利用叶龄诊断技术指导水稻施肥

施肥是水稻生产的重要环节,水稻施肥不当,是造成水稻贪青、倒伏、病害加重的重要因素之一。利用叶龄诊断技术指导水稻施肥,可有效避免上述现象的发生。介绍了叶龄诊断的一些相关指标、标准和相应的水稻长势长相,并提出了据此指导施肥的一些方法。     

西南稻区稻田肥力现状与施肥对策

在西南稻区的四川省、云南省、贵州省和重庆市实施了水稻农民习惯施肥技术与空白试验(不施肥)对比试验。结果表明,农民习惯施肥技术具有如下不足:一是水稻投入产出率低;二是肥料利用率低;三是大面积水稻产量不高,单产仅520.9 kg/667 m~2;四是水稻生产穗数不足。针对上述问题,笔者从提高水稻产量角度出发,提出了相应的施肥对策。     

寒地水稻侧深施肥技术研究

试验研究了侧深施肥技术对水稻茎蘖动态及产量的影响。结果表明,侧深施肥对水稻分蘖影响不明显,侧深施肥对水稻有一定的增产作用,三大肥测深施肥比常规施肥增产96kg／hm^2,奥宝肥侧深施肥较常规施肥增产126kg/hm^2。     

水稻抗倒伏施肥技术研究进展

倒伏是水稻生产中的一个严重问题,水稻茎秆倒伏严重影响水稻产量和稻谷品质,倒伏发生越早,损失越大。从施肥方法和肥料组成等方面,综述了防止水稻倒伏施肥技术研究进展,提出了有待拓宽和深化研究的内容。     

水稻测土配方施肥技术化验室建设及分析方法

水稻测土配方施肥技术化验室是实施水稻测土配方施肥项目的重要组成部分。辽宁省盐碱地利用研究所化验室经过自我完善,基本符合农业部《测土配方施肥技术规范》的要求,达到了水稻测土配方施肥项目的检测需要,并对基层检测部门进行示范、指导与帮助。为盘锦地区水稻测土配方施肥项目的进一步开展做出了应有的贡献。     

测土配方施肥对黑龙江省讷河市水稻生产的影响

本试验针对黑龙江省多数农民水稻生产施肥存在重氮、轻磷、忽视钾的现状,结合测土配方项目工程开展了水稻测土配方施肥研究。结果表明:与当地习惯施肥相比,应用测土配方施肥技术具有改善水稻主要经济性状、促进水稻健康生长,提高黑龙江省稻作区的水稻产量和产值,扣除投入成本,测土配方施肥比当地习惯施肥净增产值42.9～91.2元/667m2,平均74.3元/667 m2;较对照净增产值17.8～38.2元/667 m2,平均31.45元/667 m2。增加了种稻农民的经济收入。     

水稻测土配方施肥技术探讨

介绍了测土配方施肥的关键技术,探讨了水稻配方施肥技术,提出了高产水稻施肥参考模式,以期为该技术的推广应用提供参考。     

福建省水稻生产中存在的施肥问题及其对策初探

分析了福建省水稻生产中存在的施肥问题,提出了用测土配方施肥等方法来解决水稻生产中施肥问题的对策。     

水稻水气平衡栽培法适宜的施氮水平和施肥技术研究

为了探索水稻水气平衡栽培法中适宜的施氮水平和施肥技术,2011年早稻在广西北流市民乐镇民乐村进行了不同的施N水平(120,180,210和240 kg/hm2)和施肥技术(精确定量和常规施肥技术)对水稻农艺和经济性状的影响试验。结果表明:在水稻水气平衡栽培法中,每公顷施纯氮240 kg,氮、磷、钾比例为1.0∶0.5∶1.0,并采用水稻精确定量施肥技术增产效果最好。     

寒地水稻大中棚钵育摆栽超稀植栽培技术

阐述了甘南县2009年水稻生产现状及经济效益,和水稻大中棚育苗特点及建造,大中棚钵育苗技术及本田整地施肥插秧技术等。从甘南县水稻生产的实际情况出发,详细阐述了水稻生产中育苗技术、壮秧标准、苗床管理、本田整地与施肥和插秧技术要点等。     

