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Development of semi-dwarf wheat (Triticum aestivum) and rice (Oryza sativa) led to increased yields and agronomic efficiencies with less lodging. While these short-stature cereals have become common in global crop production, commercial maize (Zea mays L.) hybrids remain tall. There is no information currently available on plant N uptake or yield responses to N timing for short stature maize hybrids. We tested three hypotheses on short-stature and tall maize hybrids 1) short-stature maize hybrids would have similar yield response to in-season N application compared to tall hybrids, 2) short-stature maize hybrids would have similar dry matter and N uptake patterns to tall hybrids, and 3) there would be significant partitioning differences between short-stature and tall hybrids in dry matter and N within the plants at multiple growth stages. In ten side-by-side field trials across eight site-years in the Midwestern USA, we tested the yield response and underlying nitrogen physiology of short-stature maize hybrids and tall comparators to split-rate N application. We show that split-rate application of 50% of the total N at mid-vegetative stages (V6) averaged 0.24 t ha−1 more grain yield across 10 field trials (positive yield response in 6 out of 10 trials) compared to a single 100% up-front N application, with the same pattern for short-stature and tall hybrids. In both hybrid statures, V6 N applications showed more frequent improvement in grain yield than V12 N applications. Total N uptake at maturity was not different between short-stature hybrids and their tall counterparts (p = 0.62). N partitioning differed between short-stature and tall hybrids; leaves in short-stature hybrids had 5% higher N concentration and 13% more N content in early vegetative development, stalks had 18–27% less dry matter and 5–25% less N content, depending on growth stage, while R1 ears averaged 18% more dry matter and N accumulation (p < 0.10 in all cases). At maturity short-stature hybrids had 4% higher harvest index and 3% higher N harvest index (p < 0.10). Based on these results, we expect that N management recommendations in short-stature maize hybrids would be similar to their tall counterparts, but that short stature mitigates logistical risk by providing more flexibility for in-season N applications. This study provides a unique, robust dataset on yield and physiological response to split-rate N treatments in commercially relevant maize hybrids. • Short stature in maize simplifies in-season N application and later crop management. • Split-rate N applications at V6 increased hybrid yields 60% of the time, with similar patterns for short-stature and tall hybrids. • Overall, short-stature maize yielded similarly to tall comparators. • Short stature led to greater partitioning of N and dry matter to the grain than tall hybrids. • Greater flexibility for in-season N fertilization in short-stature maize reduces in-season application risks. [ABSTRACT FROM AUTHOR]

It is not yet clear whether the carbon released from biochar in the soil solution stimulates biological activities. Soluble fractions (AQU) from wheat and maize biochars, whose molecular content was thoroughly characterized by FTIR, 13 C and 1 H NMR, and high-resolution ESI-IT-TOF-MS, were separated in dilute acidic solution to simulate soil rhizospheric conditions and their effects evaluated on maize seeds germination activity. Elongation of maize-seeds coleoptile was significantly promoted by maize biochar AQU, whereas it was inhibited by wheat biochar AQU. Both AQU fractions contained relatively small heterocyclic nitrogen compounds, whose structures were accounted by their spectroscopic properties. Point-of-Zero-Charge (PZC) values and van Krevelen plots of identified masses of soluble components suggested that the dissolved carbon from maize biochar behaved as humic-like supramolecular material capable to adhere to seedlings and deliver bioactive molecules. These findings contribute to understand the biostimulation potential of biochars from crop biomasses when applied in agricultural production. [ABSTRACT FROM AUTHOR]

