Prediction of the environmental concentration of pesticide in paddy field and surrounding surface water bodies

Pesticides are very important in European rice production. For appropriate environmental protection, it is useful to predict the potential impact of pesticides after application, in paddy fields, in paddy runoff, and in the surrounding water, by calculating predicted environmental concentrations (PECs). In this paper, a joint simulation is described, coupling a field-scale pesticide fate model (RICEWQ) and a transportation model (RIVWQ) to evaluate the potential for predicting environmental concentrations of pesticides in the paddy field and adjacent surface water bodies and comparing the predicted values with the monitoring data. The results demonstrate that the application of the calibrated field-scale RICEWQ model is a conservative method to predict the PEC at the watershed level, overestimating the observed data; the coupled RICEWQ and RIVWQ models could be adequately used to predict PECs in the surrounding water at watershed level and in the higher tier risk assessment procedure.     

Pesticide discharge and water management in a paddy catchment in Japan

Concentrations of several pesticides were monitored in a paddy block and in the Kose river, which drains a paddy catchment in Fukuoka prefecture, Japan. Detailed water management in the block was also monitored to evaluate its effect on the pesticide contamination. The concentrations of applied pesticides in both block irrigation channel and drainage canal increased to tens of μg/L shortly after their applications. The increase in pesticide concentrations was well correlated with the open of irrigation and drainage gates in the pesticide-applied paddy plots only 1–3 days after pesticide application. High concentration of other pesticides, mainly herbicides, was also observed in the inflow irrigation and drainage waters, confirming the popularity of early irrigation and drainage after pesticide application in the area. The requirement of holding water after pesticide application (as a best management practice) issued by the authority was thus not properly followed. In a larger scale of the paddy catchment, the concentration of pesticides also increased significantly to several μg/L in the water of the Kose river shortly after the start of the pesticide application period either in downstream or mid–upstream areas, confirming the effect of current water management to the water quality. More extension and enforcement on water management should be done in order to control pesticide pollution from rice cultivation in Japan.     

Risk assessment of pesticides in paddy fields and the Safīdrūd River in Gīlān,Iran

Safīdrūd River is the longest river in northern Iran and serves 2.5 million people as a water resource for drinking, irrigation, pisciculture, and recreation. To evaluate the fate of pesticides in paddy fields on the Safīdrūd river bank and the Safīdrūd basin, a comprehensive model is developed in this paper to predict pesticide concentration. The model includes degradation and sorption to soil in paddy field and two-dimensional turbulent with degradation in river. To investigate the effects of pesticides on health, an inclusive risk assessment is defined by parameters such as the maximum annual prediction environmental concentration and mean prediction environmental concentration of pesticides in the intake zone of the Safīdrūd river for the Rasht water treatment plant. The risk quotient of all pesticides were higher than 1 (i.e., for Diazinon it was calculated to be 670) which indicate high risk in the Rasht potable water and can potentially cause various digestive cancers and other refractory and mutagenic diseases. As a result, it is necessary to codify the global planning of pesticide application in the paddy fields by the local government.     

优质水稻生产农药完全替代技术试验及其效果简报

辽宁省东港市是我国最适于优质水稻越光生长的生态地区.针对当地为水稻病虫草害常发和重发生地区,严重制约了优质水稻的高产,按有机产品生产国家标准的规定,制订了病虫草害的化学农药完全替代防控技术预案,并在2019年开展试验.对年度发生最重的3类病虫草害,放养河蟹的生物除草技术防除杂草,防除效果达93％,与化学除草剂的效果相当...     

膜下滴灌水稻栽培技术对降低甲烷气体排放以及化肥、农药施用污染的探讨

对当前传统水稻栽培技术对稻田甲烷气体排放以及化肥、农药施用后造成环境污染的现状进行了分析.采用膜下滴灌水稻栽培技术能够有效降低甲烷气体排放,减少施用化肥、农药对环境的污染;同时,膜下滴灌水稻比传统水稻在节水、增产方面有明显优势.     

