Total Above-ground Dry Matter Research Articles

Yield and dry matter production of soybean response to late planting in southwestern Japan

ABSTRACT The selection of the sowing date is one of the most important decisions in soybean production. It is important for farmers to know the expected seed yield when developing a sowing plan. The objective of this study was to quantitatively reveal the decreased seed yield ratio during late sowing in southwestern Japan under irrigated conditions. Total above ground dry matter and distribution were measured from July to August sowing in 2018 and 2019 in Fukuyama, Hiroshima, Japan. The harvest index in the August sowing did not decrease compared to the July sowing under irrigated conditions. The decrease in yield was related to the total aboveground dry matter rather than to the harvest index. The decrease in total aboveground dry matter was related to the total amount of solar radiation intercepted rather than to radiation use efficiency. A significant regression equation was obtained for the relative yield, which was calculated from the maximum seed yield observed from early to mid-July. When seeds were sown after mid-July, our result showed that the seed yield will decrease by 0.60% per day for Sachiyutaka A1 and by 0.64% for Akimaro, even under conditions of 100% seedling establishment and controlled soil water conditions. This regression equation can be used in fields as an indicator of seed yield where irrigation is possible.

Deficit irrigation effects on adjunct and all‐malt barley yield and quality

AbstractSemiarid regions are reliant on irrigation to produce large‐yielding and high‐quality malt barley (Hordeum vulgare L.). Drought in the western United States is of concern as surface and ground water reductions are occurring that affect irrigation water availability. Implementing a seasonal water deficit compared to evapotranspiration (ET) is a potential strategy to reduce water usage if yield and quality can be maintained. Research was conducted in Aberdeen, ID, on the effects of deficit irrigation on yield, grain quality, and malt characteristics. Five genotypes were selected to represent those used for large‐scale adjunct brewing and those targeted at the all‐malt craft industry. Irrigation was managed at three rates (100%, 75%, and 50%) of estimated crop evapotranspiration (ETc) using sprinkler irrigation. Total aboveground dry matter was not affected by irrigation until soft dough (Feekes 11.2). Yield was similar within a genotype with irrigation reduction from 100% ETc to 75% ETc. Averaged across genotypes, yields were 6936 kg ha−1 at 100% ETc and 6297 kg ha−1 at 75% ETc. At 75% ETc, protein remained just below the adjunct target (130 g kg−1) for four of five genotypes while all five exceeded the all‐malt target (120 g kg−1). Reduced irrigation decreased malt extract and increased diastatic power, where β‐glucan either did not differ or increased. Deficit irrigation is promising, particularly for adjunct brewing; however, expected changes to malting quality must be understood and genotype selection, altered fertilizer management, and/or changes to malting criteria may be needed for implementation.

Valorization of nitrogen-rich melamine as a nitrogen source in the production of maize (Zea mays L.)

Maize is important for the biofuel and bio-based products. Building a clean maize production system could minimize the environment pollution from the N loss from the sloping land and achieve the industrial sustainable development. As a nitrogen-rich source, melamine could be used as a slow-release nitrogen (N) fertilizer, which provides a route for the recycling of melamine waste and the combatting of N loss from fertilizers. Model N release of melamine was compared with urea, sulfur(S)-coated urea via N loss in leaching column under intermittent leaching and under the ploughing fertilizer in the farmland soil. Only 7.12 % of the total nitrogen (TN) was lost from the 21 irrigation events, while the loss of TN from urea reached 77.28 %. TN from urea would be release totally in soil within 14 days in the ploughing fertilizer experiment, but 62 % of melamine was remained after 144 days. In order to evaluate the efficacy of melamine as an N fertilizer, plot experiments with an N rate of 180 kg ha-1 were carried out using pure melamine, urea and S-coated urea as well as mixed melamine/urea at 2:8, 1:1 and 7:3 by the N ratio. Melamine fertilization alone was unable to satisfy the N demand of maize, but the melamine/urea mixture (1:1) was comparable to the commercial S-coated urea in both years in terms of the grain yield (2217 kg ha-1 in 2019, 2368 kg ha-1 in 2020), total aboveground dry matter (5076 kg ha-1 in 2019, 4815 kg ha-1 in 2020), aboveground N uptake (36 kg ha-1 in 2019, 48 kg ha-1 in 2020), partial factor productivity of nitrogen (12.32 kg kg-1 in 2019 and 13.16 kg kg-1 in 2020) and net return (1474 USD in 2019, 1606 USD in 2020). Melamine accumulation in the maize grain measured from ELISA (enzyme-linked immunosorbent assay) ranged from 0.24 to 1.8 mg kg-1. The valorization of the melamine waste into N fertilizer by blending with urea was a possible way of reducing melamine pollution, alleviating N loss in hilly area and building a recyclable agriculture system.

