Decontamination of Chlorate in Longan Plantation Soils by Bio-Stimulation with Molasses Amendment

Potassium chlorate is widely used as an active substance for flower induction in longan plantation fields for off-season production of longan fruits in northern Thailand. Contamination of groundwater with residual chlorate in soil is a cause for concern because of its toxicity to human health. Based on our previous finding that the addition of glucose or sucrose to soil was effective for accelerating the disappearance of residual chlorate in soil, the effect of the addition of molasses, which contains a high concentration of sucrose, as a substitute for glucose or sucrose was examined in laboratory and pot experiments. Under laboratory conditions, the addition of molasses to soil at the concentrations of 100 to 200 g kg⁻¹ soil strikingly enhanced the rate of disappearance of chlorate applied at 341 mg kg⁻¹ soil. Addition of diluted molasses was also effective for the accelerated disappearance of chlorate in soil when 33 g kg⁻¹ soil of molasses was added repeatedly. The effect of repeated addition of diluted molasses to soil on the decontamination of residual chlorate in soil was also confirmed in an outdoor pot experiment. These results may lead to the development of a practical method of cleaning-up chlorate-polluted soil in longan plantation fields.     

滨海盐渍土适宜土壤盐碱改良剂的筛选研究

针对黄河三角洲地区的实际情况和滨海盐渍土特点,进行利用土壤盐碱改良剂改良盐渍土的研究。引进了4种土壤盐碱改良剂,通过在中度和重度盐渍土上的试验,分析化验土壤含盐量和测定作物产量,对所测定结果进行综合分析,筛选出适宜于滨海盐渍土的最佳改良剂。试验分析结果表明,4种土壤盐碱改良剂都能降低土壤含盐量,其中盐碱土壤修复材料效果最好,是滨海盐渍土适宜的土壤盐碱改良剂。     

施用改良剂对皖南旱坡地土壤性状及烤烟产量和品质的综合效应

通过田间小区试验研究了无机矿石类及生物炭改良剂不同组合对皖南旱坡地土壤性状以及烤烟产量和烟叶品质的影响。结果表明:与对照相比,3种无机矿石材料(T20、G20、硅藻土)和2种生物炭(竹炭和砻糠炭)的改良剂的不同组合,可使土壤体积质量下降0.27~0.34 g/cm3,田间持水量提高11.6%~55.6%,pH提高了0.45~0.93个单位;烤烟产量增加26~397 kg/hm~2,烤烟烟碱与全氮含量有所下降,还原糖含量有所增加,糖碱比优化,品质进一步提升。本研究结果可以为皖南旱坡地烟区土壤改良、提高特色烟产量和品质、促进农民增产增收提供有效的指导。     

Short-term responses of two contrasting species of earthworms in an agricultural soil amended with coal fly-ash

With the renewed interest in the use of coal fly-ash for amendment of agricultural soils in Australia, we assessed how earthworms, as indicators of soil health, responded to this ameliorant. We assessed survival, weight, burrowing and elemental concentrations for earthworms of a native unnamed Megascolecid species and of exotic Aporrectodea trapezoides in intact soil cores treated with an alkaline fly-ash at rates equivalent to 0, 5 and 25 t/ha over 6 weeks. Fly-ash did not affect survival, growth, number of burrows created or phosphorus solubilisation. Transfer of the earthworms to the new environment having vastly different pH from where they were collected, and possibly overcrowding, caused mortality in the soil cores for all treatments. A. trapezoides that had smaller individuals suffered mortality of 12% compared with 23% for the larger earthworms of Megascolecids. Earthworms of Megascolecids each increased their weight by 0.24g (25% of their original weight) while those of A. trapezoides lost 0.18g each (21% of their original weight). The difference in growth between the two earthworms was associated with grazing habit and probably with the large difference in the pH between source soil and that of the core soil. Megascolecids appeared to minimize grazing on ash-tainted soil and so ingested less Zn, which was more abundant in the fly-ash than in the soil, compared with A. trapezoides that had elevated concentration of this metal. Extractable P in the soil was increased with both species of earthworms, more so with the exotic species that solubilized 11% more P than the native Megascolecids. The benign influence of fly-ash on survival and growth of worms was associated with the pH of soil remaining unchanged during the six weeks of incubation.     

