Evaluation of Mosaic MicroEssentials Sulfur Fertilizer Products for Corn Production

Transcription

1 Evaluation of Mosaic MicroEssentials Sulfur Fertilizer Products for Corn Production 2010 Research Report Dr. John Sawyer and Daniel Barker Professor and Assistant Scientist Department of Agronomy Iowa State University Introduction Previously conducted research in Iowa had indicated few crop responses to sulfur (S) fertilizer application across major soil areas (Sawyer and Barker, 2002; Sawyer et al., 2009). Recent research in northeast Iowa has documented S deficiency in alfalfa and yield increases to S application on specific areas within fields (lower organic matter, sideslope landscape position, silt loam and loam textured soils) (Lang et al., 2006). On similar soils (and coarse textured soils) in northeast Iowa where early corn growth was exhibiting strong visual S deficiencies, research has documented growth response and yield increase to S application. That research indicates S containing fertilizer products are becoming more important for crop production in that geographic area of Iowa. In conjunction with phosphorus (P) application needs when soils are deficient in available P (Sawyer et al., 2008) or P applications are made to replace harvested nutrients, coapplication of S with a P fertilizer product would enhance efficiency and consistency of the nutrient applications by meeting both fertilization requirements. The objective of this study was to evaluate the Mosaic S (MicroEssentials MES10) product [comprised of monoammonium phosphate (MAP) plus ammonium sulfate (AMS) and elemental S in equal proportions] as an S and P fertilizer source for corn production. A second objective was to provide additional data on the potential for corn response to S fertilization in Iowa. In addition to the planned objectives, a second MicroEssentials product (MESZ S-1Zn) was evaluated as a zinc (Zn) fertilizer source. Data from that product was analyzed separately from the MES10 evaluation. Materials and Methods Two on-farm producer field sites were chosen that had potential for soil S and P deficiency. One site was corn following soybean at New Hampton, IA (Sparta loamy fine sand and Dickinson fine sandy loam soils) and the other site was corn following corn at Tripoli, IA (Kenyon loam and Floyd loam soils). The Tripoli site was located on a landscape position and both sites on soils that previous research would suggest potential S deficiency and response to applied S. Both sites were tilled before planting. Fertilizer treatments were broadcast applied in the spring, prior to tillage and planting. At the Tripoli site, the cooperator did not apply any fertilizer to the study area. At the New Hampton site, the cooperator had applied anhydrous ammonia at 80 lb N/acre spring preplant.

2 2 The following S and P treatment combinations were used at both locations (Table 1). The exceptions were that the N rate applied to equalize N at the New Hampton site was 70 lb N/acre (urea applied in addition to the 80 lb N/acre applied by the cooperator), for a total of 150 lb N/acre. At the Tripoli site, 200 lb N/acre was equalized with urea across all plots. 1. S-CON: S control, zero S (equalize N to corn need for the rotation; add P at the highest MES product rate) 2. MES-10: 10 lb S/acre from MES product (equalize N; equalize P to highest P rate) 3. AMS-10: 10 lb S/acre from AMS (equalize N; equalize P to highest P rate) 4. SP-CON: S&P control, zero P and zero S (equalize N) 5. MES-30: 30 lb S/acre from MES product (equalize N; no additional P as this is the highest P rate) 6. AMS-30: 30 lb S/acre from AMS (equalize N; equalize P to highest P rate) 7. MAP-30: P rate used in the MES 30 lb S/acre rate applied from MAP (equalize N; apply AMS at highest S rate) This set of treatments allowed the following planned S and P application comparisons: MES vs. S&P control [5 vs. 4]; S control vs. S&P control [1 vs. 4]; MES vs. MAP [5 vs. 7]; MES vs. AMS [2&5 vs. 3&6]; S control vs. 10 lb S/acre (as AMS) [1 vs. 3]; and 10 lb S/acre vs. 30 lb S/acre (as AMS) [3 vs. 6]. An eighth treatment (MESZ-30) was the MESZ product applied at a rate to supply 30 lb S/acre, which also supplied 3 lb Zn/acre. The product rates were set by the rate of S application. Those rates were 10 and 30 lb S/acre. The P application rate was set by the highest rate of the Mosaic MES product (120 lb P 2 O 5 /acre). For correct comparisons, rates of P were equalized when required by the specific treatment with triple superphosphate. The P rate was constant at 120 lb P 2 O 5 /acre for all treatments except the S&P control where no S or P was applied. The N rate was constant at 150 lb N/acre (New Hampton site) or 200 lb N/acre (Tripoli site), with N added as urea as needed to equalize N. Potassium was applied at 60 lb K 2 O/acre as potassium chloride to all plots at both sites. Treatments were arranged in a randomized complete block design with four replications at each site. Soil was collected in the spring prior to treatment application from the 0- to 6, 6- to 12, 12- to 24, and 24- to 36-inch depths in each replication. The soil samples were analyzed for extractable sulfate-s at all depths. Samples from the 0- to 6-inch depth were analyzed for routine soil tests (ph, P, K, Zn, and organic matter). Ear leaf samples (10 leaves per plot) were collected at the VT (tassel) corn growth stage from all plots and analyzed for total S, total P, and total Zn concentration. Corn canopy normalized difference vegetative index (NDVI) and chlorophyll index (CHL) was determined at the V8 growth stage with a Crop Circle ACS-210 (Holland Scientific, Lincoln NE) optical canopy sensor. The NDVI index relates to plant canopy biomass (NDVI) and the CHL index plant canopy chlorophyll. Grain yield was determined for each plot and reported at 15.5% moisture.