Spectral reflection and crop parameters: can the disentanglement of primary and secondary traits lead to more robust and extensible prediction models?

Recently the application of spectral reflection data for the prediction of crop parameters for applications in precision agriculture, such as green area index (GAI), total aboveground dry matter (DM), and total aboveground nitrogen content (N content) increases. However, the usability of vegetation indices (VI) for the prediction of crop parameters is strongly limited by the fact that most VI calibrations are only valid for specific crops and growth periods. The results of the presented study based on the differentiation of primary (main driver of the reflectance signal) and secondary (not directly related to reflectance signal) crop parameters. For GAI prediction, a universal (without crop-specific parametrization) simple ratio vegetation index (SR) provided good calibration (R2 adj. = 0.90, MAE = 0.32, rMAE = 22%) and evaluation results (MAE = 0.33, rMAE = 18%). The disentanglement of primary and secondary traits allowed the development of a functional two-step model for the estimation of the N content during vegetative growth (MAE = 19.2 g N m−1, rMAE = 44%). This model was based on fundamental, crop-specific relationships between the crop parameters GAI and N content. Additionally, an advanced functional approach was tested enabling the whole-season prediction of DM and confirming a reliable GAI estimation throughout the whole growing season (R2 = 0.89–0.93).

Root-zone Temperature Effects on Spinach Biomass Production Using a Nutrient Film Technique System

Root-zone temperature (RZT) is closely related to nutrient transportation and biomass production. However, its influence on biomass production and dry matter distribution remains unknown, especially in year-long production greenhouses. We explore the potential of RZT as an environmental control method to promote spinach field production by quantifying the effects of RZT to increase spinach production. Three RZT treatments using a nutrient film technique (NFT) system quantified and evaluated the effects of spring, summer, and winter spinach cultivation. We investigated the growth characteristics, total aboveground dry matter, and fraction of dry matter distribution to the leaf and root (which corresponded with yield). The RZT effects on total aboveground dry matter varied with the average air temperature inside the greenhouse. The total aboveground dry matter correlated positively with RZT in optimal air temperature conditions (15–20 °C). The dry matter-to-leaves ratio of the spinach did not correlate significantly with RZT in suboptimal (5 °C < air temperature < 15 °C) or supraoptimal (20 °C < air temperature) conditions. Therefore, RZT can promote biomass accumulation. We suggest RZT provides a feasible method for controlling the dry matter distribution fraction. Further research into the functional role of RZT will support hydroponic growers in improving crop yield.

Physiological analysis of growth and development of winter carinata (Brassica carinata A. Braun)

