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1.
Converting rice paddy to dry land farming in the Tai Lake Basin,China: toward an understanding of environmental and economic impacts 总被引：1，自引：0，他引：1
Water pollution is a well-known major problem in the Tai Lake Basin, China. Compared to industries and domestic sewage, non-point pollution from agriculture is more difficult to detect, measure, and control. Therefore, a range of policies has been formulated, among which is that of ‘adjustment of the planting structure.’ However, this policy during implementation has been used to simply convert paddy fields to dry land and food crops to cash crops. More surprisingly, to date, no research has provided evidence that such an agricultural land-use change contributes to the reduction of agricultural nutrient pollution. Based on an extensive farm survey, this research finds that conversion of rice paddy to dry land farming has not generated a positive effect on nutrient pollution control. It is estimated that nitrogen runoff from agricultural land has increased by 11 %, while phosphorus runoff has increased more than two times since land-use patterns changed, as farmers are inclined to apply more fertilizer on dry land than in paddy fields. However, this agricultural land-use change is economically effective as land-use conversion increases the net profits of farming in a significant way. It is demonstrated that, compared to environmental concerns, economic considerations are seen to have greater benefits after such an adjustment in the planting structure. These findings have important implications for policy making by local authorities in their efforts to improve environmental management and pollution control in their territories. 相似文献
2.
东北地区主要土壤类型及其肥力指标与气象因子的相关性 总被引：2，自引：0，他引：2
应用SPSS及Excel软件,统计分析东北地区主要土壤类型的分布、利用及其养分指标与气象因子的相关性。结果表明,东北地区的主要土壤类型涵盖暗棕壤、草甸土、黑土、棕壤、白浆土、黑钙土、沼泽土、栗钙土、栗褐土等9个土壤类型。耕地利用率达到60%以上的土壤类型主要有黑土、褐土和黑钙土;草甸土、栗褐土、风沙土、棕壤、栗钙土和白浆土的耕地利用率在30%以上。土壤养分指标与气象因子表现出不同程度的相关性,土壤有机质、全氮、速效磷等土壤养分与热量因子表现出极显著的负相关,与降水量呈显著或极显著的正相关。从宏观上分析,黑龙江省土壤有机质、全氮、碱解氮、速效磷等养分指标高于吉林省和辽宁省,年平均温度、≥10℃有效积温和无霜期等热量指标辽宁省高于吉林省和黑龙江省。结合成土过程与气象因子的关系,可以说明在平均气温较高的条件下,土壤有机质分解加快,不利于养分指标的积累,土壤肥力下降。 相似文献
3.
4.
采用大田小区试验研究了不同冬季轮茬种植模式下作物养分还田特征,及其对水稻产量和稻田表水环境主要参数的影响,并对各轮茬种植模式下的经济效益进行了分析。结果表明,不同冬季轮茬作物产量差异较大,且其养分含量差异亦较大,导致各轮茬种植模式下养分还田量差异显著。“红花草-水稻”模式下,N、P素还田量均最高。从短期效应来看,冬季作物轮茬对后茬水稻株高、产量及肥料利用率的影响均不显著。然而,从环境效应角度考量,不管何种轮茬种植模式,均应充分考虑水稻季基肥到分蘖肥期间的稻田水环境效应,监测发现,稻田表水总磷（TP）、可溶性总磷（DP）平均含量几乎都超过了易引发水体富营养化的临界水平（溶解磷0.05 mg/L和总磷0.1 mg/L）。同时,从周年经济效益角度考量,“青饲小麦-水稻”和“蚕豆-水稻”种植模式具有较高收益,可进一步推广应用。 相似文献
5.
运用地理信息系统（GIS）和地统计技术,对海南定安县145个土壤样本数据进行探索性空间数据分析,得知样点土壤的有机质、全氮、有效磷、速效钾存在空间自相关,然后采用Kring球体模型插值法,输出土壤养分空间分布图,据此分析土壤养分空间分布特征。结果表明,定安县土壤有机质、全氮含量较丰富,有效磷含量缺乏,速效钾含量严重缺乏。有机质与全氮的分布格局基本相似,南部含量较高,北部含量较低,四、五等级耕地的有机质、全氮含量高,二、三等级耕地的有机质、全氮含量较低。定安县西北部有效磷含量较高,东南部有效磷含量较低,四、五等级耕地有效磷含量较低,二、三等级耕地有效磷含量较高。整个定安县速效钾缺乏,尤其是北部,二、三、四等级耕地的速效钾含量均很低。 相似文献
6.
