我国规模化牧场奶牛酮病防治状况调查分析

[目的]为了解2021年我国规模化牧场奶牛酮病发病情况和防控状况。[方法]本文选择105个规模化牧场进行调查,包括酮病发病率、诊断和监测方法、治疗方法、治愈率、防控方法和治疗成本等。[结果]牧场奶牛平均单产为9.7 t,酮病平均发病率为17.9%,高于国外控制目标。大多数牧场奶牛酮病诊断和监测,主要采用检测血液中β-羟丁酸浓度的方法,奶牛酮病治愈率无论单一或综合措施都达90%以上,奶牛酮病综合防控效果明显好于单一措施。[结论]目前我国规模化牧场奶牛酮病发病率控制目标、诊断和监测、治疗和防控仍需更多研究,完善和制定相应的技术规范,为规模化牧场奶牛酮病的高效防控提供技术支撑。     

牧草产量的遥感估算与载畜能力研究

为了切实保护草地生态环境,实现草畜平衡,以畜牧业大省青海省为例,利用经过GPS定位的青海省牧草地面观测资料,分析牧草产量与NOAA/AVHRR植被指数NDVI之间的关系,分类建立青海省牧草产量估算线形模型与指数模型.模型的拟合结果良好,相关系数平方(R2)超过0.67.大部分时次的地面实测值与遥感估算值所处的产量等级基本一致,模型精度可以应用于大范围的牧草产量预测.根据牧草遥感估测结果,计算分析青海天然草场的载畜能力.结果表明,青海省县级天然草地年最高载畜量基本呈南高北低的态势.南部大部分县以及北部的祁连县在100～200万只绵羊单位之间,海西州和海东大部分县在50万只绵羊单位以下.     

Nitrogen and phosphorous fertilizer improve pastures naturally growing under hazelnut trees

Abstract

This three-year study (2003–2005) aimed to improve the yield and quality of pastures growing naturally that are colonized by naturally occurring vegetation without agricultural input under hazelnut (Corylus sp.) orchards in the middle and eastern Black Sea regions of Turkey. There were eight treatments: 1) control; 2) fertilizer only (triple superphosphate 44% and calcium ammonium nitrate 26%) (80kg ha^?1 P and 60 kg ha^?1 N in Samsun; 100 kg ha^?1 P and 80 kg ha^?1 N in Ordu; 100 kg ha^?1 P and 40 kg ha^?1 N in Giresun); 3) lime only (calcium carbonate 94%) (3.0 t ha^?1 lime in Samsun; 4.5 t ha^?1 lime in Ordu and Giresun); 4) early cut only; 5) soil aeration only; 6) fertilizer+lime; 7) fertilizer+lime+early cut; 8) fertilizer+lime+soil aeration, laid out in a randomized complete block design with four replicates at each location. The highest dry matter (DM) yield of kg ha^?1 and crude protein content (%) was obtained from the treatments that included fertilizer. There was no difference in DM production between any of the combination treatments that involved fertilizer and the fertilizer alone treatment. Only lime and aeration applications also increased yield compared to control, but not as much as did any treatment including fertilizer. Crude protein content of the pasture ranged from 13.3 to 18.1% across locations. Nitrogen and phosphorus fertilizer are recommended to improve DM yields and herbage quality for pastures under hazelnut orchards.     