3 3 Results and Discussion New Hampton Site Soil test results (0-6 inch depth) for the New Hampton site are Mehlich-3 soil test P 33 ppm and soil test K 56 ppm, soil organic matter 2.4%, DTPA Zn 0.6 ppm and extractable soil sulfate-s 4, 4, 5, and 5 ppm, respectively, for the 0-6, 6-12, 12-24, and inch soil depths. These extractable sulfate-s results are low and at a consistent concentration with soil depth. The Mehlich-3 soil test P is in the Very High range for the soil at this site (Sawyer et al., 2008), where yield response would be small and a low probability of response expected. The DTPA Zn test is in the Marginal range of the Iowa State University soil test interpretation (Sawyer et al., 2008), with a recommended broadcast application of 5 lb Zn/acre. There was a general increase in ear leaf S concentration with application of S fertilizer, either as AMS or MES10 products (Table 2). This is indicated by the across product mean leaf S concentration with applied S and the contrast of the MES-30 and the control treatment. The increase in concentration was 0.03 to 0.05% S across S applications, but even with the 30 lb S/acre rate the concentrations were not high. Interpretation of corn ear leaf S concentration in regard to potential grain yield response is problematic as a wide range in critical concentrations have been reported in the literature and the relationship between leaf S concentration and yield response with recent research has been poor (Sawyer et al., 2009). However, the leaf S concentration with no S or P applied was quite low at 0.11% S. The low tissue S concentrations did not translate into a yield response to applied S (Table 2). Also, there were no yield differences between S fertilizer products, except that the lower rate of S applied as AMS had a lower yield than the higher S rate. This did not occur for the MES product. The same general response was measured for ear leaf P concentration as with S; an increase in leaf P of 0.03 to 0.07% P across P applications. These ear leaf S and P concentration increases indicate the crop availability of S and P from the fertilizer products, and a similar supply from each. The leaf P concentration without applied P is below the critical level (Jones et al., 1990); therefore, based on the tissue analysis expectation would be that corn yield would be increased from P application. And that is what was measured (Table 2); with a yield increase from the S-CON vs. the SP-CON and the MES-30 vs. the SP-CON. And, the yields were the same for all treatments with P applied. However, the yield response to applied P fertilizer would not be expected from the 33 ppm soil test P value, which is in the Very High range. It is unknown why there was a response to P at that soil test level, but the leaf tissue P concentration does indicated plant P deficiency. The canopy sensing indices (NDVI and CHL) followed the same trends as leaf tissue S and P concentration, and grain yield response. For each index, the values were lowest for the SP-CON and increased when there was a response to applied P (examples are the MES-30 vs. SP-CON and S-CON vs. SP-CON). Larger canopy sensing index values indicate greater crop canopy biomass and greenness. The canopy sensing also did not