A. Bhadra A. Bandyopadhyay R. Singh N. S. Raghuwanshi 《Paddy and Water Environment》2013,11(1-4):331-341
A water balance model for paddy is developed primarily based on the principle of conservation of mass of soil–water within the root zone. The water balance for paddy is different from that of field crops because paddy requires standing water in the field during most of its growth period. This model requires soil, crop and meteorological data as inputs. This user friendly model was developed using computer programmes C and Visual Basic (VB) 6.0. It simulates various water balance components such as evapotranspiration, deep percolation, surface runoff and depth of irrigation water and ponding depth in the field on a daily basis. For estimation of deep percolation loss, physically based saturated and unsaturated flow processes are incorporated into the model to consider ponding (if there is standing water in the field), saturation (if moisture content of soil is in between field capacity and saturation) and depletion (if moisture content of soil is below field capacity) phases of paddy field. This article presents development of a user friendly water balance model for paddy and also its validation using published data. 相似文献
7.
构建生态沟渠消纳水体氮磷是防控农业面源污染的重要措施.为筛选出适应湘北洞庭湖区农区沟渠生长的高富集氮、磷植物,选取津市市毛里湖稻区沟渠作为研究对象,进行生态沟渠拦截试验.于2016~2017年连续监测,系统研究狐尾藻、珍珠梅、海寿花等水生植物及组合对小流域农田排水中氮、磷的去除效果.结果表明:2年观测期(4~8月)内,拦截植物对农田排水总氮、铵态氮、硝态氮及总磷的去除率效应极显著(p<0.01),且去除率具有生长变化趋势.不同拦截植物及组合对总氮、铵态氮、硝态氮及总磷的去除率大小表现为狐尾藻+海寿花>海寿花>珍珠梅>狐尾藻>自然植被.其中,狐尾藻+海寿花组合平均总氮、铵态氮、硝态氮及总磷的去除率2016年分别为53.57%、77.35%、51.74%和61.06%,2017年分别为34.67%、66.53%、39.51%和46.05%.研究区生态沟渠对氮、磷污染物有较好的拦截效应,单种植物以海寿花的水体氮磷消纳效果较好,在此基础上混种狐尾藻,效果更佳. 相似文献
8.
土地利用方式对南方红壤养分状况的影响 总被引：1，自引：0，他引：1
土壤养分是土壤学研究重点,是衡量土壤生产力的综合指标,而土地利用方式则是人类活动影响土壤养分变化最直接、最重要、最普遍的因素。随着人类活动对土地利用的范围不断扩大、强度不断加剧,进而对土壤养分造成了不同程度的影响,尤其是对南方红壤的影响。目前,该区域土壤养分退化严重,综述近10年国内外的相关文献,在土地利用方式改变下,以土壤的物理性质、有机质、氮磷钾的动态变化趋势对土壤养分进行分析和总结,以期更准确地预测和评估不同管理措施对土壤质量的影响,并及时采取有效措施,调整生产结构,降低土壤环境污染,提高土壤性能。 相似文献
9.
设置头季稻+鱼(或泥鳅)+再生稻的栽培模式,水稻品种选用黄华占和Y两优800,分析两种模式下土壤中全量氮、磷、钾含量与速效氮、磷、钾含量表现,结果表明:(1)稻鱼模式和稻鳅模式可增加土壤中全效养分含量,全氮、全磷、全钾含量在整个生育期内维持在一个相对稳定的状态,其中以稻鱼处理效果更明显,总体高于对照田.头季稻与再生季两个生育季内全氮、全磷处于相对稳定的状态,全钾含量则在再生季略有下降;(2)稻鱼模式和稻鳅模式提高了土壤中速效养分含量,孕穗期、灌浆期、成熟期含量比分蘖期时有所提升,稻鱼模式下土壤速效养分含量整体表现要高于稻鳅模式.两个水稻品种再生季的土壤速效养分含量变化规律性不明显,但整体维持在相对稳定水平. 相似文献
10.