Variation in Contents of Total Phenolics and Flavonoids and Antioxidant Activities in the Leaves of 11 <Emphasis Type="Italic">Eriobotrya</Emphasis> Species

Eriobotrya plants are known to have significant amounts of phenolics and flavonoids, and exhibit a strong antioxidant activity. Experiments were conducted to examine variation in the contents of total phenolics and flavonoids, and antioxidant activities in the leaves of 11 Eriobotrya species (Tibet loquat, Daduhe loquat, Hengchun loquat, Taiwan loquat, Oak leaf loquat, Bengal loquat, Fragrant loquat, Guangxi loquat, Obovate loquat, Big flower loquat, and common loquat, the last species include two materials, one is a cultivar ‘Zaozhong 6’, another is a wild tree). In these species, ‘Zaozhong 6′ loquat is a cultivar. The leaf extracts of ‘Tibet’, ‘Obovate’, ‘Taiwan’, ‘Bengal’ and ‘Hengchun’ loquats exhibited significantly higher contents of total flavonoids and total phenolics, compared with those of other species. Of these 11 species, the highest contents of total phenolics and total flavonoids were observed in ‘Tibet’ and ‘Obovatae’ loquats, respectively. The significantly stronger antioxidant abilities assessed by the DPPH radical scavenging activity and reducing power were obtained in the leaf extracts of ‘Taiwan’, ‘Tibet’, ‘Bengal’, ‘Oak leaf’, ‘Hengchun’ and ‘Obovate’ loquats, compared with the other species. In addition, significant correlations were found between the contents of total phenolics or flavonoids and DPPH radical scavenging activity/reducing power. This work indicates that the leaf extracts of the wild Eriobotrya species, ‘Tibet’, ‘Obovatae’, ‘Taiwan’, ‘Bengal’, ‘Oak leaf’ and ‘Hengchun’ loquats, exhibited significantly higher levels of total phenolics and flavonoids, and significantly stronger antioxidant activities, compared with the cultivated species, ‘Zaozhong 6′ loquat, which suggests that these wild species have a better utilization value.     

Quantifying the influence of sward height, concentrate level and initial milk yield on the milk production and grazing behaviour of continuously stocked dairy cows

Two factorial design experiments were carried out in the spring of 1994 and 1995, each of 6 weeks, to quantify the effects of sward height (SH), concentrate level (CL) and initial milk yield (IMY) on milk production and grazing behaviour of continuously stocked dairy cows. In Experiment 1, forty‐five Holstein Friesian cows were in five groups with initial milk yields of 16·9, 21·1, 28·0, 31·5 and 35·5 kg d^–1, grazed sward heights were 3–5, 5–7 and 7–9 cm (LSH, MSH and HSH respectively), and concentrates were fed at rates of 0, 3 and 6 kg d^–1. In Experiment 2, 48 cows were in two groups with IMY of 21·3 and 35·5 kg d^–1, grazed sward heights were 3–5 and 7–9 cm (LSH and HSH), and concentrates were fed at 0 and 6 kg d^–1 and ad libitum. Multiple regression models were used to quantify the effects of the three variables on milk yield persistency (MYP), estimated herbage dry‐matter (DM) intake (HDMI), grazing time (GT) and rate of DM intake (RI). The partial regression coefficients showed that increased SH led to increased MYP (Experiment 1 P < 0·001, Experiment 2 P < 0·05), increased HDMI (P < 0·01, P < 0·01), increased GT (P < 0·001, P < 0·05) and increased RI (P < 0·001, P < 0·05). Increasing CL led to increased MYP (NS, P < 0·001), decreased HDMI (P < 0·001, P < 0·001), decreased GT (NS, P < 0·001) and decreased RI (P < 0·001, P < 0·001). Higher IMY level of cows decreased MYP (P < 0·001, P < 0·001), increased HDMI (P < 0·001, P < 0·001), increased GT (P < 0·001, P < 0·05) and increased RI (P < 0·05, P < 0·01). The models were highly significant (P < 0·001), and accounted for 0·48–0·87 of the total variance. The partial regression coefficients quantified the extent to which GT and RI by cows respond positively to higher IMY, and negatively to increased CL, but respond differently (GT declines in response to a higher RI) with increasing SH.     