4 4 indicate any difference between S or P fertilizer sources, except where the MES-30 had larger values than the MAP-30 treatment. Tripoli Site Soil test results (0-6 inch depth) for the Tripoli site are Mehlich-3 soil test P 6 ppm and soil test K 99 ppm, soil organic matter 2.8%, DTPA Zn 0.4 ppm and the extractable soil sulfate-s 5, 7, 8, and 6 ppm, respectively, for the 0-6, 6-12, 12-24, and inch soil depths. These extractable sulfate-s concentrations are low across the soil depth sampled, but higher than the 3-foot profile sulfate than at the New Hampton site. The soil test P is in the Very Low range for the soil at this site, where a high probability of yield response would be expected. The DTPA Zn test result is at the upper end of the Low range of the Iowa State University soil test interpretation, with a recommended broadcast application of 10 lb Zn/acre. The treatment responses at the Tripoli site were similar to those at the New Hampton site. That is, there was an increase in leaf tissue S and P concentrations with S and P application, there was an increase in canopy NDVI and CHL index values with P application, and corn grain yield increased with P application (Table 3). The tissue S concentration in the SP-CON and S-CON treatments were higher than at the New Hampton site, but the tissue P concentration much lower without P applied (would be considered deficient for leaf tissue testing). The leaf tissue S concentration was higher with the 30 lb S/acre rate compared to the 10 lb S/acre rate, but the additional S did not result in a yield difference. Also, the soil test P was in the Very Low range, and therefore there would be an expected yield response to applied P, which occurred. Grain yield response was consistent with all P applications and fertilizer sources. Across Sites When analyzed across sites (Table 4), there was a consistent response where the leaf S and P concentrations increased with S and P application; canopy NDVI and CHL index values increased with P application; and corn grain yield response was consistent from P application and with no difference between P fertilizer sources. There was no indication of yield increase from S application, or differences in S fertilizer sources. Evaluation of MESZ Comparative results for the MESZ product (MESZ-30 rate treatment) were contrasted with the S-CON, MES-30, and AMS-30 rate treatments. This allowed evaluation of the MESZ product as a Zn source, as well as a source of S and P. Results are given in Table 5 for each site and combined across sites. At the New Hampton site, all products had similar leaf S, P, and Zn concentrations. Compared to the S-CON, the leaf Zn concentration was the same but the leaf S and P concentrations were greater when S and P were applied. The leaf Zn concentrations were low, and below the 15 ppm critical concentration (Jones et al., 1990). Application of Zn in the MESZ product, however, did not increase leaf Zn concentration. The canopy index results were variable and not greater for the MESZ than the S-CON or other fertilizer sources. The grain yield responses were variable, with the AMS, MES, and MESZ

5 5 applications having the same and highest yield, but the S-CON treatment yield was the same as the MES and AMS treatments, but lower than with the MESZ. This does not indicated a yield increase from applied Zn (as the MES and AMS treatments had the same yield as the MESZ), but a combined yield response due to more than P or S alone. The Zn soil test was in the Marginal range, indicating a potential response to applied Zn, however, the leaf Zn concentration was not increased with MESZ application and the broadcast rate of Zn applied (3 lb Zn/acre with the MESZ) was less than suggested by the Iowa State University soil Zn test guidelines (broadcast 5 lb Zn/acre). At the Tripoli site, all fertilizer treatments increased leaf S and P concentrations (Table 5). The MESZ application did not increase leaf Zn concentration. There were no differences in canopy NDVI, canopy CHL, or grain yield with any fertilizer application. This indicates no response to applied Zn, despite the low tissue Zn concentration and low soil test Zn where a response to Zn would be expected. However, the rate of Zn applied (3 lb Zn/acre with the MESZ) was less than the broadcast 10 lb Zn/acre suggested by the Iowa State University soil Zn test guidelines at that soil test level. When analyzed across sites, the MES, MESZ, and AMS products applied at 30 lb S/acre resulted in a leaf S concentration increase; applied at 120 lb P 2 O 5 /acre resulted in a leaf P concentration increase; applied at 3 lb Zn/acre resulted in no leaf Zn concentration increase; and across fertilizer products resulted in no difference in canopy index values or corn grain yield (Table 5). This indicates no response to Zn application with the MESZ product. Summary These results indicate plant S response to applied S from all S fertilizer products (similar leaf S concentration response from each product), but no yield response to S application at either site in There was plant P response to all P fertilizer products (leaf P concentration increase), and a yield increase to applied P at both sites. The yield increase from P application was present for all P fertilizers. Based on the results in 2010, no difference was noted between S or P fertilizer products. There was no yield increase with application of Zn as MESZ. The MESZ product also appeared to supply plant equivalent S and P compared to the AMS and MES products. References Jones, J.B. Jr., H.V. Eck, and R. Voss Plant analysis as an aid in fertilizing corn and grain sorghum. p In R.L. Westerman (ed.) Soil testing and plant analysis. SSSA, Madison, WI. Lang, B., J. Sawyer, and S. Barnhart Dealing with sulfur deficiency in NE Iowa alfalfa production. p In Proc. 18th Annual Integrated Crop Manag. Conf Nov Iowa State Univ., Ames. Sawyer, J.E., and D.W. Barker Sulfur application to corn and soybean crops in Iowa. p In Proc. 14 th Annual Integrated Crop Manag. Conf. 4-5 Dec Iowa State Univ., Ames.

