Yield performance of spring wheat improved by regulated deficit irrigation in an arid area

A field experiment was conducted in 2003 and 2004 growing seasons to evaluate the effects of regulated deficit irrigation on yield performance in spring wheat (Triticum aestivum) in an arid area. Three regulated deficit irrigation treatments designed to subject the crops to various degrees of soil water deficit at different stages of crop development and a no-soil-water-deficit control was established. Soil moisture was measured gravimetrically in the increment of 0–20 cm every five to seven days in the given growth periods, while that in 20 increments to 40, 40–60, 60–80, and 80–100 cm depth measured by neutron probe. Compared to the no-soil-water-deficit treatment, grain yield, biomass, harvest index, water use efficiency (WUE), and water supply use efficiency (WsUE) in spring wheat were all greatly improved by 16.6–25.0, 12.4–19.2, 23.5–27.3, 32.7–39.9, and 44.6–58.8% under regulated deficit irrigation, and better yield components such as thousand-grain weight, grain weight per spike, number of grain, length of spike, and fertile spikelet number were also obtained, but irrigation water was substantially decreased by 14.0–22.9%. The patterns of soil moisture were similar in the regulated deficit treatments, and the soil moisture contents were greatly decreased by regulated deficit irrigation during wheat growing seasons. Significant differences were found between the no-soil-water-deficit treatment and the regulated soil water deficit treatments in grain yield, yield components, biomass, harvest index, WUE, and WsUE, but no significant differences occurred within the regulated soil water deficit treatments. Yield performance proved that regulated deficit irrigation treatment subjected to medium soil water deficit both during the middle vegetative stage (jointing) and the late reproductive stages (filling and maturity or filling) while subjected to no-soil-water-deficit both during the late vegetative stage (booting) and the early reproductive stage (heading) (MNNM) had the highest yield increase of 25.0 and 14.0% of significant water-saving, therefore, the optimum controlled soil water deficit levels in this study should range 50–60% of field water capacity (FWC) at the middle vegetative growth period (jointing), and 65–70% of FWC at both of the late vegetative period (booting) and early reproductive period (heading) followed by 50–60% of FWC at the late reproductive periods (the end of filling or filling and maturity) in treatment MNNM, with the corresponding optimum total irrigation water of 338 mm. In addition, the relationships among grain yield, biomass, and harvest index, the relationship between grain yield and WUE, WsUE, and the relationship between harvest index and WUE, WsUE under regulated deficit irrigation were also estimated through linear or non-linear regression models, which indicate that the highest grain yield was associated with the maximum biomass, harvest index, and water supply use efficiency, but not with the highest water use efficiency, which was reached by appropriate controlling soil moisture content and water consumption. The relations also indicate that the harvest index was associated with the maximum biomass and water supply use efficiency, but not with the highest water use efficiency.     

Water-use efficiency of dwarf-green coconut (Cocos nucifera L.) orchards in northeast Brazil

Field experiments were conducted in a tropical region to determine the water-use efficiency (WUE), yield (Y) and evapotranspiration (ET) of a 6-year-old dwarf-green coconut (Cocos nucifera L.) orchard. Three water levels were applied in plots with nine palms. The irrigation treatments denoted as T:50, T:100 and T:150 received 50, 100 and 150 L/plant/day, respectively. The actual evapotranspiration was obtained by the soil water balance (SWB) method. Yield and water-use efficiency were assessed in terms of bunches per plant, fruits per plant and water volume per fruit. The application of the SWB resulted in mean daily ET values of 2.5; 2.9 and 3.2 mm/day for irrigation treatment of T:50, T:100 and T:150, respectively, while the cumulative ET varied from 900 to 1100 mm as irrigation treatment increased from T:50 to T:150. Results also showed that ET values were higher in the beginning and end of the year and lower in the middle of the experimental period. The application of a high irrigation water volume does not necessarily resulted in high coconut fruits yield. Evapotranspiration, fruits yield and water-use efficiency were strongly affected by irrigation water volume in coconut palms. WUE values decreased with increasing irrigation water level for all productivity parameters.     

