稻田水质模型研究和应用进展

水稻生产环境特殊、生产过程中病虫草害严重,导致农药使用品种多、频次高.部分农药会淋失到周围水体中,对水体的潜在污染风险较高.随着农药监测和田间试验成本的不断提高,数学模型已成为农药登记过程中不可或缺的一部分.稻田水质模型(RICEWQ模型)作为欧洲稻田农药暴露评估最可靠和应用最广泛的模型,主要用于预测淹水稻田土壤和积水中的农药浓度,在我国也得到了初步应用.本文简要介绍了RICEWQ模型的系统结构、农药归趋的主要过程、模型的输入输出,综述了国内外相关的研究进展,以期推进RICEWQ模型在我国的应用,并为相关研究提供参考.

应用四种数值法研究稻田水生昆虫多样性(英文)

对 1998年 3月 6日至 6月 5日从广东省四会县大沙镇生物防治稻田和化学防治稻田采集到的 4 3种、 5 19只水生昆虫的分析研究。用Jaccard相似性指数、相异性指数、总体覆盖指数和发展相关指数四种生物多样性指数进行分析。结果显示 ,生物防治稻田和化学防治稻田在物种丰富度和总体丰富度上均有不同。分析显示 ,用总体覆盖指数和发展相关指数评价稻田水质更好。

加气对水稻泡田期田面水质的影响

为解决秸秆还田技术实施后南方稻田泡田期出现的水体恶化问题,模拟秸秆还田后的淹水稻田,采用加气0.5 h和不加气对田面表层水体进行处理,对田面水体中的铵态氮(NH-4-N)、硝态氮(NO--3-N)以及总磷(TP)的含量进行研究。结果表明:加气处理能使淹水条件下的田面表层水NH-4-N和TP浓度峰值分别降低77.4和29.84,且使得NO--3-N和TP浓度较快的上升、并提早出现峰值,同时使淹水初期和后期田面表层水体溶解氧含量保持较高的状态,使水体处于好气环境的时间变长,使淹水稻田面临氮磷污染的风险有所降低,从而利于作物根系生长。研究表明:对秸秆还田后泡田期的稻田进行加气处理能有效提高田面水溶解氧含量,缩短高浓度氮磷的持续时间,从而减轻水质污染的风险。

养鱼稻田栽培黑木耳的试验报告

为了探讨高寒地区利用养鱼稻田栽培黑木耳的高产技术,挖掘稻田的生产潜力,提高经济效益,1994年春,我们在滴道河乡河东村利用17亩养鱼稻田进行了“鱼、稻、耳”高产试验,并获得鱼、稻、耳全面增产、平均亩利润达1027.87元的好成果。现将试验结查报告如下:

稻鸭萍共作复合系统的主要生态效应

对稻鸭萍共作体系的主要生态效应研究结果表明,稻鸭萍共作有利于提高土壤肥力,水稻收获后的土壤有机质、碱解氮、速效磷、速效钾分别比对照增加7.95%、7.05%、6.47%和4.46%;稻鸭萍共作对杂草的控制效果达到98.94%,明显削弱了稻田优势杂草的发生与危害,稻田残存杂草为数甚少,P ielou均匀度指数显著提高;稻鸭萍共作对稻田飞虱有显著的控制效应,从而明显抑制主要由灰飞虱传毒危害的水稻条纹叶枯病的发病率;稻鸭萍共作虽然对水稻纹枯病也有明显防治效果,但不能阻止纹枯病的发生;由于绿萍吸附了稻田水体中部分有机物、腐殖质等,稻鸭萍共作区水体的化学需氧量比稻鸭共作区降低8.70%。

稻鸭共生与牧草轮作生态农业模式的效果研究

为解决大面积稻鸭共生地区养鸭所带来的恶臭和水系污染问题,并探讨稻鸭共生和紫云英轮作对周围环境和水稻生长等的影响,试验设四个处理组,分别为:稻鸭共生组(T1)、稻鸭共生+紫云英轮作组(T2)、稻田种紫云英不养鸭组(T3)、稻田不养鸭不种紫云英的传统种稻对照组(CK)。结果表明:稻鸭共生和紫云英轮作能使水稻生长更良好,得到更高的水稻产量;稻鸭共生和紫云英轮作对稻鸭农业的农业用水水质污染改善有效果;稻鸭共生和紫云英轮作能改善土壤的理化性状,相比对照组提高土壤有机质含量达0.54 g/kg,并能提高土壤中速效养份的含量;稻鸭共生和紫云英轮作,能较好地起到杂草和虫害防治效果。

