Response of grain yield and related agronomic traits of oilseed flax to diversified cropping rotations北大核心CSCD

This research aimed to identify a suitable planting pattern for oilseed flax production in a dry-farming region. A long-term field experiment was started in 2012 with a 4-year crop rotation cycle,designed to measure the effects on flax crop performance of previous crop,and various patterns of flax planting interval within the four-year rotation,compared with continuous flax cropping. Crop parameters measured included plant height,stem diameter,dry matter accumulation and distribution,and the experiment included six different crop rotation patterns：Flax→flax →flax→flax［（F）FFF］;Flax→wheat→potato→flax［（F）WPF］;Flax→potato→flax→wheat［（F）PFW］;Flax→ flax→wheat→potato［（F）FWP］;Flax→wheat→flax→potato［（F）WFP］and flax→wheat→potato→wheat［（F）WPW］. Results for the ninth year showed significantly increased grain yield（29. 89%-109. 57%）in crop rotation treatments compared with continuous cropping of oilseed flax. The ranking of the six tested rotations for yield was：（F）WPW>（F）FWP>（F）WFP>（F）PFW>（F）WPF>（F）FFF. The grain yield of oilseed flax was significantly affected by previous crop,frequency and years interval of flax cropping and number of years of continuous flax cropping. Yield was increased by 54. 45%-59. 29% under wheat stubble and potato stubble compared with oilseed flax stubble,and increased by 30. 66% and 109. 57%,respectively,under 50% and 25% frequencies,compared with 100% frequency. The grain yield of oilseed flax under two-year continuous cropping was higher by 29. 89% than four-year continuous cropping,and increased with increase in years interval between flax crops. Correlation analysis identified a significantly positive correlation between oilseed flax grain yield and effective capsule number,branch number and 1000-seed weight. The effective capsule number,branch number and 1000-seed weight of oilseed flax under rotation treatment were increased by 35. 88%-108. 91%,15. 47%-46. 19% and 14. 61%-16. 34%,respectively（P<0. 05）,compared with continuous cropping. In addition,the high grain yield of oilseed flax was accompanied by an increase in plant height,stem diameter and dry matter accumulation and these increases were,respectively,5. 11%-42. 24%,2. 77%-39. 92% and 31. 25%-117. 89% under the rotation regimes,compared with continuous cropping. Reduction in the number of years of continuous cropping years,change of crop stubble,decreased flax planting frequency and increased of interval between flax crops also improved flax crop performance. In summary,crop rotation improved the vigor of oilseed flax,resulting in greater plant height and stem diameter,improved dry matter accumulation and distribution,leading to increased branch number,effective capsule number and 1000-seed weight,and increase in the crop yield of oilseed flax. The results indicated that a multiple-crop rotation pattern was an effective way to avoid the yield reduction caused by continuous cropping in oilseed flax. The rotation： Flax→wheat→potato→wheat performed best among those tested and can be recommended as an appropriate cropping rotation for oilseed flax production in the dry region of northwest China. © 2022 Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

猪粪干、湿法厌氧发酵过程中碳、氮的流失

试验以新鲜猪粪为发酵原料,研究湿法和干法两种不同厌氧发酵过程的碳、氮排放量。湿发酵和干发酵组发酵料液的总固体(TS)含量分别为8%和20%,发酵液pH为6.8~7.4,发酵温度为35℃,体积为1.2 L,周期为21 d。试验期间每天测产气量,每4天取发酵样,测其全氮含量和TS降解率。结果表明,湿法和干法发酵组的CH4总产气量分别为9114 mL和12537 mL;CO2的总产气量分别为251.90 mmol和343.67 mmol;TS降解率分别为52.5%和29%。湿发酵的碳流失率和全氮流失率极显著高于干发酵(P<0.05)。     

