直播稻田化学除草试验

直播稻田用不同药剂在播种后各一次化除或播种后两次化除都具有很好的除草效果。播后前期是化学除草的关键时期播后前期每６６７米＾２用１０％苄嘧黄隆１５克＋６０％丁划胺６０毫升，１０％苄嘧黄隆１５克＋５０％杀草丹１５０毫升，１７．２％新幼禾葆２４０克或１５．８％幼禾葆２００克防铲均较好。     

Zero-<Emphasis Type="Italic">trans</Emphasis> shortening using palm stearin and rice bran oil

Several pilot-scale trials reported in this paper, using palm stearin-rice bran oil (PS-RBO) blends, obviously did not contain trans FA (TFA), whereas the commercial products were found to contain 18–27% TFA. The effects of processing conditions such as rate of agitation, crystallization temperature, and composition of the blends on the crystal structure of shortenings were studied. The products were evaluated for their physicochemical characteristics using DSC, X-ray diffraction (XRD), HPLC, and FTIR techniques. The formulation containing 50% PS and 50% RBO showed melting and cooling characteristics similar to those of hydrogenated commercial “vanaspati” samples. Analysis of the FA composition revealed that the formulated shortenings contained 15–19% C_18∶2 PUFA. Tocopherol and tocotrienol contents of the experimental shortenings were in the range of 850–1000 ppm with oryzanol content up to 0.6%. XRD studies demonstrated that the crystal form in the shortenings was predominantly the most stable β′ form, and there was less of the undesirable β form.     

Increasing productivity and protein content using early-maturing rices and efficient nitrogen management

Germplasm with shorter duration than that of the currently grown varieties is being generated to maximize productivity of irrigated rice. However, short-duration varieties often produce yields lower than the medium- and long-duration varieties. Experiments were conducted during the 1980–82 dry and wet seasons to increase productivity through the use of very early-maturing rices and the improved management of nitrogen (N) fertilizers.Results over three years showed that IR58 and IR9729-67-3 (growth duration 100 ± 5 days) yield as well as or higher than IR36 although earlier maturing. They generally had a higher productivity (kg ha^–1 day^–1) than IR36 (110 ± 5 days).Three years' data suggest that the improved timing of broadcast applications of urea in split doses increased grain yield comparable with the basal incorporation of slow-release sulfur-coated urea (SCU) or deep point-placement of urea supergranules (USG).Results on elite breeding lines showed that the early-maturing IR9729-67-3 produced higher protein yield ha^–1 than longer duration varieties such as IR8 and IR42 in the dry season. Furthermore, contrary to earlier results, single basal incorporation of slow-release SCU increased the protein yield of rice by 53 kg ha^–1 and deep point-placement of USG by 43 kg ha^–1 over split application of prilled urea.     

TNT红水治理研究新动态

综述了国内外治理TNT红水的研究现状及发展趋势,阐明了生化治理TNT红水的难点,给出了采用经红水驯化后的白腐菌生化治理TNT红水的技术措施、脱色方法及分析方法,指出白腐菌与木质素载体能较有效地降解TNT红水,该方法具有广阔的应用前景,同时对白腐菌处理技术的发展和应用提出建议.     

大孔树脂分离纯化商陆红色素的研究

研究了几种大孔吸附树脂和离子交换树脂对商陆红色素的静态吸附特性,筛选出一种吸附性能较好的树脂,并应用柱层析进行商陆红色素的分离纯化研究。实验结果表明:D301离子交换树脂对商陆红色素的静态吸附率达到96.0%,柱层析吸附饱和后用0.15 mol/L HCl洗脱时,洗脱率达到92.8%,洗脱液经低温干燥得到的商陆红色素色价达到45.9。     

Bauxite residue (red mud) increases phosphorus retention in sandy soil catchments in Western Australia

The Peel-Harvey estuary on the Swan Coastal Plain, Western Australia has become eutrophic partly because of the leaching of fertiliser phosphorus from sandy soils. The acid, coarse textured sandy soils are predominantly quartz, have a low iron and aluminium content and do not retain phosphorus. Red mud, derived from bauxite, is a by-product of the alumina industry and has the ability to retain phosphorus. Retention of phosphorus is enhanced when the red mud is neutralised with gypsum. Red mud has been suggested as a soil amendment to reduce phosphorus leaching.To investigate the reduction in the leaching of phosphorus from soils amended with red mud, weirs were constructed at the outlets from a pair of catchments to quantify the amount of phosphorus in the streamflow. Both catchments were deep grey Bassendean sand. One of the catchments was treated with 80 t/ha of red mud which had been neutralised with waste gypsum from the phosphate industry. The red mud was applied to the soil surface using conventional fertiliser spreading equipment. The other catchment was untreated.The red mud reduced phosphorus loss by 70% from 13.8 kg/ha on the untreated catchment, to 4.2 kg/ha on the treated catchment. Both catchments were treated with 20.4 kg/ha of phosphorus as superphosphate. The catchment treated with red mud also received a further 41.5 kg/ha of phosphorus from the phosphogypsum that was used to neutralise the red mud.Our results show that red mud reduces phosphorus leaching and is potentially a nutrient management option in sandy soils. Red mud has the potential to reduce the impact of agriculture on the estuarine environment and has implications for the continued expansion and intensification of agriculture in the Peel-Harvey catchment.     

