Physiological Basis of Irrigation Scheduling for Seed Production in Egyptian Clover Syn. Berseem (Trifolium alexandrinum L.) Crop

A field experiment was conducted to find out the critical physiological stages of irrigation schedules inducing better growth, physiological efficiency and seed yield potential of berseem ( Trifolium alexandrinum L., Var. S-99-1). For this purpose eight irrigation treatments were made comprised of four treatments of three irrigation (W₁, W₂, W₃ and W₄), three treatments of four irrigation (W₅, W₇ and W₈) and one treatment of five irrigation (W₆) at various physiological stages i. e. regeneration, flower initiation, full bloom, seed initiation and advance seed development stage.
Thus based on the experimental results the physiological role of watering in berseem seed production could be discussed as:
With-holding of irrigation either at regeneration or at full bloom stage developed potential water stress in plants as indicated by high proline content of irrigation treatments — W₄, W₁ and W₇; and further brought out disturbance on the formation of carotene, synthesis of water soluble sugar and translocation of sugar towards reproductive organs during grain development stage. These stresses adversely affected the plant growth and flowering behaviour. The irrigation at seed initiation stage increased the seed yield. Continuous irrigation did not appear to be useful. Thus it can be concluded that irrigation at three critical physiological stages i. e. regeneration, full bloom and seed initiation was found to be essential for obtaining potential seed yield of berseem.     

Growth,Meat Yield,and Economic Responses of Broilers Provided Three- and Four-Phase Schedules Formulated to Moderate and High Nutrient Density During a Fifty-Six-Day Production Period

This study examined growth responses and meat yield of broilers provided a 3- or 4-phase feeding schedule formulated to moderate or high nutrient density. Four dietary treatments were implemented consisting of high or moderate nutrient density diets that were provided for the duration of 3 phases (1 to 17, 18 to 35, and 36 to 56 d) or 4 phases (1 to 17, 18 to 35, 36 to 46, and 47 to 56 d).Provision of a 3-phase schedule did not alter growth performance, meat yield, or diet cost per final BW. Broilers receiving high nutrient diets had improved growth rate and feed conversion from 1 to 35 d. In the 3-phase schedule, birds given the high nutrient density diets had advantages in BW gain and pectoralis minor breast weight. Market changes in meat prices impact differences in gross feeding margins between diets formulated to high or moderate nutrient density more than variation in diet cost.     

施肥水平和种植密度对甜玉米叶片叶绿素含量·果穗性状·产量的影响

[目的]探索适宜当地甜玉米高产栽培的优化组合。[方法]以真甜美6号为材料,施肥水平为主处理(处理A、B、C),种植密度为副处理(处理a、b、c),研究施肥水平、种植密度对甜玉米叶片叶绿素、果穗性状和产量的影响。其中,处理A为硝酸磷375kg/hm2,二铵300kg/hm2,油升1200kg/hm2;处理B为NPK三元复合肥750~825kg/hm2;处理C为二铵300kg/hm2,尿素300kg/hm2,草木灰1500kg/hm2;处理a、b、c分别为49500、52500、57500株/hm2。[结果]甜玉米叶片总叶绿素含量以处理Ab最高,其余依次为:处理Ca>处理Cb>处理Aa>处理Bb>处理Bc>处理Ac>处理Ba>处理Cc;叶绿素a/b比值大小顺序依次为:处理Ab>处理Cb>处理Ca>处理Bb>处理Cc>处理Ba>处理Bc>处理Ac>处理Aa。果穗性状以组合处理Ab最好,其次为处理Cb。甜玉米产量从高到低依次为:处理Cb>处理Ab>处理Cc>处理Bb>处理Ca>处理Aa>处理Ac>处理Bc>处理Ba。[结论]施肥水平对甜玉米产量的影响较种植密度大,适宜当地甜玉米高产栽培的优化组合为:施二铵300kg/hm2,尿素300kg/hm2,草木灰1500kg/hm2,种植密度52500株/hm2。     

施肥对苜蓿开花期叶面积及比叶重的影响

【研究目的】研究了不同施肥处理对3年生紫花苜蓿开花期叶面积、叶干重及比叶重的影响。【方法】用叶面积扫描仪测定苜蓿叶面积,在105℃下杀青,65℃下烘干24h,称取苜蓿叶干重,计算比叶重(SLW)。【结果】①氮、磷、钾单施或不同方式的配施均能增加苜蓿开花期叶面积和叶干重。其中以K40P60配施最有利于扩大苜蓿光合叶面积。以K40P40N10配施最有利于提高苜蓿开花期叶干重。②施氮,尤其是氮与磷配施能明显提高苜蓿开花期的比叶重,以P20N10配施效果最好。而单施磷(P20、P40、P60)、单施钾(K20、K40)或K20P20配施均不利于增加苜蓿开花期比叶重。【结论】①苜蓿施K40P60最有利于扩大开花期光合叶面积,增强光合作用。②施K40P40N10最有利于提高苜蓿开花期叶干重,从而有利于晒制干草。③施P20N10能明显提高苜蓿开花期比叶重,有助于苜蓿提高其光合速率,积累更多的光合产物。     

