Agronomic management options for phosphorus in Australian dryland organic and low-input cropping systems

Maintenance of available phosphorus (P) is a problem faced by both conventional and organic systems but it is exacerbated in the latter given that manufactured inorganic sources of P fertiliser are not permitted under the International Federation of Organic Agriculture Movements certification guidelines. The focus of this paper is a discussion of potential agronomic strategies to assist in sustainable management of the soil P resource in organic and low-input broadacre farming systems within the Australian rain-fed cereal–livestock belt. The paper considers three broad strategies for agronomic management of P in this context and draws on reported research from overseas and within Australia. An analysis of the current knowledge suggests that the option most likely to ensure that soluble P is not a limitation in the system is the importation of allowable inputs that contain P from off-farm, although for much of the Australian cereal–livestock belt the immediate issue may be access to economically viable sources. Research targeted at quantifying the economic and biological benefits to the whole-farm system associated with the adoption of these practices is required. Improving the P-use efficiency of the system by incorporating species into rotation or intercropping systems that are able to use P from less soluble sources has been a successful strategy in parts of the world with climate similar to much of the Australian cereal–sheep belt, and deserves further research effort in Australia. Agronomic management to maximise quantity and quality of pasture and crop plant residues undoubtedly builds labile soil organic matter and facilitates P cycling, but the strategy may be of limited benefit in low-rainfall areas that do not have the capacity to produce large biomass inputs. Evidence that organic or low-input systems naturally increase the numbers and diversity of soil organisms is sparse and published studies from Australian systems suggest that P nutrition is not enhanced. However, seed and soil microbial inoculants to facilitate improved P uptake have been developed and are currently being field tested in Australia. Progress in selection and breeding for cereal genotypes that are more P efficient and other plant genotypes that can use less labile P sources, is gaining momentum but still remains a long-term prospect, and may involve genetic modification which will not be acceptable for organic systems.

Download Full-text

Phosphorus management on extensive organic and low-input farms

Crop and Pasture Science ◽

10.1071/cp07134 ◽

2009 ◽

Vol 60 (2) ◽

pp. 105 ◽

Cited By ~ 19

Author(s):

P. S. Cornish

Keyword(s):

Organic Farms ◽

P Deficiency ◽

Low Input ◽

Soil P ◽

Organic Systems ◽

Research Priority ◽

Reactive Phosphate Rock ◽

Certification Standards ◽

Labile P ◽

Soil Solution P

A synthesis of the Australian literature reporting soil and plant phosphorus (P) status under organic methods of broadacre farming provides clear evidence that available soil P is lower in organic systems, although there have been no reports of farm P balances that might help to explain the lower P concentrations. There is also evidence, which is largely circumstantial, to suggest that P deficiency significantly reduces productivity of broadacre organic farms, but few experiments prove this conclusively because of other confounding factors. An overview of international literature suggests similar findings for mixed farms. Nine case studies further examined the constraints imposed by P on broadacre organic and low-input farms in Australia. Two farms on fertile soils had negative P balances but maintained productivity without fertilisers by ‘mining available’ P reserves. Five extensive organic farms on inherently less fertile soils had positive P balances because P fertiliser was used. Four of these farmers reported low productivity, which was supported by comparisons of wheat yields with estimated water-limited potential yields. Low productivity appeared to be related to P deficiency despite the use of allowable mineral fertilisers, mostly reactive phosphate rock (RPR), on these farms. The apparent ineffectiveness of RPR is most likely due to the modest rainfall at these farms (380–580 mm/year). The highest research priority is to develop effective, allowable fertilisers. Until this has been achieved, or ways of using less labile P have been developed, there is a case for derogation in the Certification Standards to allow the use of soluble forms of P fertiliser on soils with low soil solution P and high soil P-sorption. Two low-input farms practicing pasture-cropping had approximately balanced P budgets and from this perspective were the most sustainable of the farms studied.

Download Full-text

Azospirillum brasilense increases corn growth and yield in conventional low input cropping systems

Renewable Agriculture and Food Systems ◽

10.1017/s1742170520000241 ◽

2020 ◽

pp. 1-9

Author(s):

Steliane Pereira Coelho ◽

João Carlos Cardoso Galvão ◽

Jeferson Giehl ◽

Édio Vicente de Jesus ◽

Beatriz Ferreira Mendonça ◽

...

