Years Of Maize Research Articles

Discrimination of New and Aged Seeds Based on On-Line Near-Infrared Spectroscopy Technology Combined with Machine Learning

The harvest year of maize seeds has a significant impact on seed vitality and maize yield. Therefore, it is vital to identify new seeds. In this study, an on-line near-infrared (NIR) spectra collection device (899–1715 nm) was designed and employed for distinguishing maize seeds harvested in different years. Compared with least squares support vector machine (LS-SVM), k-nearest neighbor (KNN), and extreme learning machine (ELM), the partial least squares discriminant analysis (PLS-DA) model has the optimal recognition performance for maize seed harvest years. Six different preprocessing methods, including Savitzky–Golay smoothing (SGS), standard normal variate transformation (SNV), multiplicative scatter correction (MSC), Savitzky–Golay 1 derivative (SG-D1), Savitzky–Golay 2 derivative (SG-D2), and normalization (Norm), were used to improve the quality of the spectra. The Monte Carlo cross-validation uninformative variable elimination (MC-UVE), competitive adaptive reweighted sampling (CARS), bootstrapping soft shrinkage (BOSS), successive projections algorithm (SPA), and their combinations were used to obtain effective wavelengths and decrease spectral dimensionality. The MC-UVE-BOSS-PLS-DA model achieved the classification with an accuracy of 88.75% using 93 features based on Norm preprocessed spectral data. This study showed that the self-designed NIR collection system could be used to identify the harvested years of maize seed.

Multi-year belowground data of minirhizotron facilities in Selhausen

The production of crops secure the human food supply, but climate change is bringing new challenges. Dynamic plant growth and corresponding environmental data are required to uncover phenotypic crop responses to the changing environment. There are many datasets on above-ground organs of crops, but roots and the surrounding soil are rarely the subject of longer term studies. Here, we present what we believe to be the first comprehensive collection of root and soil data, obtained at two minirhizotron facilities located close together that have the same local climate but differ in soil type. Both facilities have 7m-long horizontal tubes at several depths that were used for crosshole ground-penetrating radar and minirhizotron camera systems. Soil sensors provide observations at a high temporal and spatial resolution. The ongoing measurements cover five years of maize and wheat trials, including drought stress treatments and crop mixtures. We make the processed data available for use in investigating the processes within the soil–plant continuum and the root images to develop and compare image analysis methods.

Dry Matter Accumulation and Physiological Growth Parameters of Maize as Influenced by Different Nutrient Management Practices

Background: Maize, which is an important cereal for its yield potential and it can be influenced by various agronomic factors. In hybrid maize, dry matter accumulation and leaf area index are strongly affected due to applied nutrients. The amount of dry matter accumulation is directly related to the grain yield. The present study has been conducted with a focus on the effect of nutrient management on dry matter accumulation and other physiological parameters for quantifying the growth of maize. Methods: The present study was conducted during rabi season for two consecutive years of 2021-2022 and 2022-23 at the P.G. Experimental Farm of Centurion University of Technology and Management, Odisha. The experiment was laid out in randomized block design with 14 treatments and three replications. The treatment details include different recommended doses of nutrients, leaf colour chart and sufficiency index-based nitrogen management and nutrient expert based nutrient management in maize. Result: The study revealed that application of ample dose of nitrogen, i.e., 200-60-60 kg/ha of N-P2O5-K2O resulted in obtaining the highest dry matter accumulation and leaf area index of maize throughout the growth periods for both the years of maize. Further, the treatments 150% RDF and SI-based N management (N-60-60 kg/ha) at SI 90-95% also performed at par in terms of growth attributes of maize.

