Short-term effects of crop rotations and wood-residue amendments on potato yields and soil properties of a sandy loam soil

Abstract

A 3-yr study (1988–1990) was conducted on a Beaurivage sandy loam soil located in St-Lambert, Québec, Canada, to evaluate the short-term effects of crop rotations and organic amendments on soil properties and potato yields (Solanum tuberosum, L.). Treatments consisted of yearly fall rye (Secale cereale, L.) as a green-manure cover crop, barley (Hordeum vulgare, L.) grown every 3-yr in potato crop rotation, partially humified bark residues and fresh tree clippings applied once at 100 m3 ha−1 in the beginning of the experiment, and continuous potato in monoculture used as check. Fertilizer rates were applied at 150, 100, 160 and 40 kg ha−1 rates for N, P2O5, K2O5 and Mg, respectively. Results indicated that more rapid changes of soil C content were observed with ligneous material incorporation than with fall rye and barley residue additions. Compared with fresh tree cuttings, partially humified bark induced rapid changes in soil organic C and cationic exchange capacity (CEC). A temporary soil structural stability improvement was observed in 1989 under fall rye cover crop. However soil bulk density increased significantly (P < 0.05) in these plots in 1990, and this was also related to low potato yields. Barley residues and ligneous amendments significantly improved soil water content during the critical flowering stage, and this increased potato yields and specific gravity (P < 0.05). In general, soil amendment would improve potato yields and quality through improved soil water content on a short-term. Key words: Barley, rye, rotation, cover crop, ligneous amendments, potato yields, soil physical and chemical properties