Why Phenolic Acids Are Unlikely Primary Allelochemicals in Rice

Allelopathy in rice (Oryza sativa, L.) effective against weeds has been found in about 3.5% of tested rice germplasm in both laboratory and field experimentation. However, the allelochemicals responsible for growth inhibition of rice-associated weeds have not yet been identified. In the literature, phenolic acids are often mentioned as putative allelochemicals. If phenolic acids commonly reach growth inhibitory concentrations in rice ecosystems, it must be expected that the degree of tolerance to phenolic acids will vary among traditional rice cultivars or plant species adapted to rice environments having inherently different phenolic acid concentrations. Phenolic acids concentrations are normally greater in submerged than in aerobic soils. A dose–response study, however, showed that seedlings of rice cultivars adapted to submerged anaerobic soils did not have higher level of tolerance against p-hydroxybenzoic acid than did seedlings of varieties adapted to aerobic upland soils. Moreover, traditional rice cultivars had no greater tolerance than did improved cultivars that were recently bred for traits other than tolerance of phenolic acids. Similarly, there were no differences in tolerance of p-hydroxybenzoic acid between two Echinochloa weed species adapted to either anaerobic or aerobic growth conditions. Thus, neither the rice cultivars nor weed species had evolved different tolerance levels against the phenolic acid. However, all rice cultivars had significantly greater tolerance of p-hydroxybenzoic acid than did either weed species. In a second experiment, the rates at which rice plants released phenolic acids into solution cultures were measured for at least one month, the time period of greatest allelopathic activity following planting under field conditions. The maximum release rate of phenolic acids during the first month of growth was approximately 10 g/plant/day. At a conventional plant density, the release rate of phenolic acids would be approximately 1 mg/m²day. This order of release rate cannot provide concentrations remotely close to phytotoxic levels determined for these rice cultivars and weed species. The results presented in this paper do not preclude the possibility that phenolic acids might be one component in a mixture of chemicals that, when present simultaneously, are allelopathic.     

Influence of modified forms of urea and nitrogen levels on weed growth and grain yield of lowland rice

The growth of weeds and their subsequent reduction of rice yield as affected by N source neem cake coated urea (NCU), dicyandiamide coated urea (DCU), rock phosphate coated urea (RPCU), urea supergranules (USG) and prilled urea (PU) was studied on a clay loam soil at Coimbatore, India. Experiments were conducted in northeast monsoon (NEM) 1981, summer 1982, and southwest monsoon (SWM) 1982 seasons.The crop was associated with eleven weed species, and the dominant weeds wereEchinochloa crus-galli, Cyperus difformis andMarsilea quadrifolia. The weed flora varied between seasons. Deep placement of USG reduced the dry weight of weeds in NEM and summer seasons at 60, 90 and 120 Kg N ha^–1 whereas it increased the dry weight at 60 and 90 but not 120 Kg N ha^–1 in SWM season. The dry weight of weeds decreased with increased N rates for all N sources during NEM and summer seasons. In SWM season, dry weight of weeds increased with increased N rates for all N sources except USG. The grain yield of rice was drastically reduced with the deep placement of USG at 60 but not 120 Kg N ha^–1 in SWM season. The differential effect of the N sources between seasons was due to the change of the weed flora. Dominance ofE. crus-galli during SWM season had greater influence on weed dry weight and grain yield of rice.Nitrogen uptake by weeds was frequently greater in unfertilized plots, particularly in NEM and summer seasons. In SWM season, the apparent fertilizer N recovery by weeds was high for USG. It decreased from 53% for 60 Kg USG-N ha^–1 to 4% for 120 Kg USG-N ha^–1.Contribution from the part of Ph.D. work of the first author at Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore-641 003, Tamil Nadu, India.     

二氧化钛固载杂多酸催化剂的制备及其光催化性能研究

采用浸渍法以TiO2为载体制备了固载型杂多酸光催化剂--H3PW12O40/TiO2,H8SiW12O42/TiO2,H7PMo12O42/TiO2.通过Hammett指示剂与紫外光谱相结合的方法测定固体杂多酸催化剂的酸度,分别考察杂多酸种类、浸渍时间、浸渍浓度、烧结方式、烧结温度对催化剂酸度的影响,并对所制备的催化剂进行了红外光谱和光催化活性测试.结果表明,杂多酸固载到TiO2的表面,得到了催化活性较TiO2更强的复合杂多酸光催化剂,其对酸性大红3R的降解率从纯TiO2的79%提高到91%.以磷钨酸水溶液浸渍TiO2,浸渍浓度为0.10 mol·L-1 ,浸渍时间为28 h,烘干温度为120℃,微波炉焙烧功率为650 W,烧结时间为40 min制得的催化剂活性最高.在HPA-TiO2光催化系统中,杂多酸显著加速电子从TiO2表面到O2分子的传递,改变了TiO2光催化反应历程,从而提高光催化效率.     

15%恶霉灵防治水稻立枯病药效试验

田间试验表明，15％恶霉灵水剂6～8ml／m^2，对水稻立枯病的防效可达82.3％，病指防效可达89.4％，明显好于对照药剂。而且对水稻安全，能够提高秧苗素质。