Development of soil conditioner for reclaimed land desalinization based on high-iron fly ash

Paddy and Water Environment - Reclaimed soil is known to have high salinity due to poor water permeability. Soil conditioner can improve the permeability of the ground by changing the composition...     

Integrated nutrient management for environmental-friendly rice production in salt-affected rice paddy fields of Saemangeum reclaimed land of South Korea

This study was conducted in an attempt to determine the proper nitrogen and phosphorus application levels, nitrogen split application ratio, and application method for environmental-friendly rice production in a salt-affected rice paddy field, which was located in the Saemangeum reclaimed tidal belt on the western coast of South Korea, between April 1, 2003 and October 10, 2004. All treatments were replicated three times in a randomized block design (5 m × 4 m plot) with 11 treatments (total 33 plots). We designed three treatments for the evaluation of reasonable application levels of nitrogen and phosphorus fertilizers (A1–A3); five treatments to evaluate the nitrogen split application system (T1–T5); and three treatments to determine the proper application for chemical fertilizer (M1–M3). There was no significant difference of amylose and protein content among the application levels, application methods, and nitrogen split application ratios (P < 0.05). No significant differences in grain yield and yield components of rice were observed among the different application levels, application methods, and nitrogen split application ratios (P < 0.05). In order to save labor in agricultural households, preserve or enhance the grain quality of rice, and reduce nutrient losses, we determined that the optimum application level of nitrogen fertilizer was 140 kg ha⁻¹; the application split ratio of nitrogen fertilizer at four different periods was 40% for basal fertilization, 20% for maximum tilling stage, 30% for the panicle formation stage, and 10% for the booting stage; and the best application methods were deep layer application and whole layer application.     

Surface and subsurface losses of N and P from salt-affected rice paddy fields of Saemangeum reclaimed land in South Korea

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.     

二化螟危害上升原因与防治策略

对二化螟近年来在水稻上大发生的原因进行了调查和分析，并根据生产实际，提出了防治策略与措施，即以农业防治为重点，药剂防治为保障，农业防治要立足于减少虫源田，降低越冬代羽化率，药剂防治要立足于有效杀灭幼虫。     

Safe application of reclaimed water reuse for agriculture in Korea

This article describes the pilot study on the water reuse for agricultural irrigation in Korea. The project is a part of the application of wastewater reuse system for Agriculture project, a 21st Century Frontier R&D Program sponsored by the Ministry of Education, Science, and Technology and associated with the Sustainable Water Resources Research Program. The goal of the project was to develop infra-technologies necessary to reclaim wastewater for irrigation in agriculture. The project involved two phases: laboratory and field research. Reclamation techniques for irrigation and feasible reuse were developed as a first step in proposing appropriate water quality standards. Reclaimed wastewater of various qualities was used to irrigate cereal crops and vegetables, and possible adverse effects on crops, humans, and the environment were investigated. The optimal reclamation methods required to satisfy water quality standards were explored and the operational characteristics investigated. Moreover, an inventory of farmlands that could reuse reclaimed wastewater was established. Feasible delivery systems for irrigation were developed, and pilot project sites were identified. Finally, operational field data from pilot units were collected and analyzed. This research and development may help solve water shortage problems in Korea, which left unaddressed will have an adverse effect on future generations.     

旱地油菜地膜覆盖栽培的水热效应研究

油菜覆膜栽培研究表明，不同生长阶段耕层日平均土温提高0.51-0.78℃，全生育期增加有效积温140℃，土壤含水量提高0．42％－1．88％，水分利用效率提高2．79－4．10kg/mm.hm^2。覆膜栽培缩短生育期6－11d，杂油77产量达到3371.10kg/hm^2，比露地栽培增产23．11％。     

Quantitative risk assessment for reclaimed wastewater irrigation on paddy rice field in Korea

Water shortage has become an important issue for Korean agriculture. Korea suffers from a limited agricultural water supply, and wastewater reuse has been recommended as an alternative solution. This study examined the concentrations of toxic heavy metals and Escherichia coli in a paddy rice field irrigated with reclaimed wastewater to evaluate the risk to farmers. Most epidemiological studies have been based on upland fields, and therefore may not be directly applicable to paddy fields. In this study, a Beta-Poisson model was used to estimate the microbial risk of pathogen ingestion. The risk value increased significantly after irrigation and precipitation. The results of the microbial risk assessment showed that risk values of groundwater and reclaimed wastewater irrigation were lower than the values of effluent directly from wastewater treatment plants. The monitoring results of heavy metals for each irrigated paddy fields did not show specific tendency. A risk assessment for toxic heavy metals was performed according to various exposure pathways; however, the results of the carcinogenic and noncarcinogenic risk estimation showed that the risk from reclaimed wastewater-irrigated paddy fields was the lowest.     

