水田一次施肥技术应用效果研究

经2004、2005两年试验示范表明,在保水保肥地块上施用长效肥,其中纯养分N142～234kg/hm2,P2O547 kg/hm2、K2O47kg/hm2完全能够满足水稻8439～9690kg/hm2产量的养分需要,且能平稳供肥,比常规施肥节省纯氮40～161kg/hm2,“宜农”牌长效肥节肥多。漏水地块,在基施长效肥基础上,仍以补追一次氮肥为宜,追施纯氮45.0～67.5kg/hm2就能满足水稻产量需要。此项技术可以减少劳动成本,提高效益,提高肥料利用率,减少肥料对环境的污染,可以在生产上扩大推广。     

Effect of N-fertilizer application on return flow water quality from a terraced paddy field in Northern Taiwan

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.     

Spatial-uniform application method of methane fermentation digested slurry with irrigation water in the rice paddy field

Promoting biomass utilization, the objectives of this study were to clarify the spatial distribution of nitrogen, one of the most important fertilizer components in the methane fermentation digested slurry (i.e., the digested slurry), and to establish an effective method to apply spatial-uniformly digested slurry with irrigation water in the rice paddy field. A numerical model describing the unsteady two-dimensional flow and solution transport of paddy irrigation water was introduced. The accuracy of this model was verified with a field observation. The tendencies of the TN simulated in inlet and outlet portions had good agreement with the measured data and the accuracy of the numerical model could be verified. Using the numerical model, scenario analyses were conducted to determine the method for spatial-uniform application of the digested slurry with irrigation water. The simulated results indicated that drainage of the surface water and trenches at the soil surface were effective for spatial-uniform application of the digested slurry with irrigation water in the rice paddy fields. The effect of the trenches was maximized when the surface water of the rice paddy field was drained adequately.     

Prediction of paddy field change based on climate change scenarios using the CLUE model

This study simulated land-cover change using the Conversion of Land Use and its Effects (CLUE) model and predicted future changes in paddy field area under climate change scenarios A1B, A2, B1, and B2 of the Special Report on Emissions Scenarios (SRES). The CLUE model is a dynamic spatial land-use simulation model considering competition among land-use types in relation to socioeconomic and biophysical driving factors. Yongin, Icheon, and Anseong, South Korea, were selected as study areas, and scenarios were developed for regional-level simulation of land-use change. Binary logistic regressions were also conducted to evaluate the relationships between land uses and its driving factors. Finally, the simulation results suggested future changes of paddy field area under the scenario conditions. In all the scenarios, demand for cropland, including paddy and upland, decreased continuously throughout the simulation period of 2000–2100. The decrease in cropland area was particularly steep in scenario A2 in 2050. The receiver operating characteristic (ROC) values indicated that the spatial patterns of land-cover types based on the regressions were reasonably explained by the driving factors. According to the scenarios developed and location characteristics, in scenario A1B, paddy field areas were mainly transformed into built-up areas, while in the other scenarios paddy field areas were mainly transformed into forest. The approach used in this study is expected to enable exploration of future land-use changes under other development constraints and detailed scenarios.     

Aspects of the productivity of forage legumes in Northern Europe

A database on the productivity of red clover (Trifolium pratense), white clover (Trifolium repens), lucerne (Medicago sativa), lotus (Lotus corniculatus) and galega (Galega orientalis) was compiled. It contains 1852 observations for 330 trials at fifty‐three sites in eight north European countries for the period from 1977 to 1997. The database includes information on climatic and site characteristics, as well as agronomic data, collated into four smaller data sets. This has permitted four key agronomic issues to be examined, namely: (i) how yield for a given variety varies under different environmental conditions; (ii) how the relative performance of different species varies between sites; (iii) how persistence varies between species and sites; and (iv) what the nature of the relationship is between varieties, yield and sites within a species? Cluster analysis revealed that geographical location had a fairly strong influence on yield. Across sites for an individual variety, the cumulative day‐degrees during the regrowth period had the highest correlation with total yield. In terms of the relative performance of different forage legume species across sites, red clover and lucerne were estimated to yield about 2·5 t DM ha^?1 more than white clover and there was a significant impact of cumulative day‐degrees during regrowth and the age of ley on the total yield. It was found that red clover had the lowest persistence index and lucerne the highest. As regards the interaction between yield, varieties and sites, the length of growth period and the age of the ley explained two‐thirds of the variation in total yield in red clover varieties of contrasting maturity types.     