AbstractBrassica carinata is a non‐food, low‐carbon, none‐to‐low indirect land‐use change impact oilseed feedstock grown for sustainable biofuels, bioproducts, and high protein seed meal. Understanding carinata growth and development is critical to the development of best management practices for maximum productivity and profitability of double‐cropped farming systems. Field experiments were conducted during 2017–2018 (Year 1) and 2018–2019 (Year 2) winter–spring growing seasons in Quincy, Florida, to quantify the total aboveground dry matter accumulation (TDM), allocation, growth, nutrient uptake, and seed quality. The two carinata cultivars Avanza 641 and AX17012 accumulated 10826 and 9343 kg TDM ha−1 in Year 1 and 9655 and 10,642 kg TDM ha−1 in Year 2, respectively, at harvest maturity. The proportion of DM in the vegetative parts such as leaves and stems decreased, and the DM in reproductive structures such as silique walls and seeds increased with maturity. Seed yield (SY) was similar between cultivars but differed between years with Year 1 (2732 kg ha−1), producing 29% greater SY than Year 2 (1929 kg ha−1). Carinata primary stem has 17–20 leaf nodes, with 75%–88% of the axillary meristems producing primary and secondary branches. Crop growth rate (CGR) increased from vegetative to pod development for both cultivars in Year 1, while in Year 2, AX17012 and Avanza 641 attained maximum CGR at the pod development and bolting/flowering stages, respectively. Maximum seasonal nutrient uptake in leaves, stems, and siliques generally occurred in the early, mid, and late season, respectively, in both years. Seed weight, oil, monounsaturated fatty acids, C18:3, C20:1, and C22:1 concentrations increased with plant age, whereas protein, glucosinolate, polyunsaturated fatty acids, saturated fatty acids, C18:1, and C18:2 concentrations decreased with plant maturity. These results can be used for crop modeling to predict growth, development, and yield and aid in developing in‐season decision support tools.

Sowing Date and Genotype Influence on Yield and Quality of Dual-Purpose Barley in a Salt-Affected Arid Region

Dual-purpose barley is an alternative approach to producing high-quality forage yield plus an acceptable grain yield in marginal environments of arid regions that are characterized by lack of forage. Field experiment was performed in two consecutive growing seasons at an arid region affected by salinity in irrigation water and soil at Western Sinai Peninsula in Egypt. The study aimed to optimize sowing date and screen salt-tolerant barley genotypes that perform better in terms of forage yield and quality as well as grain and biomass yield production in salt-affected environment. Sowing dates, genotypes, and their interaction significantly impacted most of the studied variables such as forage yield, crude protein yield, and grain and biomass yields. The early sowing in late October yielded higher than intermediate sowing in mid-November and late sowing in early December. Some of the tested genotypes performed better than others as indicated by about 50% higher forage yield, 6% crude protein content, 39% grain and 21% biological yields (total aboveground dry matter), suggesting higher adaptation capacity. Interestingly, grain and biological yields did not differ significantly between dual-purpose approach and grain-only pattern. In conclusion, dual-purpose barley was found favorable for producing grain and forage production in similar environments under early sowing date.

Plant productivity and nutrient uptake as affected by tillage and site‐position in furrow‐irrigated rice

AbstractFurrow‐irrigated rice (Oryza sativa L.) is a relatively new production system that has been shown to have increased water‐use efficiency and reduced operational costs. However, due to spatial variations in soil moisture, field studies are necessary to evaluate potential resulting variations in rice growth and yield in the furrow‐irrigated production system. This study was conducted to evaluate the effects of tillage practice (conventional tillage, CT; no‐tillage, NT) and site position (up‐, mid‐, and down‐slope) on aboveground biomass, yield, and plant nutrient uptake from rice grown in a silt‐loam soil in a direct‐seeded, furrow‐irrigated production system in eastern Arkansas. Field research was conducted from May to September during the 2018 and 2019 rice growing seasons. Total aboveground dry matter, vegetative dry matter, and yield were unaffected (P > .05) by tillage treatment or site position in either growing season. Vegetative tissue nutrient concentrations and uptake were generally at least 10% greater (P < .05) under CT than NT but did not substantially differ by site position during the drier growing season (2018). During the wetter growing season (2019), vegetative tissue nutrient concentrations and uptake were generally at least 20% greater (P < .05) at the up‐ than at the mid‐ or down‐slope positions. Results suggest that different approaches, in terms of soil and nutrient management per site position, in combination with tillage practices, may need to be considered for implementation to maximize nutrient uptake and reduce losses, thus improving the agronomic suitability of the furrow‐irrigated rice production system.