Alfalfa stand age at termination influences soil properties, root characteristics, and subsequent maize yield

Alfalfa (Medicago sativa L.)–maize (Zea mays L.) rotation is an important cropping practice to improve crop production and soil fertility, but the effects of the alfalfa stand age on the performances of the following maize remain unexplored. It is not clear how different alfalfa stand ages at termination influence soil properties, root characteristics, and yield of subsequent maize. The aim of this study was to evaluate how alfalfa influences soil characteristics, which in turn influence the root and aboveground growth and grain yield of the following maize crop. A field experiment from 2014 to 2019 was conducted at the Lishu Experimental Station, Jilin Province, China. The field treatments included six years of continuous maize (CM), six years of continuous alfalfa (CA), three years of alfalfa followed by two years of maize (3A2M), four years of alfalfa followed by two years of maize (4A2M), and five years of alfalfa followed by one year of maize (5A1M). Only the yield for the first-year maize after alfalfa in the 3A2M, 4A2M, and 5A1M treatments significantly increased by 8 %, 23 %, and 13 %, respectively. Root biomass (RB) of CA treatment gradually increased from 2014, reaching its maximum value of 5866 kg ha−1 in 2019, which was 35 % greater than the RB accumulation under CM in the 0–60 cm soil layer. Compared with the CM treatment, 3A2M and 4A2M treatments increased RB, while 3A2M, 4A2M, and 5A2M increased root length density (RLD), root surface area density (RSAD), and root volume density (RVD) of first-year maize after alfalfa. The 4A2M treatment also increased RLD, RSAD, and RVD in the 0–60 cm soil layer of second-year maize and reduced the soil bulk density (BD) in the 0–20 cm soil layer of first-year maize after alfalfa. Only 4A2M and 5A1M treatments significantly increased soil Olsen-P and soil organic carbon by first-year maize after alfalfa. The redundancy analysis results showed that the soil water content in the critical period and soil Olsen-P were the primary factors, which explained 33.8 % and 13.0 % of variation in maize root characteristics (P < 0.01), respectively. Structural equation modeling indicated that sowing alfalfa influenced the subsequent maize yield by influencing the soil Olsen-P, soil mineral nitrogen before sowing, and root characteristics. Therefore, keeping alfalfa for at least four years should be the recommended practice owing to its ability to improve the soil properties, root growth, and subsequent maize yield.

Impact of Climate Changes on the Natural Prevalence of Fusarium Mycotoxins in Maize Harvested in Serbia and Croatia.

Ongoing climate change may affect the susceptibility of plants to attacks by pathogenic, mostly mycotoxigenic fungi with a consequent increase in the presence of mycotoxins. Fusarium fungi represent one of the most important producers of mycotoxins, and are also important pathogens of agricultural crops. Therefore, the main aim of the study was to estimate the impact of weather parameters on the natural occurrence of Fusarium mycotoxins, such as deoxynivalenol (DON), fumonisins B1 and B2 (FUMs), zearalenone (ZEN), T-2, and HT-2 toxins (T-2/HT-2) in maize samples harvested from two neighboring countries, Serbia and Croatia, during a four-year production period (2018-2021). The frequency and contamination level of examined Fusarium mycotoxins varied by maize year of production and could be linked to weather conditions per investigated country. Among them, FUMs were found to be the most common contaminants (84-100%) of maize in both Serbia and Croatia. Additionally, a critical assessment of Fusarium mycotoxins occurrence in the last 10 years (2012-2021), for both Serbia and Croatia, was done. Results pointed out the highest contamination of maize from 2014, especially with DON and ZEN, in connection to extreme levels of precipitation observed in both Serbia and Croatia, whereas FUMs occurred with high prevalence from each of the ten investigated years.

Perennial Crops Can Compensate for Low Soil Carbon Inputs from Maize in Ley-Arable Systems.

