Intensification of redclaw crayfish Cherax quadricarinatus culture: II. Growout in a separate cell system

In the process of exploring ways to intensify crayfish culture, a growout system of individual cages (cells) was designed to determine the effects of gender and cell size on the growth of the red claw crayfish Cherax quadricarinatus. Cells of three different diameters—large (25 cm), medium (20 cm) and small (16 cm)—were used. When crayfish were stocked at a mean weight of approximately 10 g, growth rate of males was significantly higher than that of females. The growth rate of the males in the large cells was 0.31±0.14 g/day, while that of the females was 0.18±0.09 g/day. The size of the cell had significant influence on the weight of males. Male crayfish in the large and medium cells grew better than those in the small cells. When males were stocked at a higher mean weight (about 23 g), their mean weight after 206 days was higher in the large cells (69.28±15.72 g) than in the small cells (58.11±12.66 g), suggesting that the growth of large males was also affected by cell size. Regardless of cell size, male animals of this species grew faster than females under conditions of individual cells. This intensive culture method appears to present a powerful improvement in yields, by as much as two orders of magnitude, in comparison with communal cultures.     

伏天灌水覆膜对土温变化及西瓜枯萎病防治

为探明南方伏天灌水覆膜土温变化特点,2004和2005年伏天,对连作大棚西瓜地灌水后畦面覆盖不同颜色、不同层数的塑料薄膜与土温变化特点和防治西瓜枯萎病（Fusariurn oxysporurn f. sp.niveum）的关系作了研究,结果表明,灌水覆膜能明显增加表土下5～20 cm土层的温度,增温幅度达10～15℃（同露地相比）;增温效果以双层白膜最好,单层白膜次之。单层白膜覆盖l0 d后其土表下5～20 cm土层的温度全天可维持40℃以上。大棚内灌水覆盖单层白膜25 d以上对第一茬连作西瓜枯萎病防效达     

不同植烟模式对烤烟产质量、土壤养分和酶活性的影响

在贵州烟区具有代表性的第四纪黄壤上,进行了连续6年的田间定位试验,研究了烤烟连作,烤烟-玉米轮作和玉米-烤烟-烤烟轮作三种种烟模式对烤烟的产量和品质,土壤养分以及酶活性的影响。结果表明,烤烟连作降低烤烟的产量、质量和土壤pH,提高有效磷和速效钾含量,抑制脲酶和蔗糖酶活性,增加过氧化氢酶活性。相反,烤烟-玉米轮作和玉米-烤烟-烤烟轮作有益于提高烤烟的产量和质量,是值得推广的种烟模式。     

Comparison of Growth and Yield Performance of Several Water Chestnut Species Collected from Southwestern Japan and Middle China

Summary

Vegetative growth characters and yield components of water chestnuts distributed in Japan and China were investigated for 12 local lines of 6 species ; i.e., 5 small and 2 medium fruit lines from Japan, and 5 large fruit lines from China. The materials were transplanted and grown in a flooded field usually used for rice cultivation in Saga City in 1995. The lines from China had higher rates of foliage formation, developed emersed leaves earlier and maintained them longer compared with the Japanese lines. The small fruit lines of Japan had the shortest growing period, although the number of rosettes was larger. The fruit yield of the small, medium and large fruit lines, was 250 to 400 g m^?2, about 600 g m^?2 and 600 to 1,000 g m^?2, respectively. The fresh weight of well-ripened fruit was 1 to 5 g for the small fruit lines, 5 to 10 g for the medium fruit lines and more than 10 g for the large fruit lines. The number of fruits per m2 increased as the fruit size of the lines decreased. However, the productivity of the water chestnut was higher in the large fruit lines than in the small or medium fruit lines.     

