Corn Production Systems Research Articles

Irrigated corn yield and soil phosphorus response to long‐term phosphorus fertilization

AbstractLong‐term experiments can help to understand soil phosphorus (P) dynamics and improve nutrient management strategies. This research evaluated long‐term (2002–2021) soil P dynamics and yield response to a range of P fertilizer rates in a continuous high‐yielding irrigated corn (Zea mays L.) experiment with low initial soil phosphorus test (SPT, 10.5 mg kg−1). The experiment was established near Clay Center, NE, and five P rates (0, 10, 20, 39, and 59 kg P ha−1) were evaluated. Soil samples at 20‐cm depth were collected in eight cropping seasons. Yield response to P fertilizer increased after 20 years from 0.64 to 2.79 Mg ha−1. The application of 39 kg P ha−1 year−1 increased soil Bray‐1 P to 19.5 mg kg−1, outyielded all other P treatments, and resulted in a positive relative P balance. Over 20 years, 0 kg P ha−1 year−1 decreased Bray‐1 P from 10.5 to 5.5 mg kg−1. Annual P rates of 0, 10, and 20 kg P ha−1 produced a negative relative P balance and SPT below the critical soil test value (CSTV). The CSTV was 22.2 mg kg−1 for a continuous irrigated corn cropping system. A 53% increase in the P fertilizer rate (from 39 to 59 kg P ha−1 year−1) produced a threefold increment in the soil test P build‐up rate. High‐yielding irrigated continuous corn production systems (>14 Mg ha−1) are required to apply at least 39 kg P ha−1 year−1 to maintain SPT and a positive relative P balance over years.

Saving water under water deficit conditions by application of Xyway LFR@FMC: Greenhouse studies

Triazole fungicides are often referred to as "stress protectants" due to their ability to enhance the abiotic stress tolerance of plants. Xyway LFR@FMC (flutriafol) is a triazole and at-plant applied fungicide. The Xyway LFR@FMC fungicide that has been introduced into corn production system starting 2020 have been observed to improve plant performance under drought stress conditions. In this study, we accessed the potential of Xyway LFR@FMC product in altering the ability of corn (Zea mays L.) plants to control transpiration rates under water deficit-stressed (DS) conditions. Plants were grown under greenhouse conditions treated with Xyway LFR@FMC at 0.56, 0.77, and 1.11 L ha−1 in experiment 1 and 1.11 and 1.26 L ha−1 rates in experiment 2. Plants treated with 1.11 L ha−1 reduced the amount of water loss in response to DS and had the highest fraction of transpirable soil water (FTSW) thresholds. There was an increase in shoot hydraulic conductance (Kshoot) by 1.11 L ha−1 in both experiments. Plants treated with 0.77 and 1.11 L ha−1 had higher LWP rates compared to other treatments under DS conditions. In conclusion, the most likely chemical ingredient in Xyway LFR@FMC fungicide triggering the transpiration control response was flutriafol. This is the first report that early stomatal closure under soil drying conditions can be induced by the application of Xyway LFR@FMC fungicide. Application of at-plant fungicide, Xyway LFR@FMC has potential to reduce the negative effect of water-deficit stress in corn along with improving plants growth and physiological performance.

Integrative application of silicon and/or proline improves Sweet corn (Zea mays L. saccharata) production and antioxidant defense system under salt stress condition

Silicon (Si) and/or proline (Pro) are natural supplements that are considered to induce plants' stress tolerance against various abiotic stresses. Sweet corn (Zea mays L. saccharata) production is severely afflicted by salinity stress. Therefore, two field tests were conducted to evaluate the potential effects of Si and/or Pro (6mM) used as seed soaking (SS) and/or foliar spray (FS) on Sweet corn plant growth and yield, physio-biochemical attributes, and antioxidant defense systems grown in a saline (EC = 7.14dS m−1) soil. The Si and/or Pro significantly increased growth and yield, photosynthetic pigments, free proline, total soluble sugars (TSS), K+/Na+ratios, relative water content (RWC), membrane stability index (MSI), α-Tocopherol (α-TOC), Ascorbate (AsA), glutathione (GSH), enzymatic antioxidants activities and other anatomical features as compared to controls. In contrast, electrolytes, such as SS and/or FS under salt stress compared to controls (SS and FS using tap water) were significantly decreased. The best results were obtained when SS was combined with FS via Si or Pro. These alterations are brought about by the exogenous application of Si and/or Pro rendering these elements potentially useful in aiding sweet corn plants to acclimate successfully to saline soil.

