Effects of mechanized deep placement of nitrogen fertilizer rate and type on rice yield and nitrogen use efficiency in Chuanxi Plain,China

This paper investigates the yield and nitrogen use efficiency (NUE) of machine-transplanted rice cultivated using mechanized deep placement of N fertilizer in the rice–wheat rotation region of Chuanxi Plain, China. It provides theoretical support for N-saving and improves quality and production efficiency of machine-transplanted rice. Using a single-factor complete randomized block design in field experiments in 2018 and 2019, seven N-fertilization treatments were applied, with the fertilizer being surface broadcast and/or mechanically placed beside the seedlings at (5.5±0.5) cm soil depth when transplanting. The treatments were: N0, no N fertilizer; U1, 180 kg N ha^–1 as urea, surface broadcast manually before transplanting; U2, 108 kg N ha^–1 as urea, surface broadcast manually before transplanting, and 72 kg N ha^–1 as urea surface broadcast manually on the 10th d after transplanting, which is not only the local common fertilization method, but also the reference treatment; UD, 180 kg N ha^–1 as urea, mechanically deep-placed when transplanting; M1, 81.6 kg N ha^–1 as urea and 38.4 kg N ha^–1 as controlled-release urea (CRU), mechanically deep-placed when transplanting; M2, 102 kg N ha^–1 as urea and 48 kg N ha^–1 as CRU, mechanically deep-placed when transplanting; M3, 122.4 kg N ha^–1 as urea and 57.6 kg N ha^–1 as CRU, mechanically deep-placed when transplanting. The effects of the N fertilizer treatments on rice yield and NUE were consistent in the 2 yr. With a N application rate of 180 kg ha^–1, compared with U2, the N recovery efficiency (NRE), N agronomic use efficiency (NAE) and yield under the UD treatment were 20.6, 3.5 and 1.1% higher in 2018, and 4.6, 1.7 and 1.2% higher in 2019, respectively. Compared with urea alone (U1, U2 or UD), the NRE, NAE and yield achieved by M3 (combined application of urea and controlled-release urea) were higher by 9.2–73.3%, 18.6–61.5% and 6.5–16.5% (2018), and 22.2–65.2%, 25.6–75.0% and 5.9–13.9% (2019), respectively. Compared with M3, the lower-N treatments M1 and M2 significantly increased NRE by 4.0–7.8% in 2018 and 3.1–4.3% in 2019, respectively. Compared with urea surface application (U1 or U2), the yield under the M2 treatment was higher by 4.3–12.9% in 2018 and 3.6–10.1% in 2019, respectively. Compared with U2, the NRE and NAE under the M2 treatment was higher by 36.9 and 36.3% in 2018, and 33.2 and 37.4% in 2019, mainly because of higher N uptake. There was no significant difference in the concentration of nitrate in the top 0–20 cm soil under U1, U2 and M2 treatments during the full heading and maturity stages. During the full heading stage, U2 produced the highest concentration of nitrite in 0–20 cm and 20–40 cm soil among the N fertilizer treatments. In conclusion, mechanized deep placement of mixed urea and controlled-release urea (M2) at transplanting is a highly-efficient cultivation technology that enables increased yield of machine-transplanted rice and improved NUE, while reducing the amount of N-fertilization applied.     

Assembly and co-occurrence patterns of rare and abundant bacterial sub-communities in rice rhizosphere soil under short-term nitrogen deep placement

Nitrogen (N) deep placement has been found to reduce N leaching and increase N use efficiency in paddy fields. However, relatively little is known how bacterial consortia, especially abundant and rare taxa, respond to N deep placement, which is critical for understanding the biodiversity and function of agricultural ecosystem. In this study, Illumina sequencing and ecological models were conducted to examine the diversity patterns and underlying assembly mechanisms of abundant and rare taxa in rice rhizosphere soil under different N fertilization regimes at four rice growth stages in paddy fields. The results showed that abundant and rare bacteria had distinct distribution patterns in rhizosphere samples. Abundant bacteria showed ubiquitous distribution; while rare taxa exhibited uneven distribution across all samples. Stochastic processes dominated community assembly of both abundant and rare bacteria, with dispersal limitation playing a more vital role in abundant bacteria, and undominated processes playing a more important role in rare bacteria. The N deep placement was associated with a greater influence of dispersal limitation than the broadcast N fertilizer (BN) and no N fertilizer (NN) treatments in abundant and rare taxa of rhizosphere soil; while greater contributions from homogenizing dispersal were observed for BN and NN in rare taxa. Network analysis indicated that abundant taxa with closer relationships were usually more likely to occupy the central position of the network than rare taxa. Nevertheless, most of the keystone species were rare taxa and might have played essential roles in maintaining the network stability. Overall, these findings highlighted that the ecological mechanisms and co-occurrence patterns of abundant and rare bacteria in rhizosphere soil under N deep placement.     