Variation in rice quality of different cultivars and grain positions as affected by water management

A field experiment was conducted to study the effect of cultivar and grain position on rice quality under different water management treatments. Water treatments significantly affected all quality traits in the study, except alkali digestibility (AD). There were significant interactions of water treatment by grain position and genotype for brown rice rate (BRR), chalky grain rate (CGR) and amylose content (AC), and interactions of grain position by water treatment and cultivar for head milled rice rate (HMRR). The interaction of water treatment by genotype for protein content (PC) was also significant. Of all variance components, water treatment ranked the highest for PC. Similarly grain position was ranked the highest for AC, BRR, CGR and HMRR. In comparison with wet cultivation, plastic-film mulched cultivation had significantly lower BRR, HMRR, CGR and higher PC. There were marked differences in milled quality, appearance and AD among differently positioned grains within a spike. For appearance and PC, the difference between plastic-film mulched cultivation and wet cultivation was greater for upland rice than paddy rice. For milled and cooking–eating quality, the difference between plastic-film mulched cultivation and wet cultivation was greater for the good quality paddy rice than the upland rice and the poor quality paddy rice. In plastic-film mulched cultivation, top grains showed lower milled quality and PC. While in wet cultivation, the opposite result was seen. With the decrease in soil water content, BRR and appearance showed increased and decreased differences among grains within a spike, respectively. The results indicate the possibility of improving rice quality by use of better water management and suitable cultivars.     

稻文化的再思考(7)——稻的起源、分化和传播

综述和讨论了稻的起源、分化和传播等的考古与现代生物学研究的一些成果。笔者根据这些研究成果描绘了稻的起源和传播路线,即稻起源于我国长江中下游地区或华南地区,分化成籼粳稻后一路向北传播至我国的北方,最后到达日本和朝鲜等国家(以粳稻为主);另一路向南和西南方向传播至我国西南地区和福建等地,再经我国西南地区传至缅甸、越南、印度等东南亚、南亚国家(以籼稻为主),最后经印度传至欧洲美洲,从福建经台湾和琉球群岛传至日本。稻的分化亦有多种研究成果和推论,但从籼粳重要的栽培特征和农艺性状基因看,一次起源的可能性更高。文中还穿插介绍了稻的起源和传播中的一些人文传说和神话故事。     

Effects of Non-flooded Cultivation with Straw Mulching on Rice Agronomic Traits and Water Use Efficiency

Rice (Oryza sativa) is one of the main foodstuffs of Chinese people. More than 30% crop field is used for rice cultivation in China. It provides 45% of crop yields in our country. However, the production of irrigated rice requires considerable water, up t…     

建设生态节约型农业促进盘锦农业可持续发展

针对盘锦市水稻生产存在水田灌溉用水量较高、水田埝梗利用率低、稻菜复种面积少、稻田养殖面积有待扩大、水田化肥利用率较低、水田污染时有发生等问题,提出大力推广节水、节地、节肥、节种、节药等技术,大力推进水稻机械化和建设生态节约型农业模式,大力推广水稻无公害、绿色、有机生产技术等对策。     

优质早稻“三高一少”栽培技术研究与应用

1999～ 2 0 0 0年以提高优质早稻成穗率、结实率、整精米率、减少农药污染为研究内容 ,选用中优早 81、香两优 6 8为材料 ,运用小区对比试验方法 ,开展了育秧方式、基本苗、施氮量、收割时期、农药防治方法等栽培试验。结合近几年优质早稻开发种植实践经验 ,对优质早稻高产栽培的主要技术指标进行了系统分析 ,形成了优质早稻“三高一少”调优保优高产栽培技术体系 ,即优质早稻每公顷产量 6 0 0 0～ 75 0 0 kg的关键技术指标。在双峰县普遍推广应用 ,效果十分显著。     

不同光质和光照度对寒地水稻秧苗素质的影响

以适合寒地种植不同生育期的水稻品种(系)为试验材料,在苗期设置不同光质和光照度的LED灯光照射处理,研究光对寒地水稻秧苗生长的影响,以期为寒地在冬季实现室内培育水稻提供参考。结果表明,两种光质处理对水稻秧苗的影响相似;不同水稻品种对光的反应有所差异,但提高光照度后水稻秧苗有叶龄进程加快、根数增多、茎基变宽、地上部干质量和根干质量增加、壮苗指数提高的趋势,适当增加光照度有利于培育水稻壮苗。与对照相比,光照度1 700 lx左右时水稻秧苗素质较差,光照度3 500 lx左右时水稻秧苗素质相近,光照度5 300 lx左右时水稻秧苗素质显著提高。     

Panicum maximum cv. Tanzânia: climate trends and regional pasture production in Brazil

