Forage Mineral Concentrations and Mineral Status of Beef Cattle Grazing Cool Season Pastures in Northwestern Florida,Emphasizing Magnesium

A 68‐day study was conducted in North Florida to evaluate forage and beef cattle serum, liver, and urine mineral concentrations, emphasizing magnesium (Mg). Forty‐two Angus, Brangus, and Romosinuano cows in early lactation were divided into two groups and placed on ryegrass or oat pasture. Samples were collected every 2 weeks except for liver biopsies, which were collected only on day 68. Mineral concentrations were determined for forage, plasma, urine, and liver samples. All forage mineral concentrations except Mg, calcium (Ca), copper (Cu), cobalt (Co), selenium (Se), and zinc (Zn) were greater than critical levels for a beef cow in lactation. Forage Mg and Cu were severely deficient in both oats and ryegrass. All blood plasma mineral levels were greater than critical levels, but plasma Mg was borderline to slightly deficient. There should be special attention given to Mg supplementation because forages are deficient and contain excess potassium (K).     

Quantifying the cool island effects of urban green spaces using remote sensing Data

Urban Heat Island (UHI) leads to increased energy consumption, aggravated pollution and threatened health of citizens. Urban green spaces mitigate UHI effects, however, it is still unclear how the green space characteristics and its surrounding environment affects the green space cool island (GCI). In this study, land surface temperature (LST) and land cover types within the outmost ring road of Shanghai, China were obtained from Landsat 8 data and high-resolution Google Earth data. The GCI effects were defined in three aspects: GCI range (GR), amplitude of temperature drop (TA) and temperature gradient (TG). Pearson correlation analysis was processed to get the relationship between the aspects and impact factors. The results indicated that the GCI principle could be explained by the thermal conduct theory. The efficient methods to decrease LST of green spaces include increasing green space area while staying below the threshold, adding complexity of green space shape, decreasing impervious surfaces and enlarging the area of water bodies. For the surrounding environment of the green spaces, increasing vegetation and water body fractions or decreasing impervious surfaces will help to strengthen GCI effects. The findings can help urban planners to understand GCI formation and design cool green spaces to mitigate UHI effects.     

滇中温凉坝子啤酒大麦氮磷钾肥效应研究

在滇中温凉坝子冲积性水稻土上,采用通用旋转回归设计方法,研究N,P和K对啤酒大麦产量的影响以及供试肥料间的相互关系。根据试验结果,建立了以啤酒大麦为目标的回归模型。应用回归模型可预报啤酒大麦产量,也可根据产量目标确定施肥量。在目前条件下当氮肥施用量大于180kg/hm^2,P2O5用量为120kg/hm^2,啤酒大麦获得4000kg/hm^2以上产量的可能性较大;当施纯氮315.0kg,P2O5191.4kg/hm^2时,啤酒大麦可获得59996kg/hm^2的最高产量。     

洋葱茎基盘腐烂病药剂田间筛选试验

为了解决甘肃河西地区洋葱茎基盘腐烂病发病重、药剂防效差的问题,本试验选取7种药剂,在移栽时进行蘸根处理,观测分析不同药剂处理对洋葱植株成活率、生育期、防治效果和产量的影响。结果表明,1%申嗪霉素悬浮剂500倍液蘸根处理对洋葱茎基盘腐烂病防治效果较好,植株成活率达到90%以上,定植后30 d的防治效果为80.89%,57 d的防治效果为64.45%,产量为7029.85 kg/667 m²,增产率达到26.77%。在洋葱定植时可以使用该药剂进行蘸根处理,57 d内对茎基盘腐烂病的防治效果较好,且减少了农药的施用量,为甘肃河西高海拔冷凉区洋葱绿色优质生产提供了技术方法。     

冷季型草坪的建植与养护管理

冷季型草坪是我国北方地区广泛栽培的草坪植被。着重介绍了冷季型草坪的建植和管理技术 ,主要从草种与品种选择、场地准备、建坪方法、苗期管理和成坪后管理等方面进行了论述。为我国北方地区建植草坪提供参考依据 ,更重要的是与国际现代化大都市草坪绿地质量相接轨     

多种冷季型草坪草种混播试验

采用4因素3水平正交组合试验，对早熟禾、高羊茅、多年生黑麦草不同播种量、种间配合比例进行了混播试验，观测成坪期、成坪时的成坪率以及当年和3年的盖度，并对草坪草质进行综合评价，结果表明：影响成坪速度、保存盖度的主要因素是草种的配合比例，影响草坪质量的主要因素是早熟禾种间配合比值。具体表现为高羊茅比值高成坪速度快，保存盖度大；早熟禾比值大，草坪质量好，表现性状稳定。提出以播种量15g/m^2，早熟禾、高羊茅、黑麦草重量比值为5：3：2的效果较为理想，重要景区草坪可适当增加早熟禾比例，以增强草坪的观赏效果。     