春小麦调亏灌溉对土壤氮磷钾的影响

对河西绿洲灌区春小麦调亏灌溉2年后的土壤碱解氮和全氮、速效磷和全磷、速效钾和全钾进行了研究,并对土壤养分年际间的差异进行了分析,旨在为该区春小麦调亏灌溉对土壤氮磷钾养分的影响研究提供一些可靠的信息。     

Effects of different soil conservation tillage approaches on soil nutrients,water use and wheat-maize yield in rainfed dry-land regions of North China

Excessive tillage compromises soil quality by causing severe water shortages that can lead to crop failure. Reports on the effects of conservation tillage on major soil nutrients, water use efficiency and gain yield in wheat (Triticum aestivum L.) and maize (Zea mays L.) in rainfed regions in the North China Plain are relatively scarce. In this work, four tillage approaches were tested from 2004 to 2012 in a randomized study performed in triplicate: one conventional tillage and three conservation tillage experiments with straw mulching (no tillage during wheat and maize seasons, subsoiling during the maize season but no tillage during the wheat season, and ridge planting during both wheat and maize seasons). Compared with conventional tillage, by 2012, eight years of conservation tillage treatments (no tillage, subsoiling and ridge planting) resulted in a significant increase in available phosphorus in topsoil (0–0.20 m), by 3.8%, 37.8% and 36.9%, respectively. Soil available potassium was also increased following conservation tillage, by 13.6%, 37.5% and 25.0%, and soil organic matter by 0.17%, 5.65% and 4.77%, while soil total nitrogen was altered by −2.33%, 4.21% and 1.74%, respectively. Meanwhile, all three conservation tillage approaches increased water use efficiency, by 19.1–28.4% (average 24.6%), 10.1–23.8% (average 15.9%) and 11.2–20.7% (average 15.7%) in wheat, maize and annual, respectively. Additionally, wheat yield was increased by 7.9–12.0% (average 10.3%), maize yield by 13.4–24.6% (average 17.4%) and rotation annual yield by 12.3–16.9% (average 14.1%). Overall, our findings demonstrate that subsoiling and ridge planting with straw mulching performed better than conventional tillage for enhancing major soil nutrients and improving grain yield and water use efficiency in rainfed regions in the North China Plain.     

玉米高直链淀粉基因ae的特异性PCR鉴定

根据ae基因序列设计21对引物,对4个常规玉米自交系和4个具有aeae纯合基因型的高直链淀粉玉米自交系及其杂交种进行特异性PCR鉴定。结果表明,引物8可将具有AeAe基因型的普通玉米自交系与具有aeae基因型高直链淀粉玉米区分开来,为将普通玉米自交系快速改良成高直链淀粉玉米自交系提供了一种有效的分子标记检测技术。     

Yield and water consumption characteristics of wheat/maize intercropping with reduced tillage in an Oasis region

Higher irrigation quota for conventional farming causes substantial conflicts between water supply and demand in agriculture, and wind erosion near soil surface is one of the major causes of farmland degradation and desertification in arid areas. This research investigated the effect of the amounts of irrigation in combination with tillage practices on soil evaporation (E), water consumption (ET) characteristics, and grain yield performance and water use efficiency (WUE) for wheat (Triticum aestivum L.) intercropped with maize (Zea mays L.) in strip planting in an Oasis region. The field experiment, conducted at Wuwei station during 2008–2010, had two tillage systems (reduced tillage with wheat stubble retention vs. conventional tillage without stubble retention), and three (low, medium, and high) levels of irrigation, in a randomized complete block design. Averaged across three years, soil evaporation with medium and high levels of irrigation was 6.8% and 5.4% greater than that with low level of irrigation, respectively. Total water consumption of wheat/maize crops under the medium and high irrigation levels was 8.5% and 18.5% greater, respectively, than that under low irrigation. However, grain yields were similar under the medium and high levels of irrigation, so was WUE. The effect of tillage on the wheat/maize intercropping was inconsistent across years or among treatments: soil moisture at harvest was 3.0–7.6% greater in the fields with reduced tillage compared with those with conventional tillage in 2008 and 2009, but no difference was found in 2010; the E/ET ratio of reduced tillage was 9% lower than the ratio under conventional tillage in 2008, 3% higher in 2010, but no difference between the two tillage systems in 2009. Across three years, there was a general trend that the WUE of the wheat/maize intercropping system with reduced tillage was greater (by 4–11%) than that with conventional tillage. We conclude that a medium level of irrigation is sufficient to achieve crop yields and WUE equivalent to those under high level of irrigation, provided that a reduced tillage practice is applied to the wheat/maize intercropping in Oasis areas.     