(1) Background: Soil organic carbon (SOC) in agricultural soils plays a crucial role in mitigating global climate change but also, and maybe more importantly, in soil fertility and thus food security. Therefore, the influence of contrasting cropping systems on SOC not only in the topsoil, but also in the subsoil, needs to be understood. (2) Methods: In this study, we analyzed SOC content and δ13C values from a crop rotation experiment for biogas production, established in southern Germany in 2004. We compared two crop rotations, differing in their proportions of maize (0 vs. 50%) and perennial legume-grass leys as main crops (75 vs. 25%). Maize was cultivated with an undersown white clover. Both rotations had an unfertilized variant and a variant that was fertilized with biogas digestate according to the nutrient demand of crops. Sixteen years after the experiment was established, the effects of crop rotation, fertilization, and soil depth on SOC were analyzed. Furthermore, we defined a simple carbon balance model to estimate the dynamics of δ13C in soil. Simulations were compared to topsoil data (0-30 cm) from 2009, 2017, and 2020, and to subsoil data (30-60 cm) from 2020. (3) Results: Crop rotation and soil depth had significant effects, but fertilization had no effect on SOC content and δ13C. SOC significantly differed between the two crop rotations regarding δ13C in both depths but not regarding content. Annual enrichment in C4 (maize) carbon was 290, 34, 353, and 70 kg C ha-1 per maize year in the topsoil and subsoil of the unfertilized and fertilized treatments, respectively. These amounts corresponded to carbon turnover rates of 0.8, 0.3, 0.9, and 0.5% per maize year. Despite there being 50% maize in the rotation, maize carbon only accounted for 20% of the observed carbon sequestration in the topsoil. Even with pre-defined parameter values, the simple carbon model reproduced observed δ13C well. The optimization of model parameters decreased the carbon use efficiency of digestate carbon in the soil, as well as the response of belowground carbon allocation to increased aboveground productivity of maize. (4) Conclusions: Two main findings resulted from this combination of measurement and modelling: (i) the retention of digestate carbon in soil was low and its effect on δ13C was negligible, and (ii) soil carbon inputs from maize only responded slightly to increased above-ground productivity. We conclude that SOC stocks in silage maize rotations can be preserved or enhanced if leys with perennial crops are included that compensate for the comparably low maize carbon inputs.

Organic matter pools in a fluvisol after 29 years under different land uses in an irrigation region in northeast Brazil

Soil organic matter (SOM) is a critical component of the soil system and a sensitive indicator of soil quality. We aimed to investigate the response of SOM pools to different land uses and management in irrigated croplands of the semi-arid region of northeast Brazil. Four sites irrigated under long-term (29 years) land uses were selected: banana (B1 and B2); elephant grass (EG) - perennial systems; maize and cowpea succession (MCP) - annual system; B1 was cropped for 17 years +2 years of maize and cowpea +17 years banana, while B2 was continuously cropped. A native forest (NF) site was selected as reference of steady state. Soil samples were collected at four depths in the rows and inter-rows of each management system. The higher decline in SOM fractions was perceived at 0–0.05 m depth and microbial indices (microbial biomass C and N, and basal respiration and metabolic quotient) were very sensitive indicators of soil quality. Perennial systems (B1 and EG) maintained the C and N stocks at higher levels equivalent to NF at the 0–0.40 m layer, while MCP and B2 had lower total organic carbon (TOC) (15 and 17%, respectively) and total nitrogen stocks (4.27 and 8.67%, respectively). Perennial cultivation with B1 and EG showed also the highest soil C and N microbial biomass and stratification ratio and, the lowest respiratory quotients, all indications of elevated soil C sequestration. In general, land use change from native forest to annual crops reduced plant residue input and increased soil disturbance, favoring higher SOM mineralization, while perennial crops and grasses were the most effective in increasing C and N stocks due to the maintenance of crop residues on the soil surface and the absence of soil tillage.

Development of RZ-SHAW for simulating plastic mulch effects on soil water, soil temperature, and surface energy balance in a maize field

A shortcoming of the RZ-SHAW model (A hybrid version of Root Zone Water Quality Model and The Simultaneous Heat and Water Model) is that it cannot simulate the plastic mulching technology which is widely used in arid areas. Our objectives in this study were to develop RZ-SHAW to include a new plastic module, and to evaluate the model’s performance over three years of maize (Zea mays L.) production in China. A new plastic module was added to compute changes in the shortwave and longwave radiation transfer, turbulent heat and vapor transfer from the surface, and the energy and water balances in the system associated with a plastic mulch layer. The modified RZ-SHAW model can adequately simulate soil water (0.017 cm3 cm−3 ≤ RMSE ≤ 0.030 cm3 cm−3) and capture the evaporation reduction and transpiration increase under plastic mulch. The model overestimated the increased soil temperatures under plastic mulch (2.3 ℃ over the 100-cm profile) compared to the measured data (1.4 ℃). Overall, the revised RZ-SHAW model adequately simulated soil water and heat exchange under plastic mulch conditions. The modified RZ-SHAW model can be used as an effective decision tool for management optimization in plastic mulched cropland.

