四川省2种生境条件下黑麦草种子生产性能的研究

对四川省的丘陵区(洪雅)和中山地区(汉源)2种生境条件下的黑麦草种子生产性能进行了研究分析,结果表明,试验两地的种子产量和质量均有显著差异.其中,洪雅点种子产量为244.0 kg/hm2,汉源点的种子产量为532.8 kg/hm2.两样地的种子质量相比,汉源点的发芽势、发芽率、四唑染色数和四唑脱氢酶均高于洪雅点.两地的种子产量与其构成因素的相关性基本一致,均呈显著相关;相关性强弱依次为:每生殖枝种子数>生殖枝数>每生殖枝小花数>分蘖数>每生殖枝小穗数>千粒重.每生殖枝种子数对种子产量贡献最大.     

厌氧发酵残留物对土壤酶动态特性的影响

通过温室盆栽生菜试验,研究厌氧发酵残留物对土壤蔗糖酶、脲酶、多酚氧化酶和中性磷酸酶动态特性以及作物产量的影响.试验以菜园土作为栽培基质,并以是否施用厌氧发酵残留物和种植作物进行设计,生菜种植期为50天,试验中间隔10天测定一次土壤酶活性.结果表明,施用厌氧发酵残留物能明显提高土壤酶的活性,且施用量越多,酶活性越高,生菜的产量也越高.栽种生菜的土壤酶活性高于相应的对照组,酶活性的变化基本和生菜的生长过程一致,在30～40天之间达到最高酶活性.土壤酶活性的提高表明,施用厌氧发酵残留物能改善土壤结构和性能,提高土壤的肥力和生产能力.     

Differential effect of nematicide treatments on tuber yields in early- and late-maturing potato cultivars

A 3-year field study examined the effects of 1,3-dichloropropene or oxamyl on tuber yields in four early- and five late-maturing potato cultivars. The nematicide treatments increased total tuber yield by ≈ 12% for early-maturing cultivars, but by less than 2% for the late-maturing cultivars. The treatments reduced the numbers of root lesion nematodes (primarily Pratylenchus penetrans ), which were the dominant plant parasitic nematodes at the site. Covariance analysis indicated that treatment effects on total tuber yield were no longer significant after adjusting for root lesion nematodes in soil at harvest, confirming that these nematodes had a direct effect on the host. As expected, there were significant inverse relationships ( P  = 0·05) between total tuber yields and numbers of root lesion nematodes in soil and in roots. However, the application of nematicides in late-maturing cultivars was found to be of no practical value. Crop production systems designed to reduce or optimize pesticide applications can form one criterion in the development of more environmentally sensitive management strategies. The merit of utilizing chemicals for root lesion nematode control are considered with regard to cultivar maturity.     

辽北水稻纹枯病和稻曲病防控效应研究

对水稻纹枯病和稻曲病进行了防控效果试验。结果表明,以全防病处理作为对照,产量损失率表现为全不防病不防纹枯病不防稻曲病,分别为5.53%,5.11%和2.79%;在孕穗期和乳熟期时,防治纹枯病有助于降低纹枯病的病情指数;不防治稻曲病的穴发病率、穗发病率、结实减退率及产量损失率因品种不同差异较大。生产中应重点对水稻纹枯病和个别品种稻曲病进行防治。     

不同接种期对香菇L-808栽培的影响

为了探究适宜香菇L-808秋栽的最佳接种期,开展了不同接种期对香菇L-808栽培的影响试验。结果表明,丽水市9月上旬接种比较适宜,子实体产量最高,不同接种期处理对香菇子实体商品性状的影响不是很大。     

Components of Liquid Media on the Production of High Spore Concentrations of Lecanicillium lecanii （Zimm.） Gams and Zare

Two Lecanicillium lecanii isolates, ATCC26854 and V3, were evaluated for spore production in liquid media. Both isolates have interesting known properties for the production of high concentrations of chitinases （ATCC26854）, and an outstanding pathogenic activity against the green cabbage aphid, Brevicorine brassiacae （L.）. The isolates were grown on thirteen different liquid media, which had been used to produce other entomopathogenic Hyphomycetes. Experiments were carried out at 27 -4- 1 ℃ with a 12：12 photoperiod using shake flasks. The production of spores was quantified during a seven days period, and the effects of the media were evaluated by determining spore concentration and morphology. Submerged conidia yields were higher with ATCC26854 than with V3 in all thirteen media, while higher concentrations （5.3×10^9, 4.6 ×10^9 and 3.4 ×10^9 conidia/mL） were found with ATCC26854 isolate in the Camaron, Minerales and Jenkins-Prior medium, respectively; lower yields （2.3 ×10^8, 2.2 ×10^8 and 2.3 ×10^8 conidia/mL） were found with the V3 isolate in Catroux, TKI and Camaron media, respectively. Spore production curves were adjusted to different sigmoid models. The process was better explained by the Richards model （r^2 = 0.99）. Concerning conidia morphology, submerged conidia seemed to look like aerial conidia, but they were different in size （ATCC26854 2.73-6.99 μm and V3 5.28-14.29 μm）; however, the dimensions fall within the ranges reported for L. lecanii. The analysis of shake flask cultures with the Richards model allowed selecting two low-cost liquid medium, Camaron and Jenkins-Prior, for scaling up conidia production for use in aphid biological control programs.     

