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Adoption of conservation practices such as no‐tillage (NT) may benefit soil properties and related yields. However, magnitude of changes is dependent upon time scale, soil characteristics, and climatic conditions, which has received little attention in eastern Canada. A 26‐yr field experiment was conducted on a clay loam soil at L'Acadie, southwestern Quebec, to evaluate the effect of NT vs. moldboard plow (MP) and mineral N (0, 80, and 160 kg N ha–1) and P (0, 17.5, and 35 kg P ha–1) fertilization on grain yields, soil properties, and annual net returns of a corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotation. Tillage was performed every year, while fertilizers were only applied to the corn phase. Throughout the years, the site responded well to N fertilization but not consistently to P. Tillage system did not affect corn grain yield in the first 10 yr, but yield gradually declined under NT and produced 2.3 Mg ha–1 less than MP with recommended N rate in the last 8 yr. By contrast, NT reduced soybean yield in the first decade (0.32 Mg ha−1) but not thereafter. After 24 yr of implementation, NT largely increased organic matter and Mehlich‐3 P and K in the 0‐to‐5‐cm surface layer, but this did not translate into higher yields. Compared with NT, MP achieved CAN$200 ha–1 more revenue during last years at recommended N rate despite higher operation costs. Results demonstrated that under northern latitudes, this clay soil was not appropriate for NT. Core Ideas: Tillage system did not affect corn grain yield in the first 10 yr following implementation.Corn with recommended N rate yielded 2.3 Mg ha−1 more under moldboard than under NT in the last 8 yr.Soybean achieved higher yields under moldboard than under NT only in the first 10 yr.No‐tillage improved soil surface chemical properties.Moldboard plow achieved about CAN$200 ha−1 more revenue than NT in this site. [ABSTRACT FROM AUTHOR]

Legume crop rotational effects are usually studied in only the first subsequent non‐legume crop even though several consecutive crops usually follow a legume. We studied the effects of field pea (Pisum sativum L.), faba bean (Vicia faba L.), faba bean green manure (faba GM), lentil (Lens culinaris Medik.), canola (Brassica napus L.), and wheat (Triticum aestivum L.), on soil microbial biomass carbon (MBC), β‐glucosidase enzyme activity, and bacterial physiological diversity in three subsequent crops at four locations. Generalized linear modeling (SAS PROC GLIMMIX) indicated that, when canola is grown 3 yr after an initial canola crop in the rotation, MBC is 4–40% (Bonferroni‐adjusted limits at 95% confidence) greater than when faba bean is the initial crop. Path modeling (SAS PROC CALIS) confirmed the negative effect on MBC by faba bean (relative to canola) as an initial crop. According to Bonferroni‐adjusted limits at 95% confidence, where faba GM was the initial crop, β‐glucosidase activity was 2–24% greater than where faba bean was the initial crop and 0.4–21.8% greater than where wheat was the initial crop. Similarly, where lentil was the initial crop, β‐glucosidase activity was 2–23% greater than where pea was the initial crop and 3–5% greater than where wheat was the initial crop. Path modeling revealed direct causal relationships from faba GM and lentil to β‐glucosidase activity. The legume crop effects on soil microbial properties were: faba GM > lentil > pea > faba bean, but we did not observe diminishing effects of the initial legumes to consecutive subsequent crops. [ABSTRACT FROM AUTHOR]

Long‐term field experiments are useful for determining cropping system productivity, stability, and resource use efficiency. With 12 yr (2004–2015) of data from five cropping systems on a long‐term experiment (> 30 yr) under semiarid conditions in Saskatchewan, Canada, a systems‐approach was used to compare grain and protein yield, stability, nitrogen (N) dynamics, N fertilizer (FUEG,P), and available N use efficiency (NUEG,P) for grain and protein. Annualized grain and protein yields for wheat (Triticum aestivum L.)‐canola (Brassica napus L.)‐wheat‐field pea (Pisum sativum L.; W‐C‐W‐P) were 2244 and 372 kg ha−1, respectively, 14 to 38% and 33 to 66% higher, respectively, than continuous wheat (ContW), summer fallow‐wheat‐wheat‐wheat (F‐W‐W‐W), F‐W‐W, and lentil (Lens culinaris Medik) green manure‐wheat‐wheat (GM‐W‐W). Fallow systems were the most stable, but less productive and well‐adapted to low‐yielding conditions, while GM‐W‐W was the least stable and poorly adapted. The ContW had below‐average stability and was better suited to high‐yielding conditions for grain. The W‐C‐W‐P consistently produced above‐average yields, and was best suited for high‐yielding conditions for grain and protein. The ContW and W‐C‐W‐P had the highest NUEG (26.4 g kg−1) and NUEP (4.1 g kg−1), respectively, with GM‐W‐W having the lowest (18.1 and 2.7 g kg−1); FUE was the reverse of NUE. This long‐term study showed that diversified cropping systems that include pulses can more consistently produce higher grain and protein yields, regardless of growing conditions, than most other systems with lower N fertilizer inputs, thereby potentially reducing the negative environmental consequences associated with N fertilizer application. [ABSTRACT FROM AUTHOR]

Currently available regression equations developed to predict pre-harvest nutritive attributes from simple field measurements taken in alfalfa (Medicago sativa L.)--grass mixtures can help producers determine when to best harvest their forages but they are applicable to only spring growth. Our objective was to develop and validate predictive equations of pre-harvest forage nutritive attributes of mixed alfalfa--grass stands for the spring and first summer growth cycles. Forage samples (n = 1856) were collected in 2015 and 2016 from three research sites in Quebec, Canada, and used to develop predictive equations that were then validated using samples (n = 315) collected on commercial farms across Quebec and compared to equations previously developed in New York State for use during spring growth. For newly developed equations with two to four field measurements, R² ranged from 0.70 to 0.84. The best equation developed to estimate a neutral detergent fiber assayed with a heat stable α-amylase and corrected for the ash content of the residue (aNDFom) had an R² of 0.82 and a root mean square error (RMSE) of 29.3 g kg-1 dry matter (DM). Some equations can be used to predict aNDFom concentration and the relative feed value of samples from commercial farms, but only if alfalfa proportion can be precisely determined. Locally developed equations resulted in better predictions than equations developed only for spring growth in New York State. Forage producers now have access to a tool to predict the pre-harvest nutritive value of their forages for two growth cycles. [ABSTRACT FROM AUTHOR]