Analysis of corn commodity production and development policy in North Minahasa, North Sulawesi Province

North Minahasa Regency is a corn development area in North Sulawesi, but its production is still low. The aim of the research is to obtain data on corn production systems and their development policies. Survey and FGD data collection techniques. Implementation February - March 2020. Analysis of quantitative data using multiple linear regression. The results showed that farmers are starting to use new superior varieties that have higher potential than local varieties, but the use of cultivation technology is still in accordance with farmers’ habits. The results of the coefficient test, the results of the t test or the sig probability value show that the area of land and labor has a calculated t value of 2.532 and 2.221; bigger than t table (2.064). This means that the variable land area and labor have a significant effect on corn production at α 5%. The potential for the development of this commodity is quite promising, but it is necessary to increase production referring to cultivation technology and product diversification.

Simulated nitrous oxide emissions from multiple agroecosystems in the U.S. Corn Belt using the modified SWAT-C model

Agriculture is a major source of nitrous oxide (N2O) emissions into the atmosphere. However, assessing the impacts of agricultural conservation practices, land use change, and climate adaptation measures on N2O emissions at a large scale is a challenge for process-based model applications. Here, we integrated six N2O emission algorithms for the nitrification processes and seven N2O emission algorithms for the denitrification process into the Soil and Water Assessment Tool-Carbon (SWAT-C). We evaluated the different combinations of methods in simulating N2O emissions under corn (Zea mays L.) production systems with various conservation practices, including fertilization, tillage, and crop rotation (represented by 14 experimental treatments and 83 treatment-years) at five experimental sites across the U.S. Midwest. The SWAT-C model exhibited wide variability in simulating daily average N2O emissions across treatment-years with different method configurations, as indicated by the ranges of R2, NSE, and BIAS (0.04–0.68, −1.78–0.60, and −0.94–0.001, respectively). Our results indicate that the denitrification process has a stronger impact on N2O emissions than the nitrification process. The best performing N2O emission algorithms are those rooted in the CENTURY model, which considers soil pH and respiration effects that were overlooked by other algorithms. The optimal N2O emission algorithm explained about 63% of the variability of annual average N2O emissions, with NSE and BIAS of 0.60 and −0.033, respectively. The model can reasonably represent the impacts of agricultural conservation practices on N2O emissions. We anticipate that the improved SWAT-C model, with its flexible configurations and robust modeling and assessment capabilities, will provide a valuable tool for studying and managing N2O emissions from agroecosystems.

Cereal rye residue management tactics influence interrow and intrarow weed recruitment dynamics in field corn when planting green

AbstractDelaying cover crop termination until cash crop planting (i.e., planting green) is an emerging no-till practice. Improved management recommendations are needed for optimizing weed suppression benefits while minimizing other pest, fertility, and crop management risks when planting green in corn production systems. In a 2-yr field experiment, we evaluated the interaction between cereal rye residue management tactics (standing residue, roll-crimping, roll-crimping with row cleaners) and herbicide programs (1-pass preemergence [PRE], 2-pass postemergence [POST]) when planting green on weed recruitment spatial patterns and corn performance compared to standard termination (14 d preplant [DPP]) and ryelage harvest (14 DPP) practices. In a 2-yr on-farm experiment, we evaluated corn performance in response to the same residue management tactics. Cereal rye biomass production varied significantly across years in on-station experiments, with average (4.9 Mg ha−1) and anomalous (9.9 Mg ha−1) levels observed in 2020 and 2021, respectively. In 2020, planting green with an integrated roll-crimper/row cleaner system resulted in greater intrarow weed density compared with planting green into standing cereal rye. Interrow weed density was lower when roll-crimping was employed compared to early termination (14 DPP). Planting green into standing cereal rye resulted in greater mean corn height (V5 stage) compared to other treatments, but corn population and yield did not differ. In 2021, few differences in weed recruitment patterns were observed, but corn population and yield were significantly lower in planting green treatments compared to early termination. In both years, late-season weed biomass was lower in two-pass POST programs compared to one-pass PRE programs. On-farm trials showed that planting green into standing residue increases corn height and can reduce corn populations, which may lead to reduce yields. Our results suggest that management recommendations for optimizing herbicide application timing should consider intrarow and interrow weed recruitment dynamics associated with residue management tactics needed to optimize corn performance.