Agronomic system for stabilizing wheat yields and enhancing the sustainable utilization of soil: A 12-year in-situ rotation study in a semi-arid agro-ecosystem

Continuous wheat (Triticum aestivum L.) cropping in the Loess Plateau of China has led to soil degradation and yield reductions. In the present study, we conducted a long-term wheat rotation experiment in Zhenyuan County, Gansu Province, China, between 2005 and 2017, where three cropping systems were tested: (1) continuous winter wheat cropping (W), (2) wheat–wheat–wheat–soybean, i.e., 3 years of wheat and 1 year of soybean (Glycine max L.) rotation (W3–S), and (3) wheat–wheat–wheat–maize, i.e., 3 years of wheat and 1 year of maize (Zea mays L.) rotation (W3-M). Equal amounts of fertilizer were applied to all treatments. All treatments were conducted for four years and repeated three times, with a total of 12 years. Continuous wheat cropping increased the soil bulk density and decreased the soil porosity compared with 2005. However, W3–S and W3-M significantly reduced the soil bulk density and increased the soil nutrients and enzyme activities in 2017 compared with continuous wheat cropping. The average increases in the soil water storage under W3–S and W3-M were 12.7% and 5.9%, respectively. During the wheat growing season, the water use efficiencies under W3–S and W3-M were 22.9% and 12.9% higher, respectively, than that under continuous wheat cropping. The average wheat yields under W3–S and W3-M increased by 25.1% and 14.1%, respectively. Furthermore, according to principal component analysis and correlation analysis, the yield increases were due to the enhanced soil quality, enzyme activities, and water use efficiency. These results suggest that rotation can enhance the soil properties, soil enzyme activity, crop yield, and soil water use efficiency. In addition, wheat–soybean rotation had more positive effects than wheat–maize rotation on the soil quality and crop productivity in the study area. However, wheat was not produced in the fourth year of rotation so the replacement crop would need to be economically viable to facilitate widespread adoption. Further investigation is also required to determine whether the lower biomass production associated with legumes was offset by the increased soil organic carbon during the wheat phase of the rotation. The best rotation method identified in this study may provide a cleaner agronomic production strategy.

Linking land use patterns and pest outbreaks in Bt maize.

Western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is a major pest of maize in the United States and is an invasive pest in Europe. Maize is the only agricultural crop on which western corn rootworm larvae can survive and this insect requires two consecutive years of maize cultivation to complete its life cycle. Transgenic maize producing insecticidal proteins derived from the bacterium Bacillus thuringiensis (Bt) is often used to manage rootworm populations. The first Bt trait, Cry3Bb1, was introduced in 2003, but larval resistance to this toxin appeared in northeastern Iowa in 2009. Rootworm management occurs on a field-by-field basis, but adult rootworm may disperse among fields. It is known that growing consecutive years of Cry3Bb1 maize within a field can lead to resistance, but the relationship of the surrounding landscape to the development of resistance is unknown. Using geospatial tools and publicly available land-use data, we examined circular areas (buffers) surrounding fields that had previously experienced high levels of rootworm injury to Cry3Bb1 maize and rootworm resistance to Cry3Bb1 maize (problem fields). We calculated the proportion of area inside each buffer planted to maize continuously for 1-9 yr, and compared these values to those for randomly selected control points throughout the state. We also calculated the proportion of the state planted to maize for at least three consecutive years for 2003 through 2018, and its relationship with the annual value of maize. We found that areas surrounding problem fields had significantly more continuous maize compared to controls, with the most continuous maize within 1.6km of problem fields. We also found that the cultivation of continuous maize in Iowa increased significantly between 2003 and 2018, and this was correlated with average annual price of maize. We hypothesize a scenario in which continuous cultivation of Cry3Bb1 maize in local landscapes, driven in part by the increased value of maize, facilitated selection for Cry3Bb1 resistance. These results suggest that land use in areas surrounding problem fields affect the rate of resistance evolution and approaches for resistance management can be enhanced by taking a landscape-level perspective.

