Status Quo of Collection and Utilization of Rice and Wheat Straw in Jiangsu Province and the Countermeasures

A case study of Jiangsu Province was conducted using questionnaires and field survey to explore the status quo of the collection and utilization of rice and wheat straw of the province. Problems in collecting the straw were analyzed taking into account meteorological data of the rice and wheat harvesting seasons in the region. Results show：（1） Currently, the main handling way of rice and wheat straw was directly returning to field. The peasant households of straw returning from investigated townships A and B respectively occupied 22.01% and 28.75% of investigation households, and both of the two townships had a considerable portion of the straw wasted or improperly disposed. In township B, over 50% of the farmer households surveyed failed to make sure of any of the straw, and as high as over55% of the straw was discarded or burnt.（2） During the rice and wheat harvesting seasons, the ten-day precipitation was among 7.21-87.28 mm, and the ten-day precipitation days were among 1.53-5.00 d. Such weather not only affected timely harvesting of rice and wheat, but also seriously impeded baling, transportation and storage of straw.（3） As the crops must be harvested in a relatively short and concentrated time period, large volumes of straw were turned out within a few days.Moreover, harvesting of the first crop often coincided with sowing, leaving little time available for straw collection.（4） Straw collection was very low in economic benefit.A farmer can only get 60-90 RMB per day from straw collection and transportation,which was much lower than what they can get by working as migrant workers in the city.（5） Machines designed for straw collection were rare and those now used in the operation were low in efficiency and needed to be improved technically,which directly affected the efficiency of straw collection. The above-listed findings indicates that time shortage, negative weather condition, low benefit and low mechanization level were major factors affecting straw collection. To solve the problems,the following proposals were brought forth, that is, improving the economic benefit of straw collection as a driving force, accelerating the research and development of rice and wheat sheaf-binding reaping machine, and setting up a long-term operational mechanism for straw recovery, in the hope that this study may provide some useful ideas to help solve the problems.

Interaction of Pb and Cd in Soil Water Plant System and Its Mechanism: II. Pb Cd Interaction in Rhizosphere *1

The interaction of Pb Cd can be observed not only in the uptake process of elements by plants and in their influence on the growth, but also in rhizosphere. The changes in extractable Cd and Pb concentrations in the rhizosphere soil of rice plants, root exudates from wheat and wheat plant and their complexing capacity with Pb and Cd were investigated under different Pb and Cd treatments. Results showed that the concentration of extractable Cd in the rhizosphere of rice in red soil was markedly increased by Pb Cd interaction. It increased by 56% in the treatment with Pb and Cd added against that in the treatment with only Cd added in soil. The considerable differences in both composition and amount of root exudate from wheat and rice were found among different treatments. Pb and Cd might be complexed by root exudates. The concentrations of free Pb and Cd in the solution were increased markedly by adding root exudate from wheat and decreased by that from rice due to Pb Cd interaction. The distribution patterns of Pb and Cd in roots were affected by Pb Cd interaction, which accelerated transport of Pb into internal tissue and retarded accumulation of Cd in external tissue.

Effects of Droughts and Floods on Crops and Preventions in Puyang City

The research analyzed characters of rice/wheat growth and yield structure in Puyang and explored the effects of droughts and floods on the crops. The re-sults showed that droughts and floods had significant effects on crop growth and yield. In Puyang, the relieving and prevention technology of the disasters is con-cluded. Specifical y, it is recommended to make ful use of agricultural climate re-sources in a rational way and select suitable crop varieties according to climate and disaster characters, fol owed by timely sowing and scientific crop arrangement. What＇s more, ploughing should proceed in deeper soil layers and management measures should be optimized to reduce the effects of disasters on crops. In addi-tion to that, disaster index system should be reinforced in terms of establishment, monitoring, warning and prevention to lay scientific foundations and provide refer-ences for safe crop production and preventing and reducing disasters.