Inclination Angle Affects Ozone Injury in the Flag Leaf of Rice

Abstract

To evaluate the effect of inclination angle of the leaf on the leaf injury of rice by O₃, we examined the effect of a 5-hr exposure to 0, 0.1, 0.3 cm³ m-³ O₃, abbreviated as O⁰, O^0.1 and O^0.3, respectively, of the flag leaf using natural-light gas-exposure chambers. The middle portion of the flag leaf was set horizontally using lead weights (H plant) and it was compared with a non-treated, erect leaf (E plant). Gas exchange and chlorophyll fluorescence were measured immediately before, immediately after, and 1 and 3 d after the start of the exposure. The net photosynthetic rate, stomatal conductance and operating quantum efficiency of photosystem II (F_q’/F_m’) were decreased by the exposure to O₃. Furthermore, the inhibitory effects of O^0.1 and O^0.3 on the H plants were severer than those on the E plants. The maximum quantum efficiency of photosystem II (F_v/F_m) in the leaf of H plants decreased immediately after exposure to O₃. These results indicate that the weaker inhibitory effect of O₃ on the erect leaf depends on the lower light intensity at the leaf surface, rather than the horizontal leaf position.

Key words: Ascorbic acid, Chlorophyll fluorescence, Gas exchange, Leaf inclination angle, Oryza sativa, O₃, Quantum efficiency.     

Time-mortality relationships of larvae and adults of grain beetles exposed to extreme cold

Mortality effects of low temperature exposure to −16 °C were investigated on larvae and adults of the grain beetles Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae), Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) and Trogoderma granarium (Everts) (Coleoptera: Dermestidae), in the laboratory. The main effects and interactions of exposure time (0.2, 0.5, 1, 2, 4, 8, 12, 24 and 48 h), developmental stage (larva and adult) and individual’s age (young and old) were examined. After 4 h of exposure 100% mortality has been achieved in most of the treatments. The only exceptions were that of old larvae of T. granarium and O. surinamensis, and adults of T. granarium which needed 48, 8, and 24 h, respectively. T. granarium was the most cold-hardy species irrespective of developmental stage, and age, followed in decreasing order by O. surinamensis and T. confusum. Younger adults were generally more susceptible to cold in the cases of O. surinamensis and T. confusum. On the contrary, older adults of T. granarium suffered higher mortality than younger ones. Larvae of T. granarium were generally more cold-tolerant than adults but the opposite pattern was observed in O. surinamensis and T. confusum. Main effects of exposure time, developmental stage and individual’s age on mortality proved to be significant for all species, with the exception of T. granarium where the effect of developmental stage proved to be insignificant. Lethal time values were estimated via probit analysis. Values of LT₅₀ ranged between 0.7 and 1.0 h for T. confusum, 0.7-1.9 h for O. surinamensis and 1.2-3.4 h for T. granarium. Our results are discussed with findings from relevant studies and the possibility of including extreme cooling to IPM programs against stored product pests is investigated.     

Variability in physicochemical and nutritional quality traits of parents,F2 and F3 generations of lentil crosses

Ten physicochemical and nutritional quality traits (100-seedweight, seed volume, seed density, bulk density, hydrationcapacity, hydration index, swelling capacity, protein, tryptophanand energy value) were examined in the seed samples of parents,F₂ and F₃ generations of three microsperma ×microsperma and two microsperma × macrospermacrosses of lentils. Significant variation for different traits wasobserved among the genotypes in both the groups and also amongboth types of crosses in F₂ and F₃ generations. Ranges,means and coefficients of variation (CV %) for various traitsamong parents, F₂ and F₃ generations of different crosses,along with the deviations between F₂ and F₃ generationmeans for various traits in different crosses are discussed. Alsosuggested is a breeding strategy for evolving lentil varieties withimproved seed yield and nutritional quality parameters.     

