Continuous Corn Treatment Research Articles

Analysis of the beneficial effects of prior soybean cultivation to the field on corn yield and soil nitrogen content.

Corn-soybean rotation is a cropping pattern to optimize crop structure and improve resource use efficiency, and nitrogen (N) fertilizer application is an indispensable tool to increase corn yields. However, the effects of N fertilizer application levels on corn yield and soil N storage under corn-soybean rotation have not been systematically studied. The experimental located in the central part of the Songnen Plain, a split-zone experimental design was used with two planting patterns of continuous corn (CC) and corn-soybean rotations (RC) in the main zone and three N application rates of 0, 180, and 360 kg hm-2 of urea in the secondary zone. The research has shown that RC treatments can enhance plant growth and increase corn yield by 4.76% to 79.92% compared to CC treatments. The amount of N fertilizer applied has a negative correlation with yield increase range, and N application above 180 kg hm-2 has a significantly lower effect on corn yield increase. Therefore, a reduction in N fertilizer application may be appropriate. RC increased soil N storage by improving soil N-transforming enzyme activity, improving soil N content and the proportion of soil organic N fractions. Additionally, it can improve plant N use efficiency by 1.4%-5.6%. Soybeans grown in corn-soybean rotations systems have the potential to replace more than 180 kg hm-2 of urea application. Corn-soybean rotation with low N inputs is an efficient and sustainable agricultural strategy.

Effects of Soybean–Corn Rotation on Crop Yield, Economic Benefits, and Water Productivity in the Corn Belt of Northeast China

The Corn Belt of Northeast China (CBNC) is the most important commercial grain base in China. However, long-term intensive cultivation has caused the productivity of black soil to decline. The sustainable development of corn and soybean is seriously threatened. Field experiments of a corn–soybean rotation were conducted to evaluate the crop yields, economic returns, and water productivity in the CBNC from 2017 to 2020. The field treatments included continuous soybean (CS), continuous corn (CC), soybean–corn (SC), and soybean–corn–corn (SCC). The total yield for 2017–2020 is compared using the equivalent yield of corn, indicating that the crop yield of the CC treatment was the highest and that of the CS treatment was the lowest. The crop yield of the CS treatment was 0.58-fold lower than that of the CC treatment. The 4-year total income of the treatments showed that the total and net revenue of the CC treatment was the highest. The 4-year total net income of the CS treatment was 0.66- and 0.72-fold lower compared with those of the SC and SCC treatments, respectively. There was no significant difference between the treatments of rotation. The crop water productivity (WPC) and biomass water productivity (WPB) of the CS treatment were the lowest, at 0.30- and 0.54-fold lower than those of the CC treatment in 2017–2020, respectively. The WPC and WPB of the CC treatment were the largest. If soybean–corn rotation was implemented in the CBNC, the SC treatment would be a better choice than the SCC treatment for the CBNC, and farmers would need to be subsidized at least USD 1047.5 ha−1 to equal the income from growing corn. In considering production, financial gains, and water productivity, the CC treatment was, as a result, still the best planting pattern for the CBNC under the test site’s conditions.

Modeling long-term water use and economic returns to optimize alfalfa-corn rotation in the corn belt of northeast China

