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Description
Introduction
Newfoundland and Labrador (NL) situated in the boreal region and faces crop production challenges due to low soil fertility, short growing seasons, and low crop heating units or growing degree days). Cover crops (CCs) have potential to improve soil fertility, soil quality and health (O’Reilly et al., 2012), reduce erosion (Blanco-Conqui et al., 2011), and enhance productivity through weed suppression (Bolandi Amoghein et al., 2013) and supplying additional forage. However, the short growing season restricts seeding of CC mixtures after harvesting primary crop. Interseeding CCs into corn can improve chances of establishment. A field research trial was conducted to: 1) assess the establishment potential of CC mixtures interseeded into silage corn, 2) determine the effects of interseeded CCs on yield and quality of silage corn, and 3) evaluate the effects of CC mixtures on soil physio-chemical properties.
Material and Methods
A field trial was conducted in Pynns Brook, NL, Canada (49.087° N, 57.541° W) (2022 & 2023). Silage corn was seeded on 3 × 4-m plots on May 25, 2022, and June 7, 2023. The experimental design was a randomized complete block design with 15 CC treatments replicated four times. CC mixtures were seeded:1) berseem clover + annual ryegrass (BCAR); 2) BC + cereal rye (CR); 3) BC + triticale (TR); 4) birds trefoil (BT) + AR; 5) BTCR; 6) BTTR; 7) hairy vetch (HV) + AR; 8) HVCR; 9) HVTR; 10) red clover (RC) +AR; 11) RCCR; 12) RCTR; 13) BTBCTR; 14) HVBCTR and 15) control (no CC). CC mixtures were interseeded into silage corn at the V4 -V6 stage. Silage corn was harvested on 7 October 2022 and 15 October 2023. CC biomass was sampled using 0.5m x 0.5m quadrats on 26 October 2022 and 7 June 2023). In 2023, CC mixtures could not be established due to poor germination. To determine soil physio-chemical properties, soil samples were collected from 0-15cm depth using a stainless auger before corn planting and after harvesting CCs.
Results
There were significant differences in biomass accumulated from different CC mixtures. RCTR produced the highest biomass (5.95 Mg ha-1), followed by RCAR and RCCR which produced 3.82 Mg ha-1 and 3.81 Mg ha-1 biomass yield, respectively. The lowest biomass (0.255 Mg ha-1) was from BTCR. There was no significant effect of CC mixture on the silage corn yield. However, corn yield significantly varied by year. Silage corn was 30% higher in 2023 compared to 2022. Interseeded CC mixtures did not significantly affect silage corn forage nutritional quality, soil bulk density, porosity, or organic matter and mineral nitrogen contents).
Discussion
Interseeded CC mixtures in silage corn established well in 2022 (Fig. 1), but there was poor establishment in 2023 due to early-season incessant rain seeding. In all mixtures, grasses consistently established, but BT did not germinate. Ultimately, grass-legume proportions in the final CC biomass were variable, and this could have implications on nitrogen capture or contributions from these CC mixtures. These findings demonstrate potential for some grass-legume combinations to contribute substantial biomass when interseeded into silage corn at the V4 – V6 stage. However, due to climatic/seasonal variability, more data is needed before recommendations can be made.,
References
Blanco-Canqui, H., Mikha, M.M., Presley, D.R., Claassen, M.M., 2012. Addition of cover crops enhances no-till potential for improving soil physical properties. Soil Sci. Soc. Am. J. 75, 1471–1482. Blanco-Canqui, H., Claassen,
O’reilly, K.A., Lauzon, J.D., Vyn, R.J., Van Eerd, L.L., 2012. Nitrogen cycling, profit margins and sweet corn yield under fall cover crop systems. Can. J. Soil Sci. 92, 353–365.
Bolandi Amoghein, M., Tobeh, A., Gholipouri, A., Jamaati-e-Somarin, Sh., Ghasemi, M., 2013. Effect of cover crop in control of weed density and some qualitative and quantitative characteristics of sunflower. Int. J. Agric. Crop Sci. 5, 1318–1323.
| Keywords | Cover crops, yield stability, soil properties, forage quality, silage corn |
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