Using cost-benefit analysis to understand adoption of winter cover cropping in California's specialty crop systems.

Winter cover crops could contribute to more sustainable agricultural production and increase resiliency to climate change; however, their adoption remains low in California. This paper seeks to understand barriers to winter cover crop adoption by monetizing their long-term economic and agronomic impacts on farm profitability in two of California's specialty crop systems: processing tomatoes and almonds. Our modeling effort provides a present, discounted valuation of the long-term use of winter cover crops through a cost-benefit analysis. A net present value model estimates the cumulative economic value of this practice. We then explore how the long-term trade-offs associated with winter cover crops can affect an operation's profits under a spectrum of hypothetical changes in California's agricultural landscape. Our analysis sheds light on the barriers to adoption by reporting benefit-cost ratios that indicate profitability across several scenarios; however, benefits and costs accrue differently over time and with long planning horizons. At the same time, a small portion of gained benefits are external to the grower. Findings from this study reveal that winter cover crops in California can be profitable in the long-term, but the extent of profit depends on the cropping system, extent of irrigation savings due to improved soil function, access to financial subsidies and climate change. Winter cover crops can return positive net benefits to growers who have flexible contractual obligations, can wait for the long-term return on investment and manage cover crops as closely as cash crops. This analysis contributes to the study of conservation agriculture practices by explaining possible reasons for low adoption through an economic valuation of the implications of soil management choices and policy counterfactuals.

Compound natural and human disasters: Managing drought and COVID-19 to sustain global agriculture and food sectors.

Individually, both droughts and pandemics cause disruptions to global food supply chains. The 21st century has seen the frequent occurrence of both natural and human disasters, including droughts and pandemics. Together their impacts can be compounded, leading to severe economic stress and malnutrition, particularly in developing countries. Understanding how droughts and pandemics interact, and identifying appropriate policies to address them together and separately, is important for maintaining a robust global food supply. Herein we assess the impacts of each of these disasters in the context of food and agriculture, and then discuss their compounded effect. We discuss the implications for policy, and suggest opportunities for future research.

Two new growth inhibition tests with the filamentous algae Ceramium strictum and C. tenuicorne (Rhodophyta).

Two growth inhibition tests using the red marine macroalgae Ceramium strictum and the brackish water relative C. tenuicorne have been developed. Besides using phenol as a reference substance, the toxicity of a metal, a flame retardant and a complex effluent water were assayed. The two methods are reliable and repeatable bioassays for salinities between 4 and 30 per thousandth. The coefficients of variation (CV) for toxicity of the reference substance phenol were 15% for the Stereo Microscope Analysis test and between 24 and 51% for the Computer Image Analysis test (n=5). Ceramium spp. are common and important primary producers in temperate coastal waters and are thus relevant as test organisms. Both algae grow well in laboratorial conditions and tests can be performed all year around.

Use of ethylenediaminetetraacetic acid in pulp mills and effects on metal mobility and primary production.

Over the last decade, the use of ethylenediaminetetraacetic acid (EDTA) has increased by a factor of three within the Swedish pulp industry. The effects of pulp mill wastewater in combination with EDTA on metal mobility and the consequences for ecologically relevant organisms have been studied. Ethylenediaminetetraacetic acid was added to pulp mill effluent water in the laboratory and compared to wastewater without EDTA. Degradation of the water was followed over a experimental period up to eight weeks and samples were taken five times for chemical analysis and at the beginning and the end for biological tests. Half a year later, the experiment was repeated. The results from both experiments showed that EDTA markedly increased the solubility of zinc, cadmium, lead, iron, nickel, and copper, whereas the solubility of vanadium, molybdenum, thallium, arsenic, and chromium was not changed by the presence of EDTA. No measurable degradation of EDTA occurred even after 5.5 months. The toxicity of the pulp mill effluent water was low, and only a slight toxic effect was observed on the reproduction of Ceramium strictum. The most pronounced effect was a stimulation in the growth of three algal species in 5 to 20% (v/v) total effluent wastewater with and without EDTA. The presence of EDTA in the dissolved fraction of the pulp mill effluent water increased the growth stimulation in 20 to 40% (v/v), possibly because of the increased availability of essential metals like iron, zinc, and copper. The capacity of the pulp mill wastewater to support algal growth was nearly as good as a rich nutrient medium for algae. The combination of poorly degradable EDTA and the increasing availability of metals might further enhance eutrophication in the recipient areas of pulp mills.