Studies of Central Australian Semidesert Rangelands. II. Range Condition and the Nutrient Dynamics of the Herbage Layer, Litter and Soil.

1981 ◽  
Vol 29 (2) ◽  
pp. 233 ◽  
Author(s):  
MH Friedel

The levels and turnover of nitrogen, phosphorus and sulfur in the herbage layer: litter and soil of three central Australian plant communities were investigated, following several years of above-average rainfall, and the possibility of a relationship between nutrient levels and range condition assessment was examined. There were only a few positive correlations between range condition and phosphorus levels, and they were not associated with the susceptibility of different soils to erosional losses. There were no positive correlations between range condition and the levels of either nitrogen or sulfur. The herbage and litter layers together, of the three plant communities, contained 30-72 kg ha-1 of total nitrogen, 4 kg ha-1 of total phosphorus and 4-7 kg ha-1 of total sulfur. These quantities were comparable to those of arid regions in other parts of the world, but the levels of nitrogen, phosphorus and sulfur in soils, estimated by incubation or extraction to be available to plants, were comparatively low. Incubated nitrogen in the 0-10 cm depth of soils was 9-14 ppm and extractable phosphorus was 3-1 1 ppm. The 0-4 cm depth of soil contained 0.5-3 ppm extractable sulfur, and concentrations decreased with depth. Total soil nitrogen was lower than that in other arid regions whereas the amount of organic carbon in soil was comparable, so that C:N was relatively high. Substantial withdrawal of nutrients from senescing plant parts and rapid cycling of nutrients through litter appeared to be responsible for maintaining the level of nutrients in the herbage layer.

2017 ◽  
Vol 4 (2) ◽  
pp. 84-88
Author(s):  
Greeshma G.M ◽  
Manoj G.S ◽  
Murugan K

Historically, Bryophytes were accounted to be a monophyletic group and were placed in an inclusive Bryophyta. Some species are aquatic though some can adapt and live in arid regions. Bryophytes size ranges from microscopic to 12 inches in length, the average size is between 0.5 – 2 inches long and colors vary from green to black and sometimes colorless. Bryophytes plays a vital role in the biosphere even their size is insignificant. As a biotic factor in the environment, they provide food for numerous herbivorous birds and animals. They prevent soil erosion by carpeting the soil. Bryophytes cause the outer portion of rock to slowly crumble as they grow with lichens on rock surfaces. And because of it they contribute and help to soil formation. When mixed with the soil, bryophytes increase the water-holding capacity of the soil and the amount of organic matter in the soil. Some bryophytes like sphagnum or peat moss has some economicimportance. It is used as packing material for breakable or fragile objects such as figurines and dinnerware’s. It is also used as packing materials for transporting plants and plant parts, since sphagnum holds water and hence prevent plants from drying during transport. As a whole, bryophytes are of little economic importance to man.


1994 ◽  
Vol 74 (4) ◽  
pp. 833-839 ◽  
Author(s):  
C. G. Kowalenko

Nitrogen, P, K, Ca, Mg and Na concentrations and accumulations in Willamette red raspberry (Rubus idaeus L.) plant parts were measured in a field study to identify a potential plant-analysis-based method for evaluating site-specific fertilizer requirements. Dry matter and macroelements accumulated steadily in new canes over the season, increased early to a stable amount in floricane laterals and ripe berries, increased and then decreased in leaves and remained stable in stems. Macroelement accumulation patterns were generally similar to dry matter accumulations. The amounts of N and K that accumulated in ripe berries were similar and about eight times greater than P, Ca and Mg. Macroelement concentrations of floricane stems, laterals and berries were more stable than in leaves, making them potentially more suitable than leaves for developing tissue analysis for fertilizer recommendations. Key words: Nitrogen, phosphorus, potassium, calcium, magnesium, sodium, Rubus idaeus


1997 ◽  
Vol 13 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Nicholas C. Songwe ◽  
F. E. Fasehun ◽  
D. U. U. Okali

ABSTRACTThe variations in macronutrient concentrations of the leaves of Terminalia superba and Pycanthus angolensis were studied and the concentrations of nutrients in leaves before abscission were compared with those after abscission. The amounts of nutrients returned to the forest floor were also computed from litter fall data at the start of maximum annual fall in the Reserve. With the exception of potassium in Pycanthus angolensis, there were significant variations in the nutrient concentrations of the two species with the time of year. With increasing leaf age the concentration of nitrogen, phosphorus, potassium and magnesium declined in Terminalia superba while magnesium concentration decreased in Pycanthus angolensis leaves. Furthermore, calcium showed an increasing concentration in Terminalia superba with increase in leaf age. The concentrations of nitrogen, phosphorus and potassium decreased before leaf fall. Estimated losses in nitrogen phosphorus and potassium before abscission were 44, 53 and 50%, respectively, whereas generally there was an increase (40%) in the concentration of calcium at leaf fall. Magnesium did not follow a definite pattern. The return of calcium through litter fall to the forest floor was the greatest of all the major elements. The distribution and variation of foliar nutrient concentrations in the leaves of Terminalia superba and Pycanthus angolensis and the importance of the amount of litter and the concentration of the various nutrients in the influencing soil fertility are discussed.


2018 ◽  
Vol 10 (6) ◽  
pp. 1755 ◽  
Author(s):  
Rachel Gioannini ◽  
Malik Al-Ajlouni ◽  
Richard Kile ◽  
Dawn VanLeeuwen ◽  
Rolston St. Hilaire

2005 ◽  
Vol 3 (4) ◽  
pp. 339-347 ◽  
Author(s):  
Megge J. Miller ◽  
John Hutson ◽  
Howard J. Fallowfield

Cyanobacterial hepatotoxins present a risk to public health when present in drinking water supplies. Existing removal strategies, although efficient, are not economically viable or practical for remote Australian communities and developing nations. Bank filtration is a natural process and a potential low cost, toxin removal strategy. Batch studies were conducted in 12 texturally diverse soils to examine the soil properties influencing the adsorption of the cyanobacterial hepatotoxins, microcystin-LR and nodularin. Sorption isotherms were measured. Freundlich and linear isotherms were observed for both toxins with adsorption coefficients not exceeding 2.75 l kg−1 for nodularin and 3.8 l kg−1 for microcystin. Significant positive correlations were identified between hepatotoxin sorption and clay and silt contents of the soils. Desorption of toxins was also measured in three different soils. Pure nodularin and microcystin-LR readily desorbed from all soils.


2019 ◽  
Vol 16 ◽  
pp. 00021
Author(s):  
Natalia Makunina ◽  
Mikhail Telyatnikov ◽  
Evgeniy Zibzeev

8 basic types of plant communities of arid regions of Altai- Sayan mountains have been revealed, their floristic classification has been carried out. Short description of the basic types has been given, their altitudinal distribution has been characterized.


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