scholarly journals Restoring the Soils of Nauru: Plants as Tools for Ecological Recovery

2021 ◽  
Author(s):  
◽  
Alexander Feary

<p>The restoration of Nauru’s mined areas is fundamental to the future wellbeing of the people and ecosystems of Nauru. Extensive open cast phosphate mining on Nauru over the last 100 years has led to soil losses and landscape degradation to the extent that over 70% of this South-Western Pacific island state is now uninhabitable and almost all productive land has been lost. Significant landscape degradation has occurred and as a consequence the soils that remain are insufficient in volume and quality to achieve the Government’s restoration goals which support the long-term development of Nauru and the well-being of its people. The aim of this research is to evaluate aspects of cover-crop use as a means for soil restoration in Nauru. This research evaluates biomass production, phytoremediation potential, and germination success for a range of species in Nauruan soils. Field trials exploring biomass production and cadmium phytoextraction were performed, as was an experiment assessing the effects of cadmium on germination success. It was found that, in the circumstances assessed, biomass productivity was significantly determined by species, mulch use, soil type, and to a small degree – cadmium. Phytoextraction was significantly determined by tissue type. Germination success was not determined by soil cadmium, but soil type was a significant factor.</p>

2021 ◽  
Author(s):  
◽  
Alexander Feary

<p>The restoration of Nauru’s mined areas is fundamental to the future wellbeing of the people and ecosystems of Nauru. Extensive open cast phosphate mining on Nauru over the last 100 years has led to soil losses and landscape degradation to the extent that over 70% of this South-Western Pacific island state is now uninhabitable and almost all productive land has been lost. Significant landscape degradation has occurred and as a consequence the soils that remain are insufficient in volume and quality to achieve the Government’s restoration goals which support the long-term development of Nauru and the well-being of its people. The aim of this research is to evaluate aspects of cover-crop use as a means for soil restoration in Nauru. This research evaluates biomass production, phytoremediation potential, and germination success for a range of species in Nauruan soils. Field trials exploring biomass production and cadmium phytoextraction were performed, as was an experiment assessing the effects of cadmium on germination success. It was found that, in the circumstances assessed, biomass productivity was significantly determined by species, mulch use, soil type, and to a small degree – cadmium. Phytoextraction was significantly determined by tissue type. Germination success was not determined by soil cadmium, but soil type was a significant factor.</p>


2017 ◽  
Author(s):  
Darshi Banan ◽  
Rachel Paul ◽  
Max Feldman ◽  
Mark Holmes ◽  
Hannah Schlake ◽  
...  

Above-ground biomass production is a key target for studies of crop abiotic stress tolerance, disease resistance and yield improvement. However, biomass is slow and laborious to evaluate in the field using traditional destructive methods. High-throughput phenotyping (HTP) is widely promoted as a potential solution that can rapidly and non-destructively assess plant traits by exploiting advances in sensor and computing technology. A key potential application of HTP is for quantitative genetics studies that identify loci where allelic variation is associated with variation in crop production. And, the value of performing such studies in the field, where environmental conditions match that of production farming, is recognized. To date, HTP of biomass productivity in field trials has largely focused on expensive and complex methods, which – even if successful – will limit their use to a subset of wealthy research institutions and companies with extensive research infrastructure and highly-trained personnel. Even with investment in ground vehicles, aerial vehicles and gantry systems ranging from thousands to millions of dollars, there are very few examples where Quantitative trait loci (QTLs) detected by HTP of biomass production in a field-grown crop are shown to match QTLs detected by direct measures of biomass traits by destructive harvest techniques. Until such proof of concept for HTP proxies is generated it is unlikely to replace existing technology and be widely adopted. Therefore, there is a need for methods that can be used to assess crop performance by small teams with limited training and at field sites that are remote or have limited infrastructure. Here we use an inexpensive and simple, miniaturized system of hemispherical imaging and light attenuation modeling to identify the same set of key QTLs for biomass production as traditional destructive harvest methods applied to a field-grown Setaria mapping population. This provides a case study of a HTP technology that can deliver results for QTL mapping without high costs or complexity.