Projected change in forage production under a range of climate scenarios is important for the evaluation of the impacts of global climate change on pasture‐based livestock production systems in Brazil. We evaluated the effects of regional climate trends on Panicum maximum cv. Tanzânia production, predicted by an agro‐meteorological model considering the sum of degree days and corrected by a water availability index. Data from Brazilian weather stations (1963–2009) were considered as the current climate (baseline), and future scenarios, based on contrasting scenarios in terms of increased temperature and atmospheric CO₂ concentrations (high and low increases), were determined for 2013–2040 (2025 scenario) and for 2043–2070 (2055 scenario). Predicted baseline scenarios indicated that there are regional and seasonal variations in P. maximum production related to variation in temperature and water availability during the year. Production was lower in the Northeast region and higher in the rainforest area. Total annual production under future climate scenarios was predicted to increase by up to 20% for most of the Brazilian area, mainly due to temperature increase, according to each climate model and scenario evaluated. The highest increase in forage production is expected to be in the South, Southeast and Central‐west areas of Brazil. In these regions, future climate scenarios will not lead to changes in the seasonal production, with larger increases in productivity during the summer. Climate risk is expected to decrease, as the probability of occurrence of low forage productions will be lower. Due to the predicted increase in temperature and decrease in rainfall in the Northeast area, P. maximum production is expected to decrease, mainly when considering scenarios based on the PRECIS model for the 2055 scenario.     

Strategies to manage weedy rice in Asia

Weedy rice, an emerging problem in Asia, increases production costs and reduces farmers' income through yield reduction and through lowered rice value at harvest. Rice farmers in many Asian countries are shifting from transplanting to direct seeding; however, due to physical and physiological similarities of weedy rice to cultivated rice and the absence of standing water at the time of crop emergence, adoption of direct-seeded rice systems makes weedy rice infestation one of the most serious problems. Selective herbicides to control weedy rice in conventional rice cultivars are not available and therefore managing weedy rice is a challenging and increasing problem for farmers in Asia. In the absence of selective herbicides, various cultural weed management strategies may help reduce the problem of weedy rice. These strategies may include the use of clean seeds and machinery, use of stale seedbed practice, thorough land preparation, rotation of different rice establishment methods, use of high seeding rate and row-seeded crop, use of purple-coloured cultivars, use of flooding, and adoption of crop rotation.     

稻曲病大发生关键因子及药剂防治研究

针对稻曲病在水稻生产上危害日趋加重的现状，2002-2005年对引起该病大发生的关键因子及药剂防治技术进行了连续4年的研究。结果表明：感病品种（组合）和水稻孕穗至抽穗期间5d以上降水天气是引起稻曲病大发生的二个关键因子‘同时，稻曲病为害程度还与水稻栽培方式、种植密度、肥水管理及施药水平等因素有关。稻曲病药剂防治技术关键：一是选用有效药剂。二是抓住施药适期施药。筛选出防治稻曲病的有效药剂有30％爱苗EC，43％好力克SC和62．25N仙生WP。稻曲病施药适期是水稻分蘖末期、破口前3～7d、始穗期3个时期。     

SWAT modeling of best management practices for Chungju dam watershed in South Korea under future climate change scenarios

Suitable and practicable best management practices (BMPs) need to be developed due to steadily increasing agricultural land development, intensified fertilization practices, and increased soil erosion and pollutant loads from cultivated areas. The soil and water assessment tool model was used to evaluate the present and future proper BMP scenarios for Chungju dam watershed (6,642 km²) of South Korea, which includes rice paddy and upland crop areas. The present (1981–2010) and future (2040s and 2080s) BMPs of streambank stabilization, building recharge structures, conservation tillage, and terrace and contour farming were examined individually in terms of reducing nonpoint source pollution loads by applying MIROC3.2 HiRes A1B and B1 scenarios. Streambank stabilization achieved the highest reductions in sediment and T-N, and slope terracing was a highly effective BMP for sediment and T-P removal in both present and future climate conditions.     

Seasonal characteristics of surface water quality in the wastewater catchment system of an urbanizing basin

Vientiane, Lao PDR, has been subject to extensive and ongoing urbanization plans, including development of natural marshes and residentialization of paddy fields into suburban areas, despite natural marshes playing a vital role in treating wastewater from urban areas. Therefore, it is important to understand the current situation regarding the nutrient balance in these natural wastewater treatment systems to predict future conditions and design appropriate measures against water quality deterioration. However, limited data are available in Vientiane on the hydrological characteristics of water and nutrient runoff that flow into marshes through drainage canals. In this study, we conducted a periodic survey of drainage canals and Mak Hiao River in the wastewater catchment system surrounding Vientiane during the rainy and dry seasons. We monitored the discharge of surface water at 21 observation sites and analyzed water quality of nitrogen, phosphorus, and total organic carbon. These observations revealed that the concentrations of dissolved nitrogen and phosphorus were significantly higher at sites in urban areas, followed by sites in the main river basin and those in agricultural areas. Dissolved nitrogen and phosphorus concentrations varied with runoff discharge, especially in urban and river basin sites, with lower concentrations in the rainy season and higher concentrations in the dry season. On the other hand, we found no significant differences between the rainy and dry seasons in nutrient concentrations in the agricultural basin. Finally, we proposed measures to counteract the deterioration of water quality during dry seasons and simulated the impact of these measures.     