Determination of the parameters of Modified Cam-Clay model for paddy grain

To determine the parameters of Modified Cam-Clay model for paddy grain, a constitutive stress-strain equation, was used to study the stress-strain behavior of paddy grain. Triaxial tests were carried out four different moisture contents of paddy. This elastoplastic model contains five parameters: the critical state ratio M, the logarithmic hardening modulus λ, the isotropic swelling index κ, the elastic modulus E and the Poisson’s ratio ν, which can be evaluated in axial compression test and the isotropic compression test. The experimental results reveal that the M of paddy grain (Xiandao 118) with four different moisture contents (11.75%, 13.34%, 14.93% and 16.43%w.b.) were 2.1195, 2.1093, 2.0931 and 2.0110, the λ were 0.1408, 0.1390, 0.1355 and 0.1304, the κ were 0.1018, 0.0935, 0.0986 and 0.0948, and the ν were 0.145, 0.152, 0.155 and 0.166, respectively. The relation equations between the elastic modulus E with generalized shearing force q and mean principal stress p were obtained from the analysis of the experimental results. The comparisons between the Modified Cam-Clay model calculated values and measured values showed that the calculated parameters of the Modified Cam-Clay model are reasonable and the model can adequately describe the stress-strain behavior of paddy grain for the conditions tested.     

Determination of the magnitudes and values for groundwater recharge from Taiwan's paddy field

Flooded paddy fields have many functions, including not only rice production, and ecological and environmental conservation. This work estimates the extent of paddy field infiltration in Taiwan by adopting a one-dimensional Darcy-based soil/water balance model SAWAH (Simulation Algorithm for Water Flow in Aquatic Habitats). A 10 cm thick plow sole layer with a hydraulic conductivity of 0.03 cm/day, coupled with the soil texture and irrigation data obtained from 15 irrigation associations, is used to estimate the volumetric amount of annual infiltration in Taiwan. Simulation results from SAWAH indicate that the plow sole layer controls the movement of infiltrated water, with a rate about 1.8 billion cubic meters annually. The estimated infiltration rate of 1.8 billion m³/yr comprises more than 40% of the annual infiltration recharge to ground water in Taiwan. Additionally, the amount of infiltration recharge to groundwater is equivalent to 20 billion Taiwan dollars NT$ (or 0.65 billion US$) while the yearly rice crop production is 35 billion NT$ (or 1.13 billion US$). It is evident that the infiltration from rice paddy is of great importance to the economy, environment, and water resources conservation in Taiwan.     

城市居民茶叶购买渠道选择及其影响因素实证研究

根据问卷调查数据,统计当前城市茶叶消费者的购买渠道分布,并应用多元离散选择模型,以网络购买渠道为参照,分析城市居民对茶叶购买渠道选择的影响因素。模型结果显示:年龄、文化程度、个人年收入、购买目的、购买次数、价格、外形和单位性质对茶叶购买渠道选择均有显著的影响;是否有饮茶习惯和性别对茶叶购买渠道选择的影响不显著。年龄越大的消费者更倾向实体店购买,购买次数越多的消费者也倾向于通过实体店购买。文化程度越高、在企业就业、收入越高、对价格敏感、关注外形的消费者则倾向于网络购买。     

Assessment of irrigation efficiencies and water productivity in paddy fields in the lower Mekong River Basin

Improving irrigation performance is a crucial issue for agriculture and irrigation development in the Lower Mekong River Basin to secure food production for people’s livelihoods. Irrigation efficiency is the most important indicator to determine the performance of an irrigation scheme. This study looks at water management practices and irrigation efficiency in three pilot sites in the Lower Mekong River Basin: the Numhoum scheme in Laos, the Huay Luang scheme in Thailand, and the Komping Pouy scheme in Cambodia. Irrigation efficiency and water productivity were analyzed using a water balance approach at the irrigation scheme level and results in the pilot areas show efficiencies that are definitely higher using this approach than by using the classical concept. Lower water productivity was observed at pilot schemes in areas of single cropping and higher productivity in areas where multiple agricultural activities were practiced. Strict and active water management is required to control and save water to meet agricultural demand and have sufficient water to expand cultivation areas while avoiding shortages. Promoting multiple uses of water for various agricultural activities in command area will increase water productivity.

Effect of swine liquid manure application in paddy field on water quality,soil fertility and crop yields

Paddy and Water Environment - Land application of animal manure has been accepted as an effective method and disposal option, which has economic, environmental and social benefits, while also...     

Parameterization of canopy resistance for modeling the energy partitioning of a paddy rice field

Paddy and Water Environment - Models for predicting hourly canopy resistance (r c) and latent heat flux (LET) based on the Penman–Monteith (PM) and bulk transfer methods are presented. The...     

Influence of precipitations and sunshine hours on yield of paddy field grown wheat (Triticum aestivum L.) in Northern Kyushu,Japan

ABSTRACT

Relationships between wheat (Triticum æstivum L.) yield components and growing season weather conditions (e.g. temperature, precipitation, and sunshine duration) were investigated for a rice-wheat rotation paddy system situated in Northern Kyushu, Japan over a 17-year period (2000–2016). A 1.0 mm increase in precipitation from 21 to 32 days after sowing decreased wheat yield by about 27 kg ha^?1 at early seedling stage with one to two leaves (Zadoks (Z) growth stage Z1.1–1.2). Number of tillers and spikes showed significant negative correlations to the amount of precipitation during the period. An hour increase in mean daily sunshine hours from 94 to 111 days after sowing resulted in an 328 kg ha^?1 rise in grain yield at stem elongation stage with the first and second node detection (Z3.1–3.2). The grain number per square meter also showed strong positive correlations to sunshine hours during the same period. However, this positive effect of sunshine was negated when precipitation exceeded about 30 mm during the early seedling stage. Consequently, precipitations at early seedling stage and sunshine hours at stem elongation stage mostly determined wheat yield in Northern Kyushu paddy field. Increasing precipitations during the early seedling stage highlights the pressing need for effective paddy field drainage management from wheat sowing through harvest.