Exploring genetic diversity for grain partitioning traits to enhance yield in a high biomass spring wheat panel

Abstract Breeding to raise yield potential through enhancing photosynthesis will have limited impact unless harvest index (HI: proportion of above-ground biomass as grain yield) is maintained or ideally increased. Boosting grain dry matter (DM) partitioning will require increased allocation of assimilates to sink organs to enhance spike growth. A high biomass spring wheat panel of 150 genotypes encompassing elite, landrace-derived and synthetic-derived lines was grown under yield potential conditions in two seasons in NW Mexico. Results showed that the incorporation of landrace-derived and synthetic-derived backgrounds into elite lines resulted in higher expression of above-ground biomass (AGDM), leaf lamina and stem DM partitioning at anthesis. However, no grain yield advantage was observed over elite lines, due to lower grain number per unit area (GN) and decreased harvest index (HI). Positive linear associations were found among spike fertility-related traits - fruiting efficiency (grains per unit of spike DM at anthesis; FE), GN and HI - which were, in turn, related positively with grain yield (GY). Stem-internode 3 length and internode 3 DM partioning were negatively associated with spike partitioning index (SPI: ratio of spike DM to total above-ground DM at anthesis) and GN, suggesting an enhanced competition for assimilates between the spike and stem internode 3 during stem elongation. Within-spike DM partitioning analysis (glume, lemma, palea, rachis, awn) showed decreased partitioning to awns was associated with increased FE and thousand grain weight (TGW). While the use of exotic material can enhance biomass, special attention needs to be paid in the selection for novel DM partitioning traits that raise HI and GN coming from the elite genepool. The selection for grain partitioning traits in wheat breeding combined with sources expressing high biomass can potentially allow breeders to increase grain carbon assimilation that will deliver higher yields.

Genotype-by-environment interaction for dual-purpose traits in sweetpotato

ABSTRACT Development of high-yielding dual-purpose sweetpotato (Ipomoea batatas [L.] Lam) genotypes is useful for cultivation in mixed crop-livestock farming systems. The objective of this study was to determine genotype-by-environment interaction (GEI) for storage root yield (SRY), vine yield (VY), root: vine ratio (RVR), total above-ground and below-ground biomass (TABGB) and root dry matter content (RDMC) among newly developed sweetpotato clones to select promising dual-purpose clones. Forty-five sweetpotato genotypes, of which 32 were newly developed candidate clones, were evaluated across six diverse environments in Rwanda. Additive main effects and multiplicative interaction (AMMI) and genotype and genotype-by-environment (GGE) biplot analyzes were used to analyze GEI. AMMI analysis revealed a relatively larger proportion of the GEI effect for SRY (31.21%), VY (37.17%), RVR (41.73%), TABGB (35.24%) and RDMC (36.23%) than for genotype and environmental effects, suggesting differential response of test genotypes across environments for the assessed traits. GGE-biplot analysis explained total variation of 72.98% for SRY, 83.26% for VY, 74.03% for RVR, 78.82% for TABGB and 56.78% for RDMC. Clone 21 with enhanced SRY and TABGB, and clone 42 for SRY had broad adaptation. For better VY, clone 733 was the best performer in environments E2 and E6 which are designated as mega-environment (MGE) 2, and clone 321 in E1, E3 and E4 (MGE 3). For RVR, clone 577 had best adaptation in E3, E4 and E5 (MGE 1), while clone 460 in E2 and E6 (MGE 2). Clones 42 and 381 were best performers for RDMC with specific adaptation in environments E3 and E1, respectively.

Cotton/mung bean intercropping improves crop productivity, water use efficiency, nitrogen uptake, and economic benefits in the arid area of Northwest China