Keyword(s):

Azospirillum Brasilense ◽

Cropping Systems ◽

Mineral Fertilizer ◽

Farming Systems ◽

Growth And Yield ◽

Higher Plant ◽

Low Input ◽

Organic Systems ◽

No Till ◽

Organic Compost

Abstract The supplementation of nitrogen can be increased by the use of nitrogen-fixing, diazotrophic bacteria such as Azospirillum brasilense. These bacteria can act to promote plant growth in various plant species, including corn (Zea mays L.). However, there is a need to understand the behavior of these bacteria in different agricultural systems. The objective of this study was to evaluate the effect on the growth and yield of corn inoculated with A. brasilense, and to identify the type of farming system which benefited most from the use of A. brasilense-based inoculants. The experiment conducted over two corn crop seasons was arranged in a 6 × 2 factorial scheme, consisting of six farming systems and the presence or absence of inoculation with the bacteria A. brasilense. The farming systems were derived from a long-term experiment with different fertilization systems that has been conducted since 1984. Among these systems, there were three conventional systems (CNT1: conventional no-till without fertilizer; CNT2: conventional no-till with 150 kg ha−1 of mineral fertilizer + 50 kg ha−1 of urea; CNT3: conventional no-till with 300 kg ha−1 of mineral fertilizer + 100 kg ha−1 of urea), and three organic systems (ONT1: organic no-till with 40 m3 ha−1 of organic compost; ONT2: organic no-till with 20 m3 ha−1 of organic compost; ONT3: organic no-till with 40 m3 ha−1 of organic compost and intercropped with Canavalia ensiformis). Although the Azospirillum population in the soil before planting was the same for all six systems, the count in the rhizospheric soil was higher in the organic systems, and there was no increase in that count due to inoculation. In this study, the only difference observed was within the CNT1 system, between the inoculated (CNT1-I) and uninoculated (CNT1-NI) treatments. In this system, inoculation resulted in an increase in plant height, in addition to higher concentrations of foliar N and P, and a higher plant survival rate, which culminated in higher yield. Corn inoculated with A. brasilense in the CNT1-I treatment showed a significant increase in yield—2839 kg ha−1 higher than that recorded for CNT1-NI. This study shows that, in the conventional low input treatment CNT1-I, inoculation with A. brasilense resulted in an increase in corn growth and yield.

Download Full-text

Devising fertiliser recommendations for diverse cropping systems in a region: the case of low-input bean/maize intercropping in a tropical highland of Haïti

Agronomie ◽

10.1051/agro:2003046 ◽

2003 ◽

Vol 23 (7) ◽

pp. 673-681 ◽

Cited By ~ 9

Author(s):

C. Clermont-Dauphin ◽

J. M. Meynard ◽

Y. M. Cabidoche

Keyword(s):

Cropping Systems ◽

Low Input

Download Full-text

Nitrate Leaching to a Shallow Mid-Atlantic Coastal Plain Aquifer as Influenced by Conventional No-Till and Low-Input Sustainable Grain Production Systems

Water Science & Technology ◽

10.2166/wst.1993.0475 ◽

1993 ◽

Vol 28 (3-5) ◽

pp. 691-700 ◽

Cited By ~ 7

Author(s):

J. P. Craig ◽

R. R. Weil

Keyword(s):