The long-term effects of alfalfa (Medicago sativa L.)-corn (Zea mays L.) rotation on soil water use and economic returns have not been evaluated and optimized in the corn belt of northeast China (CBNC). Crop modeling based on long-term weather data and short-term field data helps evaluate agricultural practices’ long-term effect. The Agricultural Production Systems sIMulator (APSIM) was calibrated and validated based on the data sets on soil water storage (SWS), aboveground biomass (biomass), and yield under continuous corn (CC), five years of alfalfa (5A), and three years of alfalfa followed by two years of corn (3A2C) cropping systems from 2014 to 2018 at Quanyangou-Lishu in Jilin province, China. The APSIM could simulate well SWS, evapotranspiration (ET), and annual biomass of alfalfa (5A) with normalized root mean square error (NRMSE) of 9.6%, 5.0% and 13.2%, respectively. This model was also confirmed to simulate well the SWS, ET, yield, and biomass of corn (CC) with the NRMSE of 9.6%, 3.4%, 6.5% and 9.8%, respectively and that of alfalfa-corn rotation (3A2C) with the NRMSE of 8.4%, 4.5%, 8.7% and 12.2%, respectively. The validated APSIM was used to optimize the alfalfa-corn rotation systems by simulating water use and economic returns under five scenarios, including CC, 3A2C, four years of alfalfa followed by two years of corn (4A2C), five years of alfalfa followed by two years of corn (5A2C) and five years of alfalfa followed by five years of alfalfa (5A5A) based on the weather data from 1984 to 2018 (35 years) at Quanyangou-Lishu (black soil with losing mollic epipedon, relatively warm and moist climate, in Jilin province, the center of CBNC), Fujia-Lishu (aeolian sandy soil, relatively warm and moist climate, in Jilin province), Chaoyang (cinnamon soil, warm and dry climate, in Liaoning province, the south of CBNC) and Hailun (black soil with moderately thick mollic epipedon, cold and wet climate, in Heilongjiang province, the north of CBNC). Dry soil layers were only found in 250–400 cm soil layer in 18-yr 5A5A or 20-yr 5A2C treatment at Chaoyang and in 350–450 cm soil layer in 20-yr 5A5A or 26-yr 5A2C treatment at Quanyangou-Lishu. At four sites, the highest and lowest mean annual biomass water use efficiency (WUEB) could be found in CC (30.91–38.93 kg ha−1 mm−1) and in 5A5A (20.53–26.31 kg ha−1 mm−1), respectively. The alfalfa-corn rotation treatments had similar WUEB ranged from 22.91 to 30.17 kg ha−1 mm−1. The NR of alfalfa-corn rotation treatments at four sites were 38–169% higher than that of CC and 6–35% lower than that of 5A5A. Alfalfa-corn rotation treatments improved the stability of NR at Fujia-Lishu and Chaoyang by the CV of 40–75% and 65–95%, compared to that of CC treatment by the CV of 79% and 101%, respectively. Among alfalfa-corn rotation treatments, the 5A2C had higher and more stable NR than 4A2C and 3A2C. Therefore, we suggested 5A2C at Fujia-Lishu and Hailun and 4A2C at Quanyangou-Lishu and Chaoyang to achieve dry soil layer’s prevention, relatively high WUEB and high and stable NR.

Soil aggregates stability and storage of soil organic carbon respond to cropping systems on Black Soils of Northeast China

Monoculture and improper management may reduce soil fertility and deteriorate soil structure in Black soils (Mollisols) of Northeast China. The experiment was carried out from 2015 to 2016 in Black Soils comprising five cropping systems: continuous corn (CC), soybean-corn rotation (SC), corn-soybean rotation (CS), fallow-corn (FC), and fallow-soybean (FS). Our results showed that CS and FS treatments significantly increased mean weight diameter (MWD) and fractal dimension (D) in mechanical stability aggregates (MSAs), and increased MWD and geometric mean diameter (GMD) in water-stable aggregates (WSAs) compared with CC treatment. These two treatments were also significantly increased water-stable aggregates stability rate (WSAR), but decreased percentage of aggregates destruction (PAD) than CC treatment. Meanwhile, CS and FS treatments exhibited a higher carbon accumulation than CC treatment in bulk soils. Soil organic carbon (SOC) concentration in WSA0.106-0.25,WSA2-5 mm and WSA0.5-1 mm had a dominant effect on aggregate stability. Simutaneously, SOC in WSA>5 mm affected SOC concentration in bulk soils. As a whole, the CS and FS treatments can increase the percentage of macro-aggregates, enhance aggregate stability, as well as increase SOC concentration in bulk soils and all soil aggregate sizes.

Alfalfa-corn rotation and row placement affects yield, water use, and economic returns in Northeast China