Effects of Direct Sowing under Mulch-Based Cropping System (DMC) on Cotton and Maize Yield and Chemical Characteristics of Ferruginous Soil (Lixisoil) in the South Sudan Area of Burkina Faso

To better understand the effects of direct sowing under mulch-based cropping system (DMC) in Burkina Faso’s cotton production systems, randomized blocks of Fisher experimental design were implemented at Farako-Ba research station from 2010 to 2019. The study was conducted on lixisoil to evaluate DMC effects on biomass production, crops yields and soil chemical properties in a maize and cotton rotation system associated with cover crop. Conventional tillage and direct seeding without cover crop were compared to DMC under B. ruziziensis (GERM. & EVRARD), DMC under B. ruziziensis + M. cochinchinensis mulch and DMC under C. juncea (L.) mulch used in association with maize. Biomass production, crop yields and soil chemistry were evaluated. Results showed that over 10 years, no-till with or without a cover crop provided cotton seed and maize yields that were statistically equivalent to the tillage commonly practiced by farmers. Cover crop has allowed increasing the biomass production compared to Conventional Tillage and Direct Seeding. Maize yield has not varied significantly with the cover crop. After 10 years of maize and cotton rotation, the improvement raised from +27% to +38% for organic matter and from +15% to +29% for nitrogen with DMC including legumes such as M. cochinchinensis and C. juncea compared to Conventional Tillage on 0 - 5 cm depth. No significant differences were found on soil pH like P2O5 and K2O content. Although DMC with C. juncea used as cover crop did not provide the best biomass production, it contributes to increase nitrogen and organic matter and presents better mineral balances in 10 years of rotation. The 5 - 10 cm and 10 - 20 cm were little influenced by DMC systems.

Can Technological Development Compensate for the Unfavorable Impacts of Climate Change? Conclusions from 50 Years of Maize (Zea mays L.) Production in Hungary

The goals of our study were to evaluate the historical aspects of maize (Zea mays L.) production in Hungary, and to provide a prognosis for the yield for 2050 based on the trends of temperature, precipitation, and climatic water balance changes. Different climate zones for the period of 1970–2019 were investigated by means of correlation analyses, normality tests, time series analysis, and multiple linear regression analysis. Two well-distinguishable linear trends in the yields were found, the first representing large-scale farming, and the second starting with the change of the socio-economic system in 1989. The annual amount of precipitation showed high variations both spatially and temporally, although no significant change was identified for the last five decades. In the period 1990–2019, not only were higher temperatures characteristic, but the frequency of extreme high temperature values (Tmax &gt; 30 °C) also increased. We quantified the heat stress, expressing it in heat stress units (HSU, °C) derived from the heat-sum of the daily maximum air temperature values above 30 °C. By 2050, the average increase in HSUs may reach 35 °C. Increasing HSU causes yield depression; according to our estimations, a 1 °C increase in HSU results in a 23 kg ha−1 yield depression of maize. Taking the unfavorable effect of heat stress and technological development into consideration, the average domestic yield of maize will be 8.2 t ha−1. Our study revealed that without taking technological development into consideration, prediction models may overestimate the adverse effect of climate change on crop production.

Spatio-temporal variabilities of soil phosphorus pool and phosphorus uptake with maize stover biochar amendment for 5 years of maize.

Phosphorus reuse by application of biochar is a recent concept that needs to be supported by long-term field data. To monitor biochar's long-term effects on P turnover, one-off biochar was applied in 2013 with mineral NPK fertilizers being applied every year since then. Biochar application rates included 0tha-1 (CK), 15.75tha-1 (BC1), 31.5tha-1 (BC2), and 47.25tha-1 (BC3). Over the 5years' field experiment, P distribution in soil profile, inorganic and organic P fractions in bulk, and rhizosphere soil and maize P uptake were determined. The results showed that biochar reduced the inorganic P fractions (Ca2-P, Ca8-P, Al-P, Fe-P and O-P by 4.8-33.7%, 8.8-59.0%, 13.7-28.6%, 8.4-17.6%, and 3.3-25.5%, respectively), and increased organic P fractions (MLOP and HROP by 67.2-11.6% and 18.8-87.7%, respectively) in bulk soil, while in rhizosphere soil, Fe-P and MLOP were decreased by 13.4-34.5% and 67.2-111.6%, respectively, in 2017. After the application of biochar for 5years, moderately labile organic phosphorus (MLOP), moderately resistant organic phosphorus (MROP), and highly resistant organic phosphorus (HROP) with different biochar treatments were enhanced by 12.8-42.7%, 20.1-48.0%, and 5.5-66.6%, respectively, but Ca8-P, Al-P, O-P, and Ca10-P were all decreased by 18.6-24.9%, 16.4-21.4%, and 3.3-23.48%, respectively. Total P storage in 0-100cm was declined by biochar. Increases in maize P uptake in the stover (38.6-71.3%) and grain (20.9-25.5%) were occurred after 31.5tha-1 and 47.25tha-1 biochar addition. To sum up, biochar is found to regulate the distribution, storage, and transformation of soil P, which lead to increase in maize P uptake.

