Stockbridge School of Agriculture

The concept of the current experiment is to study carbon storage and possible cycling in soils which alternate between saturation and nonsaturated conditions on an annual basis. To allow the data to be considered robust, or applicable to numerous locations and soil types it will be necessary to have multiple years of data, but to also have data that 'repeats' or replicates itself.

Soil organic matter acts like a sponge within the soil, retaining water, carbon, and nutrients. It also serves as a source of carbon, or food, and nutrients, like nitrogen, for soil microbes. Because soil microbes demand carbon and nutrients in specific ratios, the quantity of soil organic matter and how nutrient rich it is compared to carbon may determine: how much nitrogen is kept within microbial bodies, how much is held within soil organic matter, and how much is transformed by microbes into a plant-available form for uptake or leaching loss.

We are testing how plant viral infection impacts the effect of cover crops on soil carbon, greenhouse gas emissions, and soilnutrient status. We expect that the virus impact will vary with cover crop species and soil type. Our results are expected toinform how virus infections of cover crops may impact soil health. To quantify changes in soil carbon, greenhouse gas emissions, and nutrient status of soils subjected to virus infected covercrops, we are using a combination of field trials and pot experiments as well as basic and advanced soil characterizationtechniques.

Bursaphelenchus antoniae, a species of nematode associated with pine weevils and maritime pine, was first described in 2006 in Leiria, north-western Portugal. The nematode has evolved with the pine weevil, and the pine weevil carries the nematode to dead and dying trees where the weevil lays its eggs. During egg laying, the nematode leaves the weevil and invades the tree where it feeds on fungi that have colonized the tree internally. Inoculations in Portugal with B. antoniae showed that this nematode was not pathogenic to maritime pine, a pine native to Portugal.

It is known that legumes generally respond to existing N in the soil. When soil N is relatively high, legumes prefer to use soil N rather than to engage in symbiosis with rhizobia. However, the ecophysiological responses of legumes to existing soil-N level and the changing climate - including temperature changes and precipitation dynamics impact rhizobia nodulation - have not been studied in actual field conditions. This study seeks to understand these responses in order to improve N management, maximize the benefits of legumes, reduce off-farm inputs, and enhance soil health.

The plum curculio is an extremely destructive key pest of stone and pome fruit in commercial orchards in eastern North America. In fact, in a survey of over 100 MA and RI apple growers (conducted in mid-April 2018 by J. Piñero) this insect pest ranked first in importance. Conventional growers typically apply broad-spectrum insecticides to control plum curculio. The main goal of this project is to evaluate the attractiveness of aromatic compounds to overwintered plum curculio and to other early-season pests.

Experiments will be conducted in the greenhouse and in the field with leafy vegetables to investigate if the mineral nutrient content of these foods can be enriched through fertilization of the crops. This research will address investigations of mineral nutrients, suggested to include phosphorus, calcium, magnesium, potassium, iron, manganese, copper, and zinc, which the investigators have the capability of analyzing in their laboratories. The research will emphasize investigations with lettuce that can be cycled rapidly in greenhouse or field production.