 trees in 23 plots) and numerous factors, including climate and pollutant deposition variables. Both species exhibited increasing growth over time and eastern white pine showed greater maximum growth. Higher spring temperatures were associated with greater growth for both species, as were higher autumnal temperatures for eastern hemlock. Negative correlations were observed with previous year (eastern hemlock) and current year (eastern white pine) summer temperatures. Spring and summer moisture availability were positively correlated with growth for eastern white pine throughout its chronology, whereas for hemlock, correlations with moisture shifted from being significant with current year’s growth to previous year’s growth over time. The growth of these temperate conifers might benefit from higher spring (both species) and fall (eastern hemlock) temperatures, though this could be offset by reductions in growth associated with hotter, drier summers.

Amarna: Urban Manufacture of Luxury Items

2017 ◽  
Author(s):  
Anna K. Hodgkinson
Keyword(s):  
Far East ◽  
Ancient Egypt ◽  
Capital City ◽  
North West ◽  
Far North ◽  
The Core ◽  
The North ◽  
The Far East ◽  
Royal Road ◽  
The City

Little is necessary in terms of an introduction, since Amarna is one of the best-known settlements of ancient Egypt. The city was founded by pharaoh Amenhotep IV, known from his fifth regal year as Akhenaten, on his move away from Thebes and Memphis to found a new religious and administrative capital city. Akhenaten reigned approximately between 1348 and 1331 BC, and his principal wife was Nefertiti. Akhenaten’s direct successor appears to have been a figure named Smenkhare (or Ankhkheperure) who was married to Akhenaten’s daughter Meritaten. Like Nefertiti, Smenkhare/Ankhkheperure held the throne name Nefernefruaten. For this reason it is uncertain whether this individual was Nefertiti, who may have reigned for some years after the death of Akhenaten, possibly even with a brief co-regency, or whether this was a son or younger brother of the latter. The rule of Smenkhare/Ankhkheperure was short, and he or she was eventually succeeded by Tutankhamun. The core city of Amarna was erected on a relatively flat desert plain surrounded by cliffs on the east bank of the Nile, in Middle Egypt, approximately 60km south of the modern city of Minia, surrounded by the villages et- Till to the north and el-Hagg Qandil to the south. The site was defined by at least sixteen boundary stelae, three of which actually stand on the western bank, past the edge of the modern cultivation. In total, the city measures 12.5km north–south on the east bank between stelae X and J, and c.8.2km west–east between the projected line between stelae X and J and stela S to the far east, which also indicates approximately the longitude of the royal tomb. The distance between stelae J and F, to the far south-west, measures c.20km, and between stelae X and A, to the far north-west 19.2km. The core city, which is the part of the settlement examined in this section, was erected along the Nile, on the east bank, and it is defined by the ‘Royal Road’, a major thoroughfare running through the entire core city north–south.

Monitoring Agricultural Drought in the Near East

2005 ◽  
Author(s):  
Eddy De Pauw
Keyword(s):  
Near East ◽  
Potential Evapotranspiration ◽  
Groundwater Resources ◽  
Winter Season ◽  
Aridity Index ◽  
Agricultural Drought ◽  
Moisture Regime ◽  
Temperature Regimes ◽  
Moisture Regimes ◽  
Dry Climates

The countries of North Africa and West Asia, hereafter referred to as the “Near East,” cover a large part of the world (more than 7,200,000 km2). This region is characterized by diverse but generally dry climates, in which evaporation exceeds precipitation. The level of aridity is indicated by the aridity index, the ratio of annual precipitation to annual potential evapotranspiration, calculated by the Penman method (UNESCO, 1979). The degree of aridity is shown spatially in figure 16.1 and summarized per country in table 16.1. These data show that the region is characterized by humid, subhumid, semiarid, and arid to hyperarid moisture regimes. In addition, temperature regimes vary considerably, particularly due to the differences in altitudes and, to a lesser extent, due to the oceanic/continental influences. For most of the region, the precipitation generally occurs during the October–April period and thus is concentrated over the winter season. Table 16.1 shows that, with more than 90% of the land area in hyperarid, arid, or semiarid moisture regimes, aridity is very significant in the Near East. Turkey is better endowed with surface and groundwater resources due to the orographic capture of Atlantic cyclonal precipitation, but much of the interior is semiarid. If one excludes the hyperarid zones, which cover the driest deserts and have no potential for agricultural use, nearly 34% of the region, or about 2,460,000 km2, is dryland (i.e., the area with arid or semiarid moisture regime). These are the areas with some potential for either dryland farming (in semiarid zones) or for extensive rangeland (in arid zones). In the Near East countries, agriculture contributes about 10–20% to the gross domestic product and is therefore a major pillar of their economies. However, the indirect importance of agriculture is larger because it provides the primary goods that constitute the majority of merchandise exports and because of the relatively high number of people employed in agriculture. Because of the high degree of aridity in large parts of the region, agriculture in the Near East is particularly vulnerable to drought. Most of the agricultural systems depend on rainfall.

A Note from Far North-west New South Wales

1938 ◽  
Vol 37 (4) ◽  
pp. 316-317 ◽  
Author(s):  
A. C. Cameron
Keyword(s):  
New South ◽  
New South Wales ◽  
North West ◽  
Far North ◽  
South Wales
Sign in / Sign up

Export Citation Format

Share Document