甘肃旱地土壤的持水能力与抗旱能力

对甘肃中部及陇东地区的几种旱地黄绵土、黑沪土及褐土等土壤的持水能力及抗旱能力进行了初步研究。几种土壤的田间持水量（３０ＫＰａ时的含水量）为１６０～２４０ｇｋｇ￣（－１），有效水含量在８８～１７９ｇｋｇ￣（－１）之间，据此得出几种土壤１ｍ土层中有效水贮量变动在１３５～２１６ｍｍ之间。通过对土壤基质持水能力及持水特征的比较分析，认为褐土、红土抗旱能力最差，而几种黄绵土的抗旱能力相当强。黄绵土结构状况差、坡度大造成降雨入侵慢、影响深层贮水是造成生产上干旱严重的原因。     

不同光照条件下蒙古栎物候期及树高生长节律的研究

本文在不同光照（全光、半荫、全荫）条件下,对实生和萌生蒙古栎幼树进行了物候期及全生长季树高生长的观察和测定。结果表明,不同的光照条件通过对光照强度、光照时间及土壤温度的控制而明显地影响蒙古栎的物候期和树高生长节律。观测的同时还发现,全光照下萌生蒙古栎幼树具有次生生长现象。     

高产稳产优质耐旱型水稻新品种金穗1号选育 及旱直播栽培技术

金穗1号是以花培品种“早花2号”为亲本,与优良性状互补的品种杂交配组育成的水稻新品种。既保持了水稻品种高产稳产抗性强品质优的特点,而且抗旱性突出,适合旱直播栽培。冀东旱直播高产栽培的关键在于早播,充分利用当地的气候条件。     

二季晚稻旱床育秧适宜播种期、播种量、移栽期的研究

研究表明,二晚旱床育秧,用当家组合汕优64,播种量以1.333 kg/hm2为最佳.不同播种量早栽,产量间无显著差异,随着移栽期推迟,秧龄增大,有效穗递减,产量间差异达显著或极显著水平.不同移栽期对产量间差异达极显著水平.移栽临界期为7月28日.     

毛果青冈1年生苗各器官干物质生产分配及相关关系

通过播种育苗,研究毛果青冈Cyclobalanopsis pachyloma1年生苗各器官干物质生产分配的变化规律。经定期测定和回归分析,并拟合苗木各器官干物质生产分配及相关关系和异速生长的数学模型,结果表明:苗木干物质的生产分配在出苗期、生长初期和生长盛期末及生长后期以根为主,在生长盛期以叶为主;茎在生长盛期未分配量较多但在整个生长期其分配量均小于根和叶;苗木各器官干物质生产分配与苗木地径、苗高的生长存在着极显著的相关关系;拟合的数学模型效果好,可用来估测和分析毛果青冈1年生苗在各生长时期各器官的干物质生产分配量。图1表4参11     

线粒体磷脂酰甘油与作物幼苗冷敏感性

用差示扫描量热法分析了 6种作物幼苗线粒体极性脂和磷脂酰甘油 (PG)的热致相变。结果发现 ,抗冷性作物小麦发生相变的温度比其他冷敏感作物的低得多 ;小麦和花生线粒体 PG混合后 ,显著改变了各自的相变温度。线粒体 PG脂肪酸组成分析表明 ,脂肪酸饱和度决定其相变温度。线粒体 PG的脂肪酸饱和度与作物幼苗的冷敏感性相关     

杏鲍菇深层发酵工艺的研究

以杏鲍菇菌丝体为目标产物,通过单因素碳、氮源、无机盐、接种量、装液量及发酵时间试验,并用L9(34)正交实验法从中筛选出最佳培养基组合为蔗糖4%、黄豆粉4%、K2HPO40.05%、FeSO4·7H2O0.01%;培养6d菌丝干生物量达到最大22.96g/L。     