2020 ◽  
Vol 3 (1) ◽  
pp. 93
Author(s):  
Iulian Constantin Dănilă

Short rotation forestry (SRF) provides an important supply of biomass for investors in this area. In the NE (North-East) part of Romania at the present time are installed over 800 Ha of this kind of crops. The SRF enjoys the support through environmental policies, in relation to climate change and the provisions of the Kyoto Protocol to reduce the concentration of CO2 in the atmosphere. A precise estimate of biomass production is necessary for the sustainable planning of forest resources and for the exchange of energy in ecosystems. The use of the terrestrial laser scanner (TLS) in estimating the production of above ground wood biomass (AGWB) of short rotation forestry (SRF) brings an important technological leap among indirect (non-destructive) methods. TLS technology is justified when destructive methods become difficult to implement, and allometric equations do not provide accurate information. The main purpose of the research is to estimate the biomass productivity on tree parts in short rotation forestry with TLS technology. Measuring the hybrid poplars crops by TLS may have the following consequences: (1) Higher accuracy of the estimate of biomass production in the SRF; (2) cost and time effective measurements over the biomass of tree parts; (3) new and validated allometric equations for SRF in NE Romania; (4) solid instrument for industry to estimate biomass. TLS technology gives accurate estimates for DBH, tree height and location, as much as the volume on segments, commercial volume or crown volume can be determined. The accuracy of these values depends on the original scan data and their co-registration. The research will contribute to the development of knowledge in the field of hybrid crops.


2003 ◽  
Vol 54 (10) ◽  
pp. 957 ◽  
Author(s):  
A. G. Condon ◽  
F. Giunta

Transient waterlogging during winter and spring reduces wheat yield in many parts of southern Australia. Yield reductions from waterlogging are associated with reduced production and survival of tillers, fewer and smaller fertile tillers, and smaller grain size. Under favourable conditions, wheats that have the tiller-inhibition ('tin') gene produce a lower total number of tillers but a higher proportion of large, productive tillers and larger grains than wheats without this gene. These characteristics of restricted-tillering wheat may contribute to improved yield under transient waterlogging. We compared the growth and yield of the commercial variety Bodallin and 2 Bodallin backcross derivatives containing the 'tin' gene in 8 field trials grown on shallow, duplex soils in 1995 and 1996 at 3 locations in the south-west of Western Australia. Trials were sown at standard (1995) and standard and high (1996) seeding rates. Trial-mean yield ranged from 0.5 to 4.7 t/ha, depending on the occurrence and severity of waterlogging before anthesis and of soil water deficit before and after anthesis. Grain yield of the restricted-tillering (RT) lines averaged only c. 80% of Bodallin. At all sites and seeding rates the RT lines had fewer spikes per m2 (45% fewer, on average) but averaged 44% more grains per spike. In 1996 only, grain weight of the RT lines was 6% greater than of Bodallin. There was no evidence that the relative yield of the RT lines was greater at waterlogged sites than at other sites. Waterlogging reduced the number of fertile spikes of RT lines and of Bodallin to the same relative extent and differences in grains per spike and grain size had little effect on relative yields. Even though harvest index of the RT lines was slightly elevated in some environments, biomass production of the RT lines was low in all environments. We conclude that wheats with the 'tin' gene are unlikely to have a yield advantage under transient waterlogging unless their biomass production can match that of more freely tillering wheats.


2021 ◽  
Author(s):  
Dolapo Enahoro ◽  
Jason Sircely ◽  
Randall B. Boone ◽  
Stephen Oloo ◽  
Adam M. Komarek ◽  
...  