海南岛典型农业土壤产流与面源污染特征分析 总被引：1，自引：0，他引：1
采用径流场结合人工模拟降雨方式,研究各种降雨条件下海南岛不同土地类型产流产沙的规律与面源污染特征。结果表明：土壤（泥沙）产流系数与平均流失速率表现为暴雨＞大雨＞中雨,且暴雨时的泥沙平均流失速率为中雨时的416％、大雨时的261％,在中雨、大雨和暴雨强度下,平均径流系数分别为24.49％、33.97％和53.40％;雨强对土壤营养物质流失速率的影响达到显著水平,COD、有机质和氮素以径流流失为主,磷素以泥沙流失为主;土壤径流和泥沙中的COD、有机质、氮素和磷素流失速率随雨强的增大而增大,坡度也可明显影响面源污染物的流失;海南岛农业土壤平均流失量为3.79 t/（hm2·a）,中雨强度条件时为1.92 t/（hm2·a）,大雨强度条件时为2.57 t/（hm2·a）,暴雨强度条件时为6.87 t/（hm2·a）。海南岛农业土壤的水土流失强度较高,海南农业土壤的水土流失与农田污染物输出状况不容乐观。 相似文献
11.
Evaluation of MODIS NDVI and LST for indicating soil moisture of forest areas based on SWAT modeling
Park Jong-Yoon Ahn So-Ra Hwang Soon-Jin Jang Cheol-Hee Park Geun-Ae Kim Seong-Joon 《Paddy and Water Environment》2014,12(1):77-88
This study examined the capability of remotely sensed information gained using the terra moderate resolution imaging spectroradiometer (MODIS) normalized difference vegetation index (NDVI) and land surface temperature (LST) to explain forest soil moisture. The soil and water assessment tool (SWAT) was used for the analysis. Nine years (2000–2008) of monthly MODIS NDVI and LST data from a 2,694.4 km2 watershed consisting of forest-dominant areas in South Korea were compared with SWAT simulated soil moisture. Before the analysis, the SWAT model was calibrated and verified using 9 years of daily streamflow at three gauging stations and 6 years (2003–2008) of daily measured soil moisture at three locations within the watershed. The average Nash–Sutcliffe model efficiency during the streamflow calibration and validation was 0.72 and 0.70, respectively. The SWAT soil moisture showed a higher correlation with MODIS LST during the forest leaf growing period (March–June) and with MODIS NDVI during the leaf falling period (September–December). Low correlation was observed in the year of frequent rains, regardless of the leaf periods. 相似文献
12.
We noted that ammonia nitrogen was not adsorbed by the cultivated layers of highly permeable paddy fields during the initial
fertilization period, but reached the lower layers relatively early. In our study, we considered an exponential equation from
an aqua-environmental perspective with the goal of obtaining good growth of rice plants in order to estimate the concentrations
and integrated volume of ammonia nitrogen accompanying paddy percolation. Using this exponential equation, we were able to
derive a relation between time and concentrations of paddy percolation water, and hypothesized that if percolation rates were
less than 10 mm/day, percolation would have no effect on rice growth, while simultaneously helping to maintain the good water
quality of the extra-paddy environment. We also clarified the differences between the potential ammonia nitrogen adsorption
volume derived from the CEC value and the integrated amount of ammonia nitrogen water in soil, and considered the causes from
the perspectives of solute movement and water movement.
Electronic Publication 相似文献
13.
通过对2004-2019年辽宁省黑土地进行野外采样及分析，测定土壤碱解氮、速效磷、速效钾和pH值4个指标，利用GIS和统计分析方法，研究黑土区土壤养分指标时空特征及其与气象因子的相关性。结果表明，年际间，碱解氮含量整体上无明显变化，速效磷、速效钾含量和pH值呈增长趋势。空间上，碱解氮和速效磷含量呈东高西低分布，速效钾含量呈西南向东北升高分布，pH值呈东低西高分布。降水量对碱解氮的影响最大，风速对速效磷、速效钾和pH值的影响最大，且与速效磷和速效钾呈显著相关。风速对土壤养分的影响最大，应注重土壤养分的变化监测及风速的影响，严格控制氮磷钾肥的施用量，提升粮食综合生产能力。 相似文献
14.