Rapid determination of glucose,fructose and sucrose in potato tubers by capillary gas chromatography

Summary A method has been developed for the rapid quantification of glucose, fructose and sucrose in potato tubers by capillary gas chromatography. Baseline separation of trimethylsilyl derivatives of β-D(−) fructose, α-D(+) glucose β-D(+) glucose, myoinositol (internal standard) and sucrose was achieved in under 10 min with a detection range of 10 ng to 3 μg per component. Use of an on-column injector resulted in the retention of a proportion of injected sucrose by the column, despite an oven starting temperature of 140°C. This did not occur with a splitless injection system (inlet temperature 220°C).     

Evaluation of technologies for sequestering carbon in agricultural land by using organic filter underdrains

Technology for storing carbon in the subsoil of agricultural land using organic filter materials in underdrains was evaluated as an activity for sequestering CO₂ to mitigate global warming. First, the quantity of carbon remaining in wood chips and rice husks in underdrains was determined over 11 years after construction. Moreover, the quantity of CO₂ emissions from the construction of two underdrain types was calculated. Then, a survey was conducted to investigate the effect on greenhouse gas emissions of the filter material. The results indicate that greenhouse gas emissions would not increase. The quantity of storage carbon in the wood chip filter material of underdrains during their 15-year service life was estimated to be 6.76 tCO₂eq ha^?1. Rice husks, in contrast, were found ineffective in storing carbon. Therefore, the selection of the filter material for underdrains is important. The value of storage carbon in the wood chip filter material is similar to the amount of carbon sequestered by no-till farming, which is now being implemented as a global warming countermeasure based on soil management in agricultural land.     

Evaluation of technologies for sequestering carbon in agricultural land by using organic filter underdrains

Technology for storing carbon in the subsoil of agricultural land using organic filter materials in underdrains was evaluated as an activity for sequestering CO₂ to mitigate global warming. First, the quantity of carbon remaining in wood chips and rice husks in underdrains was determined over 11 years after construction. Moreover, the quantity of CO₂ emissions from the construction of two underdrain types was calculated. Then, a survey was conducted to investigate the effect on greenhouse gas emissions of the filter material. The results indicate that greenhouse gas emissions would not increase. The quantity of storage carbon in the wood chip filter material of underdrains during their 15-year service life was estimated to be 6.76 tCO₂eq ha⁻¹. Rice husks, in contrast, were found ineffective in storing carbon. Therefore, the selection of the filter material for underdrains is important. The value of storage carbon in the wood chip filter material is similar to the amount of carbon sequestered by no-till farming, which is now being implemented as a global warming countermeasure based on soil management in agricultural land.

     

On-the-spot identification of grain variety and wheat-quality type by Lab-on-a-chip capillary electrophoresis

Lab-on-a-chip capillary electrophoresis has been used for identification of wheat variety and quality type. Analysis of each chip takes 30 minutes for 10 samples, and distinction can be made between members of a set of 40 commonly grown Australian wheat varieties. Quality type could be predicted by analysis of the HMW and LMW glutenin subunits. The technique has also been applied to the separation of proteins from other grains and legumes, and may also be useful for identifying variety and/or quality type in these crops.     

Revegetation of barren lakeside land through growth enhancement of Xanthium italicum by rhizobacteria

This study aims to propose a methodology for establishing the optimal rule curves of reservoir operation based on a multi-use reservoir system. Located on the upper Saigon River, Dau Tieng Reservoir plays an important role in economic and social aspects: (1) flood control; (2) domestic and industrial demands; (3) flushing out salt water intrusion from the downstream area; and (4) agriculture irrigation. We propose a reservoir operation model using a constrained genetic algorithm (CGA), in which the fitness function was constrained by penalty functions. The proposed model was formulated by including various water demands configured into the objective function. The penalty functions were designed for various constraints and integrated into the objectives of the operation process to perform the fitness function. The model’s performance was simulated for the last 20 years with 1-month intervals and evaluated through a generalized shortage index (GSI). The derived results of three CGA cases with associated environmental flow requirements significantly improved the efficiency and effectiveness of water supply capability to various water demands as compared to current operation. Among the three cases, CGA case 3 achieved much better water releases from the reservoir as indicated by a small derived GSI value (0.33), the smallest shortage of environmental water (0.11 m³/s) and the highest water usage (63.8 %). Thus, the derived results of CGA case 3 were presented as the best rule curves for reservoir operation. To summarize, CGA was demonstrated as an effective and powerful tool for optimal strategy searching for multi-use reservoir operations.     