It is still a long-term challenge to improve crop production and economic benefits in arid area of northwest China. The objective of this study was therefore to propose a new and promising cotton/mung bean intercropping (CMBI) system to cope with the challenge based on the traditional monocropping cotton (MC) system. A two-year field experiment was conducted to evaluate crop production and economic benefits between the CMBI and MC systems by analyzing the total land output (TLO), aboveground dry matter, nitrogen uptake, water use efficiency (WUE), nitrogen use efficiency (NUE), partial factor productivity (PFP) of nitrogen, and economic benefits. Experiment treatments consisted of two cropping systems (MC and CMBI systems) and a combination of the CMBI system with different N-fertilizer rates [160 (N160), 315 (N315), 390 (N390), and 475 (N475) kg ha−1 in 2016, and 160 (N160), 315 (N315), and 390 (N390) kg ha−1 in 2017], respectively. All treatments were designed using a randomized complete block with three replications. The results indicated that no significant differences in growth parameters [PH (plant height), SD (stem diameter), and LAI (leaf area index)] of cotton were found between the MC and CMBI systems in 2016 and 2017. Compared with the MC system, however, the CMBI system significantly increased TLO, aboveground dry matter, total N uptake, WUE, NUE, PFP for nitrogen, and economic benefits in 2016 and 2017. The result suggested the CMBI system had greater production advantages and economic benefits than the MC system. In addition, compared to the N160 treatment, other N treatments (N315, N390, and N475) in the CMBI system significantly enhanced crop growth, TLO, total aboveground dry matter, total N uptake, WUE, and economic benefits. However, PFP for nitrogen and NUE significantly decreased with the increase of application N rates. According to analyzing the production functions of different application N treatments, we found that 390 kg ha−1 in the CMBI system might be recommended as an appropriate application N rate to improve crop production and economic benefits in the arid area of northwest China.

Evaluating Dry Matter Production and Grain Yield of Dual-Purpose Winter Wheat Using Field Experiment and Modelling

The potential of a winter wheat (Triticum aestivum L.) cultivar Wedgetail to provide grazing and grain yield under different sowing times, grazing times, and watering regimes, under current and future climate, was investigated using field experiment and simulation modelling. For the field experiment, there were two watering treatments (unirrigated (D) and irrigated (I)) and four simulated grazing treatments (ungrazed, simulated grazed at growth stage (GS) 25, simulated grazed at growth stage (GS) 32, and grazed at both GS 25 and GS 32). These were designated as D0, D1, D2, and D3, respectively, for the unirrigated treatment and I0, I1, I2, and I3, respectively, for the irrigated treatment. It was found that the soil water depletion was significantly higher (p < 0.05) for the irrigated/ungrazed treatment than that for the simulated grazed treatment. The crop simulated grazed at GS 25 recovered quicker than the crop grazed at GS 32, especially for the unirrigated treatment. As the sowing time is delayed, above-ground dry matter (AGDM) production decreases. For D2 and D3, the amount of simulated grazed AGDM was 3.46 t ha−1 and 3.55 t ha−1, respectively. For I2 and I3, the amount of simulated grazed AGDM was 4.73 t ha−1 and 4.34 t ha−1, respectively. For D1, simulated grazing increased grain yield by 7%, while for D2 and D3, it increased by 18% and 24%, respectively. For I1, simulated grazing reduced grain yield by 16%, while for I2 and I3, it decreased by 42% and 42%, respectively. Simulation using the Agricultural Production Systems sIMulator (APSIM) showed that, for winter wheat sown in the second week of March, the maximum AGDM expected one in two years at the ends of May, June, and July is 4.5 t ha−1, 5.8 t ha−1, and 6.8 t ha−1, respectively. If the crop is sown mid-April, these values are 0.8 t ha−1, 2.2 t ha−1, and 4.3 t ha−1, respectively. Yield did not show response to times of sowing from March to early April. The maximum value reached was about 4.5 t ha−1 when sown in the fourth week of March, after which it started decreasing and reached the lowest value of about 4.1 t ha−1 when sown by the end of May. The total above-ground dry matter (AGDM) obtained by grazing earlier during the feasible grazing period and again towards the end of this period was not significantly different from grazing only once towards the end of this period. The simulation results showed that winter wheat Wedgetail flowering date was less sensitive to sowing time and that yield did not show a significant response to times of sowing, with the maximum occurring for the fourth week of March sowing and the lowest for the fourth week of May sowing.