The effects of clipping height and frequency on net primary production of Andropogon gerardii (C4 grass) and Bromus inermis (C3 grass) in greenhouse experiments

There are potential agronomic and environmental benefits from incorporating warm‐season (C₄) grasses into temperate pasture systems, usually dominated by cool‐season (C₃) grasses, but there is a lack of information on how frequency and height of defoliation affects C₄ grasses. Three greenhouse experiments were conducted under (i) spring, (ii) summer and (iii) spring + summer clipping regimes. In each experiment, the effects of clipping frequency (weekly and monthly) and clipping height (clipped to 5 and 10 cm) were determined on above‐ and below‐ground net primary production (ANPP and BNPP) and total and seasonal dry matter (DM) yield for Andropogon gerardii Vitman (big bluestem, C₄ grass) and Bromus inermis Leyss (smooth brome, C₃ grass). Six replicates per treatment were used. In all experiments, ANPP and BNPP of smooth brome was greater than that of big bluestem although during late summer months big bluestem had higher DM yields of herbage than smooth brome. There were different effects of frequency and height of clipping for both species on two similar measurements: total annual DM yield and ANPP, indicating that the ability to generalize about the effects of defoliation from ecological and agronomic grassland standpoints is questionable. Clipping effects on ANPP and BNPP were different for summer‐clipped pots than for spring, and spring + summer‐clipped pots, indicating that management could be tailored to meet specific agronomic or conservation goals.     

Tillering and Yield of Rice Cultivars under a Water Storage-Type Deep-Irrigation Regime

Abstract

This study aimed to clarify the effects of water storage-type deep irrigation (WSDI) on the yields of various rice cultivars used in the Tohoku district of Japan. We compared a WSDI plot (DP) with a standard irrigation plot (SP) with regard to the growth, yield, and yield components of the rice cultivars grown in these plots during 4 years (2002–2005) in Sendai, Japan. In 2003, which had a cool summer, the yields in DP were considerably higher than those in SP, thus confirming that WSDI mitigated the cool summer-induced damage to rice. The yields in DP were not lower than those in SP during the other 3 years (normal climatic years), indicating that various cultivars could adapt to WSDI. Although high-yielding rice plants cultivated by well-experienced farmers under deep-water irrigation regimes have large panicles, the spikelet number per panicle and the yield in DP were not higher than those in SP. Based on the results of the comparison between the cultivation system of WSDI and that of high-yielding deep-water irrigation regimes practiced by such farmers, we speculated that to achieve a higher yield under WSDI, other cultivation techniques need to be incorporated into WSDI.     

河西走廊城区冷地型草坪杂草危害及防除

经过2年时间,对河西走廊城区的草坪杂草种类进行了调查统计,查清了河西走廊城区草坪杂草种类和发生规律.结果表明,常见草坪杂草有36种,隶属于18个科,篇蓄Polygonum aviculare,荠菜Capsellabursa-panis,刺儿菜Cepholanoplos segetun,车前Plantago asiatica,独行Lepidium apetalam,顶羽菊Acroptilon repens,反枝苋Amaranthus retroflexdus最为常见.4月下旬至6月下旬为杂草发生高峰期.草坪杂草可通过土壤处理、化学药剂处理茎叶、人工拔除来防治.     

气象条件对西北温凉半湿润区马铃薯块茎形成及产量的影响

利用西北温凉半湿润区马铃薯生长发育定位观测资料、加密观测和对应平行气象观测资料,应用农业气象统计分析方法,分析马铃薯块茎生长与气象条件的关系。结果表明：研究区域马铃薯播种到可收约需150～168d,需≥0℃积温2000～2300℃·d,降水量400～500mm,日照时数900～1100h;马铃薯在播种后第105天开始,块茎由缓慢生长转为迅速生长阶段,在播种后的第127天,块茎生长速度最大,播种后第149天开始,块茎生长从迅速生长又转为缓慢生长。气温对马铃薯产量形成除采收期外,均为负效应,块茎膨大期对气温变化十分敏感;降水量的影响函数同热量的影响函数呈反相位分布,除出苗期和采收期为负效应外,其余时段降水量对马铃薯产量形成均为正效应,马铃薯分枝-开花期对降水量变化十分敏感。