6 6 Sawyer, J.E., B. Lang, D.W. Barker, and G. Cummins Dealing with sulfur deficiency in crop production: the Iowa experience. p In Proc. Thirty-Ninth North Central Extension-Industry Soil Fertility Conf., Des Moines, IA Nov Vol. 25. International Plant Nutrition Inst., Brookings, SD. Sawyer, J.E., A.P. Mallarino, R. Killorn, and S.K. Barnhart A general guide for crop nutrient and limestone recommendations in Iowa. pm Iowa State Univ. Extension, Ames. Table 1. Combination of fertilizer products and rates of S and P, example for the Tripoli site. Fertilizer Product Treatment S Rate P Rate S S lb S/acre lb P 2 O 5 /acre lb product/acre S Control (S-CON) Mosaic MES (MES-10) (NH 4 ) 2 SO 4 (AMS-10) S&P Control (SP-CON) Mosaic MES (MES-30) (NH 4 ) 2 SO 4 (AMS-30) MAP (MAP-30) S, Mosaic MES10; S, ammonium sulfate; , urea; , triple superphosphate; ; monoammonium phosphate. The N application was equalized on all plots at 200 lb N/acre with incorporated urea at the Tripoli site and at 150 lb N/acre at the New Hampton site (at the New Hampton site 80 lb N/acre was applied by the cooperator as preplant anhydrous ammonia and 70 lb N/acre was applied as incorporated urea to equalize N at 150 lb N/acre). Potassium was applied as , potassium chloride, at 60 lb K 2 O/acre at both sites.

7 7 Table 2. Effect of S and P product applications on ear leaf S and P concentration, corn canopy index value, and grain yield at the New Hampton site, Treatment Tissue S Tissue P NDVI CHL Grain Yield % % bu/acre 1 S-CON MES AMS SP-CON MES AMS MAP Treatment Contrast Statistics (p>f) MES-30 vs. SP-CON < < S-CON vs. SP-CON MES-30 vs. MAP MES-10 & MES-30 vs. AMS-10 & AMS S-CON vs. AMS AMS-10 vs. AMS Indicates statistical significance of the contrast at p 0.10.

8 8 Table 3. Effect of S and P product applications on ear leaf S and P concentration, corn canopy index value, and grain yield at the Tripoli site, Treatment Tissue S Tissue P NDVI CHL Grain Yield % % bu/acre 1 S-CON MES AMS SP-CON MES AMS MAP Treatment Contrast Statistics (p>f) MES-30 vs. SP-CON <0.001 <0.001 < S-CON vs. SP-CON <0.001 < MES-30 vs. MAP MES-10 & MES-30 vs. AMS-10 & AMS S-CON vs. AMS AMS-10 vs. AMS Indicates statistical significance of the contrast at p 0.10.

9 9 Table 4. Effect of S and P product applications on ear leaf S and P concentration, corn canopy index value, and grain yield across sites, Treatment Tissue S Tissue P NDVI CHL Grain Yield % % bu/acre 1 S-CON MES AMS SP-CON MES AMS MAP Treatment Contrast Statistics (p>f) MES-30 vs. SP-CON <0.001 <0.001 <0.001 <0.001 <0.001 S-CON vs. SP-CON <0.001 < MES-30 vs. MAP MES-10 & MES-30 vs. AMS-10 & AMS S-CON vs. AMS AMS-10 vs. AMS Indicates statistical significance of the contrast at p 0.10.

10 10 Table 5. Evaluation of MESZ fertilizer, Treatment New Hampton Tissue S Tissue P Tissue Zn NDVI CHL Grain Yield % % ppm bu/acre 1 S-CON 0.13b 0.26b 12a 0.707ab 4.83ab 227b 5 MES a 0.29a 12a 0.716b 5.05a 239ab 6 AMS ab 0.29a 12a 0.703ab 4.73b 239ab 8 MESZ ab 0.29a 12a 0.700a 4.67b 243a Tripoli 1 S-CON 0.15b 0.19a 15ab 0.620a 3.27a 191a 5 MES a 0.20a 18a 0.641a 3.57a 198a 6 AMS a 0.19a 13b 0.625a 3.33a 187a 8 MESZ a 0.21a 16ab 0.646a 3.65a 199a Across Sites 1 S-CON 0.14b 0.22b 13a 0.664a 4.05a 209a 5 MES a 0.25a 15a 0.678a 4.31a 219a 6 AMS a 0.24a 12a 0.664a 4.03a 213a 8 MESZ a 0.25a 14a 0.673a 4.16a 221a Means followed by a different letter in a column within the same site or for across sites are statistically different at p 0.10.