Various mechanical plus chemical weed control systems for dry bean production were evaluated at Carrington, ND and Crookston and Staples, MN during 1991 and 1992. A dozen tillage plus herbicide weed control systems are available to growers that can provide selective and effective weed control in dry beans without reliance on chloramben—a standard herbicide on dry beans that has been lost. Dry bean yields were similar with low or high level tillage treatments because most of the herbicide treatments with one cultivation gave adequate weed control and any additional tillage did not improve weed control. Kidney bean yields and prices were greater than either pinto or navy beans so the net returns (bean market value minus production costs) were much greater for kidney bean production. Dry bean producers in the North Central part of the U.S. have at their disposal dependable mechanical plus chemical weed control systems, and their market value has been sufficient to make dry bean production very economical in this region.

Weed removal experiments in dry edible beans were conducted during 1992 and 1993 at Crookston and Staples, MN. Ten manual weed removal treatments were studied to determine when a natural infestation of weeds first reduced dry bean yield, and when weed removal could be discontinued without further loss of seed yield. Major weeds in order of average biomass production on weedy check plots at dry bean harvest over locations and years were wild mustard, foxtail spp., redroot pigweed, common ragweed, wild buckwheat, hairy nightshade, and common lambsquarters. Hairy nightshade also emerged late in the growing season and could negatively affect harvest efficiency and stain navy beans. Weed removal treatments had little effect on dry bean stands or 100-seed weights of harvested dry bean seed. The critical period for weed control in dry beans was 3 to 5 or 6 weeks after planting (WAP). Thus, weed control practices should begin no later than 3 WAP and continue until at least 5 or 6 WAP for maximum dry bean yields.

Weed management experiments with kidney beans were conducted at one irrigated site in 1991 and at two irrigated sites near Staples, MN during 1992. Green foxtail was the most difficult weed to control at the three research sites which agrees with survey results from dry bean growers regarding their worst weed problems. Hairy nightshade increased rapidly when weed management methods were reduced. Dry bean seed yields were highest in cultivated check plots on the farmer's field and in conventional practices plots at the Irrigation Research Center. Net economic returns, averaged over 1991 and 1992, for producing kidney beans at the Irrigation Research Center were $899/ha using conventional practices, $791/ha with cover crop practices, $734/ha with cultivated checks, $690/ha with herbicides only, and $208/ha on weedy checks. Kidney beans are an economical crop for North Central growers, but adequate weed management technologies are necessary for profitable production.

. 2006. Agronomic benefits of alfalfa mulch applied to organically managed spring wheat. Can. J. Plant Sci. 86: 121-131. Field experiments were established at two locations in Manitoba in 2002 and 2003 to determine N contribution, moisture conservation, and weed suppression by alfalfa mulch applied to spring wheat (Triticum aestivum L). Mulch treatments included mulch rate (amount harvested from an area 0.5×, 1× and 2× the wheat plot area), and mulch application timing (at wheat emergence or at three-leaf stage). Positive relationships were observed between mulch rate and wheat N uptake, grain yield, and grain protein concentration. At Winnipeg, the 2× mulch rates (3.9 to 5.2 t ha -1 ) produced grain yields equivalent to where 20 and 60 kg ha -1 of ammonium nitrate-N was applied in 2002 and 2003, respectively. Where mulch and ammonium nitrate produced equivalent grain yield, grain protein in mulch treatments was often higher than where chemical fertilizer was used. N uptake was also observed in the following oat (Avena sativa L.) crop. The highest mulch rate (2×) produced higher N uptake and grain yield of second-year oat compared with ammonium nitrate treatments. N use efficiency of mulch-supplied N by two crops over 2 yr [calculated as (treatment N uptake -control N uptake)/total N added] was between 11 and 68%. Mulch usually suppressed annual weeds, with greater suppression with late-than early-applied mulch. Increased soil moisture conservation was observed with high mulch rates (≥ 4.3 t ha -1 ) at three sites. Alfalfa mulch holds promise for low-input cropping systems when used on wheat at the 2× rates. Quand le paillage et l'application de nitrate d'ammonium donnent un rendement grainier équivalent, le grain du blé paillé est souvent plus riche en protéines que celui du blé fertilisé avec des engrais chimiques. On remarque aussi l'absorption de N par la culture subséquente dans l'assolement (Avena sativa L.). Le taux de paillage le plus élevé (2×) entraîne une plus forte absorption de N et un meilleur rendement grainier de l'avoine cultivée la deuxième année que l'application de nitrate d'ammonium. L'efficacité de l'assimilation du N venant du paillis par les deux cultures au bout des deux années (calculée comme suit : N absorbé du paillis -N absorbé par les témoins)/N total ajouté) se situe entre 11 et 68 %. En général, le paillis étouffe les mauvaises herbes, mais le fait davantage quand il est appliqué plus tard. Le taux de paillage élevé (≥ 4,3 t par hectare) a accru la conservation de l'eau à trois sites. Le paillis de luzerne s'avère prometteur pour les systèmes de culture à faible apport d'intrants quand on s'en sert au taux 2× avec le blé.

Various chemical and mechanical weed control treatments for kidney bean production were evaluated on irrigated, sandy loam sites from 1993 to 1995 near Staples, MN. Weed biomass can be controlled either mechanically or chemically, but a combination of the two gave the most effective and dependable weed control over years. Good weed control by either mechanical or chemical means reduced white mold infection of dry bean because of better aeration of dry bean plants and thus less favorable conditions for infection. Dry bean seed yields were inversely related to weed yields, and weed competition was similar from indigenous stands of either grass or broadleaf weeds. Row cultivation was more effective than rotary hoeing for controlling weeds, reducing white mold infection of dry bean, and increasing dry bean seed yields.