Abstract: On sites where C4-plants have replaced C3-plants, changes in soil δ13C allow the turnover of C3- and C4-derived C to be separated. Studies of decadal scale turnover of soil C following conversion to C4-plants generally lack δ13C values for previous C4-residue inputs and assume that estimates of C4-derived soil C to be based on a fixed δ13C value. Further assumptions are that changes in the initial (time-zero) soil δ13C values are insignificant following conversion to C4-plants. We tested these assumptions by measuring: 1) the δ13C of annual samples of silage maize biomass (C4-plant) and winter wheat grains (C3-plant) grown during 1988 to 2006, and 2) the δ13C of soil kept under bare fallow during 1956 to 1983. The δ13C of plants was related to climate variables, and the impact of maize δ13C was based on estimates of maize-derived soil C using different approaches to establish the δ13C in maize inputs. The δ13C of both maize and wheat decreased with time, but the rate of change and annual variations were considerably larger for wheat than for maize. Maize as well as wheat δ13C was best related to year (probably reflecting a decrease in atmospheric δ13C) and the water balance during the active growth period. Using the smallest (−12.44‰) and the largest (−11.26‰) δ13C measured during 1988 and 2006, estimates of maize-derived C in soil after 18 years ranged from 13.2% to 14.2% of the soil total C. Despite a loss of 31% of the soil C pool under bare fallow, the increase in soil δ13C was significant only at P < 0.10. We conclude that annual variations in maize δ13C values and changes in the δ13C of the soil C fraction derived from the pre-conversion C3-vegetation have only little impact on estimates of maize-derived soil C that cover a few decades. For estimates covering several decades to centuries, the subtle but consistent changes in plant and soil δ13C need to be accounted for. The variability in δ13C in wheat grains suggest that the use of any fixed δ13C value for C3-residues in estimates of C turnover in soils on which C4-plants have been replaced by C3-plants can be associated with considerable uncertainty. [Copyright &y& Elsevier]

Abstract: Achieving high productivity using organic manure as a source of N offers new soil management possibilities in intensive agriculture. Our objective was to study the growth response of winter wheat (Triticum aestivum) to different fertilization regimes in long-term experiments in Japan. Semi-dwarf wheat varieties were grown in crop rotation with maize (Zea mays) with a high rate of organic manure (OM; 80tha−1 yr−1 for >10years, estimated N application rate is 739kgNha−1 yr−1), and standard (SF; 204–252kgNha−1 yr−1) or low (LF; 102–126kgNha−1 yr−1) rates of inorganic fertilizer for 3 years. We observed greater biomass production in OM than in SF or LF, which was attributable to a higher leaf area index, leaf N status, and stomatal conductance in OM. Grain yield in OM (6.6–8.9tha−1) was significantly higher than that in LF (3.5–6.6tha−1) for both cultivars, and comparable to that in SF (6.6–8.5tha−1). However, the dry matter partitioning during the grain-filling period suggested an imbalance in the sink–source relationship in OM: the number of grains was too large for the assimilation rate. Varietal differences in grain weight in OM resulted from differences in dry matter production during grain filling and, to a lesser extent, differences in grain density. The growth pattern of wheat under intensive manure application should be modified to favor biomass production during the post-anthesis stages. Based on our results, we discuss possible strategies for wheat improvement under high soil fertility in Japan. [ABSTRACT FROM AUTHOR]

Abstract: Production of hydrogen and syngas via gasification of the corn and wheat dry distiller grains (DDGS) with oxygen in a continuous downflow fixed bed micro reactor are studied in this paper. A series of experiments have been performed to investigate the effects of reaction time (15–45 min), reactor temperature (700–900 °C) and oxygen to nitrogen ratio (0.08–0.2 vol./vol.) on product gas composition, gas yield, low heating value (LHV) and carbon conversion efficiency. Over the ranges of the experimental conditions used, the results obtained seemed to suggest that for both biomasses the operating conditions were optimized for a gasification temperature around 900 °C, an oxygen to nitrogen ratio of 0.08 and a reaction time of 30 min, because a gas richer in hydrogen and carbon monoxide and poorer in carbon dioxide and hydrocarbons. The results showed that the product gas of corn DDGS gasification has higher H2 and CO concentrations (11 and 56.5%) than that of wheat DDGS gasification (10.5 and 51.5%). In addition gasification of corn DDGS resulted to higher gas yield (0.42 m3/kg), LHV (10.65 MJ/m3) and carbon conversion efficiency (44.2%). [Copyright &y& Elsevier]

