Individual study: Deleterious activity of cultivated grasses (Poaceae) and residues on soilborne fungal, nematode and weed pests
Stapleton J.J., Summers C.G., Mitchell J.P. & Prather T.S. (2010) Deleterious activity of cultivated grasses (Poaceae) and residues on soilborne fungal, nematode and weed pests. Phytoparasitica, 38, 61-69
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Incorporate plant remains into the soil that produce weed-controlling chemicals
A set of three randomised, replicated, controlled field trials in central California, USA (Stapleton et al. 2010) found that incorporating residue of a sorghum-sudangrass hybrid (Sorghum bicolor x S. sudanense ‘sudex’) into the soil reduced weed growth, but that this effect was temporary. In the first experiment, growing and incorporating sudex reduced weed growth by 35% (136 g dry weight weed biomass vs. 208 g in control plots). In the other two experiments, weed growth was reduced by 61-89% compared to control plots 50 days after treatment, but after 57 days in the second experiment and 106 days in the third experiment this difference had disappeared. Sudex was planted in six rows in raised beds and shredded at 1.4-2.0 m tall. Experiment 1 had three treatments with four replicates in 1 m-long plots: sudex grown, shredded and left as a mulch; grown, shredded and incorporated; no sudex grown or residue added. Experiments 2 and 3 had four replicates in 4.5 x 1.5 m plots. Treatments included those from experiment 1, plus two additional treatments: shreddings added to fallow plot where no sudex had been grown; shreddings removed but roots and 3-5 cm stubble left in plots. Weed biomass was calculated by removing material from a 0.093-1 m² area.