Landslide erosion risk to New Zealand pastoral steeplands productivity

Pastoral land use in New Zealand's North Island hill terrain has led to high rates of rainstorm-induced landslide erosion higher than existed under the indigenous forest regime, with consequent soil productivity declines in the long term. To assist extrapolation of research results to other areas, and to shed light on long-term erosion risks, a simple model was developed that simulates the evolution of hillslope soil productivity, taking into account the effect of slope, rainstorm magnitude–frequency relations and soil recovery rates. Risks are evaluated by Monte Carlo simulation, and reflect parameter uncertainty as well as the natural randomness associated with climatic events. A sensitivity analysis showed that landslide risk was most affected by the rainfall threshold for landsliding, the mean of the extreme value distribution for annual maximum storm rainfall, and the maximum degree of recovery of pasture productivity following landsliding. Simulations suggest productivity stabilizes at a reduced level well before all steep terrain is affected by landsliding, and that subsequent expected landslide-induced productivity declines are too slow to provide sufficient economic motivation for measures to prevent landslide damage. A refined model showed that long-term average rates of productivity decline are sensitive to changes in recovery rates resulting from progressive removal of the soil resource. Charts summarizing simulation results can be used to estimate long-term productivity declines. Copyright © 1999 John Wiley & Sons, Ltd.     

多功能土壤改良剂对河西内陆灌区棕漠土的改良效果

[目的]解决棕漠土保水肥能力弱,有机质含量低,制种玉米产量低而不稳的疑难问题,为河西内陆灌区制种玉米产业可持续发展提供技术支撑。[方法]选择甘肃省酒泉市肃州区棕漠土,采用田间试验方法,进行多功能土壤改良剂配方筛选及对棕漠土改良效果研究。[结果]多功能土壤改良剂最佳配比为:有机生态肥∶保水剂∶制种玉米专用肥∶聚乙烯醇为0.978 3∶0.000 9∶0.019 6∶0.001 2。多功能土壤改良剂最佳施用量为68.75t/hm~2,制种玉米理论产量为6.64t/hm~2。施用多功能土壤改良剂与传统化肥比较,棕漠土总孔隙度、毛管孔隙度、非毛管孔隙度、团聚体、饱和持水量、毛管持水量、非毛管持水量分别增加22.75%,22.76%,22.74%,9.50%,22.75%,22.76%和22.74%;有机质、CEC、碱解氮、速效磷和速效钾增加35.01%,21.64%,0.63%,2.26%和2.09%;真菌、细菌和放线菌分别增加93.97%,35.35%,20.78%;蔗糖酶、脲酶、磷酸酶和多酚氧化酶分别增加61.82%,44.64%,40.00%和64.29%;制种玉米增产值和施肥利润增加39.23%和31.82%。[结论]施用多功能土壤改良剂,能有效地改善棕漠土理化性质和生物学性质,提高制种玉米产量。     

硫酸法钛石膏作为土壤调理剂在油菜上的施用效果研究

为研究钛白粉生产过程中经无害化处理的副产品钛石膏作为土壤调理剂的施用效果及安全性,试验对供试钛石膏通过成分鉴定—土柱淋溶—盆栽种植的方式,研究了钛石膏和钛石膏淋溶液中的有害元素含量以及钛石膏与土壤不同比例掺混后对油菜生长、产量和功能叶光合速率影响。结果表明:钛石膏主要成分为CaSO_4和Fe_2O_3,固体中的重金属含量均符合国家安全标准。钛石膏淋溶液中含有较少量的Ca~(2+)、Mg~(2+),不含其他有害物质,施用后不会随雨水和灌溉污染土壤和地下水。随着钛石膏添加比例的增加,油菜产量呈先增高后降低的趋势,过量的钛石膏施用会抑制油菜的生长。钛石膏与土壤按照1∶4体积比混合施用后效果最好,与常规土壤栽培方式相比,油菜出苗20天后功能叶蒸腾速率提高了11.86%;出苗30天后功能叶SPAD值增加了4.33%,收获时油菜株高提高了12.97%,产量增加了14.08%。相关性分析显示,油菜产量(y)与钛石膏添加比例(x)的关系为y=0.0001x~3-0.0212x~2+0.6966x+41.815(R~2=0.999 4),综合考虑函数及其他因素,在实际生产中若每公顷施用300t的钛石膏能起到最佳增产效果。     

