Nutrient cycling by mound building termites in low fertility soils of semi-arid tropical Australia

Soil Research ◽  
1988 ◽  
Vol 26 (2) ◽  
pp. 375 ◽  
Author(s):  
RJ Coventry ◽  
JA Holt ◽  
DF Sinclair

The capacity of three species of mound-building termites, Amitermes vitiosus Hill, Drepanotermes perniger (Froggatt), and Tumulitermes pastinator (Froggatt), to turn over plant nutrients was quantified in a semi-arid tropical woodland near Charters Towers in north-eastern Queensland. Various chemical attributes of the red and yellow earth soils, of low inherent fertility and unmodified by recent termite activity, are compared with those of the mounds of the three termite species and with the underlying, termite-modified soils. The mounds contain 21 Mg ha-l of soil, representing only 1% of the total mass of soil in the Al soil horizon but 5-7% of the plant nutrients in this system. Nutrients in the termite mounds, temporarily withheld from plant growth, are eventually returned to the soil surface by erosion of abandoned mounds. We estimate that the termites can turnover annually 300-400 kg ha-1 of soil material with nutrient levels 2-7 times that of the Al soil horizon.

1967 ◽  
Vol 69 (1) ◽  
pp. 125-130 ◽  
Author(s):  
E. A. Garwood ◽  
T. B. Williams

1. Plant nutrients, N, P and K, were applied to the soil surface or injected at a depth of 18 in. or 30 in. in perennial ryegrass swards, when the upper horizons of the soil profile were dry.2. When the surface soil was dry and a soil water deficit of 2 in. existed there was no response to surface applied N but injection of N into moist soil at a depth of 18 in. produced a marked increase of growth. At this depth of injection there was a significant positive interaction between N and PK.3. There was a substantial recovery in the herbage (59–80%) of the nitrogen applied to the subsoil, provided water was available in the soil horizon in which the nitrogen was applied.4. Failure of a grass sward to regrow after cutting when the water available to the plant has been removed from the uppermost soil horizons is largely due to a deficiency of plant nutrients in the subsoil. The major deficiency is that of nitrogen.


2020 ◽  
Vol 22 (1) ◽  
pp. 5-19
Author(s):  
Adel Sepehr ◽  
Atoosa Gholamhosseinian ◽  
Iraj Emadodin

The biocrusts are organized by soil-surface communities of biota that live within or on the very top of soil surface and play an important role in soil conservation. They include lichens, mosses, fungi, cyanobacteria, eukaryotic algae, and other heterotrophic bacteria. The interaction between biocrusts and soil is very important and good awareness from that help to better manage soil specially in arid and semi-arid areas. The linkage between cyanobacteria species and soil physicochemical parameters and mineralogy in two geomorphic zones in the northeastern Iran was studied. Samples were collected in summer along a linear transect by using 50 x 50 cm quadrates for each study zone. Individual mineral soil particles were analyzed by a scanning electron microscopy (SEM). The amounts of Na, K, Ca, and Mg contents as well as EC and SOC altered significantly between two study zones. Biocrusts increased levels of organic carbon, pH, calcium carbonate, exchangeable sodium and potassium percentages. The main soil properties of SOC, CaCO3 and amount of clay changed among biocrust sand bare soils.


1987 ◽  
Vol 3 (3) ◽  
pp. 255-263 ◽  
Author(s):  
John A. Holt

ABSTRACTThe contribution of a population of mound building, detritivorous termites (Amitermes laurensis (Mjöberg)) to nett carbon mineralization in an Australian tropical semi-arid woodland has been examined. Carbon mineralization rates were estimated by measuring daily CO2 flux from five termite mounds at monthly intervals for 12 months. Carbon flux from the mounds was found to be due to microbial activity as well as termite activity. It is conservatively estimated that the association of A. laurensis and the microbial population present in their mounds is responsible for between 4%–10% of carbon mineralized in this ecosystem, and the contribution of all termites together (mound builders and subterranean) may account for up to 20% of carbon mineralized. Regression analysis showed that rates of carbon mineralization in termite mounds were significantly related to mound moisture and mound temperature. Soil moisture was the most important factor in soil carbon mineralization, with temperature and a moisture X temperature interaction term also exerting significant affects.


2009 ◽  
Vol 36 (01) ◽  
pp. 71 ◽  
Author(s):  
C. CHOOSAI ◽  
J. MATHIEU ◽  
Y. HANBOONSONG ◽  
P. JOUQUET

2019 ◽  
Vol 32 (4) ◽  
pp. 889-905 ◽  
Author(s):  
Laura Camfield ◽  
Jen Leavy ◽  
Senait Endale ◽  
Tilahun Tefera

AbstractHow to support those responding to environmental change in resource-constrained environments is central to literature on climate change adaption. Our research explores a gap in this literature relating to the negotiation of intra-household relations and resource access across different types of household in contexts of social and environmental transition. Using the example of the semi-arid Awash region in North-Eastern Ethiopia, which has experienced drought and alien plant invasion over the past decade, we explore how men and women use changes in household structures and relationships to adapt more effectively. We draw evidence from life histories with 35 pastoralists across three rural, peri-urban and urban communities. Using Dorward et al.’s taxonomy, we find Afar people are not only ‘stepping up’, but also ‘stepping out’: shifting from pastoralism into agriculture and salaried employment. As this often involves splitting households across multiple locations, we look at how these reconfigured households support pastoralists’ wellbeing.