地下水埋深对玉米生长发育及水分利用的影响

为研究地下水埋深对作物的生长发育及水分利用的影响,选择具有代表性的夏玉米为研究对象,借助地中渗透仪,通过人工控制设置不同地下水埋深（分别设置0.2,0.4,0.6,0.8,1.0和1.2 m）,探讨地下水埋深对不同生育期夏玉米的形态指标、产量、耗水量及地下水补给量的影响,分析不同地下水埋深条件下水分利用率差异.结果表明：地下水埋深对玉米株高的影响不具有统计学意义,而地下水埋深过浅或过深均会明显抑制植株叶面积指数和茎粗的增长（P〈0.05）,地下水埋深0.4 m时叶面积指数和茎粗最大.随作物生育进程,根系数量和根系干质量随地下水埋深增大,先减小后增大.玉米灌浆前,单株根系伤流量随地下水埋深增大而增大,而灌浆前后则无显著影响.地下水位埋深过深或过浅均影响穗长、秃尖长、穗粒数、百粒质量及经济产量.分析表明,0.53 m为当地玉米产量最优地下水位埋深.玉米生长期内0~80 cm土层土壤含水量随着地下水埋深增大而降低,同一地下水埋深处理玉米生育期内土壤含水量变化幅度较小.夏玉米全生育期耗水量、阶段耗水量及耗水强度随地下水位埋深增大而直线减少,回归方程在P〈0.01水平下具有统计学意义;同样夏玉米全生育期地下水补给量、阶段地下水补给量及地下水补给强度随地下水位埋深增大而直线减少,回归方程在P〈0.01水平下也具有统计学意义.玉米水分利用率随地下水埋深增大而增大,地下水埋深1.2 m处理水分利用率最高.研究成果对江淮丘陵区地下水资源利用及评价、玉米高产高效灌溉制度的制订具有实际意义.     

Effects of shade,altitude and management on multiple ecosystem services in coffee agroecosystems

Agroforestry systems provide diverse ecosystem services that contribute to farmer livelihoods and the conservation of natural resources. Despite these known benefits, there is still limited understanding on how shade trees affect the provision of multiple ecosystem services at the same time and the potential trade-offs or synergies among them. To fill this knowledge gap, we quantified four major ecosystem services (regulation of pests and diseases; provisioning of agroforestry products; maintenance of soil fertility; and carbon sequestration) in 69 coffee agroecosystems belonging to smallholder farmers under a range of altitudes (as representative of environmental conditions) and management conditions, in the region of Turrialba, Costa Rica. We first analyzed the individual effects of altitude, types of shade and management intensity and their interactions on the provision of ecosystem services. In order to identify potential trade-offs and synergies, we then analyzed bivariate relationships between different ecosystem services, and between individual ecosystem services and plant biodiversity. We also explored which types of shade provided better levels of ecosystem services. The effectiveness of different types of shade in providing ecosystem services depended on their interactions with altitude and coffee management, with different ecosystem services responding differently to these factors. No trade-offs were found among the different ecosystem services studied or between ecosystem services and biodiversity, suggesting that it is possible to increase the provision of multiple ecosystem services at the same time. Overall, both low and highly diversified coffee agroforestry systems had better ability to provide ecosystem services than coffee monocultures in full sun. Based on our findings, we suggest that coffee agroforestry systems should be designed with diversified, productive shade canopies and managed with a medium intensity of cropping practices, with the aim of ensuring the continued provision of multiple ecosystem services.     

草坪型多年生黑麦草生殖特性及种子产量构成的研究

草坪型多年生黑麦草开花持续期为 33d ,一般情况下穗轴中部的小穗先开花 ,以后逐渐向顶部和基部发展 ;一个花序上的小花开花大部分集中在前 6d ,大约占 89 3% ;多年生黑麦草花后 2 6～ 2 7d ,小穗干重最大 ,其含水量为 41 1 5 % ,种子不易落粒 ,为种子适宜收获期。在种子生产方面 ,构成因子 (株穗数 ,小穗数 )与影响因子 (株高 ,叶重 )共同对草坪型多年生黑麦草的种子产量起作用