Single and Multispecies Cover Crop Effects on Corn Production and Economic Returns

AbstractThe adoption of cover crops (CCs) has gained popularity in the continuous corn (Zea mays L.) production system due to their multiple benefits including scavenging or fixing nitrogen (N) in the soil. However, a CC's ability to develop early cover, scavenge N, and provide N to the following cash crop is species‐dependent and affected by environment. A field study was conducted in three diverse environments to determine growth characteristics of nine CC treatments (i.e., monocultures or mixes of grasses, legumes, and brassica), and their effect on the following corn crop was compared to no cover crop treatment (noCC). Cover crops significantly differed for above‐ground biomass, plant tissue carbon (C) and N concentrations, carbon to nitrogen ratio (C/N), and total N uptake (TNU). Among monocultures, grasses had the highest biomass and C/N ratio, and legumes had the highest N concentrations and TNU. Corn grain yield was highest following radish, whereas lowest corn yield was found following cereal rye + crimson clover mix in environment 1. Cover crops varied for C/N ratios in all three environments, but only affected corn plant height (PH) and grain yield in one environment. Cover crops belonging to the same species also exhibit different responses for characteristics measured, depending upon the environment. The expected returns were also variable, especially in CC mixes. The study provides valuable information on the species‐specific functionality of CCs in continuous corn under variable environmental conditions. The information will benefit future studies to explore a high diversity mixture of CCs that may outperform across all three environments.

Nitrogen, Phosphorus, and Potassium Uptake in Rain-Fed Corn as Affected by NPK Fertilization

Effective nutrient management requires understanding nutrient uptake at various growth stages and nutrient removal by the harvested portion. Information on nutrient accumulation was provided by some older literature, and a few researchers have focused on this issue in this modern period with modern hybrids and improved corn cultivation practices. While almost all the studies were conducted in northern states of the US, information for the Southern Great Plains is still limited. To bridge this knowledge gap, a 2-year field study was conducted in a rain-fed corn production system. The study aimed to evaluate the impact of nitrogen (N), phosphorus (P) and potassium (K) fertilization on N, P, and K contents in aboveground plants at different growth stages. Pre-plant application of N (0, 67, 133 kg N ha−1), P (0 and 20 kg ha−1) and K (0 and 60 kg ha−1) fertilizers was done. Results from our study revealed that nutrient uptake values, pattern and dynamics depend on environmental conditions, soil type and management practices. N concentration in plants showed a linear response to N application rate while P and K concentrations were unaffected by NPK fertilization rates. Total N, P and K uptake was primarily driven by N application rate, showing a linear increase with higher N rates. Co-application of P and K with N did not significantly affect nutrient concentration and uptake.

Long-Term Tillage and Crop Rotation Regimes Reshape Soil-Borne Oomycete Communities in Soybean, Corn, and Wheat Production Systems.

