Compared Phosphorus Efficiency in Soybean,Sunflower and Maize

ABSTRACT

A more comprehensive understanding of the mechanisms of phosphorus (P) efficiency is agronomically significant to advance in the design of crop management schemes that increase P efficiency and reduce the need of fertilizers. Phosphorus efficiency is defined as the ability of a plant to acquire P from the soil and/or to utilize it in the production of biomass or the harvestable organ. Because most parameters related to P efficiency vary according to the growth conditions and isolation of the individual effect of P efficiency is not straightforward; plants must be grown in uniform experimental conditions to obtain a fair comparison of their nutrient acquisition and utilization. In this work, we compare the ability of soybean, sunflower, and maize to utilize and acquire soil P. Field and greenhouse experiments including different P levels were conducted. The general observation was that the three species ranked differently according to the specific parameter of P efficiency considered. Maize clearly showed higher P utilization efficiency than soybean and sunflower, either expressed as biomass or as grain produced per unit of absorbed P. In turn, soybean and sunflower exhibited higher acquisition efficiency than maize. Soybean showed the shallowest root system: 69% of the total root length was concentrated in the top 20 cm of the soil. Phosphorus uptake per unit root length was rather similar among the three species, but soybean and sunflower had higher P uptake per unit of root weight. This can be explained by the higher specific root length (SRL) and specific root area (SRA) of both dicots. For example, SRL averaged 59, 94, and 34 m g^?1 in field grown soybean, sunflower, and maize, respectively. The more favorable root morphology determined that soybean and sunflower can explore more soil with the same belowground biomass and absorb more P per unit of carbon invested belowground. Since the three species exhibited similar values of P uptake per unit root length, we hypothesize that the capacity of each segment of root to deplete soil P fractions is similar.     

Distribution of free oxides along soil profiles in time series of dry rice fields in polder lands of Kojima-basin

The distributions of free oxides along profiles of some dry rice fields were set forth in the previous reports²,³,⁴,⁶⁾, In this paper, the distribution of free oxides in dry rice field⁵⁾ in polder lands of Kojima-Basin, Okayama pref. is reported. Localities, years elapsed since the planting of rice began in each field and the characteristic of soil profiles are given in Table 1. All the fields are dry rice fields except Soil A, and carry barley or wheat in winter season. Parent materials are similar in all horizons of all soils and rich in fine particles. Fine sands (0.2-0.02 mm) are mainly composed of quartz somewhat accompanied with feldspars, mica, augite and amphibolite. Clays (< 0.002 mm) are mainly composed of halloysite accompanied with a small proportion of montmorillonite. The structure develops well in all the soils.     

山东广翅蜡蝉在青岛地区的发生规律及产卵习性

为明确山东广翅蜡蝉Ricania shantungensis Chou et Lu在青岛地区的发生情况,于2017年4月至2018年12月,采用踏查法调查该虫在山东省青岛市的寄主范围,并采用套网袋和定点观察相结合的方法调查其年生活史及成虫产卵习性。结果表明,山东广翅蜡蝉在青岛地区的寄主有27种,其中木本植物25种,草本植物2种。山东广翅蜡蝉在青岛地区1年发生2代,以卵越冬,翌年春天5月初孵化,越冬代成虫发生期为7月1日至8月10日;第1代成虫发生期为9月23日至12月4日。第1、2代卵的高峰期分别出现于7月25日和10月30日。成虫产卵对黄栌Cotinus coggygria Scop.具有明显的嗜好性,且喜将越冬卵产在东向和南向枝条上,不仅可产卵于新生嫩枝,也可以产卵于叶片主脉。本研究结果可以为青岛乃至山东地区山东广翅蜡蝉防治提供依据。     

寒地早粳杂交稻光温反应鉴定研究

经连续３年对８９份综合性状表现较好的杂交稻组合、骨干亲本和当地主栽常规稻品种的光温反应进行鉴定研究，初步明确了寒地早粳杂交组合的光温反应型，主要取决于亲本之一的恢复系，两者之间是极显著的正相关。且呈显性遗传。     

Impact of rainfed and irrigated agriculture systems on soil carbon stock under different climate scenarios in the semi-arid region of Brazil

Understanding the dynamics of soil organic carbon (SOC) is of fundamental importance in land use and management, whether in the current researches or in future scenarios of agriculture systems considering climate change. In order to evaluate SOC stock of the three districts (Delmiro Gouveia, Pariconha, and Inhapi districts) in the semi-arid region of Brazil in rainfed and irrigated agriculture systems under different climate scenarios using the Century model, we obtained RCP4.5 and RCP8.5 climate scenarios derived from the Eta Regional Climate Model (Eta-HadGEM2-ES and Eta-MIROC5) from the National Institute for Space Research, and then input the data of bulk density, pH, soil texture, maximum temperature, minimum temperature, and rainfall into the soil and climate files of the Century model. The results of this study showed that the Eta-HadGEM2-ES model was effective in estimating air temperature in the future period. In rainfed agriculture system, SOC stock under the baseline scenario was lower than that under RCP4.5 and RCP8.5 climate scenarios, while in irrigated agriculture system, SOC stock in the almost all climate scenarios (RCP4.5 and RCP8.5) and models (Eta-HadGEM2-ES and Eta-MIROC5) will increase by 2100. The results of this study will help producers in the semi-arid region of Brazil adopt specific agriculture systems aimed at mitigating greenhouse gas emissions.     

