A shortage of containers at the Port of Vancouver is slowing Canada’s exports of lentils and peas, the latest ripple in a phenomenon that has roiled trade. Companies are rushing to get the steel boxes to Asia so that consumer goods made in factories there can be shipped to North America, which is proving to be more profitable than waiting for agricultural products to be loaded and sent. As a result, tons of pea and lentil crops from the world’s biggest producer remain in storage on farms and in elevators. The bottleneck is hitting farmers just as pulse exports to Asia and India typically pick up following a large Canadian harvest.