相变材料在绿色储粮中的应用探讨

相变材料能够储存或释放显热,在熔化或凝固过程中虽然温度不变但吸收的潜热却相当大。根据相变材料可以吸收环境热能并在需要时向环境发出热能的特征,研究相变材料在粮食仓储中的应用,减小外界环境对粮仓温度的影响,达到恒温绿色生态储粮的目的。     

基于紫花苜蓿混播草地的全草型肉羊放牧育肥模式案例研究

本研究旨在探讨紫花苜蓿（Medicago sativa L.）混播草地放牧利用的生产潜力和集成全草型集约化肉羊放牧育肥技术模式。2017-2018年，在位于河北省廊坊市的中国农业科学院国际农业高新技术产业园内开展了2年羔羊育肥的划区轮牧试验，研究了紫花苜蓿混播草地的地上生物量、育肥羊增重以及羊肉品质的变化规律。结果表明：混播草地地上生物量超过11.2 tDM·hm^-2，5月份紫花苜蓿混播草地的粗蛋白为20.92%，每公顷紫花苜蓿混播草地可满足51只育肥羊、放牧育肥150天，每只增重30 kg所需的干物质、代谢能和粗蛋白三个方面的全部需求。与此同时，紫花苜蓿混播草地还可以显著增加羊肉中欧米伽3型多不饱和脂肪酸的含量，n-6/n-3比例为2.72，羊肉健康品质显著提高。以紫花苜蓿混播草地为基础的全草型肉羊放牧育肥技术具有广阔的应用前景，对我国苜蓿产业以及草地畜牧业发展具有重要意义。     

产蛋期蛋鸡不同类型玉米净能研究

本试验利用禽用开放式呼吸测热装置进行能量代谢试验,通过间接测热法结合替代法测定不同类型玉米在产蛋期蛋鸡饲粮中的表观代谢能和净能。选用34周龄产蛋期海兰褐蛋鸡180只,随机分为6组,每组30只。试验选用1种玉米-豆粕型基础饲粮和5种待测饲粮。待测饲粮由5种待测玉米(3种2018年10月收获的正常玉米和2种2016年收获储存3年的陈化玉米),分别以50%比例替代基础饲粮构成。试验鸡在舍内笼养,预试期7 d,正试期27 d,其中正试期分为3期,每期9 d(适应3 d、呼吸测热3 d、绝食测热3 d)。每期试验中,从每组中选择4只试验鸡,称重后分别放入呼吸测热装置的12个代谢室(每个代谢室2只),每2个代谢室对应1种饲粮,测定气体交换和排泄物总量,呼吸测热的同时进行消化代谢试验。结果表明:与基础饲粮相比,5种玉米待测饲粮的表观代谢能显著提高(P<0.05),3种正常玉米待测饲粮的净能显著高于基础饲粮和2种陈化玉米待测饲粮(P<0.05);2种陈化玉米的表观代谢能和净能显著低于3种正常玉米(P<0.05)。本试验中,3种正常玉米的表观代谢能分别为16.19、15.85、16.17 MJ/kg,2种陈化玉米的表观代谢能分别为15.12和15.06 MJ/kg;3种正常玉米的净能分别为12.39、12.57、12.25 MJ/kg,2种陈化玉米的净能分别为11.29和12.05 MJ/kg。     

Maize/peanut intercropping increases photosynthetic characteristics, ~(13)C-photosynthate distribution,and grain yield of summer maize

Intercropping is used widely by smallholder farmers in developing countries to increase land productivity and profitability. We conducted a maize/peanut intercropping experiment in the 2015 and 2016 growing seasons in Shandong, China. Treatments included sole maize(SM), sole peanut(SP), and an intercrop consisting of four rows of maize and six rows of peanut(IM and IP). The results showed that the intercropping system had yield advantages based on the land equivalent ratio(LER) values of 1.15 and 1.16 in the two years, respectively. Averaged over the two years, the yield of maize in the intercropping was increased by 61.05% compared to that in SM, while the pod yield of peanut was decreased by 31.80% compared to SP. Maize was the superior competitor when intercropped with peanut, and its productivity dominated the yield of the intercropping system in our study. The increased yield was due to a higher kernel number per ear(KNE). Intercropping increased the light transmission ratio(LTR) of the ear layer in the maize canopy, the active photosynthetic duration(APD), and the harvest index(HI) compared to SM. In addition, intercropping promoted the ratio of dry matter accumulation after silking and the distribution of ~(13) C-photosynthates to grain compared to SM. In conclusion, maize/peanut intercropping demonstrated the potential to improve the light condition of maize, achieving enhanced photosynthetic characteristics that improved female spike differentiation, reduced barrenness, and increased KNE. Moreover, dry matter accumulation and ~(13) C-photosynthates distribution to grain of intercropped maize were improved, and a higher grain yield was ultimately obtained.     