The demand for livestock-derived foods has steadily grown over the past decades and rising incomes and human populations are expected to see demand further increase. It is unclear if current livestock feed resources are adequately prepared to meet future demand especially given the looming challenges of climate change. Many feeds such as grasses, crop by-products, and other biomass may not be widely grown commercially or sold in formal markets but are critical sources of livestock feed in many low-resource settings in which ruminant livestock production is important. The availability of these feed types can determine the extent to which the livestock sector can expand to meet growing, and sometimes critical, demand for animal-source foods. In this paper, we compare country-level projections of livestock demand from a global economic model to simulated data on feed biomass production. Our comparisons account separately for beef, lamb, and dairy demand. The data allow us to assess the future sufficiency of key sources of feed biomass, and hence aspects of the expansion capacity of livestock production in selected countries in Southern Africa. Our simulation results project that given the interacting effects of projected climate change and changes in income and population in the region, there will not be enough feed biomass produced domestically to meet growing demand for livestock products. For three types of feed biomass (feed crops including grains, grasses, and crop by-products) for which future livestock feed sufficiency was examined, our results showed feed sufficiency declines for all three feed types in Malawi and Mozambique, for two out of three in South Africa and for one of three in Zambia, under intermediate and extreme scenarios of climate change in 2050. Our results suggest an urgent need to improve feed biomass productivity to support future supply of animal protein in the study countries.


Science ◽  
2019 ◽  
Vol 363 (6422) ◽  
pp. eaat9077 ◽  
Author(s):  
Paul F. South ◽  
Amanda P. Cavanagh ◽  
Helen W. Liu ◽  
Donald R. Ort

Photorespiration is required in C3 plants to metabolize toxic glycolate formed when ribulose-1,5-bisphosphate carboxylase-oxygenase oxygenates rather than carboxylates ribulose-1,5-bisphosphate. Depending on growing temperatures, photorespiration can reduce yields by 20 to 50% in C3 crops. Inspired by earlier work, we installed into tobacco chloroplasts synthetic glycolate metabolic pathways that are thought to be more efficient than the native pathway. Flux through the synthetic pathways was maximized by inhibiting glycolate export from the chloroplast. The synthetic pathways tested improved photosynthetic quantum yield by 20%. Numerous homozygous transgenic lines increased biomass productivity between 19 and 37% in replicated field trials. These results show that engineering alternative glycolate metabolic pathways into crop chloroplasts while inhibiting glycolate export into the native pathway can drive increases in C3 crop yield under agricultural field conditions.


SOIL ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Antonello Bonfante ◽  
Fabio Terribile ◽  
Johan Bouma

Abstract. This study focuses on soil physical aspects of soil quality and health with the objective to define procedures with worldwide rather than only regional applicability, reflecting modern developments in soil physical and agronomic research and addressing important questions regarding possible effects of soil degradation and climate change. In contrast to water and air, soils cannot, even after much research, be characterized by a universally accepted quality definition and this hampers the internal and external communication process. Soil quality expresses the capacity of the soil to function. Biomass production is a primary function, next to filtering and organic matter accumulation, and can be modeled with soil–water–atmosphere–plant (SWAP) simulation models, as used in the agronomic yield-gap program that defines potential yields (Yp) for any location on earth determined by radiation, temperature and standardized crop characteristics, assuming adequate water and nutrient supply and lack of pests and diseases. The water-limited yield (Yw) reflects, in addition, the often limited water availability at a particular location. Actual yields (Ya) can be considered in relation to Yw to indicate yield gaps, to be expressed in terms of the indicator (Ya/Yw)×100. Soil data to calculate Yw for a given soil type (the genoform) should consist of a range of soil properties as a function of past management (various phenoforms) rather than as a single representative dataset. This way a Yw-based characteristic soil quality range for every soil type is defined, based on semipermanent soil properties. In this study effects of subsoil compaction, overland flow following surface compaction and erosion were simulated for six soil series in the Destra Sele area in Italy, including effects of climate change. Recent proposals consider soil health, which appeals more to people than soil quality and is now defined by separate soil physical, chemical and biological indicators. Focusing on the soil function biomass production, physical soil health at a given time of a given type of soil can be expressed as a point (defined by a measured Ya) on the defined soil quality range for that particular type of soil, thereby defining the seriousness of the problem and the scope for improvement. The six soils showed different behavior following the three types of land degradation and projected climate change up to the year 2100. Effects are expected to be major as reductions of biomass production of up to 50 % appear likely under the scenarios. Rather than consider soil physical, chemical and biological indicators separately, as proposed now elsewhere for soil health, a sequential procedure is discussed, logically linking the separate procedures.


