Funded by Results Driven Agriculture Research (RDAR)
Intercropping is an eco-functional intensification practice that can boost crop productivity and address some of the major problems associated with modern farming practices such as pest and pathogen accumulation, soil degradation, and environmental deterioration. Intercropping is the practice of growing two or more crops in proximity. The most common goal of intercropping is to produce a greater yield on a given piece of land by making use of resources that would otherwise not be utilized by a single crop. With very few guidelines available to producers on this practice in the Peace Region, this project worked at providing producers with the information they need before embarking on large-scale intercropping operations.
What did we do?
The trial was conducted at PCBFA’s Research Farm (NW-5-82-3W6M) on RR 35, MD of Fairview, AB. The site for the trial was summer fallowed the previous year. Before seeding the site was disced and harrowed and later pre-pass sprayed with glyphosate at 0.67 L/acre.
The experimental design was a 3 x 2 factorial design with 4 repetitions consisting of the following factors:
Intercropping combinations (3 mixes & 5 monocultures)
3 intercropping treatments:
Amarillo Peas at 1.64 bu/ac + 45H37 canola at 2.71 lb/ac (we seeded at 50% peas & 50% canola)
AAC Brandon Wheat at 1.10 bu/ac + Kentucky Pride Crimson Clover 6 lb/ac (we seeded at 60% wheat & 40% clover)
Arborg Oats at 1.72 bu/ac + Amarillo Peas at 2.45 bu/ac (we seeded at 50% oats & 75% peas)
5 monocrop treatments (controls):
Amarillo Peas monoculture at 3.33 bu/ac
45H37 canola monoculture at 5.4 lb/ac
AAC Brandon Wheat monoculture at 1.83 bu/ac
Kentucky Pride Crimson Clover 15 lb/ac
Arborg Oats monoculture at 3.43 bu/ac
Seeding methods (2):
Same-row seeding (i.e., 2 crops in the same rows)
Alternate row seeding (i.e., side-by-side seeding)
The plots were seeded on May 27, 2022.
The average soil temperature and moisture at seeding were 15.5°C and 8.5% VWC (volumetric water content) respectively.
A fertilizer blend of NPKS at 141 lbs/acre at seeding was applied between rows (mid-row banding).
Peas, wheat, and oats were seeded at ¾ - 1" while clovers and canola were seeded at 0.5".
Data collection included canopy NDVI measurements, forage yield and quality, grain yield and grain protein content.
The plots were handed a few times.
What we found out
Results from testing of various intercropping treatments for grain and forage production are shown in Table 16.
Grain yields differed significantly between treatments with higher yields observed in monocultures compared to mixtures.
Grain protein values were generally >18 % with relatively high values for treatments with canola as monocrop or in mixtures. But for forage dry matter yields which varied significantly between the various treatments, NDVI readings and all forage quality indicators did not significantly differ between treatments. Crimson clover yielded the least (883 lbs/acre) while peas and canola seeded both in the same and alternate rows, each produced over 6,000 lbs/acre. Intercrops yielded better than monocultures highlighting the advantages that intercrops can bring to cropping systems while alternate row seeding showed a trend to higher yields compared to same row seeding. Forage crude protein levels were high and ranged between 12.1 to 15.8 %. Calcium contents were also relatively high with a range of 0.35 - 1.02 %, while phosphorus levels were < 0.20 %.
Water use efficiency, which measures the amount of grain/and or forage produced per unit of water used by a crop, was significantly influenced by the intercropping system. Peas and Canola intercrop, in both seeding methods of the same and alternative rows, had a significantly lower grain yield (bu/ac) and water use efficiency (Figure 4). On the other hand, when seeded in the same row, intercropping Wheat and Clover optimized water the most and was able to have a higher grain yield than all the other intercropping systems and was comparable to seeding a wheat monocrop. Intercropping Peas and Wheat in alternative rows had a greater advantage in terms of grain yield (bu/ac) and water use than seeding it in the same rows. Noteworthy is the observation that the treatments which came in high in terms of WUE in grain yield were lower in terms of forage yield.
Implication of results
In conclusion, intercrops bring an advantage in mostly forage production but not grain production as monocrops yielded better in terms of grain yields while intercrops yielded better in terms of forage yield. This increased forage yield advantage from intercrops did not produce a corresponding forage quality advantage as both crops in the intercropping mixture seem to have 'diluted' themselves quality-wise in the mixture. This also is the case with WUE, for blends which used water more efficiently in terms of grain yield did not produce corresponding high forage yields. A better picture of WUE will be obtained when both grain and forage yield are considered in its calculation.
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