The effect of air temperature increase from meteorological data on thermal microenvironment of irrigated paddy field is simulated using energy balance model. Statistical test was used to determine the existence of the trend in temperature change of data from meteorological stations in Indonesia. The temperature was tested to have positive trend, and it was used to generate future and past increase of temperature for the simulation. According to the simulation, the change in energy balance occurs following additional heat contributed by the increase of air temperature. The results show that irrigated paddy field seems to have function of decreasing effect of temperature increase whereas, evapotranspiration increases. However, increasing air temperature also increases temperature in paddy system, but seems to be more moderate than in nonpaddy field. 相似文献
15.
套种圆叶决明改善茶园生态环境促进茶树生长 总被引：1，自引：0，他引：1
针对福建丘陵山地茶园普遍面临的土壤退化,季节性干旱严重、生态组分简单、生态环境恶化等生态问题,结合目前茶园管理模式,以常规清耕茶园(定期锄草)为对照,研究行间套种豆科绿肥闽引圆叶决明(Chamaecrista rotundifolia ‘minyin’)对茶园温湿度、土壤理化性状、茶树生长等的影响。结果表明:与清耕茶园相比,套种圆叶决明显著提高茶园土壤有机质、速效氮、速效磷含量(P<0.05),其中土壤速效氮含量增加57.78 mg/kg;在夏季高温干旱时期,套种圆叶决明茶园土壤含水量(0~20 cm土层)显著提高(P<0.05),达21.84%,空气温度日变化幅度降低5.1℃,空气湿度日均值显著提高3.9%;同时显著提高夏茶氨基酸及茶水浸出物含量(P<0.05)。茶园套种圆叶决明能有效改善茶园土壤质量及光、温、湿等小气候条件,表明该品种是一种适宜山地茶园推广利用的优良绿肥。 相似文献
16.
Jae Young Cho Jae Gwon Son Jin Kyu Choi Chang Hoon Song Byung Yeoup Chung 《Paddy and Water Environment》2008,6(2):211-219
The present study was carried out to evaluate nutrient losses that occur during the course of agricultural activity from rice
paddy fields of reclaimed tidal flat. For this study, we chose a salt-affected rice paddy field located in the Saemangeum
reclaimed tidal area, which is located on the western South Korean coasts. The plot size was 1,000 m2 (40 m × 25 m) with three replicates. The soil belonged to the Gwanghwal series, i.e., it was of the coarse silty, mixed,
mesic type of Typic Haplaquents (saline alluvial soil). The input quantities of nitrogen and phosphorus (as chemical fertilizer)
into the experimental rice paddy field were 200 kg N ha−1 and 51 kg P2O5 ha−1 per annum, and the respective input quantities of each due to precipitation were 9.3–12.9 kg N ha−1 and 0.4–0.7 kg P ha−1 per annum. In terms of irrigation water, these input quantities were 4.5–8.2 kg N ha−1 and 0.3–0.9 kg P ha−1 per annum, respectively. Losses of these nutrients due to surface runoff were 22.5–38.1 kg N ha−1 and 0.7–2.2 kg P ha−1 for the year 2003, and 26.8–29.6 kg N ha−1 and 1.6–1.9 kg P ha−1 for the year 2004, respectively. Losses of these nutrients due to subsurface infiltration during the irrigation period were
0.44–0.67 kg N ha−1 and 0.03–0.04 kg P ha−1 for the year 2003, and 0.15–0.16 kg N ha−1 and 0.05–0.06 kg P ha−1 for 2004. When losses of nitrogen and phosphorus were compared to the amount of nutrients supplied by chemical fertilizers,
it was found that 11.3–19.1% of nitrogen and 0.5–1.7% of phosphorus were lost via surface runoff, whereas subsurface losses
accounted to 0.2–0.8% for nitrogen and only 0.02–0.04% for phosphorus during the 2-year study period. 相似文献
17.
