滴水量对新大豆27号根系生长及产量的影响

为揭示滴水量对超高产大豆根系生长的影响规律,设置975 m3·hm-2(W1)、1 575 m3·hm-2(W2)、2175 m3·hm-2(W3)、2 775 m3·hm-2(W4)4种滴水处理,对各处理0~100 cm土层含水量、新大豆27号根系干重、侧根长和产量进行测定分析。结果表明:随着滴水量的增加,0~40 cm土层的含水量增加;0~20 cm土层根干重密度和侧根长密度增幅最大,20~40 cm土层增幅其次;增加生育中后期0~80 cm土层总根干重和总侧根长,鼓粒初期W2、W3、W4处理的根干重分别较W1增加14.2%、30.4%、41.1%,侧根长分别较W1增加17.4%、25.7%、40.3%;提高0~40 cm土层根系活力,增加根系伤流量,提高水分利用效率,W3、W4鼓粒初期0~80 cm土层根干重分别为88.6、95.8 g·m-2,侧根长为432.4~482.9 m·m-2,产量分别为6 082.6 kg·hm-2、6 404.7 kg·hm-2,水分利用效率为1.30左右。新疆伊宁地区大豆的适宜滴水量为2 175~2 775 m3·hm-2。     

连作对新疆绿洲棉田土壤微生物数量及酶活性的影响

对新疆绿洲棉田不同连作年限棉花根际土壤微生物数量、酶活性及土壤理化性质进行研究,结果表明:(1)随着连作年限的延长,细菌数量呈现先增加后减少的趋势,真菌数量则一直在增加,放线菌趋势不明显,说明新疆绿洲棉田土壤在连作一定年限后,棉田土壤由细菌型向真菌型转变;(2)脲酶和蛋白酶活性随连作年限增加表现出先增加后减少趋势;蔗糖酶、多酚氧化酶和过氧化氢酶活性与连作年限关系不明显;(3)对微生物数量、土壤酶和土壤理化性质的相关性分析表明,脲酶和蛋白酶与细菌数量呈现良好的正相关性,其中脲酶的相关性最好,呈极显著水平(ρ＜0.01),蛋白酶呈显著水平(ρ＜0.05);土壤酶与放线菌和真菌之间没有明显的相关性;细菌数量与有机质、全氮和速效氮之间呈显著正相关,与总盐含量呈显著负相关.     

花生不同施钙量、密度对产量影响的裂区试验

探讨不同施钙量、不同播种密度对花生产量的影响,为生产上提供施用钙肥与合理播种密度的理论依据。采用两因素裂区试验,A(施钙量)因素为主处理,设有4个水平,即:A1为0石灰/hm2、A2为300kg石灰/hm2、A3为600kg石灰/hm2、A4为900kg石灰/hm2;B(播种密度)因素为副处理,设有4个水平,即:B124万粒/hm2、B228.5万粒/hm2、B331.5万粒/hm2、B436万粒/hm2;3次重复。实验结果表明:施用300石灰/hm2、播种密度28.5万粒/hm2,可获得较高产量,达到3202.83 kg/hm2和最高的净收入,达到11531.16元/hm2。     

Comparison of collagen content, distribution and architecture among the pectoralis, iliotibialis lateralis and puboischiofemoralis muscles with different myofiber composition in Silky cocks

The total amount of collagen, the relative distributions of types I and III collagens in perimysium and endomysium, and the collagen fiber architecture were compared among the pectoralis (PT), iliotibialis lateralis (ITL) and puboischiofemoralis (PIF) muscles in Silky cocks. All of the myofibers in the PT muscle were type IIB, the myofibers in the ITL muscle were divided into type IIA, 41.7% and IIB, 58.3%, and the PIF muscle was composed of type I, 24.6%; IIA, 64.6%; and transitional, 10.8%. The total amount of collagen differed significantly among the PT (2.92 mg/g), PIF (4.20 mg/g) and ITL (8.06 mg/g) material, where only the PIF was a whole muscle with epimysium. On the image analysis of the immunohistochemical preparations, the percentage area of perimysial collagen to the total area in each type differed significantly among the PIF, PT and ITL muscles, where it was 26.8, 50.0 and 74.4% for the type I collagen and 27.4, 32.9 and 61.7% for the type III collagen, respectively. In the scanning electron micrography of the perimysium in macerated preparations, thick bundles of collagen fibers were observed in the ITL muscle, thinner but broad platelets in the PT muscle, and a coarse tissue of thinner collagen fibers in the PIF muscle. However, the endomysial fabric of collagen fibrils was similar among the muscles. Small, transverse collagen fibers, which branched off from the thicker perimysia, occupied narrow interendomysial spaces and separated the primary myofiber fasciculi. The results indicate that the ITL muscle, localized in the distorted and overextended part of the leg and subject to strong external forces, had highly developed perimysial collagen fiber bundles, but the ITL endomysial collagen architecture was similar to that of the PT and PIF muscles.     