Dissection of antioxidant activity of durum wheat (Triticum durum Desf.) grains as evaluated by the new LOX/RNO method

Antioxidant activity (AA) of durum wheat (Triticum durum Desf.) grains was studied using the innovative LOX/RNO method, able to simultaneously detect different antioxidant mechanisms, and the TEAC assay, one of the most widely used assays. Insoluble-bound and free-soluble phenols, hydrophilic and lipophilic compounds were extracted from eight different whole flour samples; extracts were analyzed for AA and their content in several antioxidants. The LOX/RNO method measured very high AA values, with the highest ones [850–1500 μmol Trolox eq./g whole flour (dry weight)] for insoluble-bound phenolic extracts, highly correlated to total phenolic (r = 0.761, P < 0.001) and ferulic acid (r = 0.816, P < 0.001) contents. Hydrophilic and lipophilic extracts showed lower AA [70-140 and 40–60 μmol Trolox eq./g (dry weight), respectively], highly correlated to flavonoid (r = 0.583, P < 0.01) and protein (r = 0.602, P < 0.01), as well as β-tocotrienol (r = 0.684, P < 0.05) contents, respectively. Interestingly, the LOX/RNO method suggests that insoluble-bound phenolic compounds may exert very strong synergistic interactions within the extract. Contrarily, the TEAC assay did not correlate to any antioxidant content, resulted unable to highlight differences among samples, measured much lower AA values and did not suggest synergism. The use of the LOX/RNO method is useful to unearth new properties of phytochemicals from durum wheat grains, potentially giving health benefits.     

Plant growth and survival of five introduced and two native/naturalized perennial grass genotypes exposed to two defoliation managements in arid Argentina

The field performance of the native Pappophorum vaginatum, the naturalized Eragrostis curvula and various cultivars of the introduced Achnatherum hymenoides and Leymus cinereus was evaluated as potential forage resources in rangelands of arid Argentina during the warm seasons of 2007/2008 and 2008/2009. Plants of these grass species, obtained from seeds, were transplanted to the field in 2006, when they were 1 year old. During the study years, there were two defoliation managements: plants of all study genotypes either remained undefoliated (controls) or were defoliated twice a year during spring at 5 cm stubble height. Despite tiller number being lower (P < 0·05) on defoliated than on undefoliated plants, and total leaf length per unit basal area being similar (P > 0·05) between defoliation managements by mid‐spring, there were no differences (P > 0·05) in dry weight production between defoliated and undefoliated plants in all genotypes at the end of the second growing season. Plants of one or more of the introduced genotypes showed a similar (P > 0·05) or greater (P < 0·05), but not lower, tiller number per plant and per square centimetre, daughter tiller production, total leaf length and dry weight production per unit basal area than the native species at the end of the first and/or second growing seasons. These morphological variables were similar (P > 0·05) or greater (P < 0·05) in the native than in the naturalized genotype. Plant survival, however, was lower (P < 0·05, overall mean = 20%) in the introduced than in the native (>70%) or naturalized (>39%) genotypes at the end of the first or second growing seasons.     

Unsaponifiable lipids from haulm and tuber sprouts of potato (Solanum tuberosum L.)

Summary Fractions containing Δ⁵- and Δ⁷-sterols, 4-methyl-sterols, triterpenic alcohols, tocopherols and hydrocarbons were isolated by TLC from petroleum ether extracts of the haulm and tuber sprouts of cv Désirée. Sterol and triterpenic alcohol fractions of unsaponifiable lipids of the haulm and tuber sprouts were found to contain twelve sterols and four triterpenic alcohols, respectively. 24R-4-stigmasten-3-on, Δ⁷, Δ⁷, lanosterol, cycloeucalenol and obtisufoliol have not been identified previously in unsaponifiable lipids from haulm and sprouts. In the hydrocarbon fractions of the haulm extract, C₂₃-to C₃₃-n-parafins, C₁₉-and C₃₁-cyclohexyl hydrocarbons, C₂₂-to C₃₈-olefins and squalene were identified, and in the hydrocarbon fractions of the tuber sprouts C₁₂-to C₂₆-olefins and squalene were identified.