Effect of cutting,phosphorus and potassium fertilization on guar plant (Cyamoposis tetragonoloba) in newly reclaimed soil in Egypt

A two year experiment was carried out in newly reclaimed soils (sandy soils) to investigate the effect of cutting and phosphorus and potassium fertilization on the growth, yield, seed mucilage content and seed protein content of guar plant. The results revealed that different cutting treatments significantly decreased the plant weight, seed yield, seed mucilage content and seed protein content. Phosphorus fertilization up to 350 kg super-phosphate (15% P₂O₅)/feddan significantly increased plant weight, seed yield, seed mucilage content and seed protein content. Fertilization with 150 kg potassium sulfate (48% K₂O)/feddan was quite capable to meet guar plant potassium demands in this kind of soil. Without cutting plants, fertilization with 350 kg superphosphate and 150 kg potassium sulfate/feddan resulted in the highest seed yield, seed muculage content and seed protein content.     

普通小麦籽粒性状的主基因+多基因遗传模型分析

为给小麦遗传育种中籽粒性状改良提供参考,以小麦大粒品系0911-46为母本与小粒品系42杂交产生P₁、P₂ 、F₁ 、BC₁ 、BC₂ 和F₂共4个世代6个群体,应用主基因+多基因混合遗传模型多世代联合分析方法分析了小麦粒重、粒长、粒宽、粒厚的遗传特点。结果表明,千粒重、粒宽、粒厚都符合2对加性-显性-上位性主基因+加性-显性-上位性多基因遗传模型。2对粒重主基因都具有正向加性效应,可以增加粒重,但其互作效应有正有负且互相抵消,对粒重影响不大。粒宽和粒厚的显性效应为正向作用,有利于增加籽粒体积。粒长符合加性-显性-上位性多基因模型,无主基因。千粒重主基因+多基因遗传率在BC₁、BC₂、F₂三个分离世代分别为88.02%、78.53%、87.82%;粒长多基因遗传率在3个分离世代分别为71.95%、61.64%、62.93%;粒宽主基因+多基因遗传率在3个分离世代分别为43.90%、32.69%和68.47%;粒厚主基因+多基因遗传率在3个世代分别为50.01%、42.86%和68.63%。所有籽粒性状中以粒重的遗传力最高。     

盘锦地区耕地土壤养分情况简述

2001年开始,盘山县在耕地土壤上采集了578份监测土样,对土壤有机质、全氮、碱解氮、有效磷、有效钾和pH值等进行化验分析。结果表明,在1982年～2001年的20年间,全县耕地土壤的全氮、速效磷含量水平有所提高,有机质和速效钾的含量呈下降趋势。     

Development of a water quality tank model classified by land use for nitrogen load reduction scenarios

Water quality in the watershed mainly used for agriculture is degraded by nutrients from fertilizers and animal wastes. These diffuse (non-point) sources have accumulated in soils and been released into the river system for the long-term. In this paper, a water quality tank model classified by land use is modified for the accumulation, and total nitrogen (T-N) is simulated over 40 years in the Yamada River basin within the Lake Kasumigaura watershed, Japan. For considering the nitrogen balance, the model has a database comprising statistical data such as population, land use, rain, fertilizer, and animal waste; it calculates cumulative load in soils and dissolved load separately. The model simulated the measured data with relative error of 15% for runoff and 7% for T-N. Five scenarios for the reduction of cumulative load were developed as a countermeasure plan: soil washing, slow-release fertilizer, fertilizer application reduction, cover crop, and animal waste reduction. The results show that T-N first decreases and then increases after 30 years in the case of the slow-release fertilizer scenario and that T-N is reduced by 30% after 40 years in the case of the 100% animal waste reduction scenario.