A field study in 2014 documented corn and soybean biomass and nutrient responses between conventional-till and no-till tillage systems at Beresford, SD during cooler than normal weather conditions with adequate soil moisture. The overall study was established in 1992. Each treatment plot was monitored weekly from June to August for soil moisture, temperature, and plant growth stages. Biomass was harvested during and at the end of the growing season for yield and nutrient content. Soil moisture measured throughout the early and middle part of the growing season was determined to be sufficient for crop growth, since precipitation was much greater than normal in June (33.2 cm). However, air temperature was below normal early in the growing season and lowered Growing Degree Days (939 °C) compared to the 30-year average (139 °C). Soil temperatures (5 cm depth) were not significant between tillage treatments in the corn plots during the growing season for 12 observation dates (range 16.3 °C - 28.0 °C). Plant growth was not significantly different between tillage treatments, reflecting the lack of soil temperature differences (5 cm depth) between tillage treatments. The mid-season plant tissue and crop residue at harvest nutrient content (P, K, and Zn) were not significant between tillage treatments. Corn grain yields were 10.3 T ·ha -1 and 10.1 T ·ha -1 for conventional tillage and no-till, respectively. Soybean grain yields were 3.9 T ·ha -1 and 3.3 T ·ha -1 for conventional tillage and no-till, respectively. These results would more than likely have been much different in a warmer growing season, when soil temperature and moisture differences between tillage treatments would likely stimulate crop growth in the conventional-tilled soil. This would have also increased nutrient uptake and grain yield levels to greater degree than observed in this study.
Tillage implementation for corn and soybean production depends on agronomic, soil, and economic issues involved. A study in Southern Nebraska showed that corn grain yield was greatest with a rotation-chisel-plow system compared to disk, no-tillage, and ridge-tillage systems in years with average temperature and moisture [
A study in Michigan discussed the effects of no-till corn from wheat root shoot residue (WRSR), no wheat residue (NWR), and wheat root residue treatments (WRR) [
A study in China showed that corn grain yield was greatest when planted in a ridge-till system compared to no-till and conventional-till treatments [
A study in Central Mexico showed that increasing residue resulted in greater soil moisture content through the growing season [
A study in Washington showed that soil moisture was significantly greater with no-till compared to the sweep-till treatment which had less residue retention and less evaporation near the soil surface [
A study in Northeast China showed that soil moisture depletion in no-till was lower compared to reduced-till and conventional-till treatment, especially in the beginning and late season [
In summary, these research studies showed that crop residue cover not disturbed by tillage resulted in retention of greater soil moisture content and reduced temperature fluctuation compared to tilled soils. Soil moisture content decreased because of increased evaporation and soil temperature fluctuated more throughout the day in conventional-till. Corn grain yield also seemed to decrease with no-till and increase with conventional till treatment. However soybean grain yield seemed to increase with no-till and decrease with conventional-till treatment. It can also be concluded that during years of extreme heat and drought, the increased surface residue from no-till may benefit the growing environment by moderating temperature and maintaining moisture levels through the growing season. This would have implications for influencing corn and soybean grain yield in the dryer parts of the soybean production areas of the Great Plains.
The weather in South Dakota can be variable and tillage influences on crop growth and final grain yield can respond strongly to climatic conditions. The objectives for this research were to consider how corn and soybean crops respond to a cooler than normal growing season with adequate available soil water by: 1) Documenting how two tillage systems can influence topsoil soil temperature and soil moisture; and 2) Comparing corn and soybean growth, crop biomass production, and plant nutrient up take among two tillage treatments.
The study site was located at the SDSU Southeast Research Farm (SERF) near Beresford, SD at latitude 43.04270˚N, and longitude 96.892232˚W. The elevation of the site was 464 m above sea level. The soil type was an Egan-Trentsilty clay loam which is described as a fine-silty, mixed, and super active mesic Udic Haplustolls [
The field study began in 1992 when tillage treatments of conventional-till (CT) and no-till (NT) were established for corn and soybean in rotation. The plot dimensions for the soybean crop were 22 m wide by 100 m long. The treatments of tillage and crop were assembled as a randomized complete block with three replications. The CT system for corn production consisted of fall disk and chisel-plow operation followed by a spring fieldcultivation operation. However, for soybean production only a disking or field cultivation was performed in the spring.
