Microbial Biomass in Relation to Soil Properties under Integrated Farming Systems of Meghalaya,India

The effects of different integrated farming systems on microbial biomass was studied 20 years after their adoption at Meghalaya, India. The soil fertility was relatively greater in agricultural and agri‐horti‐silvi‐pastoral systems as a result of accumulation of leaf litter/crop residues and addition of inorganic and organic manures. Microbial biomass carbon was greatest in agricultural (378 mg kg^?1) followed by the agri‐horti‐silvi‐pastoral systems (291 mg kg^?1). The most microbial biomass nitrogen (N) and phosphorus (P) (32.4 and 17.07 mg kg^?1, respectively) were recorded in agricultural followed by agri‐horti‐silvi‐pastoral systems. Microbial biomass carbon (C) had a significant relationship with organic C, microbial biomass N, and biomass P, indicating that the living part of soil organic matter is involved in the transformation of nutrients into the labile pool and governs their availability to the plants. Application of inorganic fertilizers and organics along with lime has contributed more microbial biomass that led to more biological activity attributed in nutrient transformations and also maintained the soil fertility.     

Genetic variation in wood color and its correlations with tree growth and wood density of <Emphasis Type="Italic">Calycophyllum spruceanum</Emphasis> at an early age in the Peruvian Amazon

Calycophyllum spruceanum (Benth.) Hook. f. ex K. Shum. is an important timber-tree species in the Peruvian Amazon Basin. Markets currently prefer wood with a uniform, light yellow color, but these preferences may change in the future. As farmers and industry commonly use wood from young trees, it is important to investigate genetic and environmental variation in juvenile-wood properties to assess whether tree improvement programs could make adjustments to changing preferences. A provenance/progeny test was established to evaluate genetic variation in growth and wood properties of young trees, the strength of their genetic control as well as their interrelationships both at the genetic and the phenotypic level in different planting zones. This paper presents analyses of variation in wood color at 39 months, and their correlations with tree growth and wood basic density. CIELab means for lightness ranging from black to white (L), green to red hues (a*) and blue to yellow hues (b*) were 67.63, 5.34 and 22.12, respectively; means for chroma (C) and hue angle (h)* were 22.76 and 76.43, respectively (C and h* were estimated from a* and b*). Significant variation due to provenances and especially due to families within provenances was found in some wood color characteristics, and some color characteristics also differed significantly among planting zones. Genetic correlations indicate that, in general, selection of faster growing trees and/or trees with denser wood would have little effect on wood color and its uniformity. In general, wood color had relatively low heritability (h _i ²): among all trees, h _i ² = 0.31 for L; and variance due to families was not significant for a* and b*. Genetic control of color was highest in the planting zone where trees grew most rapidly: h _i ² = 0.48 and 0.52 for a* and b*, respectively; but variance due to families was not significant for L. Results suggest that selection based on wood color would be more effective in zones with more fertile soils and higher rainfall.      

大豆主要品质性状的稳定性研究

以生育期相近的２５个品系为材料，在８个地点同时进行试验，对大豆的主要品质性状的稳定性进行了研究。结果表明，主要品质性状的稳定性存在明显差异，蛋白质＋脂肪总量最稳定，其次是蛋白质含量及脂肪含量，这３个性状均较各脂肪酸稳定，亚麻酸的稳定性最差，这也表明其最易受环境的影响。不同品种同一性状的稳定性也存在明显差异。蛋白质含量、脂肪含量及蛋白质＋脂肪含量与其本身的稳定性无关，亚麻酸含量低的品系稳定性较好。稳     

影响面粉色泽因素的研究

为了探讨影响面粉色泽的因素，对在黑龙江省两个生态区域种植的小麦品种龙麦26和龙辐麦12的面粉色泽进行了研究。结果表明，面粉蛋白质含量与面粉明度指数(L^*值)呈极显著负相关(r=-0．70)；面粉多酚氧化酶(PPO)活性对面粉色泽影响不大；类胡萝卜素含量与面粉黄度指数(b^*值)呈显著正相关(r=0．60)；小麦籽粒性状(如容重、千粒重等)对面粉色泽也有一定影响。对不同地点种植的同一小麦品种而言，籽粒千粒重和容重越大，其面粉色泽越好，L^*值越高。     