施肥和覆盖模式对旱地冬小麦花后干物质转移、糖代谢及其籽粒产量的影响

选择不同的施肥(无机+有机)和覆盖模式,2012-2015年在典型的西北半干旱雨养农业区甘肃省农业科学院小麦研究所清水试验站进行大田试验,研究不同施肥+覆盖模式对旱地冬小麦干物质转移、糖代谢及其籽粒产量的影响,并分析糖含量与产量、物质转移之间的相关关系。结果表明,比较对照T₁(不施任何肥料),不同的施肥+覆盖模式均不同程度地提高了籽粒产量,依次为高量化肥+有机肥(T₆)>等量化肥+有机肥(T₄)>高量化肥+地膜覆盖(T₅)>等量化肥+地膜覆盖(T₃)>常规化肥(T₂)>不施肥(T₁)。增施有机肥(T₄、T₆)提高后期干物质转移量、转移比率、贡献率,增加粒重,并保证较高的有效成穗,从而增加籽粒产量,处理T₆、T₄分别比对照T₁增产119.22%和118.24%。地膜覆盖(T₃、T₅)增加了花后不同时期叶片、茎秆、叶鞘、颖壳干物质累积量和单穗粒数,为籽粒产量的提高奠定了基础。相反,地膜覆盖(T₃、T₅)降低干物质转移比率和贡献率。增施氮肥(T₃~T₆)提高了叶片干物质累积量,但过多的氮肥不利于籽粒增重,并降低了干物质转移比率和贡献率。不同的施肥+覆盖模式(T₂~T₆)降低了灌浆中前期(10、20 d )各个营养器官可溶性糖和蔗糖含量,延缓了前期叶片和叶鞘可溶性糖和蔗糖下降的速度,叶片、茎秆、叶鞘、颖壳可溶性糖含量下降最快的时期均在花后30~40 d,籽粒在花后10~20 d。相关分析表明,产量、株高、单位面积穗数、穗长、旗叶面积均与中前期(花后10、20 d)叶片、茎秆、叶鞘可溶性糖和蔗糖含量呈极显著和显著负相关。本研究结果证实,在甘肃旱地雨养农业区,结合有机肥施用(T₄、T₆),适当增加氮、磷用量完全能达到地膜覆盖对籽粒产量的增加,是更为持续、稳产的旱地小麦栽培模式。     

饮水中添加湿态发酵蛋白饲料提高奶牛产奶量试验

湿态发酵蛋白饲料是玉米经酵母发酵、提取酒精后,又经益生菌发酵、密封包装的产物,其可溶性好、易消化、易吸收、蛋白质含量高。通过对奶牛进行饲喂试验可知,奶牛日添加4kg该饲料,单产可提高2.18kg,每头牛日增利润2.03元,增产效果好,经济效益显著;另外,研究还发现,日添加4kg该饲料对乳成分无显著影响。     

Effects of feeding roasted safflower seeds (variety IL-111) and fish oil on dry matter intake, performance and milk fatty acid profiles in dairy cattle

Safflower seed has the highest concentration of linoleic acid among 80 oilseeds but little information exists on the effective use of SS for lactation cows. It was hypothesised that a diet supplemented with an Iranian SS variety (IL-111) in combination with fish oil (FO) would result in higher concentrations of trans-18:1 (including vaccenic acid) and conjugated linoleic acids in milk fat than feeding an unsupplemented control diet. Our objective was to determine the effects of feeding diets containing: (i) Control: (C); (ii) 25 g of roasted SS IL-111 (RSS); (iii) 20 g FO and (iv) 25 g RSS + 10 g FO (RSS + FO) per kilogram of dietary DM on feed intake, ruminal fermentation, milk production and fatty acid profile. Eight multiparous Holstein cows were used in a replicated 4 × 4 Latin square design study. The experiment had four periods of 21 days. Milk Fat percentage was lower (p < 0.01) with FO supplementation and averaged 19.0 and 21.5 g/kg milk with FO and RSS + FO compared with 30.3 and 32.5 g/kg with C and RSS. Feed intake also was lower (p < 0.01) with FO vs. C (23.1 vs. 24.5 kg/day) but feeding RSS resulted in greater feed intake compared with other treatments (26 kg/day). Despite lower feed intake with FO, milk production did not change from controls but feeding RSS + FO resulted in greater milk yield than controls (42.6 vs. 39.3 kg/day). Ruminal pH was greater (p < 0.01) in cows fed FO than other treatments. Supplemental FO alone or in combination with RSS resulted in dramatic increases (p < 0.01) in c9,t11-18:2 in milk fat (12.7 and 13.2 g/day vs. 5.8 and 7.02 with C and RSS). It was surprising to note that 25 g/kg RSS can improve feed intake.     

干热胁迫对紫花苜蓿形态特征及光合色素含量的影响

以6个紫花苜蓿品种为试验材料,采用盆栽并放入人工气候箱内干热胁迫处理下研究其土壤相对含水量、叶片长度、宽度、相对高度、绝对高度、茎粗等形态特征和类胡萝卜素、叶绿素含量等方面的变化规律。结果表明,随着干热胁迫的加剧,紫花苜蓿土壤相对含水量、叶片长度、叶片宽度、植株茎粗、叶绿素含量整体呈下降趋势,胁迫第12d与第4d相比,土壤相对含水量下降了64.82%,叶片长度下降了23.85%,叶片宽度下降了23.05%,植株茎粗下降了5.96%,叶绿素含量下降了12.70%;而相对株高、绝对株高、类胡萝卜素含量呈整体上升趋势,胁迫第12d与第4d相比,相对株高上升了1.61%,绝对株高上升了0.72%,类胡萝卜素含量上升了14.63%。各干热胁迫处理与其对照相比,干热胁迫对紫花苜蓿土壤相对含水量、株高、叶绿素含量和类胡萝卜素含量影响较为显著(P0.05)。     

