Content area
Full text
ABSTRACT
One of the challenges to potato (Solarium tuberosum L.) production systems is to reduce N applications without incurring any marketable yield penalty. From previous studies, it was established that red clover (Trifolium pratense L.) can encourage the development of beneficial rhizobacterial communities that promote potato growth and development, in essence making agricultural soils as or more productive for specific quality attributes. In the present 2-yr study, we examined the influence of the red clover cultivars AC Charlie, AC Endure, AC Kingston, Atlas, Marino, and Prosper on the potato cultivars Kennebec, Russet Burbank, and Shepody, grown in the following season. We found that the preceding clover cultivar had no influence on cither Kennebec or Russet Burbank. However, Shepody potato following AC Kingston showed a significant yield advantage (P = 0.05), in tonnes per hectare, over other clover cultivars (except Atlas) in the Size 2 category of tubers (tubers >51 mm in diam. and <280 g), the grade for which growers arc characteristically paid the most. We encourage breeding programs to examine the ability of any given line to manipulate its root zone microflora with respect to its own needs and to those of subsequent crops. While the complexities of plant-soil-microbial interactions are great, the beneficial biological interactions that stimulate crop yields and improve plant health can be evaluated relatively simply, and general management strategies can be devised accordingly for any given set of crop combinations and growing environments.
IT is COMMONLY held that the principal benefits of including a clover crop in a rotation sequence are the residual N left in the soil and the organic matter added (Bruulsema and Christie 1987; Christie et al., 1992). However, it is also recognized that field crop history (Glandorf et al., 1993; Leyns et al., 1990) and cultivai' selection (Chanway et al, 1988) can stimulate specific beneficial bacterial populations in the root zone that may also lead to improvements in soil fertility, crop vigor, and yield.
Along the northeastern seaboard of Canada and the USA, potato is often grown in a 3-yr crop sequence of potato, barley (Hordeum vulgare L.) underseeded with red clover, and red clover (Bernard et al., 1993). Clover plowdown in the third year is preparatory to potato planting. Sturz and Christie (1995, 1999)...