Variation in Growth and Yield Performance of Seventeen Water Chestnut Accessions (Trapa spp.) Collected from Asia and Europe

Abstract

Water chestnut is an aquatic annual herb, and its fresh, edible fruit is a valuable crop. The huge variation in growth and yield of water chestnuts has not been well documented. In this study, the yield performance of 17 water chestnut lines, eight from China (Trapa acornis L., T. bicornis L., T. bispinosa Roxb, T. quadrispinosa Roxb), one from France (T. natans L.), one from India (T. bispinosa Roxb.), three from Italy (T. natans L.), three from Japanese (T. incisa L., T. japonica Flerov, T. natans.L. var. rubeola Makino), and one from Korean (T. japonica Flerov.) were cultivated in Saga City, Japan during the summer, 2005, and the morphological characters of their fruit were analyzed. European lines were early flowering, but had a lower yield due to poor canopy density and lower rosette density. All the Asian lines had a higher rosette density. In spite of the smaller number of fruits per rosette, the Chinese lines had a higher yield than the other lines because the fruit was larger. The yield performance of the Indian line was similar to that of the Chinese lines. The Korean and Japanese lines produced a large number of small fruits per unit land area. Apart from the variation in fruit size, a huge variation in shape including the height, width and the spines were observed. Path analysis revealed that productive rosette number m-² and the single fresh fruit weight are two direct yield determinants while number of fruits per rosette has indirect negative influence on yield via productive rosette number and single fruit weight.     

The effects of compost in a rice–wheat cropping system on aggregate size,carbon and nitrogen content of the size–density fraction and chemical composition of soil organic matter,as shown by 13C CP NMR spectroscopy

We investigated whether the long‐term application of compost from agricultural waste improved soil physical structure, fertility and soil organic matter (SOM) storage. In 2006, we began a long‐term field experiment based on a rice–wheat rotation cropping system, having a control without fertilizer (NF) and three treatments: chemical fertilizers (CF), pig manure compost (PMC) and a prilled mixture of PMC and inorganic fertilizers (OICF). Following the harvest of wheat in 2010, the mean‐weight diameter (MWD) of water‐stable aggregates and the concentration of C and N in bulk soil (0–20 cm; <2 mm fraction) were significantly greater (P < 0.05) in PMC and NF plots than in CF or OICF plots. Pig manure compost significantly increased the proportion of >5‐mm aggregates, whereas CF significantly increased the proportion of 0.45‐ to 1‐mm aggregates. The C and N contents of all density fractions were greater in PMC than in other treatments with levels decreasing in the following order: free particulate organic matter (fPOM) >occluded particulate organic matter (oPOM) > mineral‐combined SOM (mineral–SOM). Solid‐state ¹³C CPMAS NMR spectra showed that alkyl C/O‐alkyl C ratios and aromatic component levels of SOM were smaller in PMC and OICF plots than in CF plots, suggesting that SOM in PMC and OICF plots was less degraded than that in CF plots. Nevertheless, yields of wheat in PMC and NF plots were smaller than those in CF and OICF plots, indicating that conditions for producing large grain yields did not maintain soil fertility.     

樟子松固沙林经营技术的研究

通过合理的经营技术，可培育产量高，质量好，防风效能持久的樟子松固沙林。     

大豆专用复混肥对轮作、连作大豆增产机理的研究

采用盆栽试验、田间试验及室内分析相结合的方法 ,研究了含有沸石、腐殖酸、稀土的大豆专用复混肥对轮作、连作大豆的增产机理。结果表明 ,施用大豆专用复混肥对轮作、连作大豆具有明显的改土、增加肥效、抗逆、提高光合效率和促进大豆生长的作用 ,最终表现出明显的增产效果。大豆专用复混肥的综合施用效果以连作大豆好于轮作大豆     

设施园艺连作障碍研究进展

随着经济的发展,设施园艺正趋于规模化和产业化。在经济效益的驱使下,设施园艺发生了大面积的连作障碍,从而限制了设施园艺的可持续发展。该研究从土壤的理化性质、生态环境、植物的自毒作用等方面阐述了连作障碍产生的原因,并提出一系列缓解措施,旨在为设施园艺连作障碍的研究提供一定的参考依据。     

北方日光温室黄瓜栽培存在的突出问题及对策

对北方地区日光温室黄瓜生产中存在的温室结构不合理,连作障碍严重和药害发生频繁等问题进行了阐述,并提出了相应的解决方法。