节水抗旱稻的培育与产业发展

节水抗旱稻（Water-saving and drought-resistance rice,WDR）是指既具有水稻高产优质特性,又具有旱稻节水抗旱特性的一种新的栽培稻类型（NY/T 2862-2015）,是在水稻科技进步的基础上,通过进一步整合现代优良水稻与旱稻品种的优良特性而成。节水抗旱稻的节水、抗旱和耐直播能力较强,可采用“旱直播旱管”的绿色栽培模式,可在水田不淹水栽培,大幅度节约灌溉用水,减少面源污染和甲烷排放,也可在旱地或山坡地种植,拓展水稻种植空间。本文简要介绍了节水抗旱稻的概念、特点以及培育与改良策略,表列了团队育成审定的23个节水抗旱稻品种及各自主要特点及适种区域,对节水抗旱稻的产业发展目标进行了讨论。     

Pesticide diversity in rice growing areas of Northern Vietnam

Pesticide use in developing countries increases rapidly. In many regions, we miss knowledge of how frequently pesticides are applied and which active ingredients are used. We present a new cost-efficient and rapid assessment method of recording pesticides diversity in rice-dominated landscapes and present some evidence of the misuse of active ingredients in our study regions. We investigated 17 rice fields in two regions of Northern Vietnam in 2014 and 2015. At each region, we explore the abundance of pesticides used with three methods including (1) the novel approach of collecting pesticide packages close to our target rice fields, (2) observations of farmers spraying pesticides in the surrounding and (3) interviewing local farmers. By collecting pesticide packages, we found 811 packages containing 74 different active ingredients. On average, 19 active ingredients (ranging from four to 40 active ingredients) were applied with an average content of 275.3 g of active ingredients per site. Insecticide packages (39%) were most abundant followed by those of fungicides (31%), herbicides (16%) and other active ingredients (14%). On all sites, active ingredients banned in the European Union were applied by the farmers. Collecting pesticide packages proved to be an efficient and rapidly implemented method to obtain some baseline information about pesticide application (for Northern Vietnam). We suspect that improved agricultural extension services could contribute to good agricultural practices in pest management. Generally, better information and education for local farmers for appropriate use of pesticides seem a necessity.     

The role of paddy rice in recharging urban groundwater in the Shira River Basin

Agricultural fields in the middle Shira River basin play an important role as a source of groundwater recharge; however, the water balance between the agricultural water and river water is unclear. This study was conducted to investigate the water balance in the fields by measuring the stream flow of agricultural water channels, which draw water from the Shira River. The flow rate of water channels was found to increase in the beginning of May, which corresponded to the cultivation of paddy rice fields. During summer, the total agricultural intake was comparable to the river flow observed in the middle Shira River Basin. Determination of the water budget for the targeted area revealed that most of the recharged water was dependent on agricultural irrigation from the river. The annual recharge of the overall target area was estimated to be as high as 15,300 mm. In addition, the infiltration rate was as high as 170 mm/day in the paddy fields during summer, and as high as 30 mm/day in the upland fields during winter. In order to recover the groundwater recharge in this region, it is necessary to extend the submerged period to include periods in which the stream water in the Shira River is not subject to heavy rainfall as well.     

A general adaptation strategy for climate change impacts on paddy cultivation: special reference to the Japanese context

Climate changes due to global warming may affect paddy cultivation considerably. Climate changes directly affect rice plant growth, and within paddy cultivation catchments, alter the hydrological regime including flood patterns and water availability for irrigation, and drainage. Although increased atmospheric CO₂ concentrations in the future may enhance plant growth through the CO₂ fertilization effect, impacts of climate change on agriculture are complicated and difficult to predict precisely. This is especially the case for assessing impacts on paddy cultivation, where basin hydrological behavior needs to be understood in detail. Possible adaptations to reduce negative impacts should be tailored to local conditions, which modify climate change impacts on paddy cultivation. In this article, climate change impacts on paddy cultivation are reviewed and a general adaptation strategy is discussed with special reference to the Japanese context.