In spring 2014, fertilizer potassium was surface-applied as potash (0-0-60) at the rate of 240 kg K ha−1 to both crops with a broadcast application before the tillage operation. Nitrogen was applied to the corn plots before planting as surface application of urea-ammonium-nitrate solution (28-0-0) at a rate of 550 liters ha−1 to provide 220 kg N ha−1 with drop nozzles as a pre-plant application for both tillage systems. Corn (hybrid PIOO193AM) was planted at the rate of 71,000 seeds ha−1 in mid-May. Soybean (variety AG2135) was planted at the rate of 330,000 seeds ha−1 in late May in 27 cm rows for all treatments.
Soil cores were removed from the 0 - 15 cm depth randomly within each plot area between rows at the beginning of the growing season from each treatment plot. The soil was dried and ground to prepare for analysis at the SDSU soil testing lab using standard procedures [
The plant growth stage rating was documented weekly from June to August, as an average for each measurement in which three plants per plot were selected. Corn plant samples were collected during the growing season from at least four to five rows from the border of the plots. Within those rows, the middle three plants that were most representative of the whole plot were harvested.
Soil temperature and moisture were measured on the same day and time of day on a weekly basis. Soil moisture content was measured at a 5 cm soil depth with a model Field scout TDR 300 Soil Moisture Meter Item # 6430f3, (Spectrum Technologies, 3600 Thayer Court, Aurora, IL 60,504). Raw moisture measurements were calibrated according to actual volumetric water content measurements determined from another experiment (data not shown). Soil temperature was measured at a two in. depth with a model HH21 Microprocessor Thermometer, Type J-K-T Thermocouple, Ω-OMEGA (OMEGA Engineering, INC. One Omega Drive, P.O. Box 4047, Stamford, Connecticut 06907-0047).
Ten whole above-ground corn plants were sampled at the V6 [
Total above-ground soybean plant tissue was sampled at the R1 [
Corn and soybean grain was harvested by small plot combine after reaching physiological maturity along the entire length of the treatment plots from the middle of the plot. Grain was weighed and analyzed for moisture content and test- weight. Grain yields were estimated on an acre basis. Grain samples were prepared for analysis as the tissue was before. Data were entered into an Excel spreadsheet and analyzed using R software and using the “Agricolae” package [
Corn and crop soybean residue was collected from a 6.5 m2 surface area after grain harvest for all treatment-replications. The crop residue was weighed in the field then a subsample was dried to determine biomass harvest weight. The biomass was prepared for analysis (P, K, and Zn) as for the plant tissue analysis. Grain yield was also analyzed for the nutrient content as previously described.
The average mean air temperature was just slightly below normal for May and June compared to the 30-year average, but 2.6˚C below normal for July, and 1.1˚C below normal for August (
Soil organic matter content ranged from 4.80% to 4.97% and soil pH ranged from 5.40 to 5.47 among treatment replications which was very narrow (
The mean soil temperature for corn with conventional-till was generally greater in the early part of the growing season (June 6: 28.6˚C) compared to the late growing season with (August 21: 23.3˚C) (
The mean soil temperature for soybean with conventional-till was generally higher in the early part of the growing season (June 6: 26.1˚C) compared to the late growing season with (August 21: 23.7˚C) (
The calculated mean soil moisture content for corn for the tillage treatments was generally adequate for the early part of the growing season (June 3: 30.2% vs. 28.9%, respectively, for CT vs. NT) as well in the later part of the growing season (August 21: 28.1% vs. 28.0%, respectively) (
One would expect that the residue cover in the no-tillage treatment to reduce soil evaporation compared to the conventional-till treatment since the residue acted as a barrier to evaporation and reflected the sun’s energy. Cooler than normal growing season air temperatures reduced the soil evaporation potential in these treatments. The result was that there was no difference in the soil moisture content between tillage treatments. These results could have been much different in a drier or warmer growing season. Soil moisture content was usually high among tillage treatment. Perhaps higher rainfall in the early part of the growing season reduced nitrogen availability because of leaching. It is also possible that denitrification occurred in these soils (not measured) which was usually wet during the early part of the growing season. This could also have influenced crop growth since available soil N levels may have been reduced.