夏玉米侧深种肥同播技术

播种是夏玉米生产的最关键技术环节,种肥同播技术一次作业完成多项任务,近年来得到推广应用。该项技术在应用过程中存在着肥害烧苗,增产效果达不到预期等问题。为解决诸类问题,提出了侧深玉米种肥同播技术。侧就是侧施肥,实现种肥分离,解决肥害烧苗问题。同时,5厘米的种肥距离是保证肥料就近供应的理想位置,达到防肥害、增肥效的优化布置。深的要求是深施肥,垂直方向上,肥料比种子要深5厘米以上。肥料就施在地表下8-10厘米的位置。满足玉米生长发育需求,随着养分溶解下渗,诱导根系向深层发育,促根壮秆。侧深种肥同播技术的关键就是选好品种,用好种子,以测深施肥为抓手,测土配方,单粒精播,提高播种质量,通过有害生物绿色防控,精细管理,实现肥效利用率高,产量高,品质好,收益高。     

USE OF CONTRAST-ENHANCED COMPUTED TOMOGRAPHY TO ASSESS ANGIOGENESIS IN DEEP DIGITAL FLEXOR TENDONOPATHY IN A HORSE

We compared contrast-enhanced computed tomography (CT) and high field magnetic resonance (MR) imaging in a horse with deep digital flexor tendonopathy. Lesions in the distal extremity were documented grossly and histopathologically. In contrast-enhanced CT, the deep digital flexor tendon lesions were markedly contrast enhancing with evidence of angiogenesis in the core and dorsal border lesions. The lesion morphology was clearly delineated on MR imaging, but without contrast media angiogenesis cannot be identified. Gross examination, histopathologic examination, and CD31 immunohistochemistry confirmed the tendonopathy and an increased presence of small blood vessels. In this horse, deep digital flexor tendon lesions appeared similarly on contrast-enhanced CT and MR imaging. Contrast-enhanced CT may be an alternative to MR imaging for assessing tendon and ligament injury in the digit of the horse.     

高效深栽造林钻孔机的研制与试验

荒漠化是当今世界威胁人类生存的重要问题,深栽造林技术可以有效提高干旱沙地造林成活率和保存率,所以高效深栽造林设备的研究就显得尤为重要。论文首先对国内外干旱沙地深栽造林方式及相关机具进行了综述比较,得出深栽造林钻孔机的造林成活率最高,但是造林效率还需要提高。在对工作环境进行了解的基础上,提出了深栽造林钻孔机的总体方案,以LH1630-2拖拉机为动力底盘,采用全液压驱动与控制的方式,完成了各个关键零部件的设计选型和样机的制作与装配,并在内蒙古林场进行了深栽造林钻孔实地试验。试验结果表明,深栽造林钻孔机钻孔过程比较顺畅,钻孔效率相比传统的单钻深栽造林钻孔机提高了约1倍,可达到180孔/h,钻孔直径为90 mm左右,钻孔最大深度可达1.7 m,钻孔间距可以在2.5~4 m之间调整,钻孔行距可以通过拖拉机的行驶在1~4 m之间调整,对于适合在本地区生长的杨树树种,深栽造林的成活率可达90%以上。研究结果可为深栽造林钻孔的设计和应用提供参考。     

Deep-water rice production as influenced by time and depth of flooding on the east coast of India

The saucer-shaped landform, high rainfall due to the south-west monsoon (June–September) and poor drainage conditions make certain parts of the east coast of India susceptible to waterlogging during the rainy season. There is no alternative other than to grow rice in the coastal lowlands, where surface water accumulation of 0.5–2.0 m occurs during the rainy season. In this study, the physical environments of a representative deep-water ecology were characterized and the performance of improved deep-water rice (DWR) varieties (Hangseswari, Saraswati, Ambika, Sabita) was compared with that of local varieties (Bankei, Dhalakartik) at three water depths (shallow flooded [0.6–0.8 m], medium flooded [0.8–1.2 m] and deep flooded [>1.2 m]). The rainfall–flooding depth relationship was also studied and the probability of successful crop production in relation to the time and depth of waterlogging was investigated, based on historical (34 years) flood data from the region. Among the varieties studied, ‘Hangseswari’ was found to have superior physiological traits for growth, development and production of grain yield and hence may be considered for inclusion in further DWR breeding programs. With the introduction of improved DWR varieties, productivity during the rainy season was enhanced and farmers received good yield (2.05–2.95 t ha^?1) and net return (4500 Rs ha^?1).     

GROWTH AND FRUIT QUALITY RESPONSES OF HYDROPONICALLY CULTIVATED EGGPLANTS TO MINERAL CONTROLLED DEEP SEA WATER

A suitable application of the deep seawater for high quality eggplant (Solanum melongena L.) production was examined on vegetative growth and fruit yield with special reference to qualities of fruits. Mineral controlled deep sea water was prepared by electrodialyzing deep sea water with a selective membrane cartridge for the exchange of monovalent ions. Eggplant plants variety ‘Ryoma’ were grown in the NFT system with the applications of 2% mineral controlled deep sea water to the standard nutrient solution (mineral controlled deep sea water treatment-MDST) under greenhouse condition with four replications. With the treatment eggplant had larger vegetative growth rate than with the control. Furthermore, MDST showed that total fruit yield and marketable fruit yield was 14% and 23% higher than the control. In this study, a new methodology to produce high quality eggplants enriched in sugar, minerals, and dry matter was demonstrated by applying the natural resource.     

Effect of placement of coated urea fertilizer on root growth and rubidium uptake activity in soybean plant

Abstract

We reported in the previous paper (Takahashi et al. 1991) that the deep placement of slow release N fertilizer (coated urea) contributed to a stable increase of soybean (Glycine max L. Merr.) yield. In the previous study we observed that the deep placement of coated urea did not depress appreciably the nitrogen fixation by root nodules although fertilizer N was efficiently utilized. We assumed that the N absorbed from the roots in the deep layers did not cause nodule senescence, contributed to the maintenance of the leaf activity during the maturation stage, and that the increase in the availability of carbohydrate and N improved seed production. In the current report the effects of placement of coated urea fertilizer on the root growth and activity were studied by measuring the root dry weight and Rb absorption activity.     

桃果深加工及其副产物综合利用研究进展

本文阐述了现阶段国内外主流桃果深加工制品的发展现状,分析了国内外对桃果果壳和桃仁等副产物的综合利用方式,并对我国桃产业发展前景进行了总结与展望。