Effects of formic acid and potassium diformate on the fermentation quality,chemical composition and aerobic stability of alfalfa silage

The objective of this study was to evaluate the efficacy of potassium diformate (KDF) as a potential additive for alfalfa silage. Fresh alfalfa was untreated or treated with formic acid (4 g/kg fresh weight, FW) or three concentrations of KDF (4, 5.5 or 7 g/kg FW). After 60 days of ensiling, the addition of formic acid and greater levels of KDF (5.5 and 7 g/kg) effectively reduced silage pH and inhibited the undesirable bacteria, indicated by lower butyric acid, ethanol, ammonia N concentrations and microbial populations (including enterobacteria, yeasts, moulds and clostridia). Additives decreased the dry‐matter loss, and more water‐soluble carbohydrates were preserved in the silages with formic acid or potassium diformate than in the control. Alfalfa silages treated with formic acid at 4 g/kg FW or potassium diformate at 5.5 or 7 g/kg FW were classified as the highest quality silage based on the higher Flieg's point (above 70) and remained stable for more than 9 days during aerobic exposure. Potassium diformate is recommended as an effective additive for alfalfa silages at a level of 5.5 or 7 g/kg FW under the humid and hot conditions of southern China.     

Maize harvest index and water use efficiency can be improved by inhibition of gibberellin biosynthesis

Possibilities to improve maize harvest index and nutrient utilization efficiency by application of plant growth regulators were investigated. In container experiments, the effects of different growth regulators on the development of the maize (Zea mays L.) cultivars Pioneer 3906 and Fabregas were tested. Paclobutrazol (PAC) and chlorocholine chloride (CCC), two inhibitors of gibberellin biosynthesis, as well as gibberellic acid (GA₃) were applied at growth stage V5. Three weeks after application of PAC, shoot growth of both maize cultivars was strongly affected with a significant decrease in plant height in the PAC treatment by 44% and 36% for Pioneer 3906 and Fabregas, respectively. The growth‐retarded plants had higher leaf areas and reduced transpiration rates. The higher shoot growth after GA₃ application was accompanied by a reduction in leaf area and an increase in transpiration rate during 1 week before anthesis. CCC treatment showed no significant effects on plant height, leaf area and transpiration rate. The PAC‐treated cultivar Pioneer 3906 produced several cobs per plant, which were mainly barren at maturity. However, PAC application to Fabregas resulted in just one cob per plant with good kernel development and a grain yield, which was not significantly reduced in comparison with the control. With this similar grain yield in combination with a straw yield decrease of 32%, the harvest index was significantly improved by 12%. In addition, with PAC‐treated Fabregas plants, a 19% increased water use efficiency of the grain (WUE_grain) during the critical period of kernel setting was achieved. In this maize cultivar, CCC application also improved harvest index by 5%, but no effect on WUE_grain occurred. GA₃ treatment decreased harvest index of both maize cultivars, and it either reduced WUE_grain (Pioneer 3906) or showed no effect (Fabregas). Utilization efficiencies of N, P and K were not increased with growth regulator application, even in the PAC‐treated Fabregas plants with a significantly improved allocation of assimilates to the grain, mirrored by the higher harvest index. The results indicate that fertilizer applications must be adjusted to the reduced demand of growth‐retarded plants, most likely leading to higher nutrient utilization efficiencies.     

3,5-二硝基水杨酸法与酶法测定甜玉米还原糖和蔗糖含量的比较

针对目前测定甜玉米还原糖和蔗糖含量的3,5-二硝基水杨酸法和酶法进行比较研究,分析两者在育种中的应用。结果显示:酶法的测量准确度比3,5-二硝基水杨酸法高,且其稳定性和重现性都优于3,5-二硝基水杨酸法。通过两种方法对10个甜玉米杂交种种子的还原糖和蔗糖含量的测定,证实了两种方法在甜玉米还原糖和蔗糖含量的检测上是一致的。从育种实践考虑,酶法适于样品数较小的检测,3,5-二硝基水杨酸法更适合于大批量样品的检测。     

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。     

东北棕壤长期不同施肥处理轮作大豆氮素吸收和土壤硝态氮特征

【目的】在玉米–玉米–大豆轮作体系下,基于棕壤肥料长期定位试验,研究不同施肥处理对东北地区大豆生物量、产量、各部位吸氮量及收获期土壤0―100 cm硝态氮累积的影响,为该地区合理施肥提供理论依据和科学指导。【方法】棕壤肥料长期定位田间试验始于1979年,包括不施肥(CK)、单施氮肥(N)、氮磷钾肥配施(NPK)、低量厩肥(M1)及其与化肥配施(M1N和M1NPK)、高量厩肥(M2)及其与化肥配施(M2N和M2NPK)9个处理。厩肥为猪厩肥,1992年后大豆季不施猪厩肥,仅在玉米季相关处理中施用。39年后,调查分析了大豆生物量、产量、氮素吸收利用及大豆收获期0―100 cm土壤硝态氮累积特征。【结果】高量、低量厩肥配施化肥处理大豆生物量、产量、总吸氮量及各部位吸氮量均显著高于单施氮肥和不施肥处理,其中,M1NPK处理大豆生物量、产量和总吸氮量最高,分别为9107、2979和314.2 k g/h m^2,较其他处理分别提高了6.1%~133.6%、23.9%~232.5%和11.7%~359.4%。施肥提高了大豆氮收获指数,但氮素生理效率降低。NPK和M1NPK处理的氮素收获指数最高,均为63.5%,而氮素生理效率较CK分别降低了30.6%和28.1%。大豆收获期各处理土壤硝态氮累积量随土层深度的增加而降低。与播前相比,大豆收获期单施氮肥处理的0―100 cm土层硝态氮积累量显著增加,NPK处理变化不显著,M1、M1N和M1NPK处理显著降低。低量厩肥配施化肥处理收获期0―100 cm土壤硝态氮积累量远低于高量厩肥配施化肥处理,较播前平均降低了79.2%。所有处理中,土壤硝态氮积累量以M1NPK处理最低,比其他处理平均降低了58.2%。【结论】在东北棕壤地区玉米–玉米–大豆轮作体系下,玉米季低量厩肥(13.5 t/hm^2)与氮磷钾化肥配合施用时,大豆季仅施氮磷钾化肥既可提高大豆生物量、产量,促进氮素吸收,同时还可降低大豆收获期土壤硝态氮累积量,降低环境风险,是该轮作体系较为合理的施肥方式。     