The growth stage for both crops progressed in both tillage systems from the vegetative to the reproductive growth stage from June 3 to August 21 (
During a warmer growing season, one would expect that crops growing in the tilled treatments would advance farther compared to the no-till treatments. Slightly higher soil temperatures were observed in the middle of the growing season for the conventional-till plot (
Adequate soil moisture levels together with cooler than normal air temperatures probably lowered the evaporation potential in the conventional-till treatments. This probably slowed growth in the conventional-till treatment and so the crop advanced for both tillage treatments similarly in the early part of the growing season.
The total tissue P, K, and Zn-nutrient concentration for corn at the V6 stage of growth was sufficient for the conventional-till treatment by (0.34%, 3.3%, and 25.6 ppm). The total P, K, and Zn-nutrient concentration was also sufficient for the no-till treatment by (0.35%, 3.3%, and 22.6 ppm) (
and Zn were similar between tillage treatments, these nutrients were available at similar levels in both tillage systems in the early part of the growing season. These results could have been much different in a drier season where the average temperature could also have been greater and growth stimulated to a greater extent in the conventional-till treatment.
The total tissue N, P, and Zn-nutrient concentration was sufficient (3.7%, 0.34%, and 44.6 ppm) for soybean at R1 growth stage [
The mean corn grain yield for the conventional-till treatment (10,311 kg∙ha−1) was only slightly greater than the yield of the no-till treatment (10,123 kg∙ha−1) and was not significant (
The mean soybean grain yield (3961 kg∙ha−1) for the conventional-till treatment was greater than the yield of the no-till treatment (3295 kg∙ha−1) but was not significant (
The mean corn grain nutrient concentration for P, K, and Zn was 0.24%, 0.32%, and 12.2 ppm, respectively, for the conventional-till treatment (
The mean soybean grain nutrient concentration for P, K, and Zn was 0.50%, 1.66%, and 31.3 ppm, respectively, for the conventional-till treatment. The soybean grain nutrient concentration for P, K, and Zn was 0.54%, 1.70%, and 33.4 ppm, respectively for the no-till treatment. The difference in soybean grain nutrient concentration for P and Zn was not significant different between tillage treatments. However P, nutrient was significantly different within the conventional-till treatment. This indicated that nutrient uptake to the grain was not influenced by tillage.
The mean nutrient concentration of corn residue for P, K, and Zn was 0.05%, 0.85%, and 13.20 ppm respectively, for the conventional-till treatment (
The mean nutrient concentration of soybean residue for P, K, and Zn was 0.08%, 1.14%, and 32.67 ppm respectively for the conventional-till treatment. The nutrient concentration of soybean residue for P, K, and Zn was
Mean | |||
---|---|---|---|
Filed Crop | Tillage | Grain Yield 2014 | Grain Yield 2010-2013 |
kg∙ha−1 | kg∙ha−1 | ||
Corn | CT | 10,311 | 11,121 |
Corn | NT | 10,123 | 9966 |
P-values (α = 0.05) | 0.803 | ||
Significance | N.S. | ||
Soybean | CT | 3961 | 3550 |
Soybean | NT | 3295 | 3362 |
P-values (α = 0.05) | 0.167 | ||
Significance | N.S. |
N.S. Not significant paired comparison at the alpha = 0.05 level.