Assessing the Performance of Maize (Zea mays L.) as Trap Crops for the Management of Sunflower Broomrape (Orobanche cumana Wallr.)

Sunflower broomrape (Orobanche cumana Wallr.) is a weedy root parasite that causes huge damage to sunflower (Helianthus annuus L.). Trap crop can stimulate parasitic seed germination without attachment in trap crop, and it was considered as economic methods for controlling the parasite. In this study, co-culture and pot experiments were conducted to assess the allelopathic activity of maize (Zea mays L.) to stimulate broomrape seeds germination and to evaluate the performance of maize rotation for reducing sunflower broomrape infection. All the tested maize cultivars could induce sunflower broomrape germination, and the most active maize cultivar was N314, which induced approximately 40% broomrape seeds germination. Rotation of maize significantly reduced broomrape infection on subsequent sunflower and increased sunflower biomass. After cultivated N314 for 3 years, broomrape attachment on sunflower was the lowest (0.8 attachment plant−1), and the dry mass of sunflower shoot (28.7 g plant−1) was approximately twice higher than the sunflower without previous crop. The effectiveness of broomrape management was significantly different among various maize cultivars. Meanwhile, the differences among cultivars were decreased with the years of maize cultivated prolonged. Our results confirmed that maize was significantly effective in reducing the sunflower damage caused by sunflower broomrape and suggested that maize rotation could be included in the integrated management of sunflower broomrape.

Phosphorus-induced zinc deficiency in maize (Zea mays L.) on a calcareous chernozem soil

Abstract A long-term fertilizer experiment was set up on a calcareous chernozem soil with a wheat-maize-maize-wheat crop rotation, as part of the National Long-Term Fertilization Experiments (NLTFE) Network, set up with the same experimental pattern under different soil and agro-climatic conditions in Hungary. The effect of P fertilization on the soil, on maize yields, and on leaf P and Zn contents in the flowering stage were examined in the trials. In certain years, foliar zinc fertilizer was applied, in order to prove that yield losses due to P-induced Zn deficiency can be compensated by Zn application. Calcium-ammonium nitrate, superphosphate and 60% potassium chloride were used as NPK, and Zn-hexamine (in 1991) and Zn-sulphate (in 2006) as foliar Zn fertilizers. In the years since 1970, averaged over 36 maize harvests, treatments N3P1K1 and N4P1K1, involving annual rates of 150 to 200 kg ha−1 N, 100 kg ha−1 K2O and 50 kg ha−1 P2O5, gave the highest yields (8.3 t ha−1 grain on average). As the years progressed, treatments exceeding 50 kg ha−1 P2O5 a year were found to have an increasingly unfavourable effect. Based on the yields of ten cycles (36 maize years), variants P2, P3 and P4 resulted in 16–30–45 t ha−1 grain yield losses in comparison to variant P1. Investigations carried out in 1987, 1991 and 2006 showed that the leaf Zn content on plots with more than 150 to 200 mg kg−1 AL (ammonium lactate)-soluble P2O5 (over 30 mg kg−1 Olsen-P) dropped below 15 mg kg−1 and the P/Zn ratio rose to above 150 or even 250 in the flowering stage in two years. As a consequence of P-induced Zn deficiency, maize grain yields fell by 2 t ha−1 in two of the years investigated and by almost 5 t ha−1 in one year at the P4 level (200 kg ha−1 P2O5 year−1), in comparison to the P1 variant (50 kg ha−1 P2O5 year−1). When 1.2 kg ha−1 foliar Zn was applied in the form of zinc hexamine, 1.7 to 1.8 t ha−1 maize grain yield surpluses were obtained on plots with higher P levels in 1991. In 2006 the P-induced Zn deficiency caused unexpectedly high (almost 5 t ha−1) grain yield losses on plots with higher P levels, so the maize grain yield surpluses obtained in response to 1.2 kg ha−1 foliar Zn application, in the form of zinc sulphate, were as high as 1.6 to 3.8 t ha−1. The data clearly indicate that maize yields are impeded by both poor and excessive P status. Soil and plant analysis may be useful tools for monitoring the nutritional status of plants.

