TBARS – Research Findings (2016) from the experiments on Nutrient Management

Spring Cereals:

 Fall vs. spring application of N fertilizers (urea and ESN) for spring wheat production:

• Fall application of N was made on October 6, 2015 and the spring application at seeding on May 6, 2016, as per treatments. N was applied @ 80 kg/ha in all treatments, except the check (No N).
• Application of N (@ 80 kg N/ha as urea or ESN or their blends applied in fall/or spring) significantly improved the grain yield by 1,170 kg/ha to 2,483 kg/ha as compared to the check.
• ESN @ 80 kg N/ha applied in spring recorded the highest grain (~4,800 kg/ha) and biomass (10,773 kg/ha) yields.
• Spring applied ESN gave 1,244 kg/ha extra grains and 920 kg/ha higher straw yield than urea at the same rate of N (80 kg/ha); due probably to excessive rains in June this year. Blends of urea and ESN (3:1 or 1:1 on N basis) equaled ESN alone in grain, straw and biomass yields.
• When the two fertilizers were applied in the fall, increase in grain yield by ESN over urea was 225 kg/ha.
• Grain yields from the fall or spring applied urea were the same.
• Grain protein ranged from 12.6 % with no N to 14.3 % with ESN applied in spring and wasn’t affected by the time of N application.
• Averaged over three years (2014-‘16), highest grain yield (4,456 kg/ha) was obtained with spring application of a blend of urea @ 60 kg N/ha + ESN @ 20 kg N/ha. Spring applied urea was only marginally better in grain yield (129 kg grains/ha) than its fall application. Grain protein content was highest (15.3 %) with spring applied ESN.

Grain Legumes and Oil Seeds:

 Effect of P and bio-ag products on soybean grain yield:

• Neither application of 20 kg P₂O₅/ha nor seed treatment with Jumpstart (Penicillium bilaii; a fungus providing better access to soil and applied P) improved the soybean yield.
• Seed treatment with Quickroots increased the soybean grain yield significantly by ~900 kg/ha as compared to the check. Quickroots is a microbial (Bacillus amyloliquefaciensand Trichoderma virens based) seed treatment to improve NPK availability.

Maximizing canola yield with nitrogen and other nutrients and fungicides/growth retardant:

• Nutrients (N, S, B, Zn and Mn) effect on canola yield was assessed over uniform recommended rates of P and K.
• Application of N @ 150 kg/ha raised the canola seed yield from 1,414 kg/ha in the check to 2,687 kg/ha. Addition of S, B, and Mn (but not Zn) one by one improved the yield further. The seed yield went up to 3,869 kg/ha with NSBZnMn (1,182 kg/ha more than N alone).
• Nutrient use efficiency (kg yield/kg applied nutrients) was highest (18.5) with NSBZnMn.
• Spraying fungicide or growth retardant (Manipulator) didn’t improve the seed yield.

Maximizing canola yield with rates and sources of nitrogen and growth retardant:

• Response to N @ 60,120 and 180 kg/ha from urea, as compared to check was 517, 1,337 and 2,237 kg/ha, respectively. Corresponding responses from urea + ESN (3:1 ratio on N basis) were 768, 2,032 and 3,119 kg/ha, respectively. This is a huge response to application of N; more so with urea + ESN!
• Averaged over N rates, urea + ESN gave ~550 kg/ha more seed yield than urea alone; only at an extra cost of ~$12/ha.
• Manipulator 620 (growth retardant) spray @ 1.8 l/ha didn’t affect the plant height, but increased the seed yield by ~230 kg/ha (averaged over sources and rates of N).
• Highest straw yield (6,559 kg/ha) was recorded when canola was supplied with 180 kg N/ha (120 kg from urea and 60 kg from ESN) and sprayed with Manipulator @ 1.8 l/ha. This treatment also produced the highest seed (5,349 kg/ha) and biomass (11,908 kg/ha) yields!

Effect of nitrogen and growth regulator on flax seed yield:

• Application of N (@ 35, 70 and 105 kg/ha) increased the flax seed yield significantly and the response to N exhibited a Law of Diminishing Returns.
• Seed yields at 70 and 105 kg N/ha from urea were 3,070 and 3,236 kg/ha. Corresponding straw yields from these two treatments were 4,778 and 4,833 kg/ha, respectively.
• Substitution of 1/3^rd N from ESN in the 105 kg/ha N treatment increased the seed yield only marginally (104 kg/ha) as compared to N from urea alone at equivalent rate. However, urea + ESN produced the highest biomass yield (8,209 kg/ha)!
• Growth regulator (Manipulator 620) spray improved the seed yield by ~200 kg/ha.

Effect of P and K on flax seed yield:

• Application of P₂O₅ or K₂O (both @ 20 or 40 kg/ha) didn’t exert any significant influence on flax seed (3,146-3,603 kg/ha) or straw (5,047-5,591 kg/ha) yield. It seems that abundant soil moisture throughout the growing season enhanced the P and K availability from the native soil sources.

