Multi-thematic delineation of 'natural zones' of arable fields and their correspondence to spatial yield variation

Properties such as soil apparent electric conductivity (ECa), topography and other site-related data (e.g. canopy reflectance from aerial images) vary across field. The agronomic effects of such variability can sometimes be seen in the spatial variations of crop yield on that field. However, yield maps do not always represent the natural boundaries based on site characteristics. Identification of these boundaries as “management zones” (MZ) can be beneficial in crop management and improving crop input use efficiency. A simple methodology is required to delineate such zones. This research presents an effective methodology to delineate MZ in an irrigated and a non-irrigated (rain-fed) arable maize field in New Zealand. Elevation data for the sites were acquired from Google Earth images and a soil survey. Soil ECa was collected from a soil survey with an electromagnetic device. Yield values (t/ha) were obtained from combine harvesters equipped with yield monitor and Global Positioning System (GPS), over the course of four years for the irrigated site, and two years for the non-irrigated site. The yield data was quality controlled using a filtering system to remove outliers and technically non-plausible data. The data sources were combined in Geographic Information Systems (GIS) and three MZ were delineated for each field through standard clustering methods. The maize yields were aggregated per derived MZ to compare yields between different MZ-classes. The results showed that there was some consistency in yields related to the MZ, derived without yield data. In both the non-irrigated and irrigated fields, the lowest yield consistently occurred in the same class each year, however, the MZ-class with the highest yield varied year to year. The results show that it is possible for the studied type of fields to delineate ‘natural’ clusters or zones of site properties that can be used as MZ-classes as they represent different yield levels. The required inputs are freely available and easily obtained data

Gender and displacement in Jaffna, Sri Lanka

This report presents the preliminary results of a household survey of internally displaced persons (IDPs) in Jaffna District in Northern Province, one of the areas that still has a large IDP population. The main focus of this survey conducted in October 2020 employing Covid-19 safety protocols was to examine the gendered experiences arising from protracted displacements spanning over three decades. The survey covered 220 households (182 male-headed and 38 female-headed), which accounts for 54.3 per cent of the total IDP households in the Jaffna District. Among other topics, the survey gathered data on the respondents’ current living conditions, finances, asset ownership, safety and security concerns, access to services, social networks and relationship with other IDPs and the host community, and water, sanitation and hygiene issues they face. It also gathered data on the respondents’ pre-displacement experiences to compare that with their current lives, in order to examine the role of displacement in gendered issues they face

Protein quality of foods made incorporating Cycas circinalis seed flour

Among the cycad species Cycas circinalis and Cycas zeylanica are native to Sri Lanka. Foods such as pittu and roti made by incorporating Cycas circinalis seed flour are consumed by Sri Lankans living in areas where the plant grows. Although previously reported data indicate that the content of protein in C. circinalis seeds is comparable to that of wheat flour, no data is available on the quality of cycad seed proteins. The present study was aimed at evaluating the quality of proteins in C. circinalis seed flour, pittu and roti made by incorporating cycas seed flour.The moisture, insoluble (IDF) and soluble dietary fibres (SDF), crude protein and digestible carbohydrate contents were measured by AOAC official methods (1984), method of Asp et al, Lowry’s method/ Folin Ceocalteau method and Holm’s method respectively. Quality of proteins was estimated by AOAC Official method 960.48, using an animal bioassay.Digestible carbohydrate content was highest in soaked seed flour (50.0±2.03). Among the cycad foods, highest protein content (10.3±0.01) and total dietary fibre content (7.7) were in roti and this could be due to the addition of wheat flour to roti instead of rice flour in pittu. Highest weight gain was observed in reference group fed with casein containing diet. The significantly high weight gain in the seed flour fed group compared to roti and pittu fed groups may be due to the high feed intake. No significant weight gain difference was observed between roti and pittu fed groups. Protein quality of C. circinalis seeds was comparable with that of common maize but all protein quality parameters [Protein Efficiency Ratio (PER), Food Efficiency Ratio (FER), Net Protein Retention (NPR) and Protein Retention Efficiency (PRE)] were significantly low compared to the reference protein diet. Although not significant, NPR and PRE values in roti (1.4±0.6 and 8.5±3.7) were higher than test food made with pittu or raw seed flour.Key words: protein quality, Protein Efficiency Ratio (PER), Food Efficiency Ratio (FER), Net Protein Retention (NPR) and Protein Retention Efficiency (PRE

Determinants of corporate environmental disclosures in Sri Lanka: the role of corporate governance

Purpose This study explores the levels of and trends in corporate environmental disclosure (CED) among a sample of Sri Lankan listed companies from 2015 to 2019. Furthermore, this article examines the firm-level determinants of CED, including corporate governance (CG) mechanisms, in Sri Lanka from a multi-theoretical perspective. Design/methodology/approach Using a sample of 205 firm-year observations, this paper distinctively applies a panel quantile regression (PQR) model to examine the determinants of CED in Sri Lanka. This method was supported by estimating a two-step generalized method of moment (GMM) model to tackle any possible existence of endogeneity concerns. Findings The authors’ findings indicate an increasing trend in CED practice among the sampled companies (i.e. 41 firms, the only adopters of the GRI framework) in Sri Lanka from 2015 to 2019. However, it is still considered at an early stage compared with other developed counterparts. Furthermore, this study suggests that board size, board independence, board meetings, industry type, profitability and firm size are positively associated with CED level. In contrast, and consistent with our expectation, CEO duality is negatively attributed to the disclosed amount of environmental information in the Sri Lankan context. Research limitations/implications The authors’ empirical evidence reiterates the crucial need to propagate and promote further substantive CG reforms, mandating CED in Sri Lanka. Originality/value The authors’ findings provide much-needed insights for indigenous companies, operating across similar emerging economies, to understand how CED can be incorporated into their reporting process based on the GRI framework in order to enhance their firm value, reduce legitimacy gaps and mitigate other operational risks

In situ measurement of root reinforcement using corkscrew extraction method

Mechanical root reinforcement is an important parameter to evaluate for stability analysis of rooted slopes. The contribution of roots is however difficult to quantify in situ without time-consuming methods or heavy equipment. Here we report field testing using the newly developed “corkscrew” method at two different sites with plantings of conifers and blackcurrant. In both sites we found positive correlations between root quantity and root reinforcement in surface layers where many roots were found. Below 125 mm depth, no correlations could be found, probably due to variability in soil stress and gravel content. Roots were shown not only to increase the soil peak strength, but also to add ductility to the soil, i.e., adding strength over much larger displacement ranges. Measured reinforcement, although similar to other experimental studies, was smaller than predicted using existing models. This may be attributed to the distinct difference in shear displacement required to mobilize the strength of rooted soil as compared with fallow soil. At displacements sufficient to mobilize root strength, the soil strength component has reduced from peak to a much smaller residual strength. The corkscrew method proved a promising tool to quantify root reinforcement in field conditions due to its ease of use and short test duration.</p