高寒沙区植被恢复过程中表层土壤因子的变化规律

对青海沙珠玉地区人工植被恢复过程中表层土壤因子性状的研究表明:人工植被恢复对干旱区土壤有很好的改良效果。随着流动沙丘被固定,土壤逐渐出现结皮层,颗粒组成中砂粒质量分数逐渐降低,粉粒质量分数增加,土壤有机质和全氮质量分数逐渐增加,pH值有降低的趋势。由线性回归分析可看出,表层土壤中有机质和全氮质量分数与砂粒质量分数呈显著负相关,而与粉粒质量分数呈显著正相关。干旱沙区的土壤要恢复到自然的水平需要相当长的时间,因此,对于荒漠化地区土壤保护是一个极为重要的问题。     

Within-Field Variability of Winter Wheat Yield and Grain Quality versus Soil Properties

Within-field variability in wheat grain yield and its quality always exists in production fields and depends, among other factors, mainly on various soil properties related to nutrients and water availability. The aim of the research was to examine the relationships between selected soil properties such as texture; pH; content of the available phosphorus (P), potassium (K), magnesium (Mg), and organic carbon; and winter wheat grain yield and quality under rainfed conditions. Six crop fields with winter wheat (Triticum aestivum, L.) in three sites located in different regions of Poland were examined during two seasons. The grain yield was mainly determined by the soil texture, and the majority of the chemical soil properties did not have a significant effect on grain yield. The grain quality traits were determined by the examined soil properties to a smaller degree than grain yield. The relationships were not consistent across sites and years.     

杏杂种一代群体产量形成因素的研究

 以5～6年生的‘凯特’ ב新世纪’F₁ 代群体52个株系为试材, 对株系的自交坐果率、有效花比率、平均单果质量及单株坐果数等性状的变异及其与单株产量的相关性进行了研究, 结果表明, ①杏自交坐果率、有效花比率、平均单果质量、单株坐果数及单株产量等性状在F₁ 代广泛变异, 其中单株坐果数及自交坐果率的变异系数最大, 分别为102.0%和99.5% , 说明这两个性状的选择潜力较大; ②单株坐果数、自交坐果率及有效花比率均与单株产量极显著正相关, 相关系数( r) 分别为0.945、0.541和0.439, 且自交坐果率、有效花比率与单株坐果数的相关性亦达到极显著水平, 说明自交坐果率及有效花比率均是株系产量形成的主要因素; ③平均单果质量与单株产量的相关系数虽然为负值( r = - 0.176) , 但相关性不显著, 出现这种结果主要是由于在多因素相关分析系统中, 其他因素相互影响造成的。因此, 在本试验体系中, 果实大小不是产量形成的主要因素; ④依据上述相关性的研究结果, 初步提出并讨论了丰产选择与品质选择的“二次选择法”。     

Quality fruit improvement in sweet pepper culture by bumblebee pollination

The percentage of ovules that set seeds per fruit has been used to evaluate the bumblebee activity of a two campaigns greenhouse trial. The experiment was carried out with two commercial cultivars of sweet pepper, ‘bell’ type, called Bardenas and Vergasa. The averages of the percentages of seed set per fruit of the two campaigns were 49.8% (Bardenas) and 40.7% (Vergasa) on the pollination treatment, whereas the averages of the control (self-pollination) treatment were 27.5% and 25.7%, respectively. Percentages of seed set per fruit was strongly related with the number of bee visits, but weakly with duration of visits.     

长货架期树莓高代品系特性及主要性状相关性

试验测定了树莓不同品系果实产量,并对与货架期相关的果实品质及主要性状进行了相关性分析。结果表明,SJR941-18,SJR941-1和SJR944-2是果实较大的品种。Boyne,Festival,Killarney和SJR941-5茎的耐寒性显著优于其他品种,使这些品种有较高的产量。树莓果实产量与茎的活力和健康花芽数呈显著正相关,与死亡茎长度呈显著负相关。茎的活力与健康花芽数、健康茎长度呈显著正相关。果实硬度和可溶物含量、果实表面绒毛多少与解冻后果汁百分比亦有显著相关性。     

非参数度量在棉花区试数据分析中的应用

简明介绍了非参数分析方法 ,并运用该方法对安徽省棉花区试资料进行分析。结果表明 :参试品种D1 80丰产性、稳产性较好 ;皖杂 3号丰产性较好而稳产性较一般 ;绿杂棉 1号丰产性较差 ,稳产性较好。笔者还对利用非参数度量方法分析棉花品种区试数据的一些相关问题进行了探讨