Management Practices ◽

Production Systems ◽

Cropping Systems ◽

Cropping System ◽

Atlantic Coastal Plain ◽

Grain Production ◽

Nitrogen And Phosphorus ◽

Mineral N ◽

Low Input ◽

No Till

In December, 1987, the states in the Chesapeake Bay region, along with the federal government, signed an agreement which called for a 40% reduction in nitrogen and phosphorus loadings to the Bay by the year 2000. To accomplish this goal, major reductions in nutrient loadings associated with agricultural management practices were deemed necessary. The objective of this study was to determine if reducing fertilizer inputs to the NT system would result in a reduction in nitrogen contamination of groundwater. In this study, groundwater, soil, and percolate samples were collected from two cropping systems. The first system was a conventional no-till (NT) grain production system with a two-year rotation of corn/winter wheat/double crop soybean. The second system, denoted low-input sustainable agriculture (LISA), produced the same crops using a winter legume and relay-cropped soybeans into standing wheat to reduce nitrogen and herbicide inputs. Nitrate-nitrogen concentrations in groundwater were significantly lower under the LISA system. Over 80% of the NT groundwater samples had NO3-N concentrations greater than 10 mgl-1, compared to only 4% for the LISA cropping system. Significantly lower soil mineral N to a depth of 180 cm was also observed. The NT soil had nearly twice as much mineral N present in the 90-180 cm portion than the LISA cropping system.

Download Full-text

Land Uses, Altitude and Texture Effects on Soil Parameters. A Comparative Study in Two Districts of Nagaland, Northeast India

Agriculture ◽

10.3390/agriculture11020171 ◽

2021 ◽

Vol 11 (2) ◽

pp. 171

Author(s):

Gaurav Mishra ◽

Rosa Francaviglia

Keyword(s):

Soil Properties ◽

Soil Texture ◽

Soil Parameters ◽

Available Phosphorus ◽

Land Uses ◽

Management Options ◽

Available N ◽

P Content ◽

Significant Difference ◽

Soc Stocks

Northeast (NE) India is a typical tropical ecosystem with a luxuriant forest vegetation cover, but nowadays forests are under stress due to exploitation and land use changes, which are known to affect soil health and productivity. However, due to a scarcity of data, the influence of land uses and altitude on soil properties of this peculiar ecosystem is poorly quantified. This study presents the changes in soil properties in two districts of Nagaland (Mon and Zunheboto) in relation to land uses (forest, plantation, jhum and fallow jhum), altitude (<500 m, 500–1000 m, >1000 m) and soil texture (coarse, medium, fine). For this, a random soil sampling was performed in both the districts. Results indicated that soil organic carbon (SOC) stocks and available potassium (K) were significantly influenced by land uses in the Mon district, while in Zunheboto a significant difference was observed in available phosphorus (P) content. SOC stocks showed an increasing trend with elevation in both districts. The influence of altitude on P was significant and the maximum concentration was at lower elevations (<500 m). In Mon, soil texture significantly affected SOC stocks and the available N and P content. The variability in soil properties due to land uses, altitudinal gradients and textural classes can be better managed with the help of management options, which are still needed for this ecosystem.

Download Full-text

The Therapeutic Effect of Extracellular Vesicles on Asthma in Pre-Clinical Models: A Systematic Review Protocol

Journal of Respiration ◽

10.3390/jor1010009 ◽

2021 ◽

Vol 1 (1) ◽

pp. 84-95

Author(s):

Patience O. Obi ◽

Jennifer E. Kent ◽

Maya M. Jeyaraman ◽

Nicole Askin ◽

Taiana M. Pierdoná ◽

...

Keyword(s):

Systematic Review ◽

Extracellular Vesicles ◽

Current Knowledge ◽

Grey Literature ◽

Specific Treatment ◽

Therapeutic Effects ◽

Management Options ◽

Paracrine Signalling

Asthma is the most common pediatric disease, characterized by chronic airway inflammation and airway hyperresponsiveness. There are several management options for asthma, but no specific treatment. Extracellular vesicles (EVs) are powerful cellular mediators of endocrine, autocrine and paracrine signalling, and can modulate biophysiological function in vitro and in vivo. A thorough investigation of therapeutic effects of EVs in asthma has not been conducted. Therefore, this systematic review is designed to synthesize recent literature on the therapeutic effects of EVs on physiological and biological outcomes of asthma in pre-clinical studies. An electronic search of Web of Science, EMBASE, MEDLINE, and Scopus will be conducted on manuscripts published in the last five years that adhere to standardized guidelines for EV research. Grey literature will also be included. Two reviewers will independently screen the selected studies for title and abstract, and full text based on the eligibility criteria. Data will be extracted, narratively synthesized and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. This systematic review will summarize the current knowledge from preclinical studies investigating the therapeutic effects of EVs on asthma. The results will delineate whether EVs can mitigate biological hallmarks of asthma, and if so, describe the underlying mechanisms involved in the process. This insight is crucial for identifying key pathways that can be targeted to alleviate the burden of asthma. The data will also reveal the origin, dosage and biophysical characteristics of beneficial EVs. Overall, our results will provide a scaffold for future intervention and translational studies on asthma treatment.