2002 ◽  
Vol 53 (10) ◽  
pp. 1137 ◽  
Author(s):  
T. L. Botwright ◽  
A. G. Condon ◽  
G. J. Rebetzke ◽  
R. A. Richards

Improved early vigour in wheat (Triticum aestivum L.) has been proposed as an important trait for increasing grain yield through greater water-use efficiency in rainfed, Mediterranean-type environments. Three years of field trials were undertaken in Western Australia at 2 sites, Merredin (low rainfall, 244 mm in the growing season) and Wongan Hills (medium rainfall, 308 mm), to examine the influence of increased early vigour on crop growth and yield. The effect of breeding for greater early vigour was tested in 1998 and 1999 using 3 high vigour and 3 low vigour BC2:F5 lines of the cultivar Amery backcrossed to a 'high vigour' donor. Averaged across environments, the high vigour backcross lines had a 10% increase in early vigour (i.e. leaf area/plant) at 50 DAS compared with the low vigour lines. Differences in yield across environments were associated with variation in total rainfall, rainfall distribution, and soil properties. In the wetter of the 2 years (1999), greater early vigour translated to increased yield of c. 12%, averaged across environments, but there was no difference in yield in either environment in the drier year (1998). Potential deleterious effects of the recurrent parent on yield were eliminated in field trials in 1999 and 2000 by manipulating early vigour through varying grain size (25, 35, or 50 mg) or seeding density (50, 200, or 400 plants/m2) of Amery at sowing. Large grain increased the embryo size and early vigour at 50 DAS in both environments in 1999. This translated to greater biomass production at anthesis and maturity to increase grain yield at Wongan Hills in 1999. In contrast, there was no relationship between grain size, biomass production, and yield at Merredin in 1999 or at either site in 2000. Sowing density treatments also had no effect on yield in 2000. In conclusion, there is potential to increase yield of wheat by selecting for greater early vigour in a wheat breeding program. The expression of vigour in field conditions and the translation of this improvement to higher yields is, however, dependent on the environment. Current yield limitations arising through backcrossing with a high vigour, yet poor yielding donor, need to be addressed.


2015 ◽  
Vol 45 (1) ◽  
pp. 72-78 ◽  
Author(s):  
Altevir Signor ◽  
Arcangelo Augusto Signor ◽  
Wilson Rogério Boscolo ◽  
Adilson Reidel ◽  
Sidnei Klein ◽  
...  

This study evaluated the periphyton production on artificial substrates considering it as a source of low cost live food for fish. Blades of artificial substrates such as wood, black plastic, acrylic, fiberglass, ceramics and glass (all with 144cm2 blades, 24 for each substrate) were submerged 20.0cm below the water column for 35 days in the winter and 42 days in the summer. The blades were randomly installed in 200m3 pond and evaluated for the biomass production at different phases during the summer and winter. Four blades of each substrate were collected weekly, and the periphytic community was carefully scraped with a spatula and fixed in 4% formaldehyde. The periphytic biomass productivity was evaluated by artificial substrate area and per day. The results evidenced the characteristic periodicity in periphyton biomass production and a significant variability in the collect period and season in the different artificial substrates used. Ceramic and wood showed the best results in the summer while wood showed the best results in the winter. The priphyton biomass productions differ among periods, substrates and seasons. Wood and ceramics could be indicated for periphyton biomass production in either winter or summer.


Sign in / Sign up

Export Citation Format

Share Document