春小麦高蛋白品系F93-486主要性状的遗传研究

以高蛋白品系Ｆ９３－４８６为母本，武春１号和陇春８号为父本组配了２个组合，在每个组合中获得Ｐ１、Ｐ２、Ｆ１、Ｆ２、Ｂ１和Ｂ２６个群体，并以此为供试材料对Ｆ９３－４８６的蛋白质含量，角质率等性状的遗传规律进行了研究。     

Ability of different plant species to promote microbiological processes in semiarid soil

In semiarid climate soils, the establishment of a plant cover is fundamental to avoid degradation and desertification processes. A better understanding of the ability of plants to promote soil microbial processes in these conditions is necessary for successful soil reclamation. Six different plant species were planted in a semiarid soil, in order to know which species are the most effective for the reclamation of semiarid areas. Six years after planting, the rhizosphere soils were studied by measuring chemical (pH, electrical conductivity, total organic carbon and other carbon fractions), physical (% of saggregates), microbiological (microbial biomass carbon and soil respiration), and biochemical (dehydrogenase, phosphatase, β-glucosidase and urease activities) parameters. In general, in all the soil–plant systems plant nutrients, organic matter and microbial activity increased compared to the control soil. For some species, such as Rhamnus lycioides, the increase in the total organic carbon content (TOC) in the rhizosphere zone was almost 200%. A positive correlation was found between TOC and water-soluble carbon (p<0.001); both parameters were negatively correlated with electrical conductivity. Microbial biomass carbon and soil respiration were highest in the rhizosphere of Stipa tenacissima (98% and 60%, respectively, of increase on soil control values) and Rosmarinus officinalis (94% and 51%, respectively, of increase on soil control values). These microbiological parameters were correlated with the percentage of stable aggregates (p<0.01). Enzyme activities were affected by the rhizosphere, their values depending on the shrub species.     

不同密度和施肥量对党参品质及其病害程度的效应研究

针对影响党参等级、浸出物、农残、重金属和病害率的栽植密度和施肥量二因素,采用2因素8水平3重复随机区组法进行研究。结果表明,一等品比例较小且集中于60万株/hm2处理;二等品所占比例最大的是90万株/hm2和360 kg/hm2组合。二等品总额中,施肥量相同条件下,所占比例大小顺序是60万株/hm2＞90万株/hm2＞75万株/hm2＞105万株/hm2处理;所有产品以三等品为主;浸出物全部高于标准值,大于70.0%的有4个组合;在密度相同条件下,As、Cu含量最大值基本都在360 kg/hm2施肥量下产生;Pb最大值则在0施肥下产生;Cd基本都趋近于0.01%;Hg含量规律性不强。根病害率最低的是75万株/hm2和360 kg/hm2组合,为1.48%。密度和施肥量科学合理的配置不仅对品质有重要意义,而且也有助于提高商品性。     

温度与土壤水分对玉米种子萌发及幼苗生长特性的影响

以沈单16、豫玉22为试验材料,研究不同温度、土壤水分对玉米种子萌发及幼苗生长特性的影响.结果表明,随温度与土壤水分的下降种子发芽势、发芽率均呈降低趋势.温度与土壤水分对幼苗生长各指标的影响不同,玉米芽鞘长、幼苗长、贮藏物质转运率和叶绿素含量均随温度与土壤含水量的降低而减小;过氧化物酶活性、脯氨酸含量呈先增加后降低的趋势.在环境温度低于15℃恒温条件下,玉米种子发芽率迅速降低,土壤含水量低于10％时种子不能正常萌发;在15℃及以下低温,土壤含水量低于10％时玉米幼苗生长受到抑制.持续性低温、干旱胁迫不利于玉米种子的正常萌发与幼苗的生长.