纳米矿物基土壤调理剂对水稻富集镉的影响

将纳米矿物基土壤调理剂应用于镉污染耕地水稻种植,施用土壤调理剂对水稻产量无显著影响,但可显著降低稻米中的镉含量,也可以有效降低土壤中有效态镉的含量。施用该土壤调理剂1 500~4 500 kg/hm2,土壤有效态镉含量下降25.00%~35.71%,稻米镉含量则下降20.31%~50.00%,降镉效果随调理剂用量的增加而提高。同时,对纳米矿物基土壤调理剂的降镉机理进行了探讨,对材料应用的经济效益进行了简要分析。     

金龟子绿僵菌在草原羊草和克氏针茅根际的种群动态和根内宿存鉴定

绿僵菌防治草原蝗虫效果显著,其在草原田间的存活能力影响其持续控害效果。除了侵染昆虫,绿僵菌还具有在植物根际宿存和根内生的生活方式,但相关宿存规律和内生性的研究报道很少。本文研究了绿僵菌在内蒙古草原两种优势种植物羊草和克氏针茅根际的种群数量变化并对其在这两种草的根内宿存进行了鉴定。结果表明,在干旱的内蒙古草原,绿僵菌施用后种群数量在30 d内快速下降,但能够以低密度在羊草、克氏针茅根际土壤中至少延续宿存75 d,羊草根际环境比较利于绿僵菌生存。对菌株egfp基因标记的特异PCR检测证明了绿僵菌在羊草和克氏针茅根内宿存。试验数据为指导植保生物防治中充分利用绿僵菌的昆虫病原性和植物内生特性提供理论基础,也将成为绿僵菌物种生活方式多样性、与植物互作及共进化研究的重要基础。     

Divergent effects of defoliation intensity and frequency on tiller growth and production dynamics of Pascopyrum smithii and Hesperostipa comata

Rotational stocking theoretically enables regrazing of regrowth, but regrowth may be limited in xerophytic vegetation. We tested the hypothesis that regrowth would be slow and fixed in Hesperostipa comata (a caespitose, drought‐tolerant grass), while growth would be flexible in Pascopyrum smithii (a rhizomatous, less drought‐tolerant grass) under increasing defoliation and moisture, by assessing tiller growth rates, population dynamics and plant yield on marked plants in a Dry Mixed Grass prairie. Plots were clipped in late summer to simulate a deferred control, or intermittently during the growing season (May–August) at high intensity–low frequency (HILF), low intensity–high frequency (LIHF) or high intensity–high frequency and crossed with two water treatments (ambient and addition) in both a xeric upland and a mesic lowland. Growing season defoliation increased tiller growth rates of P. smithii in the upland, whereas HILF and LIHF reduced growth in the lowland. All defoliation regimes increased tiller growth for H. comata. Tiller populations of H. comata increased with frequent defoliation, while tiller populations of P. smithii decreased regardless of defoliation regime. Frequent defoliation, regardless of intensity, reduced yield relative to the deferred control for both grasses. While water addition consistently increased growth rates and reduced differences in tiller number among defoliation treatments, the regrowth of both grasses remained similar under varied defoliation with ambient moisture. High moisture conditions also promoted regrowth more in P. smithii compared to H. comata. In summary, neither grass species displayed an inherently fixed or flexible tiller or plant yield response in response to defoliation or moisture.     

硅钙钾镁肥对浙江省酸性水稻土壤的改良效果

为了明确新型土壤调理剂——硅钙钾镁肥对浙江省酸性水稻土的改良效果,通过连续3 a的田间小区试验,研究硅钙钾镁肥不同用量与化肥配施对水稻产量及土壤养分含量的影响。结果表明,与习惯施肥相比,施用硅钙钾镁肥水稻增产明显,以施用硅钙钾镁肥1 500 kg·hm^-2增产效果较好。在土壤改良方面,施用硅钙钾镁肥可以提高土壤pH值,降低土壤交换性氢和交换性铝含量,提高土壤有效硅和盐基离子含量。