修剪施肥相结合对低产低效茶园茶叶品质的影响

[目的]研究修剪和施肥交互作用对低质低效茶园茶叶品质的影响,探讨修剪方式和施肥方式对低产低效茶园质量的提升作用。[方法]4种修剪方法分别为轻修剪、深修剪、重修剪和台刈,2种肥料分别为氨基酸肥和塔式生物肥,分析水浸出物、氨基酸、茶多酚、咖啡碱含量。[结果]轻修剪结合施用有机肥可提高茶叶水浸出物和茶多酚含量;重修剪结合施用有机肥可提高茶叶氨基酸含量,降低茶叶咖啡碱含量。[结论]该研究可为低产低效茶园茶叶的高产优质栽培提供参考。     

基于混合蛙跳算法的灌溉制度寻优应用研究

针对灌溉制度优化设计问题,以灌溉-产量灌溉制度模型为目标函数,随机生成灌溉制度,采用混合蛙跳算法对其进行优化,得到了最优灌溉制度。实例验证表明,混合蛙跳算法应用于灌溉制度寻优切实、可行,为灌溉制度寻优提供了一种新的方法。     

Evaluation of Mixed-Feeding Schedules with Varying Dietary Protein Content on the Growth Performance and Reduction of Cost of Production for Sutchi Catfish,Pangasius hypophthalmus (Sauvage) with Silver Carp,Hypophthalmichthys molitrix (Valenciennes)

Abstract

An on-station pond trial was conducted for 6 months to investigate the suitability of mixed-feeding schedules with varying protein levels on the growth of sutchi catfish, Pangasius hypophthalmuswith silver carp, Hypophthalmicthys molitrixwith a view to minimizing the cost of production. Five different feeding regimes employed were: high protein diet (30% protein, H), low protein (15% protein, L), one day low protein diet followed by one day high protein diet (1L/1H), 7 day low protein diet followed by 7 day high protein diet (7L/7H), and 14 day low protein diet followed by 14 day high protein diet (14L/14H). Ten experimental ponds each of 0.008 ha size were divided into 5 treatment groups each with two replicates. Fishes were stocked at the ratio of 80:20 (sutchi catfish:silver carp) at the total rate of 25,000/ha. Feeding rate was calculated only on the basis of sutchi catfish weight only and fish were fed at the rate of 15,10, 8, and 5% of their body weight for 1st, 2nd, 3rd months, and the rest of the experimental period, respectively. The ranges of water quality parameters during the study period were: temperature 22°C to 32.8°C, dissolved oxygen 4.30 to 7.44 mg/L, pH 6.85 to 7.50, and transparency 21.9 to 32.2 cm. The result of the study showed that significantly (P < 0.05) higher fish weight gain was achieved in feeding schedules of H and 1L/1H and lowest with 14L/14H. The feed conversion ratio (FCR) values ranged between 2.06 and 2.51 with H and 1L/1H showing significantly the best FCR. The FCR values were very low when weight of silver carp was considered which ranged between 1.58 and 1.68. The survival (%) of sutchi catfish were lower (78.1 to 82.5%) compared to that of silver carp (90–95%). The total production of sutchi catfish ranged between 3594 and 7095 kg/ha and silver carp ranged between 1777 and 2220 kg/ha. A simple economic analysis showed that fish in 1L/1H fed alternately with low and high protein diets resulted in the highest net profit. The result of the study suggest that for profitable sutchi catfish farming in Bangladesh, farmers can adopt a mixed-feeding schedule of alternated low and high protein diet instead of continuously feeding a high protein diet.     

宁夏干旱风沙草原区紫花苜蓿地下滴灌水肥耦合试验研究

针对宁夏干旱风沙草原区紫花苜蓿地下滴灌灌溉制度、水肥协同效应不明确的问题。通过田间试验,对不同水肥组合下地下滴灌紫花苜蓿株高、土壤水分、产量及水分生产效率等指标进行综合分析,结果表明,处理D11条件下地下滴灌紫花苜蓿生长状况较好。研究提出了宁夏干旱风沙草原区苜蓿地下滴灌水肥耦合灌溉制度为:灌溉定额为3150m3/hm^2,灌水次数为12次,施肥量N为90kg/hm^2、P2O5为126kg/hm^2、K2O为108kg/hm^2。     

氮肥不同施用时期对春玉米早衰的影响

采用盆栽试验研究氮肥不同施用时期下春玉米早衰特性。结果表明,合理的增加追肥次数能提高穗粒数和千粒重,进而提高玉米的籽粒产量。当氮肥分别在基施、拔节期与大喇叭口期1∶3∶1施用时,春玉米生育后期的穗叶叶绿素含量和SOD活性较一次性基施有不同程度的提高,而叶片形态指标和丙二醛(MDA)含量却降低,有效地延缓了玉米的衰老。对照(无氮肥)处理的穗叶叶绿体破裂解体,基粒和基质片层结构膨胀,导致叶片的叶绿素含量下降、光合能力降低而出现早衰。     

设施蔬菜生产节水灌溉制度研究现状及发展趋势

该文论述了节水灌溉对蔬菜生长发育的影响,评价了目前设施蔬菜生产过程中各种灌溉方式的特点和存在的问题。文中分析了设施栽培的耗水特点,指出一个良好的适于设施栽培的灌溉系统应具备的条件,在此基础上提出了对建立蔬菜生产优化灌溉制度的途径,并进行了初步的可行性分析。