风沙土玉米钾肥适宜用量的研究

田间试验结果表明:在吉林省西部风沙土上,施用钾肥对玉米有明显的增产效果。施用K2O 75kg/hm2,相对增产值为23.6%,化肥利用率达31.7%,千粒重和穗粒数最高,为最佳用量。     

Influence of amount and frequency of protein supplementation to ruminants consuming low-quality cool-season forages: efficiency of nitrogen utilization in lambs and performance of gestating beef cows

We evaluated the influence of amount and crude protein (CP) supplementation frequency (SF) on nitrogen (N) use by wethers and the performance of late-gestation beef cows. In exp. 1, seven Western whiteface wethers (31.8 ± 1.4 kg) were used in an incomplete 7 × 4 Latin square to evaluate intake and N use. Wethers received one of the seven treatments in a 2 × 3 factorial design containing two levels of supplemental soybean meal offered at a rate of 100% (F) or 50% (H; 50% of F) of the estimated CP requirement daily, once every 5, or once every 10 d, plus a non-supplemented control (CON). Low-quality cool-season forage (4.9 % CP; dry matter [DM] basis) was provided daily for ad libitum intake. Experimental periods lasted 30 d. In exp. 2, 84 Angus × Hereford cows (560 ± 35 kg) were stratified by age, body condition score (BCS), and expected calving date and allocated to 1 of the 21 feedlot pens (three pens per treatment). Pens were randomly assigned to receive the same treatments as in exp. 1 and cows had free access to low-quality cool-season forage (2.9% CP; DM basis). Cow body weight (BW) and BCS were measured every 14 d until calving and within 24 h after calving. In exp. 1, supplementation did not alter total DM and organic matter (OM) intake (P ≥ 0.26), but both parameters linearly decreased as SF decreased (P = 0.02). Supplementation increased DM, OM, and neutral detergent fiber (NDF) digestibility (P ≤ 0.02). Additionally, F feeding linearly increased DM, OM, and NDF digestibility as SF decreased (P ≤ 0.04). Digestibility of N, N balance, and digested N retained were greater with supplementation (P < 0.01), and N digestibility linearly increased as SF decreased (P = 0.01). Mean plasma urea-N concentration was not only greater (P < 0.01) for supplemented vs. CON wethers but also greater (P = 0.03) for F vs. H. In exp. 2, pre-calving BCS change was greater (P = 0.03) for supplemented cows. A linear effect of SF × supplementation rate for pre-calving BCS change was noted (P = 0.05), as F-supplemented cows lost more BCS compared with H as SF decreased. When considering supplementation intervals greater than 5 d, reducing the quantity of supplement provided, compared with daily supplementation, may be a feasible management strategy to maintain acceptable nutrient use and animal performance while reducing supplement and labor costs.     

施氮量和种植密度对中油杂11产量的影响

研究结果表明,随着栽培密度的增加,中油杂11冬前绿叶数、最大叶叶面积、有效分枝数、有效角果数、千粒重等呈下降趋势.该品种在中等肥力水平下的适宜种植密度为每公顷12万株.随着施氮量的增加,其有效分枝数、有效角果数、千粒重、产量呈先上升后下降的趋势,在种植密度为每公顷12万株、施氮量为150kg的条件下可获得最高产量.     

祁连山东段六种灌丛降雨再分配特征

基于2018 年6?9 月野外采集的数据,采用野外观测与统计分析相结合的方法,研究了祁连山天祝地区金强河流域典型灌丛:山生柳(Salix oritrepha)、硬叶柳(Salix sclerophylla)、绣线菊(Spiraea salicifolia)、头花杜鹃(Rhododendron ca pitatum)、金...     

青藏高原低云量的年际变化及其稳定性

利用青藏高原80个测站1961-2000年1～12月低云量资料,分析了青藏高原低云量的年际变化规律.结果表明:青藏高原的低云量从东南向西北减少,云量的稳定性夏季高于冬季,南部高于北部.江河上游区域、藏东谷地、川西高原、甘南高原和祁连山区是青藏高原低云量多,且比较稳定的地区;青藏高原西部低云量月变化振幅大,尤以西南部为最,夏季云量最多;高原东南部江河上游区和藏东谷地3～9月低云量多,且起伏变化小,6月和9月出现峰值;高原东南部低云量稳定性较好;低云量的年际变化总体呈下降趋势, 江河上游区和高原东南部的低云量变化缓慢,高原西北部有显著上升趋势;变化趋势在季节上表现为冬、春、夏、秋西北上升西南下降,春、秋季中东部持平,夏、冬略降.     

锌、铁、钼配施对紫花苜蓿产草量及锌铁钼含量和吸收量的影响

采用随机区组试验设计,研究锌、铁、钼配施对紫花苜蓿(Medicago sativa L.)产草量及锌铁钼含量和吸收量的影响,为其合理施肥提供依据。结果表明:锌、铁、钼以不同比例配施均能提高紫花苜蓿产草量,且单施锌(12kg·hm^-2)、铁(15 kg·hm^-2)、钼(0.5 kg·hm^-2)或两两配施效果显著(P<0.05);尤其是锌(12 kg·hm^-2)和钼(0.5 kg·hm^-2)配施,产草量最高(7.01 t·hm^-2),较对照增产25.40%。锌、铁、钼以不同比例配施对紫花苜蓿锌铁钼含量和吸收量影响不尽相同,锌(12 kg·hm^-2)、铁(15 kg·hm^-2)、钼(0.5 kg·hm^-2)三者互作能显著(P<0.05)提高苜蓿锌铁钼的含量和锌钼吸收量,钼锌互作能显著(P<0.05)提高苜蓿钼和锌的含量和吸收量;单施锌或锌铁互作能显著(P<0.05)提高苜蓿锌的含量和吸收量;单施钼或钼铁互作能显著(P<0.05)提高苜蓿钼的含量和吸收量;而单施铁或与锌或钼互作均未能显著提高苜蓿铁的含量和吸收量。