供氮方式对冬马铃薯氮肥利用效率及氮素去向的影响

以马铃薯费乌瑞它为试材,采用田间微区~(15)N示踪技术,研究施N量160kg·hm~(-2)全部基施(T1)、55%基施+45%在齐苗期追施(T2)、55%基施+30%在齐苗期追施+15%在现蕾期追施(T3)3种方式,对冬马铃薯氮肥利用效率及去向的影响。结果表明:马铃薯吸收的N约46%~52%来源于当季施用的氮肥,48%~54%来自土壤和种薯;肥料N利用率为35.16%~39.99%,残留率为47.71%~51.78%,损失率为8.23%~15.50%。3种施氮方式下,肥料N主要残留在0~15cm土层。随施氮时间后移,肥料N残留在0~15cm土层呈上升趋势,在15~45cm土层呈下降趋势。施氮方式对马铃薯干物质积累总量和块茎干物质积累量影响不明显,但T3肥料N利用率、肥料N残留率明显大于T1、T2。因此,综合经济效益和环境效益,T3施氮方式的效果较为理想。本研究为马铃薯氮素养分的有效管理提供了指导依据。     

Herbicide options for effective weed management in dry direct-seeded rice under scented rice-wheat rotation of western Indo-Gangetic Plains

Farmers' participatory field trials were conducted at Madhuban, and Taraori, the two participatory experimental sites/locations of the Cereal Systems Initiative for South Asia (CSISA), a collaborative project of IRRI and CIMMYT in Karnal district of Haryana, India, during Kharif (wet season) 2010 and 2011. This research aimed to evaluate preemergence (PRE) and postemergence (POST) herbicides for providing feasible and economically viable weed management options to farmers for predominant scented rice varieties. Treatments with pendimethalin PRE fb bispyribac-sodium + azimsulfuron POST had lower weed biomass at 45 days after sowing (DAS). At Madhuban, highest grain yield of scented basmati rice (3.43 t ha⁻¹) was recorded with the sequential application of pendimethalin PRE fb bispyribac-sodium + azimsulfuron POST. However, at Taraori, yields were similar with pendimethalin or oxadiargyl PRE fb bispyribac-sodium and/or azimsulfuron POST. Applying oxadiargyl by mixing with sand onto flooded field was less effective than spray applications in non-flooded field. The benefit-cost ratio of rice crop was higher with herbicide treatments at both sites as compared with the non-treated weed-free check except single PRE and POST applications and sequential application of oxadiargyl PRE fb oxadiargyl PRE. In a separate experiment conducted at Nagla and Taraori sites, scented rice cultivars' ('CSR 30′ and 'Pusa 1121′) tolerance to three rates of azimsulfuron (15, 25, and 35 g ai ha⁻¹) was evaluated over two years (2010 and 2011). CSR 30 (superfine, scented) was more sensitive to higher rates (35 g ai ha⁻¹) of azimsulfuron as compared to Pusa 1121 (fine, scented). Crop injuries were 8 and 28% in case of CSR 30; 5 and 15% in Pusa 1121 when applied with azimsulfuron 25 and 35 g ai ha⁻¹, respectively. Azimsulfuron applied at 35 g ai ha⁻¹ reduced yield in both cultivars but in CSR 30 yield reduction was twofold (11.5%) as that of Pusa 1121 (5.2%).     

Effect of energy and protein levels on performance,egg quality,and nutrient digestibility of laying pigeons

A total of 3,240 female Taisheng pigeons at 40 wk age were fed 9 diets containing 3 ME levels (2,630, 2,770, and 2,940 kcal/kg) and 3 CP levels (14.0, 15.0, and 16.0%) in a factorial arrangement. These diets were fed to investigate the effects of ME and CP on performance, egg quality, and nutrient digestibility. Female pigeons were housed under the same managerial conditions and randomly assigned into 9 treatments (6 replicates of 60 birds each). Two female–female paired pigeons housed in one cage were under a 16L:8D lighting cycle. Feed in pellet form and water were provided for ad libitum consumption. The study lasted 12 wk. As dietary ME level increased from 2,630 to 2,940 kcal/kg, BW, egg production, and apparent DM, crude fat (CF), and phosphorus (i.e., P) digestibilities increased (P < 0.05), feed intake decreased (P < 0.05), and feed conversion efficiency increased (P < 0.05). Increasing the level of dietary protein from 14 to 16% resulted in an increased (P < 0.05) BW, shell percentage, length of the major axis, and DM digestibility. Therefore, dietary ME had a greater influence on the performance of Taisheng laying pigeons than did dietary protein.     

仿生法评定抗草甘膦玉米和转Bt基因玉米的酶水解物能值的研究

本试验旨在分析抗草甘膦玉米和转Bt基因玉米原料及饲粮与同源非转基因玉米原料及饲粮体外总能消化率以及酶水解物能值,为转基因玉米的营养实质等同性仿生评定方法的研究提供参考。试验采用单因素完全随机设计,使用单胃动物仿生消化系统模拟饲料原料和饲粮在鸡胃肠道的消化过程,分析同源非转基因玉米、抗草甘膦玉米和转Bt基因玉米以及对应的3种玉米-豆粕饲粮在不同体外模拟消化阶段的干物质消化率、总能消化率和酶水解物能值的差异。结果表明:同源非转基因玉米、抗草甘膦玉米和转Bt基因玉米以及对应饲粮在常规概率成分含量上是相似的。抗草甘膦玉米及饲粮与同源非转基因玉米及饲粮相比,在干物质和能量胃消化率、全消化道消化率及酶水解物能值上均没有显著差异(P0.05)。转Bt基因玉米全消化道总能消化率低于同源非转基因玉米(P=0.03,变异系数=0.50%),对应玉米饲粮的酶水解物能值则高于同源非转基因玉米饲粮(P=0.02,变异系数=1.12%),但均处于仿生消化系统测试的误差范围内(变异系数≤1.64%)。由此可见,抗草甘膦玉米的酶水解物能值与同源对照玉米没有差异,而转Bt基因玉米存在统计学意义上的差异,但所有的测值均处于仿生消化系统的测试误差之内。仿生法发现的差异是否具有生物学意义有待体内试验验证。仿生法可为转基因饲料营养等同性研究提供一种新方法。