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Yield effects of agricultural cooperative membership in developing countries: A meta-analysis
No full textThis study uses a meta‐analysis to synthesize the effects of agricultural cooperative membership on the yield of crops and livestock. It collects 158 estimated yield effects from 42 studies, covering 19 developing countries. Our analysis finds evidence that there exists positive publication bias in the empirical literature, confirming that researchers and journals have a preference to publish articles that report positive and significant results. After correcting for publication bias, we find that cooperative membership has a small‐sized and insignificant effect on the yield. The meta‐regression analysis reveals that variation in the reported yield effects can be largely explained by the study attributes such as the sample type (full sample vs. subsample), membership ratio, econometric approaches (instrumental‐variable based parametric approach, non‐parametric approach or ordinary least square regression), effect size types (average treatment effects on the treated, average treatment effects, or coefficient), agro‐product type (grain or others), and climate zones (tropical or non‐tropical)
Seedling and field assessment of wheat Triticum aestivum dwarfing genes and their influence on root traits in multiple genetic backgrounds
No full textDeployment of the Rht-B1b and Rht-D1b dwarfing genes helped facilitate the Green Revolution to increase wheat yields globally. Much is known of the influence of these genes on plant height and agronomic performance, but not of their effects on root architecture. We assessed 29 near-isogenic lines (NILs) representing 11 Green Revolution and alternative dwarfing genes across multiple genetic backgrounds for root architecture characteristics in controlled and field environments. Genetic background did not influence plant height, but had a small and significant (P<0.05) effect on root architecture. All dwarfing gene NILs were significantly (P<0.01) shorter compared with tall controls. The Green Revolution Rht-B1b and Rht-D1b sometimes had longer seedling roots but were not different from their respective tall controls for root depth in the field. The Rht8, Rht12, and Rht18 dwarfing gene NILs produced long seminal roots in seedling pouches, and a greater maximum rooting depth (MRD) and root penetration rate (RPR) in the field. Genotypic increases in MRD and RPR were strongly correlated with increased harvest index and grain yield, particularly in dry environments. Careful root phenotyping highlights the potential of novel dwarfing genes for wheat genetic improvement under water-limited conditions
Livelihood dynamics in Henan County on the Qinghai-Tibet Plateau—A transdisciplinary systems perspective
Get PDFThis was an invited presentation based on the publication:
Lucock, X., Woodford, K., & Li, X. (2022). Sustainable Land Use and Livelihood Dynamics in Henan County on the Qinghai–Tibet Plateau—A Transdisciplinary Systems Perspective. Sustainability, 14(13), 7785. MDPI AG. Retrieved from http://dx.doi.org/10.3390/su1413778
A dose–response analysis of rice yield to agrochemical use in Ghana
Get PDFIn recent years, Ghanaian agriculture has witnessed a surge in the use of agrochemicals, with the likely consequence that nonoptimal levels of application could cause environmental damage and economic losses. We identify the factors that affect the adoption of agrochemicals and the intensity of use in Ghanaian rice farming. We estimate the average treatment effects of chemical fertilizer and herbicide adoption using a Dose–Response Model (DRM). Our results show that a wide range of socioeconomic factors, including education, asset ownership, extension service, off-farm income, and land ownership affect adoption and use intensity of agrochemicals. On average, chemical fertilizer usage is associated with a 10% increase in the average treatment effect; low levels of chemical fertilizer have a negative impact on rice yield, and the result turns positive with more intensive use. Similarly, herbicide treatment generates a 7% increase in the average treatment effect, but higher herbicide levels will have negative causal effects on rice yield, and the result worsens with more herbicide treatment. Both agricultural technologies were designed to be used together, hence the appropriate mix of levels and intensity is crucial to achieve greater benefits. The DRM accounts for heterogeneity in the sample and is a useful tool to develop guidance on optimal levels of agrochemicals
Design guidelines: The relationship between well-being, universal design and landscape architecture : A dissertation submitted in partial fulfilment of the requirements for the Degree of Master of Landscape Architecture at Lincoln University
Get PDFWell-being and mental health issues are becoming more and more important nowadays, especially while the world is experiencing the COVID-19 pandemic. It is well-known that natural environments have the ability to restore mental status. There are existing design guidelines to provide criteria and suggestions to guide people.
