ABSTRACT
Objective To evaluate and compare the short-term effects of two kinds of plastic mulch on Oncomelania hupensis snail control in irrigation and drainage ditches with snails in Yunnan Province. Methods The irrigation and drainage ditches with high density of Oncomelania hupensis snails were chosen as the investigation sites,and then 4 groups were set,namely a colorless plastic mulch group,black plastic mulch group,colorless plastic mulch with molluscicide group and black plastic mulch with molluscicide group. The snail situation of the 4 groups was surveyed before the experiment and 7,14,21,30 days after covering plastic mulch,and the snail death rates were compared among the 4 groups. Meanwhile,the hourly temperatures of soil surface,soil surface under plastic mulch and soil layer 5,15 cm under the surface as well as the weather situation during the study period were measured and recorded. Results The average snail mortality rate of the colorless plastic mulch group was only 15.29% that was higher than that of the black plastic mulch group(6.56%)(P 0.05). Both kinds of plastic mulches could raise the temperature of the soil surface under plas-tic mulch and the soil layer below it,and the temperature of soil under the mulches increased over the cover time,and the aver-age temperature of the soil surface under the black mulch in 30 days was higher than that under the colorless mulch. Conclu-sion It is not suitable to use plastic mulch only in irrigation and drainage ditches with snails widely in Yunnan Province be-cause of its low effect,and if necessary,the molluscicide should be added.
ABSTRACT
In this work a field study was conducted to evaluate the effect of coloured plastic mulch on growth and yield of chilli from October 2005 to April 2006. The plastic mulches were transparent, blue, and black and bare soil was the control. Different mulches generated higher soil temperature and soil moisture under mulch over the control. Transparent and blue plastic mulches encouraged weed population which were suppressed under black plastic. Plant height, number of primary branches, stem base diameter, number of leaves and yield were better for the plants on plastic. At the mature green stage, fruits had the highest vitamin-C content on the black plastic. Mulching produced the fruits with the highest chlorophyll-a, chlorophyll-b and total chlorophyll contents and also increased the number of fruits per plant and yield. However, mulching did not affect the length and diameter of the fruits and number of seeds per fruit. Plants on black plastic mulch had the maximum number of fruits and highest yield. Thus, mulching appears to be a viable tool to increase the chilli production under tropical conditions.
ABSTRACT
Objective To study the effects of cultivation methods on growth dynamics in the aerial part and root of Angelica sinensis and Ditylenchus destructor, rate of early bolting, and yield of A. sinensis as well. Methods Compared with conventional planting, ridge planting, furrow planting, white plastic mulch coverage, and black plastic mulch coverage were used to evaluate the effects of cultivation methods on dry matter accumulating and growth dynamics of A. sinensis. Results The influence of black plastic mulch coverage to growth dynamics of A. sinensis is the biggest, next for white plastic mulch coverage. There is the best inhibition to D. destructor under ridge planting. Black plastic mulch coverage can enhance the rate of early bolting. The treatment of black plastic mulch coverage has the highest yield, which can increase the yield by 33.4% (4 650 kg/hm2) compared to conventional planting; next for the treatment of white plastic mulch coverage, which increased the yield by 24.3% (3 372.2 kg/hm2) compared to conventional planting. But there were no significant effects of ridge planting and furrow planting on increasing yield. Conclusion The cultivation methods of black plastic mulch coverage should be brought into wide use in A. sinensis cultivation.