Soil-borne oomycetes include devastating plant pathogens that cause substantial losses in the agricultural sector. To better manage this important group of pathogens, it is critical to understand how they respond to common agricultural practices, such as tillage and crop rotation. Here, a long-term field experiment was established using a split-plot design with tillage as the main plot factor (conventional tillage (CT) vs. no till (NT), two levels) and rotation as the subplot factor (monocultures of soybean, corn, or wheat, and corn-soybean-wheat rotation, four levels). Post-harvest soil oomycete communities were characterized over three consecutive years (2016-2018) by metabarcoding the Internal Transcribed Spacer 1 (ITS1) region. The community contained 292 amplicon sequence variants (ASVs) and was dominated by Globisporangium spp. (85.1% in abundance, 203 ASV) and Pythium spp. (10.4%, 51 ASV). NT decreased diversity and community compositional structure heterogeneity, while crop rotation only affected the community structure under CT. The interaction effects of tillage and rotation on most oomycetes species accentuated the complexity of managing these pathogens. Soil and crop health represented by soybean seedling vitality was lowest in soils under CT cultivating soybean or corn, while the grain yield of the three crops responded differently to tillage and crop rotation regimes.

Assessing Grain Yield and Achieving Enhanced Quality in Maize by Next Generation Fertilizer: A Review

It explores the potential of advanced fertilizers in improving maize yield and quality while addressing environmental and socioeconomic concerns. Investigating the innovations in fertilizer technologies and their impact on maize cultivation, identifying research gaps and suggesting policy recommendations. The potential of advanced fertilizers for enhancing maize yield and quality while tackling environmental and socioeconomic issues: Advanced fertilizers, marked by enhanced nutrient use efficiency and targeted nutrient delivery, present valuable prospects for sustainable corn farming. This includes progress in fertilizer technologies, combined management strategies, and the effects of these cutting-edge products on corn yield and quality. Additionally, we explore research gaps, areas requiring further study, and policy suggestions to support the adoption of advanced fertilizers in corn production systems. By seizing these opportunities and addressing the related challenges, the global agricultural community can strive for more sustainable, efficient, and productive corn farming practices that contribute to improved food security and nutrition.

A global meta‐analysis of cover crop response on soil carbon storage within a corn production system

AbstractBy influencing soil organic carbon (SOC), cover crops play a key role in shaping soil health and hence the system's long‐term sustainability. However, the magnitude by which cover crops impacts SOC depends on multiple factors, including soil type, climate, crop rotation, tillage type, cover crop growth, and years under management. To elucidate how these multiple factors influence the relative impact of cover crops on SOC, we conducted a meta‐analysis on the impacts of cover crops within rotations that included corn (Zea mays L.) on SOC accumulation. Information on climatic conditions, soil characteristics, management, and cover crop performance was extracted, resulting in 198 paired comparisons from 61 peer‐reviewed studies. Over the course of each study, cover crops on average increased SOC by 7.3% (95% CI, 4.9%–9.6%). Furthermore, the impact of cover crop–induced increases in percent change SOC was evaluated across soil textures, cover crop types, crop rotations, biomass amounts, cover crop durations, tillage practices, and climatic zones. Our results suggest that current cover crop–based corn production systems are sequestering 5.5 million Mg of SOC per year in the United States and have the potential to sequester 175 million Mg SOC per year globally. These findings can be used to improve carbon footprint calculations and develop science‐based policy recommendations. Taken altogether, cover cropping is a promising strategy to sequester atmospheric C and hence make corn production systems more resilient to changing climates.

Towards reducing chemical usage for weed control in agriculture using UAS imagery analysis and computer vision techniques

Currently, applying uniform distribution of chemical herbicide through a sprayer without considering the spatial distribution information of crops and weeds is the most common method of controlling weeds in commercial agricultural production system. This kind of weed management practice lead to excessive amounts of chemical herbicides being applied in a given field. The objective of this study was to perform site-specific weed control (SSWC) in a corn field by: (1) using a unmanned aerial system (UAS) to map the spatial distribution information of weeds in the field; (2) creating a prescription map based on the weed distribution map, and (3) spraying the field using the prescription map and a commercial size sprayer. In this study, we assumed that plants growing outside the corn rows are weeds and they need to be controlled. The first step in implementing such an approach is identifying the corn rows. For that, we are proposing a Crop Row Identification algorithm, a computer vision algorithm that identifies corn rows on UAS imagery. After being identified, the corn rows were then removed from the imagery and remaining vegetation fraction was classified as weeds. Based on that information, a grid-based weed prescription map was created and the weed control application was implemented through a commercial-size sprayer. The decision of spraying herbicides on a particular grid was based on the presence of weeds in that grid cell. All the grids that contained at least one weed were sprayed, while the grids free of weeds were not. Using our SSWC approach, we were able to save 26.2% of the acreage from being sprayed with herbicide compared to the current method. This study presents a full workflow from UAS image collection to field weed control implementation using a commercial size sprayer, and it shows that some level of savings can potentially be obtained even in a situation with high weed infestation, which might provide an opportunity to reduce chemical usage in corn production systems.