Crop | Tillage | P | K | Zn |
---|---|---|---|---|
% | ppm | |||
Corn | CT | 0.24 | 0.32 | 12.2 |
Corn | NT | 0.22 | 0.31 | 11.6 |
P-values (α = 0.05) | 0.295 | 0.802 | 0.230 | |
Significance | N.S. | N.S. | N.S. | |
Soybean | CT | 0.50 | 1.66 | 31.3 |
Soybean | NT | 0.54 | 1.70 | 33.4 |
P-values (α = 0.05) | 0.014 | 0.090 | 0.155 | |
Significance | * | N.S. | N.S. |
N.S. Not significant paired comparison at the alpha = 0.05 level. *Significant paired comparison at the alpha = 0.05 level.
Crop | Tillage | P | K | Zn |
---|---|---|---|---|
% | ppm | |||
Corn | CT | 0.05 | 0.85 | 13.20 |
Corn | NT | 0.04 | 0.91 | 14.43 |
P-values (α = 0.05) | 0.408 | 0.796 | 0.329 | |
Significance | N.S. | N.S. | N.S. | |
Soybean | CT | 0.08 | 1.14 | 32.67 |
Soybean | NT | 0.08 | 0.97 | 44.80 |
P-values (α = 0.05) | 0.539 | 0.026 | 0.327 | |
Significance | N.S. | * | N.S. |
N.S. Not significant paired comparison at the alpha = 0.05 level. *Significant paired comparison at the alpha = 0.05 level.
Crop | Tillage | Dry Weight |
---|---|---|
kg∙plot−1 | ||
Corn | CT | 3.36 |
Corn | NT | 2.86 |
P-values (α = 0.05) | 0.394 | |
Significance | N.S. | |
Soybean | CT | 2.36 |
Soybean | NT | 2.13 |
P-values (α = 0.05) | 0.346 | |
Significance | N.S. |
N.S. Not significant paired comparison at the alpha = 0.05 level.
0.08%, 0.97%, 44.80 ppm, respectively for the no-till treatment.
When comparing the mean nutrient concentration of corn residue for conventional-till to the no-till treatment, the nutrient differences for P, K, and Zn levels were + 0.01%, −0.06%, and −1.2 ppm, respectively for the specific nutrient. Similar to the other tissue nutrient levels, the difference in corn residue nutrient concentration was not significantly different between tillage treatments.
When comparing the mean nutrient concentration of soybean residue for conventional-till to no-till treatment, the nutrient differences for P, K, and Zn levels were +0.00%, −0.17%, and −12.13 ppm, respectively for the specific nutrient. The difference in soybean residue nutrient concentration for P and Zn was not significant between tillage treatments. However, the K nutrient levels were significantly different between the tillage treatments.
The mean corn residue dry weight for conventional-till treatment was greater (3.36 kg∙plot−1) than that (2.86 kg∙plot−1) of the no-till treatment (
The precipitation in the early growing season was higher than normal (30-year average) and air temperature in the early part of the growing season was lower than normal in June 2014. This influenced the GDD’s which were lower than normal in the early part of the growing season. As the result, there was no significant difference in soil temperature (5 cm depth) between tillage treatments in the early part of the growing season, removing the advantage of tillage for increasing early season soil temperatures. In the middle of the growing season, growth stages of the conventional-till treatments were slightly more advanced than the no-till treatments, but were not significantly different. The grain yields and nutrient removal were not influenced by tillage treatment. The growth and grain parameters of crops growing in the conventional-till treatment were suppressed due to the lower than normal air temperature and higher than normal soil moisture content during the early part of the growing season. This provided roughly equivalent growing environment for plants growing in the conventional and no-till treatments. As a result, no differences in growth and yield parameters of the crop were observed between tillage treatments. A warmer and a drier growing season would probably have shown a significant difference in soil temperature, soil moisture, dry matter production, nutrient concentration, and grain yield between tillage treatments.
Jesper K. V.Nielsen,Howard J.Woodard, (2015) Corn and Soybean Responses to Two Tillage Systems in a Cool Growing Season. Open Journal of Soil Science,05,157-168. doi: 10.4236/ojss.2015.58016