A Functional Analysis of Pedotransfer Functions Developed for Sri Lankan soils: Applicability for Process-Based Crop Models

As measurements are expensive and laborious, the estimation of soil hydraulic properties using pedotransfer functions (PTFs) has become popular worldwide. However, the estimation of soil hydraulic properties is not the final aim but an essential input value for other calculations and simulations, mostly in environmental and crop models. This modeling approach is a popular way to assess agricultural and environmental processes. However, it is rarely used in Sri Lanka because soil hydraulic data are rare. We evaluated the functionality of PTFs (developed to estimate field capacity (FC) and the permanent wilting point (PWP) of Sri Lankan soils) for process-based crop models. We used the Agricultural Production Systems sIMulator (APSIM) as the test model. Initially, we confirmed the importance of PWP (LL15) and FC (DUL) by assessing the sensitivity of the soil input parameters on the growth and yield of rice under rainfed conditions. We simulated the growth and yield of rice and the four selected outputs related to the APSIM soil module using the measured and estimated values of FC and PWP. These simulations were conducted for ten years in 16 locations of Sri Lanka, representing wet, intermediate, and dry zones. The simulated total aboveground dry matter and weight of the rough rice, using both input conditions (the measured and PTF-estimated soil hydraulic properties), showed good agreement, with no significant differences between each other. Outputs related to the soil module also showed good agreement, as no significant differences were found between the two input conditions (measured and PTF-estimated soil hydraulic properties). Although the DUL and LL15 are the most influential parameters for the selected outputs of APSIM–Oryza, the estimated FC and PWP values did not change the predictive ability of APSIM. In this way, the functionality of PTFs for APSIM crop modeling is confirmed.

Development and evaluation of HUME-OSR: A dynamic crop growth model for winter oilseed rape

A new dynamic crop growth model based on empirically derived allometric partitioning rules was developed for winter oilseed rape. The model simulates dry matter production, nitrogen uptake and distribution, leaf, stem and pod area expansion and yield formation under optimal and water- and nitrogen-limited conditions.The model includes hibernation, senescence due to self-shading, freezing and aging, translocation of assimilates and nitrogen, light absorption and reflection by flower layer and oil synthesis. It was parameterized with two data sets from Hohenschulen, northern Germany, and validated with datasets from Germany, France, Great Britain, and the Czech Republic.Model performance in terms of prediction of total aboveground dry matter production gave an RMSE of 180 g m−2 and the linear regression between measured and simulated root/shoot ratios gave an r2 of 0.64. In addition, nitrogen uptake (RMSE 4.26 g m−2) and distribution (r2 simulated/measured leaf N/stem N = 0.44) are quite well represented. In contrast, year-to-year variability of final seed yield was less correctly estimated, probably due to variation in the harvest index, which is not included in the model prediction. Relative differences in seed yield due to sowing date and nitrogen application were well reproduced in most cases. Therefore the model has potential to be used for supporting optimization of management strategies, climate change scenario studies and future breeding progress.

Temporal Dynamics and the Contribution of Plant Organs in a Phenotypically Diverse Population of High-Yielding Winter Wheat: Evaluating Concepts for Disentangling Yield Formation and Nitrogen Use Efficiency.

Enhancing crop nitrogen use efficiency (NUE) is a key requirement for both economic and ecological reasons. Consequently, the genotypic potential for NUE in winter wheat (Triticum aestivum L.) requires further exploitation. Emerging plant phenomic techniques may provide knowledge about traits contributing to grain N uptake (GNup) and grain yield (GY). However, the understanding of beneficial strategies concerning the temporal dynamics of NUE and GY formation and the role of plant organs is still scarce especially under high-yielding European conditions—particularly to discriminate interesting lines in the breeding process. Thus, screening for potentially useful NUE traits in terms of variation, stability, and contribution to target traits will be an essential prerequisite for the development of efficient phenotyping strategies. Therefore, 46 NUE and yield formation traits were assessed in a population of 75 breeding lines over 3 years from 2015 to 2017 in southern Germany, including dry matter (DM), N concentration, and N uptake at anthesis and maturity, both at the aboveground-plant and plant organ levels. Significant genotype and genotypexenvironment effects were observed for all traits. While GY was more related to post-anthesis assimilation, also DM translocation contributed substantially to GY by 31–44%. At maturity, total aboveground DM as opposed to harvest index predominantly determined GY. NUE for GY was better described by N uptake efficiency than by N utilization efficiency. GNup was greatly influenced by variation in GY, but not in grain N concentration, and by total N uptake and not the N harvest index. Post-anthesis N uptake highly depended on the year and was low in comparison to N translocation. However, post-anthesis N uptake was always correlated with GNup, suggesting the need to also consider stay-green strategies under temperate growing conditions. While anthesis traits were only moderately descriptive, GY will be enhanced by increasing total biomass and the N uptake efficiency. Similarly, targeting total N uptake, particularly at post-anthesis, seems to be a rewarding strategy to boost GNup. Thus, high-throughput phenotyping should be targeted rather toward detecting traits related to DM and N acquisition than to the internal allocation and rather to post-anthesis than to anthesis traits.