Diversifying corn production systems with living mulches in the southeastern United States

AbstractLiving mulch (LM) production systems are gaining traction as an alternative to the use of annual cover crops in the southeastern United States, warranting research on the viability and functionality of this system. Our objective was to evaluate the benefits of LM in corn silage and grain production and to evaluate the potential of LM grazing during the corn (Zea Mays L.) growing season. The experiment was conducted in Spring Hill, TN in 2020 and 2021 and consisted of two mulch species, white clover (WC) (Trifolium repens L.) and a mixture of crimson clover (Trifolium incarnatum L.) and cereal rye (CCCR) (Secale cereale L.). Cull cows were used for the grazing periods (4 weeks before planting and after the harvest of corn). The study evaluated the botanical composition, mulch mass, nutritive value, corn silage and grain production, and cow average daily weight gain (ADG). The WC treatment had a greater weed control than CCCR. In 2020, when differences in mulch mass were observed, CCCR had greater mass than WC mass due to the weed presence. Meanwhile, in 2021, the mulch mass did not differ between WC and CCCR, with both treatments showing less mass in spring and early summer. Grain production was 30% less than silage in 2020 and 90% less in 2021. The ADG was only observed for WC (0.5 kg−1) paddocks. It was concluded that WC as LM has greater corn production than CCCR treatments. The LM for grazing is a beneficial strategy if feeding costs are greater than $2.22 head day−1.

전과정평가법을 활용한 고구마 및 풋옥수수의 탄소배출량 산정

In this study, we calculated the carbon emissions of sweet potato and corn production systems using Life Cycle Assessment methodology with the national Life Cycle Inventory database and the latest Korean statistics for agricultural products. Previous calculations of carbon emissions for sweet potato and corn were not accurate because they did not reflect current statistics and cultivation management. Fertilizer and electricity consumption are the highest among the materials input to 1 kg for sweet potato production, with fertilizer amount of 2.94E − 01 kg/kg and electricity consumption of 1.32E − 01 kWh/kg. Also, fertilizer amount is the highest among the materials input to 1 kg for corn production, with fertilizer amount of 9.16E − 01 kg/kg. Direct emission of greenhouse gases showed a carbon footprint of 2.70E − 01 kg CO₂-equivalent (eq.)/kg for sweet potato and 1.98E − 01 kg CO₂-eq./kg for corn. Also, the result of Life Cycle Impact Assessment for sweet potato and corn production systems, Global Warming Potential for characterization value was 2.70E − 01 kg CO₂-eq./kg for sweet potato and 1.98E − 01 kg CO₂-eq./kg for corn. The results of this study will be able to contribute to improving accuracy and reliability of carbon footprint of agricultural products.

Long term influence of alternative corn cropping practices and corn-hay rotations on soil health, yields and forage quality