不同外源激素对糜子成穗及产量的影响

研究不同种类外源激素对糜子成穗及产量的影响。用5种外源激素在糜子3~4叶期喷施,连续处理2次,喷清水为对照。记录糜子苗期基本苗数、拔节期总茎数、成熟期穗数等性状,用统计软件SPSS 17.0进行统计分析。结果表明,施用脱落酸（ABA）能够显著降低糜子的分蘖数,施用赤霉素（GA₃）、吲哚乙酸（IAA）、矮壮素（CCC）也能减少糜子分蘖数,但是与对照差异不显著,施用多效唑（PP₃₃₃）对糜子分蘖数没有明显影响;施用GA₃、IAA、CCC能够增加分蘖穗数,而ABA、PP₃₃₃降低分蘖穗数;各处理分蘖成穗率都较对照高,ABA处理分蘖成穗率为最高达到25.20%;ABA处理主茎穗占比较对照增加,分蘖穗占比降低;GA₃、IAA、CCC处理主茎穗占比相对于对照降低,分蘖穗占比增加,PP₃₃₃处理与对照相近;5种外源激素对糜子产量的影响差异显著,施用ABA产量最高,可能与主茎穗占比高和分蘖成穗率高有关系。在糜子3~4叶期喷施5种外源激素,对糜子有显著作用的是ABA,主要表现在ABA能够降低糜子分蘖数,保证了主茎的成穗数量,增加了分蘖成穗率,从而提高了糜子产量。     

大豆玉米持续轮作免耕对土壤养分及作物产量的影响

为了解决免耕减产、秸秆焚烧污染环境、种植结构不合理等问题,试验通过设置免耕和传统垄作田间对比试验,研究了2013年到2016年连续4年大豆玉米轮作免耕对土壤养分及作物产量的影响,研究结果可为免耕技术推广及黑龙江省农业持续发展提供理论参考和技术保障。试验结果表明,大豆玉米持续轮作免耕条件下0-7.5 cm、7.5-15 cm、15-22.5 cm、22.5-30 cm土壤养分指标全氮、全磷、全钾、碱解氮、速效磷、速效钾、有机质含量均高于垄作处理,且耕作对全氮、全磷、碱解氮、速效磷、速效钾、有机质含量影响显著；耕作对土壤容重影响显著,免耕处理各层土壤容重高于垄作处理,免耕处理15-22.5 cm与22.5-30 cm土层之间容重差异不显著,而垄作处理各层土壤容重差异显著；与垄作相比,2013年和2015年免耕大豆增产率分别为16.37%和25.33%,2014年和2016年免耕玉米产量增产率分别为0.88%和9.50%。大豆玉米轮作免耕较垄作平均节约成本640元/hm2,平均增收2220元/hm2。     

丘陵山地用小型自走式青贮机的设计思考

玉米是世界三大主要粮食作物之一，收获是玉米生产的重要环节。设计一款适合偏远山区、丘陵地区等路况复杂、地块小且不规则地使用的青贮机有很好的应用价值。本文通过对设计内容的研究与分析，得出设计流程，为物理样机提供理论依据。     

大型组合式机械通风玉米穗储粮仓的设计

本研究针对大农户玉米穗储藏的实际情况，研制了大型组合式机械通风玉米穗储粮仓，并对其进行了装粮试验。结果表明：该型储粮仓机械性能稳定，结构组装方便，降水、防霉、防鼠效果显著，可有效降低粮食产后损失，保证粮食品质。 [关键词] 粮仓|玉米穗|机械通风     

苜蓿青贮销售的“痛点”与突破

苜蓿蛋白质含量高,消化率高,营养价值好。随着畜牧业的发展和农业结构的调整,我国苜蓿种植面积逐年扩大。由于收获期雨热同季导致割晒苜蓿自然晒干较为困难,所以制作成青贮成为近几年苜蓿高效利用的重要方法之一。苜蓿青贮具有适口性好、易于保存、加工损耗低等优点,国内苜蓿种植户纷纷加入制作苜蓿青贮的队伍,但并未推动该产业快速、良性发展。本文探讨苜蓿青贮销售的痛点和难点,并提出建议,以期为同行提供参考。