The impact of ozone exposure, temperature and CO2 on the growth and yield of three spring wheat varieties

When assessing potentials for crop production under future climatic conditions, multiple environmental parameters need to be included. An increase in carbon dioxide [CO2], higher temperatures, and regional changes in tropospheric ozone [O3] will influence the growth responses of existing crop species and varieties. Ozone is phytotoxic and a plant stressor at current concentrations, reducing yields worldwide, but possible interactions with changes in other abiotic factors have been considered very little. In this study, we have used eight combinations: two levels of temperature, two levels of [CO2], and three [O3] exposure regimes to assess the impact of medium-to-high ozone concentrations (80–100 ppb) on wheat growth when other abiotic factors change. Two modern spring wheat varieties (KWS Bittern and Lennox) and a landrace variety (Lantvete) were grown to maturity in climate chambers. We examined plant performance during growth as development rate, rate of photosynthesis, stomatal conductance, water use, and at harvest as total aboveground dry matter and grain yield. All three varieties lost yield in all treatments compared to the ambient treatment that had the following settings: Lowest temperature, ambient [CO2], and very low [O3]. For episodic ozone exposure in the ambient or high [CO2] and high-level temperature treatment, the yield losses were 18 and 25%, respectively, for KWS Bittern; 44 and 34% for Lennox; and 16 and 37% for Lantvete. The yields of the modern varieties are significantly higher than the landrace variety in two out of eight treatments, although they are higher by weight in seven of the eight treatments. The landrace variety’s fraction loss from its highest grain yield in the ambient treatment to the high-[CO2]-and high-level-temperature-treatments was smaller than the modern varieties’, showing a comparably higher degree of plasticity of performance. Current crop varieties might be more sensitive to ozone than older varieties, emphasizing the need of future breeding programs to expand the gene pool to provide more climate robust crops.

Physicochemical and Structural Characteristics of Corn Stover and Cobs After Physiological Maturity

Corn stover removal for biofuels production removes potentially recyclable nutrients and carbon challenging the sustainability of the process. Therefore, this study focused on quantifying the distributions of dry matter, nitrogen, phosphorus, potassium, carbon, sugars and lignin in corn stover fractions, and cobs. In 2016 and 2017, corn plants from different hybrids were collected from a corn field in Ohio at two maturity levels. The properties were evaluated for different non-grain corn plant fractions (i.e., stover fractions above and below ear, and cob). Stover fractions below and above ear (not including cobs) and cobs contributed, respectively, to 42–56%, 31–38%, and 13–18% of the total non-grain aboveground dry matter in 2 years. Glucose and lignin concentrations were uniformly distributed and ranged from 321 to 407 mg/g and 87 to 158 mg/g, respectively, for both years. Cobs contained the highest concentration of other sugars (351–361 mg/g) in both years, compared to 217–298 mg/g in other fractions. Nitrogen and phosphorus were uniformly distributed across the different corn stover and cob fractions, ranging between 4–20 mg/g and 0.2–1.5 mg/g, respectively. Potassium concentration was the highest in stover fraction below ear (10–24 mg/g) compared to 5–11 mg/g in other fractions. The results suggest that harvesting cob and above ear stover fractions from the field would allow corn stover collection with suitable sugar concentrations for biofuels/products while retaining stover fractions with higher nutrients concentrations in the field.

