Sequence effects among crops on alluvial-derived soil compared with those on glacial till-derived soil in the northern Great Plains, USA

The dynamic cropping systems concept proposes a long-term strategy of crop sequencing to achieve production, economic and soil care goals through sound ecological management. This requires that agriculturalists have comprehensive information about how crop species affect following years’ crops. Little research exists about how differences in soil type and properties change crop sequence effects. Sandy loam, alluvial-derived soil in south central North Dakota, USA (400mm/yr precipitation) was the site of a crop sequence experiment in which four species – maize (Zea mays L.), dry pea (Pisum sativum L.), spring wheat (Triticum aestivum L.), and soybean (Glycine max (L.) Merr.) – were grown in strips one year and in perpendicular strips the following, with spring wheat planted a third year. No-till management was used with three replications in land and two in time. Results were compared with those from two 10×10 sequence experiments on silt loam, glacial till-derived soil. Soil water depletion (SWD) and root growth were deeper in sandy loam soil than in silt loam. During a year of above average precipitation, prior year soybean enhanced spring wheat yield on sandy loam soil by 14% above average, but prior year spring wheat reduced it by 14%. During a year of deficient precipitation, prior crop effects on spring wheat yield ranked in order of expected springtime soil water storage: dry pea, 11%; spring wheat, 4%; soybean, −5%; maize, −10%. Prior crops’ SWD largely determined spring soil water, with maize having greatest depletion. Excluding results from a year of low precipitation, prior crops’ effects on spring wheat yield on sandy loam soil were similar to results found at two sequence experiments on silt loam soil: dry pea – generally positive effect (N-production, water conservation); spring wheat – negative (disease); soybean – positive (N-production); maize – generally negative (heavier water use). Same year comparison of three crops (nine sequences) on sandy loam soil vs. silt loam showed average dry pea and spring wheat yields being equivalent (P<0.10). However, average maize yield was 37% lower on silt loam, with maize-after-maize yielding 54% less. The site with sandy loam land had topsoil with lower soil quality indicators (organic C, water holding capacity) than silt loam. However, no-till management and previous grass rendered productivity of the soils equivalent, and superior capacity of the sandy loam site subsoil to conduct water and be conducive to root growth lessened negative, water-generated crop sequence effects.