Modifications to continuous corn production systems can reduce environmental impacts and soil degradation, yet the social viability of these modifications is linked to the degree to which they also influence yields and crop quality. In this study, we focus on forage production systems and evaluate how yields, crop quality, soil health indicators, and associated ecosystem services are influenced by corn-hay rotation treatments, cover cropping, and tillage reduction in silage production using a unique 10-year dataset from Borderview Research Farm in Vermont, United States. Physical, chemical, and biological soil health indicators were monitored annually alongside yields and crop quality in a randomized complete block design experiment. We use a mixed model analysis of variance approach to demonstrate significant influences of time and treatments on yields, crop quality and soil health parameters (at p < 0.05). The winter rye cover crop treatment had no significant influence in this study. No-till significantly increased aggregate stability and had no significant effect on other metrics. When cover crop and no-till were combined, they significantly increased soil organic matter content, respiration and aggregate stability. The cover crop, no-till, and no-till cover crop combination treatments had no significant effect on yields or forage quality, suggesting these conservation practices can be adopted without sacrificing yields. Our study also found that corn-hay rotations can significantly increase soil organic matter, respiration, aggregate stability, and crude protein content compared to continuous corn, but they can negatively influence active carbon, total dry matter yield and digestibility. The length of rotation influences the degree to which corn-hay rotations maintain or reduce yields when compared to continuous corn. Shorter rotations of perennial forages (4 years of hay, 6 years of corn) can sustain dry matter yields that are not significantly different from continuous corn, but longer perennial forage rotations (8 years of hay, 2 years of corn) will significantly reduce overall dry matter yields. Among the treatments, no-till in combination with cover cropping in corn silage fields, and a rotation of 4 years of hay to 6 years of corn are likely to achieve the greatest overall benefits in forage production systems.

Interseeding Wide-Row Corn with Forage Cover Crops: Investigating System Potential for Expanded Economic Opportunities in Corn Production Systems

Intercropping forages with corn can improve cropping system productivity relative to single crop systems. However, limited light resources in 76 cm corn rows may impede successful forage establishment. This study assessed whether the combination of intercropped high value forage cover crops and wider corn rows could result in economically viable crop production systems in the Upper Midwest. A high value forage mixture was interseeded into standing corn at three working farms in the Rice and Goodhue Counties, MN, USA. Treatments were comprised of four row widths: 76 cm with no forage cover crop (best management practices, BMP), 76 cm with a forage cover crop (BMP + CC), 76 cm + CC, and two skip rows every fourth row (Balanced), and 152 cm + CC (WIDE). The WIDE, Balanced, and BMP + CC corn treatment reduced corn yields relative to the 76-cm treatments. However, the forage cover crop yields for all treatments optimized for light resources (Balanced and WIDE) ranged from 945 to 1865 kg ha−1 a forage quality (CP and RFV) equivalent to alfalfa. Our economic analysis revealed that high yielding, quality forage crops can offset up to 12.6% of economic losses caused by grain reductions. Wide-row intercropped systems may be economically viable for producers looking for opportunities to reintegrate their crop and livestock production systems, but further work is needed to refine this system for farm use.

Active and passive sampling methods for grubs of the Asiatic garden beetle, Maladera formosae (Coleoptera: Scarabaeidae), in a corn-soybean rotation

Beginning in the mid-2000s, grubs of the Asiatic garden beetle, Maladera formosae (Brenske) (syn. M. castanea [Arrow]), emerged as significant early-season pests of field corn grown in sandy soils of the Great Lakes region. Overwintered grubs move towards the soil surface in springtime to resume feeding on roots, causing stand losses of up to 40%. Scouting for M. formosae is problematic as the grubs are subterranean, and the adults are nocturnal. The objective of this study was to evaluate sampling methods currently in use for other annual white grub species specifically for use with M. formosae grubs in corn production systems. In a series of two experiments, we evaluated the ability of the compact cutter, golf hole cup cutter, and wire-mesh bait station to detect M. formosae grubs and sense varying population densities. The cup cutter, which takes a deeper but smaller soil volume sample than the compact cutter, sampled more grubs per soil volume and was more sensitive to smaller grub populations. The bait station, a passive sampling technique, and cup cutter were both successful at detecting M. formosae before planting. However, the cup cutter is more adequate and economical since it can be used with less equipment in a single trip to the field. Identification of a standardized sampling methods will enable researchers to predict future infestations and ultimately lead to the development of economic threshold levels for M. formosae in row crop agroecosystems.