Effect of sulphur on flax seed yield:

• Application of S @ 10, 20 or 30 kg/ha had no impact on seed yield of flax. It seems that sulphur availability from the soil source wasn’t limiting due to more than enough rainfall during the growing season.

Grasses:

 Residual effect of urea and its blends with ESN and ammonium sulphate on forage grasses mixture – Timothy (Itasca) 50 %, Bromegrass (Peak) 42.5 %, and Orchard grass (Dividend VL) 7.5 %:

• No fertilizers were applied this year and only one cut was taken.
• None of the fertilizer treatments had significantly higher yield than the check (no fertilizer treatment); though the best yielding (4,572 kg/ha) fertilizer treatment was urea @ 58.25 kg/ha + ESN @ 26.25 kg/ha + ammonium sulphate @ 20.5 kg/ha.
• Protein content varied from 6.4 % in the check (No N) to 8.0 % with urea @ 58.25 kg/ha + ESN @ 26.25 kg/ha + ammonium sulphate @ 20.5 kg/ha (Total 105 kg N/ha) and 8.6 % with urea @ 84.5 kg/ha + ESN @ 35 kg/ha + ammonium sulphate @ 20.5 kg/ha (Total 140 kg N/ha). The latter treatment recorded the highest RFV.
• Thus the beneficial residual effect of the fertilizers applied in the previous years was exhibited in the protein content only.

Effect of potassium (K) and sulphur (S) on forage grasses mixture – Timothy (Itasca) 50 %, Bromegrass (Peak) 42.5 %, and Orchard grass (Dividend VL) 7.5 %:

• Treatments included all combinations of K (70, 140 and 210 kg K₂O) and S (0 and 24 kg S/ha) and a check with no K or S.
• There was no significant effect of the treatments on the average dry matter yield for 3 years (2014-‘16), which varied from 6,600 kg/ha in the check to 7,216 kg/ha with 140 kg K₂O/ha (recommended rate as per the soil test). It appears that due to adequate rainfall during the period of this experiment, nutrient availability and supply from the soil wasn’t limiting.
• S, but not K, improved the protein content. Neither of the two nutrients increased the RFV.

Alfalfa:

Evaluation of NK21 as a source of N and K for alfalfa (one cut in 2015 and two in 2016):

• NK21 (a blend of ammonium nitrate and muriate of potash) was compared at two rates of N (21 and 31.5 kg/ha) and K₂O (87.7 and 98.2 kg/ha) with equal amounts of N and K from ammonium sulphate supplemented with muriate of potash. In NK21 treatments, S to equal amounts of ammonium sulphate in the other treatments was applied as potassium sulphate. K levels were adjusted to equal in both the fertilizers (ammonium sulphate and NK21).
• NK21 and ammonium sulphate significantly improved the dry matter yield as compared to the no N, K or S check (7,218 kg/ha over 2 years).
• Highest yield obtained with NK21 @ 31.5 kg N/ha (9,244 kg/ha) wasn’t significantly better than that with ammonium sulphate (8,954 kg/ha) at the same rate of N. A reverse trend in yield with the two fertilizers was noticed at the lower rate of N (21 kg N/ha).
• Averaged over the two N rates (21 and 31.5 kg/ha) dry matter yields with the two fertilizers were about the same (~8,800 kg/ha).
• N application improved the protein content by maximum up to 1.7 % points in the first cut and up to 3.7 % points in the second cut. Protein contents with NK21 and ammonium sulphate were similar; both in the first and the second cut.
• ADF and NDF appeared to be higher and TDN and RFV lower with NK21 than that with ammonium sulphate in the first cut. In the second cut, these values didn’t differ much.
• The experiment will be repeated next year for proper evaluation of NK21.

Take home messages:

• Apply nutrients at the recommended rates that would vary from crop to crop.
• Application of N could be applied in the fall/or spring.
• Apply N from three sources; ammonium sulphate (at the rate equal to meet S requirements), urea and ESN; with 1/3^rd to 1/4^th N coming from ESN. Apply entire amount of ESN in the seed row at seeding. Due to polymer coating and slow release of N from ESN, it is harmless to seedlings or crop plants. N released in the seed row is right in the root zone and will quickly be taken up by the roots without any loss of N. Yield and protein advantages from part use of N from ESN makes it economically rewarding! Two of our producers adopted this practice in seeding winter wheat/and rye in the fall 2016.
• Supplement NPK fertilizers with S, B, Zn and Mn (based on soil tests) to maximize your economic returns. S and B are deficient in our soils, Zn is critical for corn (and also for aging alfalfa fields) and Mn for some crops.

Best wishes for the Crop Season 2017! May you get bumper crops and rewarding yields!