These guidelines help designers promote mental health and well-being through designing therapeutic gardens and gardens in general health facilities. However, these guidelines are either too broad or too specific to apply, as there is a lack of guidelines that have been created for promoting well-being and mental health in universal public spaces. On the other hand, universal design guidelines could be applied to all kinds of design. These guidelines are seen as a basic consideration in landscape design, but there is little focus on exploring the potential of improving well-being through practising universal design. By identifying and understanding the relationship between universal design guidelines, landscape architecture and well-being, this paper will propose new frameworks for future study
Vegetation of roadside cuttings and its effect on erosion in the Port Hills of Christchurch, New Zealand : A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science at Lincoln University
Get PDFSoil erosion is a concerning issue in New Zealand that threatens the environment, people, and the economy. Sediment runoff caused by erosion enters waterways and presents numerous ecological and health issues. Roadside cuttings are a visible source of erosion in urban and rural landscapes and, with little space available in the road corridor for treatment, sediment runoff often flows directly to waterways and harbours, where it accumulates. The revegetation of bare soils on roadsides does not only have the potential to reduce erosion and sediment runoff but also offers an opportunity to increase the native vegetative cover and provides other ecosystem services, such as nutrient cycling, which can improve soil health in the long run.
This study examines the vegetation of roadside cuttings in the Port Hills of Christchurch to understand what influences it, and assess how it affects the ability of the soil to withstand erosion. Furthermore, an assessment of erosion control products was also carried out to identify the best product to achieve the greatest amount of plant cover in loess roadside cuttings.
Roadside cuttings are dominated by naturalised grasses and a higher proportion of native cover is found mostly in well-vegetated areas. This shows that there is a need to optimise the vegetation cover in roadside cuttings to further increase and preserve the native plant cover. The results of this study show that plant cover in roadside cuttings is important in resisting erosion in sedimentary soils. The soil aggregate stability is high when the corresponding levels of vegetation cover are also high (specifically, a 70–100% cover). Soil aggregate stability can determine the ability of soil to retain its structure or resist different environmental stresses, like erosion. Soil aggregate stability is also more significant in grasslands than in shrubland since grasslands tend to have higher organic matter, cation exchange, and plant available nitrogen, based on the soil analysis. Species diversity and evenness are also higher in grasslands, and this could be driven by the higher level of nutrients found in grasslands.
However, there are many challenges to consider when conducting revegetation in roadside cuttings. Roadside cuttings in the Port Hills have a low level of phosphorus (P), organic matter, and cation exchange capacity. These low level of nutrients, which are essential to plants, could limit their growth. Furthermore, soil moisture varies in different areas of the slope and this can also affect the growth performance of plants. Elevation, longitude, and the interaction between the slope and aggregate stability strongly influence plant communities in roadside cuttings. Other environmental variables, such as slope angle, aspect, and surrounding vegetation, should also be considered in the restoration of roadside cuttings.
