Mayweed chamomile (Anthemis cotula L.) biology and management—A review of an emerging global invader

The globally invasive weed, mayweed chamomile (Anthemis cotula L.) is an annual, bushy, ill-scented herb, originating in Eurasia. It is aggressively weedy in croplands, field-side ditches, wet areas and along roadsides, especially in slightly acidic, nitrogen-rich, clay-loam soils. In addition to interfering with crop growth, the weed causes dermatitis and eye irritation in humans, skin rashes and sour mouth in domesticated mammals, and off-flavours in cow's milk through forage contamination. Although A. cotula may be managed effectively with some broadleaf herbicides in cereal crops, it is much more difficult to manage in broadleaved crops and cover crops. In some regions, aggressive use of relatively few herbicides has selected for acetolactate synthase herbicide resistance in A. cotula. Therefore, A. cotula poses serious ecological and economic challenges in many regions. Despite this threat, the details of A. cotula biology and ecology in the context of environmental change remain relatively unknown. For example, the reason for the invasiveness of A. cotula remains uncertain, but is presumed to be due to abundant seed production, allelochemicals, mycorrhizal associations, minimal herbivory in invaded ranges, ability to attract generalist pollinators through an extended flowering period and adaptive capacity in a wide range of soil types and conditions. In this paper, we comprehensively review the literature and ongoing work on A. cotula and provide a research agenda to improve understanding and management of this species.     

Evaluating smallholder farmers’ demand for rice variety attributes in Nepal

Despite the release of many modern varieties of rice (Oryza sativa), farmers in Nepal have been cultivating relatively few rice varieties. The objective of this study is to estimate farmers’ demand for rice variety attributes and to identify the factors that influence their decision regarding varietal choice. Yield increase is considered jointly with other attributes, such as cooking and eating quality, drought tolerance, and maturity period. Choice experiments were conducted and results showed that there was significant demand from farming households for yield increase, improvement in cooking and eating quality, tolerant to drought, and short maturing varieties. The choice data were analyzed using a multinomial and random parameter logit model. From a policy perspective, results showed that for broader adoption of crop varieties, variety development programs should give priority to aforementioned attributes rather than solely on increased crop productivity.     

Walkable Neighborhood Systems

This essay defines walkable neighborhood systems, summarizes the negative impacts of suburbia on the economy as a whole, and presents indirect pricing as a major cause of suburbia. The paper proposes several pricing reforms and green mobility as solutions based on prices that reflect full costs. Several hypotheses are presented concerning the performance of walkable neighborhood systems and the concept of an inflection point for the takeoff of non‐auto modes when density within a walkable area reaches economies of scale. It proposes research on old neighborhoods as a way to quantify relationships in the absence of pricing reforms. The paper discusses building types and high rise, and how at highest densities there may be diminishing returns. While it is natural for most scholars to study dominant land uses, there is a need to understand better dense walking neighborhoods as solutions to the costs of suburbia and to enhance their functioning to show a path to a sustainable future.     

Effect of three different oil cake-based diets on pond production performance of silver barb, Puntius gonionotus (Bleeker)

One of the three iso-nitrogenous (30% crude protein) and iso-energetic (15.0 MJ kg⁻¹ diet) oil cake-based diets (groundnut, D-1; soybean, D-2 and mustard, D-3) was fed to the fingerlings (6.61 ± 0.06 g) of silver barb ( Puntius gonionotus ) for 120 days in triplicate fertilized ponds (0.04 ha) with a stocking density of 9000 fish ha⁻¹. Fish were fed at 10% of their body weight for the first month, followed by 3% in the second and 2.5% in the third and fourth months of the culture period. The fish fed diets D-1, D-2 and D-3 grew from initial weights of 6.67, 6.67 and 6.50 g to 320.23, 298.23 and 305.13 g respectively. No significant variation ( P >0.05) was found in the growth and nutrient utilization of fish fed different dietary treatments. Net profits of Indian Rupees 67 385, 59 535 and 65 790 ha⁻¹ were obtained in fish fed D-1, D-2 and D-3, respectively, within 120 days of culture. The results of this study suggest the possibility of the use of mustard oil cake as a dietary protein source for pond culture of silver barb in addition to groundnut and soybean oil cakes without compromising the growth, nutrient utilization, production performance and economics of culture of this fish.