Regenerating Agricultural Landscapes with Perennial Groundcover for Intensive Crop Production

The Midwestern U.S. landscape is one of the most highly altered and intensively managed ecosystems in the country. The predominant crops grown are maize (Zea mays L.) and soybean [Glycine max (L.) Merr]. They are typically grown as monocrops in a simple yearly rotation or with multiple years of maize (2 to 3) followed by a single year of soybean. This system is highly productive because the crops and management systems have been well adapted to the regional growing conditions through substantial public and private investment. Furthermore, markets and supporting infrastructure are highly developed for both crops. As maize and soybean production have intensified, a number of concerns have arisen due to the unintended environmental impacts on the ecosystem. Many areas across the Midwest are experiencing negative impacts on water quality, soil degradation, and increased flood risk due to changes in regional hydrology. The water quality impacts extend even further downstream. We propose the development of an innovative system for growing maize and soybean with perennial groundcover to recover ecosystem services historically provided naturally by predominantly perennial native plant communities. Reincorporating perennial plants into annual cropping systems has the potential of restoring ecosystem services without negatively impacting grain crop production and offers the prospect of increasing grain crop productivity through improving the biological functioning of the system.

Remote estimation of fraction of radiation absorbed by photosynthetically active vegetation: generic algorithm for maize and soybean

ABSTRACTThe objective of this study is to develop generic algorithm for estimating fraction of radiation absorbed by photosynthetically active vegetation not requiring parameterization for C3 and C4 crops, maize and soybean, with contrasting photosynthetic pathways, canopy architectures and leaf structures. The study based on data acquired during eight years, altogether 16 site years of maize (12 irrigated and 4 rainfed, nine hybrids) and for 8 site years of soybean (4 irrigated and 4 rainfed, three cultivars). The red edge normalized difference vegetation index (NDVI), green NDVI and wide dynamic range vegetation index (WDRVI) were found to be accurate in estimating fraction of photosynthetically active radiation (PAR) absorbed by photosynthetically active green vegetation in maize and soybean with root mean squared error (RMSE) of 0.057, 0.067 and 0.069, respectively.

Effect of crop residue and potassium management practices on productivity and economics of conservation agriculture based maize (Zea mays)-wheat (Triticum aestivum) cropping system

A field experiment was conducted in kharif and rabi seasons of 2014-2016 at ICAR-IARI, New Delhi to study the effect of crop residue and potassium (K) on productivity and economics of maize (Zea mays L.) and wheat (Triticum aestivum L.) under conservation agriculture (CA) based maize-wheat cropping system. The experiment was conducted in split plot design with four levels of crop residue in main plot, viz. no crop residue (CR), 2.0 tonnes/ha CR, 4.0 tonnes/ha CR, 6.0 tonnes/ha CR and five potassium levels, viz. no K, 50% RDK, 100% RDK, 150% RDK, 50% RDK+KSB in sub-plots. Results revealed that the yield attributes, grain and stover/straw yield were significantly influenced by the crop residue and K management practices over the control in both crop during both the years. Treatment with 50% RDK+KSB showed the significantly highest values of all yield attributes like, number of grains/cob, grain weight/cob, test weight and grain (4.91, 5.39 tonnes/ha) and stover yield (8.41, 9.07 tonnes/ha) in maize. In wheat also number of spikes/m2, grains/spike, spike weight, test weight and yield (5.16, 5.45 tonnes/ha) and straw yield were significantly higher over the control and 50% RDK. However this treatment was at par with 100% RDK and 150% RDK. Among the residue management practices 4.0 tonnes/ha CR registered significantly higher yield attributes, grain yield and stover/straw yield over no crop residue and 2.0 tonnes/ha CR and it was on par with 6.0 tonnes/ha CR in maize and wheat crops. The highest cost of cultivation was reported in 150% RDK and lowest cost of cultivation, highest gross returns, net returns and B: C ratios in maize and wheat were recorded in 50% RDK+KSB. Among residue management practices no CR registered the highest net returns and these were on par with 2 tonnes/ha CR in both the years of maize. However, in wheat highest returns were reported with 4.0 tonnes/ha CR and this was statistically at par to all the residue management practices except no CR. In both the crops, no CR showed highest B: C ratio followed by 2.0 tonnes/ha CR and 4.0 tonnes/ha CR. Lowest B: C ratio was recorded with 6.0 tonnes/ha CR. The strong correlation was observed between different yield attributes and yield in both the crops. Thus, application of 4.0 tonnes/ha CR and 50% RDK+KSB was cost effective, eco-friendly and sustainable K management practices under CA based maize-wheat cropping system and this may be recommended to farmers for adaptation.