Effects of maturity genes E2 and E3 on yield formation in soybean cultivar Enrei in warm region, Fukuyama in Japan

ABSTRACTUnderstanding how maturity genes affect soybean yield formation will provide important information for crop management decisions. This study aimed to reveal how maturity genes E2 and E3 in the soybean cultivar ‘Enrei’ affect yields and yield formation in warm regions of Japan. ‘Enrei’ (e2e3) and three near-isogenic lines of ‘Enrei’ (e2E3, E2e3, and E2E3) were cultivated in 2016 and 2017 in Fukuyama, Japan (34°30′N, 133°23′E). Two sowing dates were set in each year (June sowing and July sowing). E2 extended the period from emergence to R1 and also the period from R1 to R7, whereas E3 extended only the period from emergence to R1. Interaction between E2 and E3 did not affect duration of the period from emergence to R1, but did affect the period from R1 to R7. Although seed yield did not differ between genotypes in the June sowings, the effects of E2 and E3 on seed yield in July sowing were both significant and interaction between E2 and E3 also observed. The total number of nodes increased in E3 genotypes in both sowing dates, especially in E2E3. Pod-set ratio was lower in E2 and E3 genotypes than in e2 and e3 genotypes in the June sowings, but did not differ between genotypes in the July sowings. The high yield of E2E3 genotypes in the July sowings was attributed to increased number of nodes and flower production while maintaining pod-set ratio. Appropriate choice of sowing date is suggested to be essential when using E3 genotypes.Abbreviations: HI: harvest index; NIL: near-isogenic line; RUE: radiation use efficiency; TDM: total above-ground dry matter; TRI: total solar radiation intercepted

Global sensitivity analysis of the APSIM-Oryza rice growth model under different environmental conditions

This study conducted the global sensitivity analysis of the APSIM-Oryza rice growth model under eight climate conditions and two CO2 levels using the extended Fourier Amplitude Sensitivity Test method. Two output variables (i.e. total aboveground dry matter WAGT and dry weight of storage organs WSO) and twenty parameters were analyzed. The ±30% and ±50% perturbations of base values were used as the ranges of parameter variation, and local fertilization and irrigation managements were considered. Results showed that the influential parameters were the same under different environmental conditions, but their orders were often different. Climate conditions had obvious influence on the sensitivity index of several parameters (e.g. RGRLMX, WGRMX and SPGF). In particular, the sensitivity index of RGRLMX was larger under cold climate than under warm climate. Differences also exist for parameter sensitivity of early and late rice in the same site. The CO2 concentration did not have much influence on the results of sensitivity analysis. The range of parameter variation affected the stability of sensitivity analysis results, but the main conclusions were consistent between the results obtained from the ±30% perturbation and those obtained the ±50% perturbation in this study. Compared with existing studies, our study performed the sensitivity analysis of APSIM-Oryza under more environmental conditions, thereby providing more comprehensive insights into the model and its parameters.

Effects of late sowing on soybean yields and yield components in southwestern Japan

ABSTRACTSoybean production in southwestern Japan tends to be unstable owing to wet soils during the rainy season. Although late sowing after the rainy season can avoid excess water, information on its yield potential is limited. The objective of this study was to reveal the effect of late sowing on yields and yield components of new soybean cultivars developed for warm regions. The experiment was conducted in 2016 and 2017 in Fukuyama, Hiroshima, Japan. Upland fields converted from paddy fields with a subirrigation system were planted in June (normal) or July (late sparse or late dense). Lodging was prevented with a net. The effects of late sowing and dense treatment were analyzed in relation to solar radiation use. In 2016, differences in yield among cultivars and among environments were not significant. In 2017, yield was significantly reduced following late sparse sowing. The total aboveground dry matter at maturity was correlated with total solar radiation intercepted (r = 0.76) but not with radiation use efficiency (r = 0.47). Late sowing increased harvest index (HI) significantly from 0.464 to 0.571 in 2016 and from 0.524 to 0.585 in 2017, but density had no significant effect. The changes in HI were correlated with stem dry weight (r = −0.80 in 2016 and r = −0.79 in 2017) rather than seed yield (r = 0.08, n.s. in 2016 and r = 0.19, n.s. in 2017). Thus, under irrigation, late dense sowing might stabilize yield in southwestern Japan because of higher HI.Abbreviations: DM: dry matter; FOEAS: farm-oriented enhancing aquatic system; HI: harvest index; RUE: radiation use efficiency