Planting systems in the corn belt of Northeast China (CBNC) have been adjusted to solve the problem of black soil productivity decline caused by long-term intensive cultivation. To this end, field experiments with the alfalfa (Medicago sativa L.)-corn (Zea mays L.) rotation and row placement were conducted to evaluate soil water, crop yield, and economic returns in the CBNC from 2014 to 2018. The three treatments included continuous corn (CC), continuous alfalfa (CA), and three years of alfalfa followed by two years of corn (3A2C). Corn was planted in the row (R) or interrow (IR) space of the previously planted alfalfa in the 3A2C treatment in 2017 and 2018. Planting alfalfa increased farmer income, and the 5-yr total revenue of the CA treatment was 41% greater than that of the CC treatment. There was no difference in total evapotranspiration (ET) between the CC and CA treatments, and the 5-yr biomass water use efficiency (WUEB) of the CA treatment decreased by 48%, compared with that of the CC treatment. The 3A2C treatment increased corn leaf area index, biomass, and yield. Corn yield of the 3A2C treatment was 8% greater than that of the CC treatment in 2017. The 5-yr net revenue of the 3A2C treatment increased by 24% compared with that of the CC treatment. Corn planting in the first year after alfalfa removal reduced ET. The ET of the 3A2C treatment decreased by 12% in 2017 compared with that of the CC treatment, The WUEB of the 3A2C treatment was 18% and 14% greater than that of the CC treatment in 2017 and 2018, respectively. Corn planted into the previously planted alfalfa row produced 4% and 6% greater yield and 12% and 18% greater WUEB than corn planted in the interrow space in 2017 and 2018, respectively. Therefore, an alfalfa-corn rotation system suitable for use in the CBNC and found to economically benefit farmers consisted of three years of alfalfa followed by two years of corn planted in the previous alfalfa crop row (3A2C-R).

Mechanisms of soil carbon accrual and storage in bioenergy cropping systems

AbstractAnnual row cropping systems converted to perennial bioenergy crops tend to accrue soil C, likely a function of increased root production and decreased frequency of tillage; however, very little is known about the mechanisms governing the accrual and stability of this additional soil C. To address this uncertainty, we assessed the formation and stability of aggregates and soil organic C (SOC) pools under switchgrass, giantmiscanthus, a native perennial grass mix and continuous corn treatments in Michigan and Wisconsin soils differing in both texture and mineralogy. We isolated different aggregate size fractions, >2 mm, 0.5–2 mm, and <0.5 mm, using a procedure intended to minimize alterations to aggregate biological and chemical properties. We determinedSOC, permanganate oxidizable C (POXC), and microbial activities (i.e. enzyme activities and soil respiration rates) associated with these aggregates. Soil type strongly influenced the trajectory of aggregate formation and stabilization with differences between sites in mean aggregate size, stability,SOCand microbial activity under perennial vs. corn cropping systems. At the Michigan site, soil microbial activities were highest in the >2 mm aggregates, and higher under the perennial grasses compared to corn. Contrastingly, in Wisconsin soils, microbial activities were highest in the <0.5 mm aggregates and evidence for soil C accrual under perennial grasses was observed only in a fast turnover pool in the <0.5 mm aggregate class. Our results help explain cross‐site variability in soil C accrual under perennial bioenergy crops by demonstrating how interactions between belowground productivity, soil type, aggregation processes and microbial communities influence the rates and extent ofSOCstabilization. Bioenergy cropping systems have the potential to be low‐C energy sources but first we must understand the complex interactions controlling the formation and stabilization ofSOCif we are to maximize soil C accrual.

Farm Management Effects on Rhizosphere Colonization by Native Populations of 2,4-Diacetylphloroglucinol-Producing Pseudomonas spp. and Their Contributions to Crop Health

ABSTRACT Analyses of multiple field experiments indicated that the incidence and relative abundance of root-colonizing phlD+ Pseudomonas spp. were influenced by crop rotation, tillage, organic amendments, and chemical seed treatments in subtle but reproducible ways. In no-till corn plots, 2-year rotations with soybean resulted in plants with approximately twofold fewer phlD+ pseudomonads per gram of root, but 3-year rotations with oat and hay led to population increases of the same magnitude. Interestingly, tillage inverted these observed effects of cropping sequence in two consecutive growing seasons, indicating a complex but reproducible interaction between rotation and tillage on the rhizosphere abundance of 2,4-diacetlyphloroglucinol (DAPG) producers. Amending conventionally managed sweet corn plots with dairy manure compost improved plant health and also increased the incidence of root colonization when compared with nonamended plots. Soil pH was negatively correlated to rhizosphere abundance of phlD+ pseudomonads in no-till and nonamended soils, with the exception of the continuous corn treatments. Chemical seed treatments intended to control fungal pathogens and insect pests on corn also led to more abundant populations of phlD in different tilled soils. However, increased root disease severity generally was associated with elevated levels of root colonization by phlD+ pseudomonads in no-till plots. Interestingly, within a cropping sequence treatment, correlations between the relative abundance of phlD and crop stand or yield were generally positive on corn, and the strength of those correlations was greater in plots experiencing more root disease pressure. In contrast, such correlations were generally negative in soybean, a difference that may be partially explained by difference in application of N fertilizers and soil pH. Our findings indicate that farming practices can alter the relative abundance and incidence of phlD+ pseudomonads in the rhizosphere and that practices that reduce root disease severity (i.e., rotation, tillage, and chemical seed treatment) are not universally linked to increased root colonization by DAPG-producers.