Download Full-text

Phony peach disease: past and present impact on the peach industry in the southeastern U.S.A

CABI Agriculture and Bioscience ◽

10.1186/s43170-021-00049-4 ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Kendall A. Johnson ◽

Clive H. Bock ◽

Phillip M. Brannen

Keyword(s):

New Technologies ◽

Current Knowledge ◽

Future Research ◽

Management Options ◽

Disease Epidemiology ◽

Pathogen Diversity ◽

Foundational Research ◽

Global Threat ◽

And Control ◽

The Impact

Abstract Background Phony peach disease (PPD) is caused by the plant pathogenic bacterium Xylella fastidiosa subsp. multiplex (Xfm). Historically, the disease has caused severe yield loss in Georgia and elsewhere in the southeastern United States, with millions of PPD trees being removed from peach orchards over the last century. The disease remains a production constraint, and management options are few. Limited research has been conducted on PPD since the 1980s, but the advent of new technologies offers the opportunity for new, foundational research to form a basis for informed management of PPD in the U.S. Furthermore, considering the global threat of Xylella to many plant species, preventing import of Xfm to other regions, particularly where peach is grown, should be considered an important phytosanitary endeavor. Main topics We review PPD, its history and impact on peach production, and the eradication efforts that were conducted for 42 years. Additionally, we review the current knowledge of the pathogen, Xfm, and how that knowledge relates to our understanding of the peach—Xylella pathosystem, including the epidemiology of the disease and consideration of the vectors. Methods used to detect the pathogen in peach are discussed, and ramifications of detection in relation to management and control of PPD are considered. Control options for PPD are limited. Our current knowledge of the pathogen diversity and disease epidemiology are described, and based on this, some potential areas for future research are also considered. Conclusion There is a lack of recent foundational research on PPD and the associated strain of Xfm. More research is needed to reduce the impact of this pathogen on peach production in the southeastern U.S., and, should it spread internationally, wherever peaches are grown.

Download Full-text

How will future climate depending agronomic management impact the yield risk of wheat cropping systems? A regional case study of Eastern Denmark

The Journal of Agricultural Science ◽

10.1017/s0021859620001045 ◽

2021 ◽

pp. 1-16

Author(s):

J. Macholdt ◽

J. Glerup Gyldengren ◽

E. Diamantopoulos ◽

M. E. Styczen

Keyword(s):

Climate Change ◽

Crop Production ◽

Cropping Systems ◽

Future Climate ◽

Catch Crops ◽

Agronomic Management ◽

The Future ◽

Yield Risk ◽

Management Factors ◽

The Impact

Abstract One of the major challenges in agriculture is how climate change influences crop production, for different environmental (soil type, topography, groundwater depth, etc.) and agronomic management conditions. Through systems modelling, this study aims to quantify the impact of future climate on yield risk of winter wheat for two common soil types of Eastern Denmark. The agro-ecosystem model DAISY was used to simulate arable, conventional cropping systems (CSs) and the study focused on the three main management factors: cropping sequence, usage of catch crops and cereal straw management. For the case region of Eastern Denmark, the future yield risk of wheat does not necessarily increase under climate change mainly due to lower water stress in the projections; rather, it depends on appropriate management and each CS design. Major management factors affecting the yield risk of wheat were N supply and the amount of organic material added during rotations. If a CS is characterized by straw removal and no catch crop within the rotation, an increased wheat yield risk must be expected in the future. In contrast, more favourable CSs, including catch crops and straw incorporation, maintain their capacity and result in a decreasing yield risk over time. Higher soil organic matter content, higher net nitrogen mineralization rate and higher soil organic nitrogen content were the main underlying causes for these positive effects. Furthermore, the simulation results showed better N recycling and reduced nitrate leaching for the more favourable CSs, which provide benefits for environment-friendly and sustainable crop production.

Download Full-text