余姚市杭州湾沿岸基干林带生长现状及土壤改良效应

为了解余姚市杭州湾沿岸基干林带建设情况,于2018年10-11月对各基干林带的生长状况和土壤改良情况进行调查和研究。结果表明,基干林带整体造林保存率达85%,林分平均郁闭度>0.65,造林总体质量良好。2010年造林林带的平均蓄积量和平均生物量最高,2010年和2013年造林林带生长最快,其中以35杨Populus sp.,竹柳Salix fragilis,水杉Metasequoia glyptostroboides的生长最快。竹柳,木麻黄Casuarina equisetifolia以及部分臭椿Ailanthus altissima和35杨长势较差,其他树种长势良好。造林可提高土壤总氮和有机质含量,并可有效降低含盐量。不同造林树种均可有效提高根际土壤总氮和有机质含量,并可显著降低土壤含盐量;乌桕Sapium sebiferum可有效提高根际土壤总磷水平。综上分析,35杨,乌桕,黄连木Pistacia chinensis,夹竹桃Nerium indicum等可作为余姚市杭州湾沿岸基干林带的适宜树种优先选用。

Analysis of pH Value and Primary Nutrients in Blueberry Garden Soil

In order to explore the soil nutrient characteristics and put forward the improvement measures, a field experiment was arranged and performed. The experiment was conducted to evaluate the pH value and primary nutrient status in blueberry garden soil by means of collecting 21 soil samples from the main production base of blueberries in Qingdao, according to the specific requirements of blueberries for soil pH and organic matter and the second national soil survey nutrient classification standard. Results showed that the blueberry garden soil had the following characteristics： acidic soil, low organic matter content with significant differences among different bases, moderate total nitrogen and alkaline hydrolysis nitrogen contents, high available phosphorus content and above moderate available potassium content. Then, it is found that the primary causes were the differences in soil basic fertility, excessive use of sulfur, inadequate inputs of organic matter, not thorough soil improvement, and imperfect fertilizer management in the blueberry gardens. Finally, the corresponding improvement measures were put forward, for example, increasing organic fertilizer and organic matter covering, as well as the application of CaCO_3 and formulated fertilization.

Morphological comparison between a selected fast-growing strain and the common cultured strain of turbot Scophthalmus maximus

To evaluate the effect of genetic improvement of the turbot Scophthalmus maximus, we analyzed morphological differences between a fast-growing strain obtained by family selection and the common cultured strain, by principal component analysis, stepwise discriminant analysis, and t-tests. Although they clearly differed morphologically, plots of the principal components of the two strains partially overlapped. However, the difference between the strains was supported with very high precision by discriminant analysis. The t-tests revealed that 4 of the 13 morphological traits analyzed were highly significantly different (P<0.01), 4 traits also differed significantly (P<0.05), and the remainder did not differ significantly. The coefficients of difference of the 13 traits were all lower than the threshold value between subspecies (1.28). Together, the results indicate that a trend for segregation of characters from the common cultured strain have already appeared in the selected fast-growing strain but the degree of segregation have not risen to subspecies level.

Conocarpus Biochar Induces Changes in Soil Nutrient Availability and Tomato Growth Under Saline Irrigation

Thermally modified organic materials commonly known as biochar have gained popularity of being used as a soil amendment.Little information, however, is available on the role of biochar in alleviating the negative impacts of saline water on soil productivity and plant growth. This study, therefore, was conducted to investigate the effects of Conocarpus biochar(BC) and organic farm residues(FR) at different application rates of 0.0%(control), 4.0% and 8.0%(weight/weight) on yield and quality of tomatoes grown on a sandy soil under drip irrigation with saline or non-saline water. The availability of P, K, Fe, Mn, Zn and Cu to plants was also investigated. The results demonstrated clearly that addition of BC or FR increased the vegetative growth, yield and quality parameters in all irrigation treatments. It was found that salt stress adversely affected soil productivity, as indicated by the lower vegetative growth and yield components of tomato plants. However, this suppressing effect on the vegetative growth and yield tended to decline with application of FR or BC, especially at the high application rate and in the presence of biochar. Under saline irrigation system, for instance, the total tomato yield increased over the control by 14.0%–43.3% with BC and by 3.9%–35.6% with FR. These could be attributed to enhancement effects of FR or BC on soil properties, as indicated by increases in soil organic matter content and nutrient availability. Therefore, biochar may be effectively used as a soil amendment for enhancing the productivity of salt-affected sandy soils under arid conditions.

Effects of Biochars and Other Organic Soil Amendments on Plant Nutrient Availability in an Ustoxic Quartzipsamment

A sandy soil, Nampong soil （classified as Ustoxic Quartzipsamment）, was incubated under controlled condition i） to compare the mineralization of major plant nutrients derived from different types of biochars and other organic soil amendments; ii） to examine their effects on soil properties and plant nutrient availability; and iii） to evaluate the plant nutrient losses in leachate from the rooting zone of soil incorporated with the different amendments. The experiment was arranged in a completely randomized design with 3 replications. Five treatments of soil amendments used were cassava stem base biochar （CSB）, rice husk biochar （RHB）, chicken manure （CM）, compost （CP）, and no amendment application （control）. The RHB treatment released the highest amounts of mineralized NO^-N, available P and K （2.30-17.26, 5.50-42.90 and 43.00-187.63 mg kg-1, respectively） while the CM treatment releasing the highest NH4＋-N in the range of 1.86-53.67 mg kg-1. The CSB and RHB treatments showed better continuity of mineralization of nutrients than the treatments of CM and CP, particularly in the case of the CSB treatment. In the soil column incubation experiment, the amounts of NH4＋-N and NO3-N in all treatments barely changed on Day 1 to Day 30 of incubation and then the amounts increased markedly on Day 60. On Day 601 the RHB treatment contained a very high amount of NO3--N （〉 250 mg kg-1）. This suggests that N would become more available 30 d after the incorporation. The CM treatment gave the highest amounts of organic matter and available P in the ranges of 4.64-8.94 g kg-1 and 14.41-36.33 mg kg-1, respectively, during the 60-d column incubation. The CSB treatment tended to have higher available K throughout the measuring period. The NO3--N was leached from the soil column quite quickly on Day 1 of incubation while the loss of NH^-N decreased slightly from Day 1 until the end of the measurement. The amounts of P and K losses varied with the type of soil amendments, and the pattern of the loss was irregular.