2014 ◽  
Vol 153 (2) ◽  
pp. 371-380 ◽  
Author(s):  
A. L. A. NEVES ◽  
R. D. SANTOS ◽  
L. G. R. PEREIRA ◽  
G. F. OLIVEIRA ◽  
C. B. SCHERER ◽  
...  

SUMMARYForage sorghum (FS) (Sorghum bicolor(L.) Moench) is a key feed source for ruminants owing to its high yield and drought tolerance. The present paper assessed the agronomic characteristics, silage quality, intake and digestibility of five new Brazilian sorghum cultivars (BRS Ponta Negra variety, BRS 655 hybrid, BR 601 hybrid, BRS 506 variety and BRS 610 hybrid). Forages were grown (randomized complete block design) in a typical Brazilian north-eastern semi-arid climate, irrigated with 267 mm water, harvested as plants reached the soft dough stage of grain maturity and ensiled under laboratory and farm conditions. Apparent digestibility of the silages was determined using 25 Santa Inês lambs. BRS 506 outperformed the other cultivars in dry matter (DM) and digestible DM yields/ha. BRS 506 exhibited the lowest neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents and the highestin vitrodry matter digestibility (IVDMD) of the cultivars examined. BRS 655 produced the lowest level of lactic acid and the highest pH and ammonia-N concentration. There was no difference in intake or digestibility of DM among cultivars. Silages produced from BRS Ponta Negra resulted in higher crude protein (CP) intake than BRS 655. Silages made from BRS 506 and BRS Ponta Negra resulted in a greater digestibility of CP than those produced from BRS 655. Intake of NDF in silages generated from BRS Ponta Negra and BRS 610 was higher than that found in other cultivars. Although an average Brazilian North-eastern FS exhibited similar characteristics to other cultivars grown in dry regions around the world, the results indicated that BRS 506 had a yield advantage and higher nutritive value under Brazilian semi-arid conditions as compared to the other cultivars examined.


1968 ◽  
Vol 8 (33) ◽  
pp. 425 ◽  
Author(s):  
EJ Sparke ◽  
DR Lamond

This paper reports an experiment examining the effect of age and protein supplementation on growth and fertility of Shorthorn-Devon cross heifers grazing natural pastures in the summer rainfall, subtropical environment of the Upper Clarence valley, north-eastern New South Wales. Heifers born over the period October to January 1963-64 were weaned in June 1964 and allotted at random within age groups (by month of birth) to a supplemented or non-supplemented treatment. The supplemented heifers were given linseed meal during the dry winter period each year from 1964 to 1966 inclusive (May-June to September-October). They were weighed each month and joined with bulls in the early summer of 1965 (2 years) and 1966 (3 years). They were examined for pregnancy in the autumn, and their calves were identified at birth. Supplemented heifers gained weight throughout and non-supplemented heifers generally lost weight in the winter periods. At two years fertility was closely related to liveweight at joining in supplemented heifers, but not in others. Heifers born in January gave the poorest reproductive performance, as the two supplemented ones that became pregnant in 1965 died at calving, and two-thirds of the non-supplemented ones were still empty after joining as 3-year-olds. The advantage of high 2-year-old fertility gained by heifers born in October and November, due to their greater size at joining, was partly offset by low fertility when lactating the following year. It is concluded that a decision as to whether a heifer should be supplemented during a period of nutritional stress prior to joining ought to be based on the probability of her reaching a prescribed target weight at joining as a result of receiving the supplement. The target weight for lactating heifers was at least 100 Ib higher than for dry hdfers. The results also indicate specific areas for further research.


Koedoe ◽  
1994 ◽  
Vol 37 (2) ◽  
Author(s):  
W.S. Matthews ◽  
G.J. Bredenkamp ◽  
N. Van Rooyen

An analysis of the vegetation of the relatively low altitude regions of the North-eastern Mountain Sourveld of the eastern Transvaal escarpment is presented. Releves were compiled in 53 stratified random sample plots. ATWINSPAN-classification, refined by Braun-Blanquet procedures, revealed seven plant communities. In the hierarchical classification one class, one alliance, four associations, four subassociations and two valiants are recognised. Formal syntaxonomic descriptions of the syntaxa are given. All communities are related to specific environmental conditions, of which geology, aspect, altitude and rockiness of the soil surface are the most important.


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