Archive for: Cereals

Most of the soil organic matter is composed of humic substances (Nardi et al. 2002). Humic substances nurture plant cell membrane functions and encourage nutrient uptake. In the past ten years, there has been a growing body of evidence supporting the use of bio-stimulants in agriculture for both horticultural and field crop production systems, where they have been shown to increase root growth, enhanced nutrient uptake, and increase stress tolerance. du Jardin (2015) defined plant bio-stimulants in five categories: 1) microbial inoculants, 2) humic acids, 3) fulvic acids, 4) protein hydrolysates, and 5) amino acids, and seaweed extracts.

Fulvic acid, is of particular interest, as it is a natural chelator and thus helps facilitate migration of metal ions and nutrients across tissue membranes (Sun et al, 2012). It also retains many properties that make it ideal for foliar tank mixes, such as: (a) high solubility under different pH conditions (b) high cation exchange capacity, and (c) recorded absence of antagonistic effects with nutrients or pesticides. Owing to its low molecular weight (a few hundred Daltons), it can easily cross plant tissue membranes, and remains in solution even at high salt concentrations. All of which are considered ideal for foliar nutrient applications.

At the North Peace Applied Research Association, an experiment was designed to determine if foliar applications of Nitrogen with or without additions of fulvic acid have an effect on yield and leaf nitrogen content in canola, field pea and wheat. For field pea, only one treatment was conducted where foliar application of fulvic acid at 0.65 L ac-1 was applied at the 6th node and at the 12th node stage. This treatment was compared against a control where peas were sown in furrow with 13-33-0-15S at 120 lb ac-1. Above ground biomass was collected one week after foliar applications on each crop. For canola and wheat, the experiment was designed as a complete randomized block design with four treatments: (1) Dry urea at 150-175 lb ac-1 treated with fulvic acid at 0.3 L ac-1 applied at seeding, (2) Dry urea at seeding at 80-105 lb ac-1 followed by two foliar applications of liquid urea at 20 L ac-1, (3) Dry urea at 80-105 lb ac-1 treated with fulvic acid at 0.3 L ac-1 at seeding and two foliar applications of liquid urea with fulvic acid at 20 L ac-1 and 0.65 L ac-1, respectively and (4) seeding application of dry urea at 80-105 lb ac-1 treated with fulvic acid at 0.3 L ac-1 followed by two foliar applications of fulvic acid with a nitrogen, calcium and magnesium supplement (Nitro 18) at 0.65 L ac-1 and 20 L ac-1, respectively. In addition, a control treatment was included consisting of a sole application of dry urea at seeding at 150-175 lb ac-1.

Knowing the levels of nitrogen in your soil provides a base in which one can confidently decide on the amount of fertilizer that must be applied to achieve a desired yield. Similarly, being conscious of carbon levels in soil provides an indication of amendments required, such as manure or green manure (cover crops). To know how much N is available to the plant, a standard soil chemical test exposes soil samples from the field to a salt solution. The cations from the salt solution compete with cations on clay mineral surface exchange sites, thereby releasing N ions in solution. Extraction of nitrogen and/or carbon can also be achieved by combustion, where the soil samples are burned, and the emanating smoke is tested for C and N content. Soil chemical analyses will provide results for C as percentage of organic matter (%OM) and N as either ammonium (NH4+) and/or nitrate (NO3-) ions. The Haney soil analysis test, developed by Rick Haney at United States Department of Agriculture research station in Temple, Texas, is an alternative test to the standard soil chemical analyses for carbon and nitrogen. The Haney soil test replaces a salt solution with water as the extraction medium.

This project investigates methods to lower input costs and maximize profit, not necessarily yield. The rate of fertilizer applied to a crop should influence its growth and the amount of C and N readily available for the season. Cash crops such as canola, pea, and wheat were selected and sown under three different fertility levels (no fertilizer, 30%, and a 100% of the nitrogen rates recommended by the Haney soil test). This experiment was treated as a randomized complete block design and replicated four times. This trial will be conducted again in 2021.

Canola

There was no significant difference in canola yield when subject to either 0%, 30%, or 100% of the Haney soil test recommended fertilization levels (P=0.13). Applying 0% of the recommended nitrogen led to the lowest yield of 6.8 bu/ac; applying 100% led to the highest, 8.3 bu/ac. The C.V. is 54.8, too high for results to be accepted as reliable. As with other experiments, this is likely due to weather-induced stress.

Field Pea

Treatment yields all fell within the range of 6-9 bu/acre. There was no significant difference in pea yields when subject to either 0%, 30%, or 100% of the Haney soil test nitrogen recommendations (P=0.4). As with canola, the coefficient of variation coinciding with the pea yield analysis was high at 28.4. Consequently, the results are unlikely to be indicative of true treatment effects.

Spring Wheat

The mean weight yields from each of the three treatments spanned two bushels/acre (50 bu/ac to 52 bu/acre). Similarly, test weight values for each treatment were nearly the same, 63-64 lb/bu. There was no significant difference in wheat yield regardless of the level of nitrogen applied (P=0.98). Likewise, test weight values were not significantly different (P=0.47), nor were protein contents (P=0.85).