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Sustainable agriculture in China is highly threatened by rapid urbanization, land degradation and high population pressure. Yunnan Province, south-west China, is 94% mountainous and lacks flat land. Food shortages and inappropriate cultivation have led to intensive cultivation of steep, marginal and fragile land and have increased soil erosion. To curb this situation and assist with poverty alleviation, it is crucial to develop more productive and sustainable cropping systems. An experiment was conducted on sloping areas from 1999 to 2001 in Wang Jia Catchment, Yunnan Province. The project aim was to evaluate the effects of five selected cultivation practices on maize productivity and soil properties. The treatments were: (1) downslope cultivation without mulch, (2) contour cultivation without mulch, (3) contour cultivation with polythene mulch, (4) contour cultivation with polythene and wheat straw mulch (Integrated Contour with Plastic and Straw Mulch Treatment, INCOPLAST) and (5) contour cultivation with polythene mulch and intercropping, wide and narrow row spacing, with soybean in wide row spacing. Crop growth parameters and soil physical properties were measured throughout the cropping seasons. Considering three years data, contour cultivation with polythene mulch generally increased soil temperature by a mean of 1-2°C. The polythene retained considerably more soil moisture during dry weather. However, during wet weather, polythene prevented rainfall directly falling on the soil, which led to less soil moisture content. The soil temperature and moisture regimes under polythene mulch made plants grow faster and canopies develop well, leading to higher final yields. The benefit of polythene was 33-54% more yield than downslope cultivation without mulch treatment, over three seasons. Contour cultivation plus polythene and straw mulch retained significantly higher soil moisture levels. The yield of this treatment in 1999 was ranked second, but in 2000 it had the highest yield and in 2001 it was also more effective than contour cultivation with polythene mulch treatment. Contour cultivation with polythene mulch and intercropping improved maize yield. The soybean harvest also contributed to net income, the crop had a similar function to straw mulch and increased N availability. Contour cultivation increased yields over the range 7.2-11.2% over three seasons compared with downslope cultivation, equivalent to ~500-1000 kg per hectare more grain produced. There were few clear trends in soil properties over the 1999-2001 period. However, N concentrations increased in the contour cultivation with polythene mulch and intercropping treatment. Both contour cultivation with polythene and straw mulch and contour cultivation with polythene mulch and intercropping gave apparent increases in total K, probably resulting from both decayed straw and decomposed soybean leaves. In terms of simple cost-benefit evaluation, downslope cultivation had the lowest input and output, while contour cultivation had a similar input, but a higher output. Contour cultivation with polythene had the highest net return. Contour cultivation with polythene and straw had a high output but did not give a higher net return than contour cultivation with polythene. Contour cultivation with polythene mulch and intercropping generally had the highest input and output and could give a higher net return than contour cultivation with polythene when the soybean harvest was successful, but over three years this treatment had the greatest risk from crop failure. It is recommended that replacing downslope cultivation with contour cultivation can increase crop yields and this simple action could contribute to the development of more sustainable cropping systems in Yunnan. Polythene mulch achieved higher maize yields but its environmental impact requires further study. It is considered that contour cultivation with polythene and straw mulch or soybean intercropping could contribute towards more productive and sustainable cropping systems where soil conservation is high priority. The technique could assist with long-term soil, water and nutrient conservation and improved crop productivity.

Fucoxanthin is an epoxy carotenoid with important beneficial bioactivities. In this study, a type of microalgae (diatom) Thalassiosira weissflogii was used as the feedstock for fucoxanthin extraction. Effects of solvent types, feedstock conditions, presence of antioxidants, and extraction time on fucoxanthin yield were investigated. Results suggested diatoms might be a more cost effective source for fucoxanthin extraction than brown algae. Wet diatoms can achieve high extraction yields over a much shorter period. Yield was 100.7 ± 5.8% of the average total available fucoxanthin in the diatoms after 10 min of extraction with acetone. Adding 0.3% of the antioxidant, butylated hydroxyanisole (BHA), during extraction may not increase the yields significantly in the short time, but it could prevent the further potential decomposition of fucoxanthin. Several studies have suggested that fucoxanthin has anti‐obesity, anti‐diabetic, and anti‐cancer properties. We sought to determine whether fucoxanthin, gavaged daily, would demonstrate anti‐obesity and anti‐diabetic properties in rats fed a high‐fat/high‐sucrose diet. To accomplish this, we performed an energy balance study in three groups of Wistar rats. Two groups of rats were fed a high‐fat/high‐sucrose diet. One of these groups was gavaged daily with fucoxanthin, while the other group was gavaged with vehicle. The remaining group was fed a low‐fat diet and was gavaged daily with vehicle. Food intakes and body weights were determined daily for approximately 12 weeks. After 10‐11 weeks on the respective diets, a subset of rats from each group was placed in metabolic cages for 3 days to determine energy expenditure, RQ, and physical activity. Lastly, all rats were given iii an oral glucose tolerance test to determine how the diets and fucoxanthin treatment affected insulin sensitivity. Results obtained in this study were contrary to the hypothesis that fucoxanthin has anti‐obesity and anti‐diabetic properties. In fact, we found that fucoxanthin‐treated rats fed a high‐fat/high‐sucrose diet gained significantly more body fat than vehicle‐treated rats fed the same diet. The increase in body fat associated with fucoxanthin treatment did not appear to be related to a change in the energy expenditure. Rather, the increase in body fat appeared to be due to a non‐statistically significant increase in food intake and an increase in the energetic efficiency of the calories that were consumed. In addition, fucoxanthintreated rats fed the high‐fat diet also showed greater insulin resistance as compared to the vehicle‐treated rats fed the high fat diet. No difference in insulin resistance was found between low‐fat‐fed and high‐fat‐fed rats treated with vehicle. The greater insulin resistance of fucoxanthin‐treated rats may reflect greater amounts of overall fat gain or perhaps a greater amount of fat deposition in nonadipocytes tissues. The present study suggests that caution should be exercised when considering whether fucoxanthin has anti‐obesity and anti‐diabetic bioactivities. The specific experimental conditions under which fucoxanthin is extracted and tested may greatly affect the outcome of such studies.