The long-term effects of fire regime on primary production of montane grasslands in South Africa

Natural grasslands deliver essential ecosystem services through plant production, which enhances water supply, nutrient cycling, soil retention and greenhouse gas mitigation. Although the condition of montane grasslands for provision of ecosystem services is maintained by regular annual or biennial burning, controversy exists over the impact of different frequencies and seasons of burning on grassland productivity. The objective of this study was to determine the long-term effects of different burning regimes on primary production and quality of the montane grasslands of the KwaZulu-Natal Drakensberg. There were no significant differences in the mean standing live mass between 30 years of annual winter and biennial spring burning. However, in unburnt areas productivity was 20% lower (118.2?g m?2) than in regularly burnt grassland (144.7–154.5?g m?2). Crude protein did not vary between the annual winter and biennial spring treatments (95–113?kg ha?1), but was significantly lower in unburned areas (45?kg ha^?1). However, an infrequent fire in a protected area caused a temporary spike in crude protein (16%) compared with regular burning (5–10%), which can benefit wildlife. We conclude that montane grasslands can be burnt annually or biennially in the dormant season to promote long-term productivity.     

喷雾干燥技术制备饲用乳酸菌微胶囊制剂的研究进展

乳酸菌微胶囊技术是将核心菌体包覆于胃不溶、肠溶性的安全、特殊壁材中,可增加菌体对不良环境(胃液、胆盐等)的抵抗力,使其顺利到达肠道以发挥益生作用,且利于储存、加工和运输。利用喷雾干燥技术进行微胶囊制备具有包被速率快、生产成本低、适用于连续化生产等优点,但由于其存在较高进出口风温度及快速脱水过程,对于饲用乳酸菌的微胶囊制备在壁材物质及制备参数等方面具有严格的要求。为此,作者从工艺过程、壁材选择、工艺参数选择及其产品效果分析等方面,对近年来喷雾干燥技术在乳酸菌微胶囊制备方面进行了综述,以期为推动乳酸菌微胶囊制剂的研制及其在动物生产中的应用提供依据。     

放牧强度和放牧时间对牦牛干物质采食量及其表观消化率的影响

垂穗披碱草/星星草混播草地3个放牧季节的牦牛放牧试验结果表明:放牧强度和放牧时间对牦牛采食量均有极显著的影响(P<0.01),在放牧期内,牦牛干物质的采食量随放牧强度的增加而减小,而且随放牧时间的延续,各放牧区牦牛的干物质采食量均在8月5-20日达到最大;放牧强度对牦牛粪干物质的影响极显著(P<0.01),而放牧时间(季节变化)对它的影响不显著(P>0.05);极轻度和轻度放牧区牦牛干物质的消化率均在7月20日-8月5日达到最大,而中度和重度放牧区均在8月20日-9月5日达到最大。     

Effects of variety, cropping year, location and fertilizer application on nutritive value of durum wheat straw

This study was carried out to assess the effects of variety, year, location and level of fertilizer application on chemical composition and in sacco dry matter (DM) degradability of durum wheat straw as well as to understand the relationship between straw quality and agronomic traits of the crop and to assess the possibilities of selecting wheat varieties that combine high grain yield with desirable straw quality. Two local (Arendeto and Tikur sinde) and two improved (Boohai and Gerardo) varieties of durum wheat (Triticum turgidum Desf.) were used in the experiment. The four varieties were grown at two locations (Akaki and Ejere) in the years 2001/2002 and 2002/2003 in 5 x 5 m plots in three replications. Diammonium phosphate and urea fertilizers were applied at four levels (0/0, 32/23, 41/23 and 64/46 kg/ha of nitrogen/phosphorus). Straw quality was assessed based on chemical composition and in sacco DM degradability. Correlation of straw quality with grain and straw yield and with other agronomic characteristics of the crop was determined. The potential utility index (a measure that integrates grain and digestible straw yield) was used for ranking of the varieties. The local varieties had higher crude protein (CP) and lower neutral detergent fibre contents and higher digestibility than the improved varieties. The cropping year and location had significant effect on CP content and degradability of the straw, which could be due to climatic variation. However, the fertilizer level did not have any significant effect on straw quality except that the CP content of the straw tended to increase with increasing level of fertilizer application. Based on the potential utility index the varieties ranked, in a decreasing order, as Tikur sinde > Arendeto > Gerardo > Boohai and the ranking was consistent across years and locations. Except the CP content, straw quality was not negatively correlated with grain and straw yield. This indicates that there is a possibility of selecting varieties of wheat that combine high grain and straw yield with desirable straw quality.