A comparison of fractal analytical methods on 2- and 3-dimensional computed tomographic scans of soil aggregates

Computed tomographic (CT) images of small (approximately 3 mm diameter) intact aggregates from an agricultural soil of two contrasting management histories were analyzed. Fractal analysis was employed to quantify the heterogeneity of mass and pore space within individual aggregates. Three fractal analytical methods were compared: 1) density scaling fitted to a solid mass fractal model, 2) density scaling fitted to a pore–solid fractal model, and 3) cumulative pore number scaling. Ten aggregates from a continuous corn treatment and another 10 aggregates from a five-year crop rotation treatment were each scanned to obtain a 2-D CT image. Two of these aggregates, one from each treatment, were scanned fully for 3-D reconstructions. The objectives were to 1) demonstrate the utility of industrial quality CT scanning and density scaling for deriving fractal parameters, including the ability of 2-D scans to represent 3-D structures, and 2) compare the three fractal analytical methods to identify which worked best for estimating fractal parameters of individual soil aggregates. The results showed that density scaling methods are compatible with CT scanning and that solid mass fractal models described the 20 aggregates better than pore–solid fractal models. Comparison of the 2-D and 3-D data suggested that some fractal parameters, including the fractal dimension, can be obtained from 2-D slices of a whole soil aggregate. This study demonstrated a non-disruptive approach to quantify internal heterogeneity of individual soil aggregates, which can be used to address scaling issues of soil structure and to predict soil behavior and soil quality.

Tillage System and Crop Rotation Effects on Dryland Crop Yields and Soil Carbon in the Central Great Plains

Winter wheat (Triticum aestivum L.)–fallow (WF) using conventional stubble mulch tillage (CT) is the predominant production practice in the central Great Plains and has resulted in high erosion potential and decreased soil organic C (SOC) contents. This study, conducted from 1990 through 1994 on a Weld silt loam (Aridic Argiustoll) near Akron, CO, evaluated the effect of WF tillage system with varying degrees of soil disturbance [no‐till (NT), reduced till (RT), CT, and bare fallow (BF)] and crop rotation [WF, NT wheat–corn (Zea mays L.)–fallow (WCF), and NT continuous corn (CC)] on winter wheat and corn yields, aboveground residue additions to the soil at harvest, surface residue amounts at planting, and SOC. Neither tillage nor crop rotation affected winter wheat yields, which averaged 2930 kg ha−1. Corn grain yields for the CC (NT) and WCF (NT) rotations averaged 1980 and 3520 kg ha−1, respectively. The WCF (NT) rotation returned 8870 kg ha−1 residue to the soil in each 3‐yr cycle, which is 2960 kg ha−1 on an annualized basis. Annualized residue return in WF averaged 2520 kg ha−1, which was 15% less than WCF (NT). Annualized corn residue returned to the soil was 3190 kg ha−1 for the CC (NT) rotation. At wheat planting, surface crop residues varied with year, tillage, and rotation, averaging WCF (NT) (5120 kg ha−1) > WF (NT) (3380 kg ha−1) > WF (RT) (2140 kg ha−1) > WF (CT) (1420 kg ha−1) > WF (BF) (50 kg ha−1). Soil erosion potential was lessened with WCF (NT), CC (NT), and WF (NT) systems because of the large amounts of residue cover. Levels of SOC in descending order in 1994 were CC (NT) ≥ WCF (NT) ≥ WF (NT) = WF (RT) = WF (CT) > WF (BF). Although not statistically significant, the CC (NT) treatment appeared to be accumulating more SOC than any of the rotations that included a fallow period, even more rapidly than WCF (NT), which had a similar amount of annualized C addition. Reduced tillage and intensified cropping increased SOC and reduced soil erosion potential.