Weed growth and crop yield responses to tillage and mulching under different crop rotation sequences in semi‐arid conditions

AbstractConservation agriculture (CA) is thought to reduce weed pressure from the third year of adoption, when recommended practices are followed. Weed growth and crop yield were assessed during the third and fourth year of maize–cowpea–sorghum rotation, second and third year of maize–cowpea rotation and first and second year of maize monocropping on a clay loam soil at Matopos Research Station (annual rainfall, 573 mm) following recommended CA management practices. Each experiment had a split‐plot randomized complete block design with mouldboard plough (CONV), minimum tillage (MT) with ripper tine and planting basins as main‐plot factor and maize residue mulch rate (0, 2 and 4 t/ha) as a subplot factor, with threefold replication. All subplots were surface mulched and weeded by hoe at the same time. We hypothesized that under MT weed growth would be considerable with maize monocropping but from year 3 of CA, weed growth would decrease and crop yield increase relative to values from unmulched CONV. Minimum tillage increased weed growth in 2nd year of maize monocropping. Under the maize–cowpea rotation, the considerable weed growth in planting basins was likely due to the large intrarow spacing and poor light competiveness of the cowpea variety. Mulch contributed to weed growth being suppressed by up to 36% under CA in the maize–cowpea–sorghum rotation relative to unmulched CONV. When planted on the same date, crop yield did not differ between CA and unmulched CONV. Maize–cowpea–sorghum rotation grain yield (3143 kg/ha) was double that under monocropping, probably due to improvements in soil physical and chemical conditions.

Does grassland introduction into cropping cycles affect carbon dynamics through changes of allocation of soil organic matter within aggregate fractions?

Implementation of ley grassland into crop rotation could have positive influence in soil ecosystem services such as C storage. The periodical changes of land-use plus the in situ labelling given by the introduction of maize crops under ley grassland induce differences in soil organic matter (SOM) that could be traced either by stable isotopes or by the characterization of plant biomarkers such as lignin derived phenols. Evaluation of SOM dynamics is often limited by the complexity of soil matrix. To override these limitations, a hierarchical approach to decompose the soil mosaic into aggregates has been proposed in this study. Soil and plant samples were collected from a long-term experimental area in Lusignan (western France). Soils from four different treatments (bare fallow, permanent maize, permanent grassland, and ley grassland based on 6years of grassland followed by 3years of maize) were sampled, fractionated into water stable aggregates, and finally analysed for carbon, nitrogen, and lignin contents, as well as for 13C isotopic signature.Soils under ley and permanent grassland stored higher amount of SOM in larger aggregates and preserved more efficiently the lignin stocks than the corresponding samples under permanent maize. Contemporary, finer fraction of ley grassland showed higher mean residence time of organic carbon, probably due to a legacy effect of the previous years under grassland. Even if maize derived SOM was identified, the grassland footprint was still dominating the ley grassland soils, as described by the principal component analysis. Strong correlation between these results and the quality and stoichiometry of the vegetal litter returned to soil were found, evidencing the needs for a comprehensive evaluation at a molecular level of all the parameters modified by land-use changes, including tillage, to understand the potential for carbon storage of different agroecosystems.