A 2023 research trial looking at 'Hybrid Brown Mustard and Composite Yellow Mustard response to Soil Test Fertility Recommendations' was done across three locations in Saskatchewan last year Swift Current, Indian Head, and Redvers.
Amber Wall, the Assistant Manager with Wheatland Conservation Area, says the ADOPT trial focused on AC Yellow 80 and AC Brown 18 and the addition of zinc and boron based on the soil test recommendations.
She notes they were targeting a 40-bushel-per-acre crop of brown mustard, and 30 bushels per acre for yellow at Indian Head and Redvers, with the targets being 35 and 25 for Swift Current.
In this demonstration, six treatments for each variety were set up with fertilization rates for NPKS ranging from zero to 125 per cent of the recommended fertilizer rate with no other nutrients. While treatments four and five also included the micronutrients, so 100% of the recommended rate of NPKS, plus five pounds per acre of boron, and 5 pounds per acre of zinc in treatment five. Treatment 6 is exceeding the limits, so fertilizing for 125% of the recommended fertilizer rate of NPKS.
She noted the residual nutrients at each site showed low or very low residual nitrogen, with medium phosphorus and sulphur at Swift Current, and even higher sulphur levels at Indian Head and Redvers at almost up to 90 pounds per acre.
The focus of this trial is on zinc and boron, with very low boron and low zinc residual found at Swift Current, Indian Head had high boron and medium zinc, while Redvers had medium boron residual and low zinc.
All sites were seeded in mid to late May, the brown mustard was seeded at 8.4 lbs per acre and yellow at 11.6 lbs per acre.
The zinc and boron products came from Nexus BioAg with the Boron being a granule bore at 15% boron, while the zinc product was a granule with zinc sulfate at 35.5% zinc and 18% sulfur both were side bounded along with the recommended NPCS.
She says the study showed no significant difference between varieties but it did show that mustard will respond to proper micronutrient management.
"The results for Brown 18 at Indian Head and Swift Current did not show a large response to fertility, but the yellow 80 showed an increased emergence in response to both boron and zinc. For Redvers, the addition of zinc showed an obvious increase in plant stand for Brown 18, and the boron elicited a response there as well. Yellow 80 had a slight increase with fertility but not a lot of variability between treatments there. Yield potential was obviously brought down by the lack of moisture at all three sites, so we didn't quite get to those targeted yields. Yields presented here in pounds per acre overall, averaging 1200 lbs per acre or 24 bushels an acre. "
Wall points out that when all three sites were averaged together, varieties did not significantly differ, but the yield was different at each site as we expected.
For Swift Current, AC Brown 18, yields ranged from 700 to 1100 pounds per acre, so 14 to 22 bushels an acre. There was no significant difference from 50 to 100 per cent of the recommended fertility response plus boron, but we see a response from the additional zinc and the 125 per cent of additional macronutrients. Yellow 80 yields ranged from 700 to 1200 pounds per acre yield response from both boron and zinc. The addition of boron and zinc yielding higher than the extra macronutrients, the 125% recommended.
Indian Head where we saw the medium and high zinc and boron levels in the residual soil results, there was not as much of a response here other than yellow 80 with a small increase from the zinc treatment compared to the 100% recommended fertilizer rate. Overall more of a response from the increased macronutrients which was expected given the very low nitrogen in the soil tests.
At Redvers, both varieties saw a response to zinc, and similar to Swift Current, it was not significantly different than the 125% recommended fertility rate. Again, knowing residual N was low, we can assume that the response is to nitrogen. Boron residual levels were medium at this site, so not surprising that there wasn't a response there, but the zinc treatment showed a good yield response.
She notes when you average the yield for all three sites, we do see an overall yield response with increased fertility for the most part to zinc and nitrogen, as for boron, it's important to note the organic matter, which for example at our Swift Current site was low.
Organic matter can contribute to low boron availability, but it's also noted in previous research that large yield responses to boron fertilization in Western Canada are rare. For boron in this study, the most notable response was from the yellow mustard at Swift Current, where the soil residual levels were considered very low.
Wall says they also looked at lodging and days to maturity.
Looking at the results for lodging, brown mustard showed slightly higher lodging than yellow 80 and increased with fertility. It was also site specific with Redvers having the highest ratings.
Days to maturity results showed one to two days longer to mature at Indian Head and Redvers on treatments with higher fertility.
Overall, there was a response to zinc in most cases with the exception of the brown mustard at Indian Head and not a strong response to boron, but we did see yellow 80 have a small yield response at Swift Current the only site where residual levels were low.
She says this study demonstrates the importance of soil testing and that mustard will respond to proper micronutrient management.
The mustard trial was one of 70 projects Wheatland Conservation completed in 2023.
Wall detailed the research project at the Saskatchewan Mustard AGM on Friday.