Erosion control products, such as coir fibre blankets (jute), wool blankets, and hydromulches, are effective in reducing surface runoff on bare slopes. In successfully establishing higher vegetation cover and higher species abundance, hydromulch on an organic base with a seed mixture of Festuca rubra, Agrostis capillaris, Poa annua, and Trifolium pratense, which is a product of PGG Wrightson Seeds, was most effective. The cover and survival of native plug plants planted on roadside cuttings were higher on rolled erosion control products such as jute, wool, and the combination of jute and hydromulch (PGG), since these products had less plant competition from naturalised herbaceous, grasses, and woody vegetation
Immigration and regional housing markets: Prices, rents, price-to-rent ratios and disequilibrium
No full textThe study examines the relationship between immigration and regional housing markets using wavelet coherence analysis in conjunction with Granger causality tests. We find that while there are some regional differences in the relationships, the impact of immigration on house rents is consistently more pronounced than the impact on house prices and, in the short to medium term, an increase in immigration leads to a decrease in price-to-rent ratios. The study uses data sets for different regional housing markets in New Zealand, a country with one of the highest immigration-to-population ratios in the world during the sample period of 1996–2017
Limiting grazing periods combined with proper housing can reduce nutrient losses from dairy systems
No full textPasture-based and grass-fed branding are often associated with consumer perceptions of improved human health, environmental performance and animal welfare. Here, to examine the impacts of dairy production in detail, we contrasted global observational (n = 156) data for nitrogen and phosphorus losses from land by the duration of outdoor livestock grazing in confined, grazed and hybrid systems. Observational nitrogen losses for confined systems were lowest on a productivity—but not area—basis. No differences were noted for phosphorus losses between the systems. Modelling of the three dairy systems in New Zealand, the United States and the Netherlands yielded similar results. We found insufficient evidence that grazed dairy systems have lower nutrient losses than confined ones, but trade-offs exist between systems at farm scale. The use of a hybrid system may allow for uniform distribution of stored excreta, controlled dietary intake, high productivity and mitigation of animal welfare issues arising from climatic extremes
Characterization of two conserved cell death elicitor families from the Dothideomycete fungal pathogens Dothistroma septosporum and Fulvia fulva (syn. Cladosporium fulvum)
No full textDothistroma septosporum (Ds) and Fulvia fulva (Ff; previously called Cladosporium fulvum) are two closely related Dothideomycete fungal species that cause Dothistroma needle blight in pine and leaf mold in tomato, respectively. During host colonization, these pathogens secrete virulence factors termed effectors to promote infection. In the presence of corresponding host immune receptors, however, these effectors activate plant defenses, including a localized cell death response that halts pathogen growth. We identified two apoplastic effector protein families, Ecp20 and Ecp32, which are conserved between the two pathogens. The Ecp20 family has four paralogues in both species, while the Ecp32 family has four paralogues in D. septosporum and five in F. fulva. Both families have members that are highly expressed during host infection. Members of the Ecp20 family have predicted structural similarity to proteins with a β-barrel fold, including the Alt a 1 allergen from Alternaria alternata, while members of the Ecp32 family have predicted structural similarity to proteins with a β-trefoil fold, such as trypsin inhibitors and lectins. Using Agrobacterium tumefaciens-mediated transient transformation assays, each family member was assessed for its ability to trigger cell death in leaves of the non-host species Nicotiana benthamiana and N. tabacum. Using this approach, FfEcp20-2, DsEcp20-3, and FfEcp20-3 from the Ecp20 family, and all members from the Ecp32 family, except for the Ds/FfEcp32-4 pair, triggered cell death in both species. This cell death was dependent on secretion of the effectors to the apoplast. In line with recognition by an extracellular immune receptor, cell death triggered by Ds/FfEcp20-3 and FfEcp32-3 was compromised in N. benthamiana silenced for BAK1 or SOBIR1, which encode extracellular co-receptors involved in transducing defense response signals following apoplastic effector recognition. We then investigated whether DsEcp20-3 and DsEcp20-4 triggered cell death in the host species Pinus radiata by directly infiltrating purified protein into pine needles. Strikingly, as in the non-host species, DsEcp20-3 triggered cell death, while DsEcp20-4 did not. Collectively, our study describes two new candidate effector families with cell death-eliciting activity from D. septosporum and F. fulva and provides evidence that members of these families are recognized by plant immune receptor
The third independence referendum in New Caledonia – a fallback to colonialism?
No full textThe third and final referendum in the French overseas territory New Caledonia on December 12, 2021, was wasted. Although the vote was legal and the result was clear (96.5% voting against independence), we argue – along with various international observers – that the schedule did not respect Kanak cultural traditions and the vote should be considered as undemocratic. As engaged scholars with different scientific backgrounds (geography, agronomy, education) and of different origins (German, British-Australian, French-Caledonian and indigenous Kanak), we critically examine the circumstances of the third referendum and analyse the reasons for the non-participation of the majority of independence supporters. We offer a number of observations on future prospects for the interrupted decolonization process and recommend the consideration of new forms of partnerships between France and New Caledonia