Fenpyrazone is a novel 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide used for postemergence (POST) application to control annual monocotyledon and dicotyledon weeds in summer maize (Zea mays L.). Annual double-cropping systems are popular on the North China Plain, especially summer maize in rotation with winter wheat (Triticum aestivum L.) or garlic (Allium sativum L.). In addition, vegetable crops have shown different levels of sensitivity to HPPD-inhibiting herbicides that were applied to preceding maize fields. However, there is no information about the effects of fenpyrazone on the succeeding crops. Here, field experiments were conducted twice at Dawenkou and Mazhuang to evaluate the response of successive rotation crops such as winter wheat, garlic and spinach (Spinacia oleracea L.) to fenpyrazone that was applied to preceding summer maize fields. Compared with the untreated weed-free control, none of the fenpyrazone treatments resulted in significant differences in the emergence of wheat, garlic and spinach at either location. When fenpyrazone was applied at 3 times the recommended rate to the preceding maize fields, there was no significant reduction in the wheat and garlic biomass despite the height of the garlic plants being reduced by 4.1% at 20 d after sowing (DAS) compared to that of the untreated weed-free control. Compared with wheat and garlic, spinach was more sensitive to fenpyrazone applications to preceding summer maize fields, and it reduced the plant heights by 2.6–17.1% at 20 DAS compared to those in the untreated weed-free control, with the loam soil in Mazhuang causing a higher biomass reduction than the sandy loam soil in Dawenkou. However, the biomass reduction stopped at 40 DAS, and no yield reduction was observed at harvest for all the fenpyrazone treatments at both locations. Based on this study, farmers on the North China Plain can safely grow winter wheat, garlic and spinach following fenpyrazone POST application at the recommended rate to preceding summer maize. • Spinach was more sensitive to residue from QYC101, compared with wheat and garlic. • QYC101 residue caused higher biomass reduction in loam soil than sandy loam soil. • No yield reduction was observed for all QYC101 treatments in two types of soil. • Farmers can safely grow wheat, garlic and spinach following QYC101 POST application. [ABSTRACT FROM AUTHOR]

Crop residue is an abundant and lucrative biomass resource in China, which is expected to decrease its reliance on coal and petroleum through the use of crop residue. This study was conducted with the data of crop production released by the National Bureau of Statistics of China and 1417 valid face-to-face questionnaires on residue utilizations. It was found that the crop residue increased from 725.47 Mt in 2007 to 897.06 Mt in 2016 at the annual rate of 2.63%. It amounted for 897.06 Mt including 781.32 Mt field residue and 115.74 Mt and process residue, respectively in 2016. Field residue retained in field exhibited the highest ratio (35.19%), for bioenergy use was less than 1%. A total amount of available field residue (AFR) for bioethanol was 254.57 Mt in 2016. Maize provided the greatest quantity of AFR (95.00 Mt), followed by rice (78.90 Mt) and wheat (18.89 Mt), sum of three accounted for 76% AFR in China. The largest AFR was found in Heilongjiang (39.79 Mt), followed by Henan (31.03 Mt) and Jilin (22.51 Mt). The density of AFR exhibited high in NEC and CSC and southeast provinces of SWC. The bioethanol potential was 124.3 Mt in 2016, with maize, rice and wheat residues representing 77.8% of the total. The four top-ranked provinces of bioethanol potential were Heilongjiang, Henan, Jilin, and Sichuan. It was suggested that financial and taxation support are necessary to promote cellulosic bioethanol research and industrial use in its early stage. Image 1 • China's crop residue increased from 725.47 Mt in 2007 to 897.06 Mt in 2016. • Available residue of maize, rice, and wheat were shared 75.7% of total in 2016. • Field residue retained (35.19%) and burnt (25.20%) in the field were the highest. • Heilongjiang, Henan and Jilin produced the highest available residues with 93.3 Mt. • Bioethanol production potential from field residue was 124.3 Mt in total. [ABSTRACT FROM AUTHOR]