Abbreviations: CP: Chikushi Plains; FARC: Fukuoka prefectural Agriculture and Forestry Research Center; SARC: Saga prefectural Agricultural Research Center; DAS: days after sowing     

Measuring the implicit value of paddy irrigation water: application of RPML model to the contingent choice experiment data in Japan

For efficient use of water as a limited resource, evaluation on the water value is critical, but there is little information in Asian paddy irrigation. This paper proposes the method for measuring implicit price of paddy irrigation water by using the choice experiment (CE) data with contingent scenarios. Empirical results demonstrated that (a) the estimated implicit price of water showed reasonable value as compared to the production indexes, (b) the random parameter multinomial logit model was more suitable than the conventional multinomial logit model to treat the CE data, and (c) the implicit price is much lower than the full cost price, indicating that full cost pricing probably damages and ruins rice production too seriously in Japan. As seen above, the method proposed here is useful for decision making on water pricing policies and easy to apply to different irrigation systems under limited data of water value.

Soil microbial activity and community composition as influenced by application of pig biogas slurry in paddy field in southeast China

Paddy and Water Environment - A 6-year field experiment was conducted to assess the effects of biogas slurry (BS) application on rice yield, soil nutrients, soil microbial activity...     

德宏州第三轮甘蔗品种水田区试点新植试验总结

德宏州四个水田区试点经过一年的新植试验,综合各区试点的试验结果表明:综合性状表现好的前三个种是新台糖28号、德蔗03-83、园林6号;表现较好的是福农15号、粤糖00-236;表现一般的是巴西固氮种、桂糖94-119.     

A decision-making model for rice paddy cropping in an urbanizing area of the Lao PDR

In Southeast Asia, economic and population growth are expected in the near future. Rapid change is anticipated especially in the Lao PDR. Concern has been expressed that population growth will lead to an increased demand for food and economic growth to changes in the use of land. For food production to keep pace with the growth of population, it is very important to understand decision-making in rice paddy cultivation in urbanizing areas; for this reason, this study with the SEM model was conducted. The original data were collected by a questionnaire survey in some Lao villages; the survey included questions on various conditions, such as the availability of water in the dry season (irrigation), the access to a city, and job opportunities other than farming. The findings of the study demonstrate that the planting of a second rice crop was related to such factors as the productivity of rain-fed rice and cash crops and, most importantly, job opportunities other than farming.     

Multi scale analysis of the factors influencing wheat quality as determined by Gluten Index

In recent years, the Israeli wheat industry has suffered from quality problems that can endanger the possibility of using the wheat to produce bread. The aim of this study is to understand how climatic and management factors, such as N fertilization, emergence date and wheat cultivar, affect the Gluten Index (GI) - a main wheat quality parameter in the Israeli commercial market. The study was undertaken at individual producer fields across southern Israel on three different scales: regional, farm, and the field. Overall, 1800 samples of 15 genotypes were collected, over three consecutive seasons, 2006-2008, from commercial fields throughout the area, from experiments conducted in the fields of the Gilat Research Center, and in the fields of Kibbutz Sa’ad. Climatic variables were mapped exclusively and on the basis of maximum temperature and rainfall data, and were collected in the course of the entire season and during certain periods. Relationships between climatic variables and GI were determined by multivariate regression analyses. On regional scale, the ability of explaining the differences was low, while on the farm and field scale, variation explanation was generally higher. The factors that were found to be most influential on wheat quality in southern Israel are: (1) type of variety; (2) negative influence of cumulative temperature stress; (3) negative influence of excess water; and (4) negative influence of excess nitrogen fertilization. It was found that the genotype is the most important factor influencing GI, but environmental and crop management factors also have a strong effect on the frequency and severity of GI depreciation. The probability of GI reduction increases in “too good” (excess fertilization, redundant irrigation) and in “too bad” conditions (water and temperature stress). Hence, when farmers make decisions regarding sowing, applying nitrogen and/or supplemental irrigation, they must also consider quality parameters, such as GI and not only yield quantity.     

铁岭地区稻田土壤养分肥力状况调查报告

为掌握铁岭地区稻田土壤肥力变化情况,提高水稻产量及品质,特采集土样进行检测。结果表明,铁岭地区稻田土壤中有效磷、有效钾含量丰富;碱解氮、有机质和全氮含量处于中等水平;有效硅、交换性钙和交换性镁含量很丰富;有效铜、有效锌和有效锰含量很丰富;有效铁含量丰富;有效硼含量处于中等水平;土壤酸碱度差异很大。     

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.