NITROGEN USE EFFICIENCY IN DRY BEAN GENOTYPES

Dry bean is an important legume crop for Latin American people and nitrogen is one of the most yields limiting nutrients for bean crop. A greenhouse experiment was conducted to evaluate nitrogen (N) use efficiency of 20 dry bean genotypes. Genotypes were grown on an Oxisol and two N levels used were without N application (low level) and an application of 400 mg N kg^?1 (high level). Shoot dry weight, grain yield and yield components, N concentration and uptake in shoot and grain were significantly affected by N and genotype treatments. Grain yield had a highly significant (P < 0.01) association with shoot dry weight, pod number, grains per pod and 100 grain weight. Among the 20 genotypes tested, Perola, CNFR 7847, CNFR 7865, CNFP 7777 and CNFM 6911 were found to produce reasonably good yield at low N rate as well as responded well to applied N. Whereas, some genotypes like BRS Radiante, CNFP 7624, CNFM 7875, CNFM 7886, CNFC 7813, CNFC 7827, CNFP 7677 and CNFP 7775 produced very good yields at higher N rate but very low yields at lower N rate. Hence, these genotypes are good for farmers using higher technology. Nitrogen concentration and uptake were higher in dry bean grains compared with shoot and 63% of N accumulated at zero N rate and 75% N accumulated at 400 mg N rate were translocated to grain across 20 genotypes. Nitrogen uptake efficiencies were having highly significant (P < 0.01) quadratic relationship with grain yield. This indicates that improving N uptake in dry bean plants can increase grain yield.     

Variations in annual precipitation and selenium accumulation by Milk‐Vetch

Four Se accumulators and two non‐accumulator plants were examined for their Se content in wet and dry years. No significant change in Se quantity was noted in the non‐accumulators in relation to variations in annual precipitation. However, the concentration of Se found in accumulator plants is significantly higher in wet years than in dry ones. Furthermore, in wet years there is a higher percentage of water soluble Se in these plants than in dry ones. The soils supporting these plants were also examined for their Se content. In dry years these soils contain more water soluble Se than in wet ones but, in dry years, this form of Se is less available due to the lack of available moisture. High precipitation may tend to reduce absorption of Se by plants by diluting the water soluble Se present in the soil solution, but it is clear that it also promotes absorption of Se by encouraging vigorous growth of these accumulator plants.     

Tree biomass,resource use and crop productivity in agri-horti-silvicultural systems in the dry region of Rajasthan,India

A combination of silvicultural species [Prosopis cineraria (L.), Ailanthus excelsa Roxb. and Colophospermum mopane (J. Kirk ex Benth.)] were planted with horticultural species [Ziziphus mauritiana (L.), Cordia myxa (Forster), and Emblica officinalis (Gaertn)] and intercropped with wheat (Triticum aestivum). Z. mauritiana +P. cineraria combination produced greater fruit, fodder and fuel wood and was less competitive to wheat crop. Crop yield reduced by 5% to 23% in the agroforestry systems than the yield in sole crop plot. Lowest yield was in C. mopane + C. myxa combination. Fodder yield was 0.53, 0.20 and 0.07 t ha^?1 from C. mopane (cursive), P. cineraria and A. excelsa, respectively, whereas utilizable biomass was 2.63 t ha^?1 from C. myxa (cursive) + P. cineraria, 2.21 t ha^?1 from C. myxa (cursive) + C. mopane and 2.18 t ha^?1 from Z. mauritiana + P. cineraria combinations. Soil organic carbon and NH₄–N increased (by 7% and 8%, respectively), whereas NO₃–N and PO₄–P decreased in agroforestry compared to the sole tree plots. Primary root attributes of P. cineraria, A. excelsa and C. mopane were higher in agroforestry and mostly concentrated in the top 0–25 cm of the soil layer. Z. mauritiana + P. cineraria were the best combination with minimum yield reduction and were found to be beneficial in enhancing soil fertility.