Preparing the campus terraces for winter

Yesterday was  a cold, wet morning to spread horse manure on the campus terrace market garden.

The end of the growing season is a good time to apply raw manure in order to minimize contact with edible crops. Organic standards prohibit harvest of organic crops within 120 days of incorporating raw manure, if the edible portion of the crop comes in contact with the soil. This precaution reduces the risk of transmitting human pathogens, such as E. coli.

We removed most of the remaining crops and the irrigation lines before spreading.

We took the inedible crop biomass that we pulled from the garden to Kwantlen's green bin for composting. It was disappointing to see that some green bin users had dumped plastic bags full of organic waste in the bottom of the bin. This plastic may contaminate the compost produced from our waste, and will certainly present a challenge for the compost operation that processes it. According to Canadian composting guidelines (pdf), 500 mL of compost used for growing food crops should contain no more than one piece of plastic or other foreign matter larger than 25 mm. 

KPU's green bin is a recent and welcome addition to campus, but its proper use will require education of the campus community. 

We left a few cold-tolerant crops, such as parsnips, carrots, kale, and chard. The parsnips and carrots will be sweetest after frost, but we won't be able to harvest them until early February if we want to comply with organic standards.

The few kale plants that we left are infested with aphids, so won't be harvested. Those aphids are supporting a very strong population of aphid predators and parasitoids, including lady beetles, syrphid flies, aphid midges, and wasps. We left the kale and a bank of flowering perennials to help the beneficials survive until next year.

The plant nutrients present in manure are less stable than those in compost. To reduce nutrient loss we incorporated the manure into the soil by raking, then seeded a winter cover crop mix consisting of 40% rye, 40% wheat, and 20% crimson clover. We distributed 1.7 kg of the mix over the 288 square meters of the market garden (~60 kg/ha), then raked again to incorporate the seed.

The deep-rooted grasses will help retain nutrients leached from the manure, and the crimson clover will fix additional nitrogen from the atmosphere. The winter cover will help prevent erosion by wind and water. Next spring, the new Agroecosystems Management class will cut these cover crops and incorporate them into the soil to add organic matter and release some of the nutrients that they retain this winter. 

The garden looks bare now, but we put up a big new sign to let the campus community know that it's still active.

With almost continuous rain since yesterday, the seeds were already beginning to swell, and some radicles had emerged, when I came to work this morning. 

Final orchard harvest and manure spreading

By the end of September the students had completed the final harvest at the orchard site. During the last two classes of the month they harvested 1.2 metric tons of squash, potatoes, corn, carrots, and apples.

It felt like a substantial harvest after spending much of the summer working on the campus terraces. The terrace harvest was spread out over six months, peaking in July, when we collected 140 kg of produce.

The orchard harvest was over in two weeks, but was more than three times as large as all six months of campus harvests combined.

The difference was due to the fact that we had 1,000 square meters to work with at the orchard, but just 288 square meters on campus. The yield per square meter was the same at both sites.

Once the harvest was in, we spread manure from a horse farm located about 350 meters from the orchard site. Our manure spreader holds about 750 liters, and we emptied it every 35 meters. We fertilized the area where we harvested potatoes.

We seeded the harvested area to a winter cover crop mix of barley and crimson clover.