Estimating C inputs retained as soil organic matter from corn (Zea Mays L.)

In agroecosystems, the annual C inputs to soil are a major factor controlling soil organic matter (SOM) dynamics. However, the ability to predict soil C balance for agroecosystems is limited because of difficulties in estimating C inputs and in particular from the below-ground part. The objective of this paper was to estimate the proportion of corn residue retained as SOM. For that purpose, the results of a 13 C long-term (15 yr) field study conducted on continuous silage corn and two silage corn rotations along with data from the existing literature were analyzed. The total amount of corn-derived C (0‐30 cm) was about 2.5 to 3.0 times higher for the continuous corn treatment (445 g m 2 ), compared to the two rotational treatments (175 and 133 g m 2 for the corn-barley-barley-wheat and corn-underseeded barley hay-hay rotations, respectively). Assuming that the C inputs to the soil from silage-corn was mainly roots and would have been similar across treatments on an annual basis, the total amount of cornderived C for the two rotational treatments was approximately proportional to the number of years the silage-corn was present in the rotation (4 yr). The results from the current study indicate that about 17% of root-derived C is retained as SOM. This value is higher than those reported in the literature for long-term studies on shoot-derived C (range of 7.7 to 20%, average of 12.2%), which is in agreement with previous studies showing that more C is retained as SOM from roots than from shoots.

Long-term (35 years) effects of fertilization, rotation and weather on corn yields

Long-term effects of fertilization, crop rotation and weather factors [temperature, precipitation, net radiation, maximum (potential) evapotranspiration (ET) and corn heat units (CHU)] on the sustainability of corn grain yields were investigated over 35 yr. Treatments included fertilized and unfertilized continuous com and rotation corn-oats-alfalfa-alfalfa. The fertilized rotation corn treatment produced the greatest corn grain yields (15% moisture content) with an average of 7.75 t ha−1 followed by the fertilized continuous corn treatment with 6.02 t ha−1. Fertilization increased grain yield for continuous corn treatments by 279% and increased grain yields in the rotational corn treatments by 70%. Corn grain yields increased with time with the fertilized rotation treatment, remained relatively constant with the fertilized continuous corn and decreased with the unfertilized treatments. Growing season precipitation was the only weather variable tested which was significantly related to corn grain yield. Precipitation in July was proportional to corn grain yield for all fertilized treatments. Weather variation played little role for unfertilized corn. Continuous corn production was sustained (yields did not decrease with time) when fertilizer was added. There was a considerable yield advantage with fertilized corn when grown in a rotation compared with fertilized continuous corn. Fertilization and crop rotation practices increased and buffered corn yields. Key words: Long-term, corn, yield, fertilization, rotation, weather

Corn Fertility Treatments and the Surface Structure of a Poorly Drained Soil

AbstractFertility treatment effects on annual measurements of bulk density, total porosity, and air‐filled porosity taken from the 0.05‐ to 0.15‐m depth of a Brookston clay loam soil (clayey, mixed, mexic Typic Haplaquolls), inclusive from 1957 to 1982, were evaluated. Additional bulk density, porosity, stability, and penetration resistance measurements were made on samples taken from the 0.05‐ to 0.15‐m and 0.15‐ to 0.25‐m depths in 1983. The treatments were (i) continuous corn (Zea mays L.) with no fertilizer; (ii) continuous corn with 298 kg/ha NH4NO3 annually; (iii) continuous corn as in (ii) plus 672 kg/ha of 5–8.8–16.6 (5–20–20) annually; and (iv) a corn, oats (Avena sativa L.), and alfalfa (Medicago sativa L.) rotation receiving 168 kg/ha of 5–8.8–16.6 (5–20–20) for oats. In general, bulk density increased as total and air‐filled porosities decreased with time for all treatments. However, the rotation treatment had lower bulk densities and higher total porosities than the continuous corn treatments. There were no significant differences in bulk density or porosity among the continuous corn treatments. The 1983 stability and penetration data did not show any meaningful treatment effects. However, the stability data illustrate the weak structure of this soil. Monoculture corn appears to play a minor role in the structural deterioration of this poorly drained, weakly structured soil.