某灌区存在的问题及节水配套改造建设的必要性分析

牡丹江市南江灌区是黑龙江省中型灌区之一,位于黑龙江省牡丹江市境内,牡丹江中游。灌区地势东南高西北低,灌区东至磨刀石镇,西靠共荣三队,南至温春镇,北到青梅村。江灌区总土地面积8.12万hm2,其中耕地面积为1.68万hm2,由于骨干工程标准低、渠系不健全、田间工程不配套、工程年久失修、缺乏科学管理和水资源浪费严重等因素,制约了灌区发展,得出南江灌区节水配套改造工程是灌区发展的必然产物,是当地灌区人民的头等大事,是灌区经济发展面临的重大问题,对灌区进行配套及节水改造是十分必要和迫切的。

Impacts of climate change on agricultural water resources and adaptation on the North China Plain

Climate change is having a considerable impact on the availability of water resources for agricultural production on the North China Plain （NCP）, where the shortage of water is currently disturbing the stability and sustainability of agricultural production with respect to the drying tendency since the 1950s. However, although potential evapotranspiration （ET） has shown a decreasing trend under climate change, actual ET has slightly increased with an acceleration in hydrological cycling. Global climate model （GCM） ensemble projections predict that by the 2050s, the increased crop water demand and intensified ET resulting from global warming will reduce water resources surplus （Precipitation-ET） about 4%-24% and increase significantly the irrigation water demand in crop growth periods. This study assesses possible mitigation and adaptation measures for enabling agricultural sustainability. It is revealed that reducing the sowing area of winter wheat （3.0%-15.9%） in water-limited basins, together with improvement in crop water-use efficiency would effectively mitigate water shortages and intensify the resilience of agricultural systems to climate change.

Changing Land Use Pattern in India and Its Impact on Supply of Fresh Vegetables

The investment opportunities created by economic policies and increasing urbanization have enhanced demand for urban and peri-urban land. Fertile agricultural land is being converted to other uses. Around 1/3 more of the existing area under forests is needed to meet the targets of national forest policy. In the last two decades, 9% pastures have disappeared. The hills being removed cause threat to environment. The farmers seem to overuse land and other inputs. In the peri-urban areas agricultural fertile lands are many times forcefully acquired for non-agricultural uses, which result in violent protests and judicial interventions. A few cases of vast land use change, motive forces for such change, effect of change in land use on livelihood and on quality and costs of fresh vegetable supply are discussed in this paper. The partially used and unused data collected for earlier studies and some data collected for this paper have been used. The increase in land prices due to enhanced income of some sections, future need of prime land and returns from other than agricultural uses seem to be the driving force for change in land use, affecting the livelihood of people dependent upon farming who are migrating to nearby areas. Each shift of peri-urban agriculture will result in loss of quality, increase wastage by 6% and enhance costs of leafy vegetables by more than 5.5%. For an ideal urban land use, a balanced multi land use policy emphasizing peri-urban agriculture and forestry is suggested.

Nutrient Content in Irish Rainfall Water

Emissions of gases from industrial activities and even from agriculture activities and from soil as releasing of nitrogen from soils to atmosphere have been increasing steadily therefore, acid rain is the concern throughout the world. The hill field at the UCD research farm was chosen as the representative of good versatile, on which moderate to intensive farming is practised in the drier rainfall areas of Ireland. Nutrient contents in rainfall water samples were measurable, although the site of rainfall sample collection is located in the east of the country far away from the Atlantic Ocean. TDP （total dissolve phosphorus） concentrations in rainwater samples were very low. While DRP （dissolve reactive phosphorus） is the main component in some samples, the DUP （dissolve unreactive phosphorus） is dominant in others. DRP values accounted for less than 50% of dissolved phosphorus in rainfall. Sodium （Na） and Chloride （CI） ions had the highest concentration value, because most of Irish rain originates from the Atlantic Ocean. Nitrate （NO3） had the highest value 15.2 lag.mLl but it associated only with mineral fertiliser spreading time.

Cross River Watershed Hydrologic Adjustment： Pre- and Post-June 2012 Mega-storm

The Cross River watershed was disturbed by historic logging activity during the past century, but under the management of the USDA （United States Department of Agriculture） Forest Service, the area has mostly recovered from ecological disturbance. Today a new threat is being imposed by climate change; changes affect not only the temperature but also more extreme wind and rain In 2012, a mega-storm event passed through the north shore region of Lake Superior overwhelming many watersheds with excessive rain and runoff. As part of a Cross River study for the Forest Service, pre- and post-event hydrologic adjustment of the Cross River watershed were captured. Samples were collected for δD and δ18O during April, July, and September to estimate HRT （hydraulic residence time） using the stable isotopes of hydrogen and oxygen, The results showed that water collected throughout the watershed shifted toward the signature of the mega-event precipitation signature, then slowly diffused with new precipitation and fractionation processes that resumed into the summer and fall.