Prairie strips reduce fecal indicator bacteria concentrations in simulated runoff

AbstractVegetative filter strips (VFS) have shown promising results in reducing the downstream transport of many agroecosystem contaminants. A recently developed type of VFS, prairie strips, has been shown to significantly reduce the impact of corn and soybean production systems on water quality in terms of sediment, nitrogen, and phosphorus losses. This study assessed potential additional benefits of prairie strips to include the reduction of pathogens. To assess the impact of prairie strips on manure‐laden agricultural runoff, we utilized a physical model of prairie strips in a laboratory flume to conduct highly controlled overland flow experiments. Escherichia coli and Enterococcus concentration reductions of up to 45% and 65% were observed for runoff and infiltration flows, respectively, while mass load reductions of up to 65% were observed for surficial runoff flows. The degree of concentration or mass load reductions was dependent on the residence time of the flow within the strip and the partitioning of overland flow running onto the strip to infiltration and runoff flows. Based on our results and a review of the literature, we developed a design method to provide guidance on the width of prairie strip buffer needed to achieve a user‐defined reduction of fecal bacteria concentration.

Modeling the Impact of Deficit Irrigation on Corn Production

Deficit irrigation or intentional under-irrigation offers the potential for sustainable water resources management. The DSSAT CERES-Maize and AquaCrop models were coupled to simulate the effects of deficit irrigation on corn yield and water productivity. The models were calibrated and validated using observed values of crop and biomass yield under 40%, 50%, 60%, 70%, and 80% depletion of the available soil water. Model simulation results showed that a 15% level of deficit irrigation results in maximum yield while a 60% level of deficit irrigation leads to maximum water productivity. Results suggest that it is not necessary to use large amounts of water in order to obtain high crop yield. The net irrigation application depths ranged from 60 mm to 134 mm, with a depth of 77 mm as optimum under 60% deficit irrigation when applied at the start of tasseling to grain filling. This study demonstrated the applicability of deficit irrigation as a water-saving management strategy for corn production systems. Crop models such as DSSAT CERES-Maize and AquaCrop proved to be viable tools to support decision making in corn production systems in the Philippines, especially when employing deficit irrigation.

Cover crops and preemergence herbicides: An integrated approach for weed management in corn-soybean systems in the US Midwest

Adoption of a fall established, high biomass cereal rye cover crop has potential to diversify weed management in corn and soybean production systems, reducing the selection pressure for resistance to postemergence herbicides. However, farmers and crop consultants express concern about limited weed suppression from an overwintering cover crop in areas where high biomass production is limited by cooler spring temperatures, such as in the Upper-Midwest U.S. Use of a preemergence herbicide, regardless of cover crop adoption, is a standard recommendation for improving early season weed control in corn and soybean. Field experiments were conducted at two sites in Wisconsin to assess the effects of six soil management practices (tillage, no-till, and four cereal rye cover crop termination timings/methods) with or without the use of a preemergence herbicide on weed suppression at the time of postemergence herbicide application and crop productivity. Results showed that cereal rye biomass increased > 6x between termination at the time of cash crop planting versus termination two weeks later. In corn and soybean, weed ground cover was lower for soil management with cereal rye cover crop terminated two weeks after cash crop planting (≤ 7% weed cover) compared to all other soil management practices (≥ 23% weed cover) when a preemergence herbicide was not used. Use of a preemergence herbicide resulted in low weed ground cover across treatments in corn (≤ 7% weed cover) and soybean (≤ 13% weed cover). Corn and soybean yield was not affected by preemergence herbicide treatments. Corn yield was lower at the south-central Wisconsin location for the soil management with a cereal rye cover crop terminated two weeks after cash crop planting (9.82 Mg ha-1) compared to all other soil management practices (≥ 12.07 Mg ha-1); at the southwest Wisconsin location, corn yield was greater for the conventional tillage treatment (14.28 Mg ha-1) compared to all other soil management treatments (≤ 10.89 Mg ha-1). Soil management did not affect soybean yield, although yields were different between locations with 3.44 Mg ha-1 at the south-central Wisconsin compared to 4.77 Mg ha-1 at the southwest Wisconsin location. These results indicate that in the absence of a high biomass cereal rye cover crop, preemergence herbicides are important for in-season weed control. Also, the inclusion of a late-terminated cereal rye cover crop in soybean should be considered as an effective management practice for reducing weed ground cover without affecting crop yield.