Water management methods regulate water temperature in paddy fields, which affects rice growth and the environment. To understand the effect of irrigation conditions on water temperature in a paddy field, water temperature distribution under 42 different irrigation models including the use of ICT water management, which enables remote and automatic irrigation, was simulated using a physical model of heat balance. The following results were obtained: (1) Irrigation water temperature had a more significant effect on paddy water temperature close to the inlet. As the distance from the inlet increased, the water temperature converged to an equilibrium, which was determined by meteorological conditions and changes in water depth. (2) Increasing the irrigation rate with higher irrigation water amount increased the extent and magnitude of the effects of the irrigation water temperature. (3) When total irrigation water amount was the same, increasing the irrigation rate decreased the time-averaged temperature gradient effect over time across the paddy field. (4) Irrigation during the lowest and highest paddy water temperatures effectively decreased and increased the equilibrium water temperature, respectively. The results indicate that irrigation management can be used to alter and control water temperature in paddy fields, and showed the potential of ICT water management in enhancing the effect of water management in paddy fields. Our results demonstrated that a numerical simulation using a physical model for water temperature distribution is useful for revealing effective water management techniques under various irrigation methods and meteorological conditions.
相似文献18.
《Plant Production Science》2013,16(3):323-335
AbstractTo ensure higher yields, farmers in China have increased cropping intensity with a large input of chemical fertilizer and livestock manure since 1980s, which has led to unsustainable agricultural productivity and environmental quality. This study aimed to evaluate the effects of intensive cropping on nutrient absorption and biomass production of crops and to determine the controllable source of residual nutrients in soil in the coastal area of Lake Dianchi, China. Soil and crops were sampled in 32 vegetable fields and four paddy fields; and simultaneously surveyed. In vegetable fields, cropping intensity and input to each crop were extremely high; and, 58, 72, and 20% of nitrogen, phosphorus, and potassium were not absorbed by the crop. Nitrogen absorption ratios of the vegetables were low. The amount of nitrogen absorbed from sources other than chemical fertilizer by vegetables, namely, from soil, manure, or irrigation water, in the fields with three to nine years cultivation duration was higher than those with zero to two years cultivation duration. Reduction of input should be more efficient than enhancing output to decrease soil nitrogen, phosphorus, and potassium; and, reducing input of chemical fertilizer should be more efficient than reducing input of manure. These results should be helpful for reducing agricultural pollution in China. 相似文献
19.
Effect of N-fertilizer application on return flow water quality from a terraced paddy field in Northern Taiwan 总被引：1，自引：0，他引：1
Shih-Kai Chen Cheng-Shin Jang Shu-Ming Chen Kun-Hung Chen 《Paddy and Water Environment》2013,11(1-4):123-133
Intensive use of chemical fertilizer for crops may be responsible for nitrogen and phosphate accumulation in both groundwater and surface waters. The return flow polluted by nutrients not only results in the limitation of water reuse goals but also creates many environmental problems, including algal blooms and eutrophication in neighboring water bodies, posing potential hazards to human health. This study is to evaluate the N-fertilizer application of terraced paddy fields impacting return flow water quality. Water quality monitoring continued for two crop-periods around subject to different water bodies, including the irrigation water, drainage water at the outlet of experimental terraced paddy field, and shallow groundwater were conducted in an experimental paddy field located at Hsin-chu County, Northern Taiwan. The analyzed results indicate that obviously increasing of ammonium-N (NH4 +-N) and nitrate-N (NO3 ?-N) concentrations in the surface drainage water and ground water just occurred during the stage of basal fertilizer application, and then reduced to relatively low concentrations (<0.1 mg/l and <3 mg/l, respectively) in the remaining period of cultivation. The experimental results demonstrate the potential pollution load of nitrogen can be reduced by proper drainage water control and fertilizer application practices. 相似文献
20.
Based on an experimental field study in Japan, a model was developed to simulate dissolved nitrogen in water ponded in a paddy field. As input data, the model uses meteorological data, water balance in the field, nitrogen concentration in inlet water, and the nitrogen contribution of applied fertilizer. Five model parameters need calibration. A practical application of the model is the simulation of NH4-N and NO2+3-N concentrations in water ponded in a paddy field. The model improves our understanding of the interactions between forms of dissolved nitrogen in ponded water and can explain the complex changes in dissolved nitrogen concentrations in water ponded on a paddy field. 相似文献