水稻施用控释复合肥效果初报

2009-2011年大区定位对比试验结果表明,水稻施用控释复合肥具有明显的增产节肥效果,较常规施肥增产7%～25%,节肥10%～20%,667 m2节省施肥用工1～2工;控释复合肥能提升土壤肥力,土壤有机质、全氮、碱解氮、有效磷、速效钾比常规施肥分别提高5.0%,20%,3.3%,73.0%和24.3%;施用控释复合肥能明显改善稻田水质,有效控制农业面源污染。

Nitrogen Losses from Flooded Rice Field

A field microplot experiment was conducted during the tillering stage of paddy rice to investigate nitrogen(N) Iosses from flooded rice fields following fertilizer application. After application of ammonium bicarbonate,most of nitrogen in the floodwater was present as NH4-N and its concentration varied widely with time.Concentrations of both NO3-N and NO2-N in the floodwater were low due to the weakened nitrification.Under flooded anaerobic reducing conditions, soil solution concentrations of NO3-N and NH4-N were nothigh, ranging from 0.6 mg L-1 to 4.8 mg L-1, and decreased with soil depth. However, the groundwater wasstill contaminated with NO3-N and NH4-N. Rainfall simulation tests showed that the N losses via runoff inrice fields were closely related to the time intervals between fertilizer applications and rainfall events. Whena large rain fell for a short period after fertilizer application, the N losses via runoff could be large, whichcould have a considerable effect on surface water quality. Both irrigation and N fertilizer application mustbe controlled and managed with great care to minimize N losses via runoff from agricultural land.

Production Benefits of Double-Cropping Rice Under Optimized Application of Nitrogen and Potassium Fertilizers Combined with Chinese Milk Vetch and Straw Co-Returning to Fields

In order to explore the technology and effects of reducing nitrogen and potassium fertilizer applications in double-cropping rice,a field plot experiment was conducted to study the effects of optimized application of nitrogen and potassium fertilizers combined with returning Chinese milk vetch and straw to fields on yield,fertilizer utilization efficiency,net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO_(2) concentration(Ci),chlorophyll content(SPAD value)and soil physical and chemical properties in late rice harvest period.The results showed that the optimized application of nitrogen and potassium fertilizers combined with the integrated technology of Chinese milk vetch and straw co-returning to the field could enhance the photosynthetic efficiency of double-cropping rice,increase rice yield,and enhance soil biological activity,especially T4 treatment involving the returning of Chinese milk vetch and straw to the field instead of 30%nitrogen fertilizer achieved the highest rice yield,fertilizer use efficiency,net photosynthetic rate and soil biological activity.Compared with the conventional fertilization treatment T2,the total rice yield of T4 treatment increased by 4.1%,among which the early rice and late rice increased by 6.3%and 2.4%,respectively;Pn,Gs and SPAD values of flag leaves at full heading stage significantly increased,and the contents of soil active organic carbon,alkali hydrolyzed nitrogen,available phosphorus and readily available potassium significantly increased.

Agro-pedological Assessment of the Traditional Yuanyang Rice Terraces of Yunnan Province, China

As a contribution to a long-term evaluation of the sustainability of agro-ecosystems in the Yuanyang rice terraces, this paper reviews the bio-physical environment of the terraced landscape in a small catchment around Qingkou village and assesses soil fertility in the village crop growing area. A soil- landscape organization pattern was developed using a geomorphopedological approach. Anthropogenic, climatic and topographic factors were identified as the main soil forming factors. Soil capability and associated edaphic constraints were assessed and the main soil types were identified and classified using FAO protocols. Spatial patterns of soil fertility appear quite homogeneous. Soils are acid and cation exchange capacity and nutrient reserves are generally low. The agro-ecosystem has largely been developed by the Hani population. This agro-ecosystem has succeeded in maintaining a relatively dynamic nutrient circulation system. Current research is focusing on： （i） the evaluation of the representativeness of the studied area compared to the whole terraced system in the Yuanyang terraced landscape; （ii） measurements of nutrients flows at the field scale; （iii） the effects of soil properties on crop yields; and （iv） up-scaling field levels results to larger spatial units.