Bumblebees are widely used to pollinate various crops, especially tomato, in greenhouses and fields. Here, we investigated whether different sugar solutions have any effects on the oviposition and colony development of Bombus terrestris queens. The types of sugar solution used were a white sugar solution, brown sugar solution, dark brown sugar solution, and prepared sugar solution; all solution contained with a 40% sugar concentration and 0.3% sorbic acid. Among these sugar solutions, B. terrestris queens reared on the white sugar solution exhibited the best results; the rates of oviposition, colony foundation and progeny-queen production were75.0± 11.0, 33.0 ± 9.6 and 21.7 ± 7.3, respectively, which corresponded to 1.1-33.0-fold increases over the results of other sugar solutions. Queens reared on the prepared sugar solution did not found any colonies. The death rate within one month was lowest for the queens reared on the white sugar solution at 26.1 ± 10.9%, which was 1.2–2.0-fold lower than the rate for the other sugar solutions. Furthermore, the numbers of progeny produced by queens reared on the white sugar solution, 131.4 ± 38.8 workers and 51.0 ± 40.6 queens, were also higher, corresponding to 1.1-1.2-fol d increases compared to queens raised on the other sugar solutions. Therefore, the white sugar solution was the favorable sugar solution for the egg-laying and colony developmental characteristics of B. terrestris queens.

In Korea, the developmental gap is deep between rural and urban areas in spacial aspect and, or between agricultural and industrial side. So there are much room for improvement in agri. development in national standpoint as well as in individual farmer's level. In this respect, agricultural financing is requisitive to speed up the pace of agricultural development and in result, to contribute to improvement of farm income. By the way, farmers' credit demands are always in excess-demand status and they rely on private money-lenders in the burden of high interest rate. In agricultural financing market, there are two kinds of credit ; institutional credit and non-institutional credit market, that is private money-lending. In institutional credit, there are mutual credit system operating by the primary coops and policy credit system by NACF financed by Government in part. Here, in this paper, I venture to study on the improvements of the policy credit system to increase and activate the supply function of agri. policy credit into farmers to enhance their socio-economic status.

The effects of long-term fertilization on soil properties and nutrient availability are not well documented for cassava cultivation in Vietnam. In 1990, a field research plots were established with 12 treatments to test the effect of different rates of nitrogen (N), phosphorus (P) and potassium (K) on soil properties in Acrisols at Thai Nguyen University in Northern Vietnam. In 1999, composite soil samples (0 to 20cm depth) were collected from eight selected plots for measurements of nutrient supply rates by ion exchange membrane probes and for growing corn and canola in a growth chamber with and without added lime. Generally, long-term nitrogen (N) fertilization increased available N supply rates but decreased available potassium (K) and magnesium (Mg). Long-term phosphorus(P) applications increased canola N, calcium (Ca) and Mg uptake. Canola P uptake increased with increased P rates only when lime was added. Long-term K applications increased canola N, K, Ca, Mg uptake but only significantly increased corn N uptake. Liming significantly increased uptake of N, P, K, Ca, Mg and S for both corn and canola. However, N H4- N, K and Mg soil supply rates were reduced when lime was added, due to competition between Ca from the added lime and other nutrients.