两种产地藏羊肉挥发性风味物质和脂肪酸组成比较研究

为评定不同地区藏羊肉的挥发性风味物质和脂肪酸组成,选取甘肃省甘南藏族自治州和青海省海北藏族自治州的藏羊各20只,分别取背最长肌进行肉品质、脂肪酸以及挥发性成分组成、感官评价等指标的测定。结果表明,两种产地的藏羊宰后pH45min和pH24h均在正常范围内,且二者之间无显著性差异;甘南藏羊的色泽和嫩度优于海北藏羊;共检测出18种脂肪酸,其中包括7种饱和脂肪酸和11种不饱和脂肪酸。两种产地藏羊肉的脂肪酸组成和含量均存在显著差异,甘南藏羊脂肪酸组成比例更佳,ω-6/ω-3接近1∶1,显著低于海北藏羊（P<0.05）。共检测出12类70种挥发性风味物质,气味活性值（OAV）分析结果表明,甘南藏羊肉比海北藏羊肉具有更丰富的肉脂香味和果香味。综上,甘南藏羊肉的脂肪酸和挥发性成分组成都更加优异,感官评分更高。     

Plant community characteristics and their relationships with climate in the Hexi Corridor region of northwestern China

Species, coverage, density, appearance, important values and above ground biomass of desert plant communities in the Hexi Corridor region in northwestern China were investigated. Data on the meteorological factors at the investigation sites were collected. Their relationships were statistically analyzed. The results show that the composition of plant species and total density in the Hexi Corridor region are positively correlated with elevation and longitude, but negatively with latitude. The relation decreases from the southeast to the northwest in this region. In the desert regions with an accumulated temperature of >10°C greater than 3200°C, the shrubs, including semi-shrubs, occupy dominant positions in the communities. Their importance values reach 100. When the accumulated temperature is about 3000°C, the communities are often in some type of transition, either with herbage being the dominant species, with some semishrubs or shrubs as companion species, or the dominant species being semi-shrubs with some perennial herbage as companion species. In desert communities with an annual precipitation of over 110 mm, the main life forms of plants are semi-shrubs or perennial herbs. When precipitation is less than 110 mm, the main life forms of the vegetation are dwarf shrub or annual herbs. In the extreme arid regions with annual precipitation of around 50 mm in the northwestern part of the Hexi Corridor, barely some annual herbage come to life during the rainy season. Desert ecosystems consist of sparse vegetation with small biomass. They change with climate factors and are especially sensitive to precipitation, which is particularly important for their conservation. __________ Translated from Acta Botanica Boreali-Occidentalia Sinica, 2007, 27(5): 859–863 [译自: 西北植物学报]     

四川南部杂交水稻植株体内氮素来源分析

以宜香1577和II优838为材料,在四川南部地区根据不同水稻品种植株一生需氮量和土壤供氮能力对杂交水稻生产中的氮肥用量进行分析.结果表明,从播种到成熟过程中,不同水稻品种植株体内氮含量不断增加,一直处于吸氮过程.四川南部地区杂交水稻生产中所需氮肥除化肥供给外,土壤也能提供比较丰富的氮素养料.四川南部土壤营养成分十分丰富,供氮能力极强,适合于水稻等耐肥农作物的生产.在杂交水稻生产过程中,施氮肥水平不应设计太高,必须将土壤供氮这一因素考虑进去,以免因氮肥过量而倒伏和减产.     

南北盘江地区水土流失危害与防治对策

阐述了南北盘江地区的基本情况、水土流失现状及水土流失带来的各种危害。在此基础上,提出了具体的防治对策。     

江淮丘陵易旱地区棉花节本高效综合栽培技术规范

针对安徽省江淮丘陵地区土层瘠薄 ,涵养水肥能力弱 ,多灾易旱 ,大部分地区植棉技术水平低 ,管理粗放 ,棉花单产低 ,植棉效益不高等状况 ,开展了以棉花节本、高效为中心 ,进行包括棉花品种筛选、简化栽培、抗旱节水栽培、平衡施肥、病虫草害综合防治技术等研究 ,最后将研究成果与已有技术组装配套 ,建立了以简化栽培、抗旱节水栽培为主体的节本高效的综合栽培技术体系 ,根据该体系提出了江淮丘陵地区棉花节本高效的综合栽培技术规范