《中国图书馆分类法》（第四版）S8类的修订实践

参加了《中国图书馆分类法》（第四版）＂S农业科学＂类中的＂S8畜牧、动物医学、狩猎、蚕、蜂＂部分的修订工作。介绍了《中国图书馆分类法》的作用和修订工作的实践,提出了《中国图书分类法》的维护建议。     

Metabolic Responses Induced by Serial Harvesting of Alfalfa Pasture Established on Amended Acid Soil

Abstract

Alfalfa pasture has not been sustainable on the coastal plain of the United States because of its intolerance to soil acidity. This study examined the responses of alfalfa metabolism to differential amendments of acid soil and to serial harvesting. The soil was spatially amended with different quantities of flue gas desulfurization sludge and gypsum after liming to pH 7. The serial harvests oscillated the RNA synthetic activity of glutamate dehydrogenase (GDH) from an oxidized to a reduced state irrespective of the soil amendments. The amplitudes of the redox cycles changed from one harvest to the next, thus demonstrating improved regrowth persistence. The chlorophyll, hexose, nucleotide, and protein contents, and the fructose‐1, 6‐bisphosphatase activity, decreased and fluctuated inconsistently in the successive cuttings. Consideration of the metabolic responses per harvest showed that the alfalfa had optimized saccharide metabolism in the first harvest, optimized RNA metabolism in the second harvest, optimized saccharide and RNA metabolism in the third harvest, and depressed saccharide metabolism in the fourth harvest, thereby optimizing the regrowth potential of the alfalfa pasture. Sustainability of the pasture was conferred by the coordinate compensatory regulation of metabolism in response to the synergistic interaction between the differential amendments and the nitrogen (N) nutrient excreted by the alfalfa into the soil.     

Environmental and Economic Benefits of Saline-Sodic Soil Reclamation Using Low-quality Water and Soil Amendments in Conjunction with a Rice–Wheat Cropping System

A combination of appropriate crop rotation(s) and management interventions has the potential to transform saline‐sodic soil and water resources from an environmental burden into an economic asset. We carried out 2‐year field studies in the Indus Basin of Pakistan to evaluate different irrigation and soil management options of using saline‐sodic waters (SSW) and soils for reclamation and for growing salt‐tolerant cultivars of rice (SSRI‐8) and wheat (SIS‐32). These soils have variable levels of salinity and sodicity (EC_e 9–44 dS m^?1 and SAR 83–319). The treatments on both the sites were the same and consisted of: (1) Irrigation with SSW, (2) Irrigation with freshwater (FW), (3) Soil application of gypsum at 100 % gypsum requirement of soil + SSW (G + SSW), (4) G + one irrigation with SSW and one with FW (G + 1SSW + 1FW), (5) G + two irrigations with SSW and one with FW (G + 2SSW + 1FW), (6) Farm manure at 25 Mg ha^?1 each year before rice + one irrigation with SSW and one with FW (FM + 1SSW + 1FW) and (7) FM + two irrigations with SSW and one with FW (FM + 2SSW + 1FW). Rice was grown as the first crop. After harvesting final wheat crop (fourth in sequence), maximum decrease in bulk density and increase in infiltration rate was observed with G + 1SSW + 1FW while FM + 1SSW + 1FW treatment showed higher decrease in pH_s and EC_e. Significantly the highest decrease in SAR occurred at both sites with G + 1SSW + 1FW. Maximum yields of rice and wheat were generally observed with G + 1SSW + 1FW. The crop yield and economic benefits with treatments showed a positive correlation with that of improvement in soil physical and chemical properties. Overall, the greatest net benefit was obtained from G + 1SSW + 1FW treatment. We also found that the farmers’ management skills were crucial in the overall success in improving crop yields during reclamation of saline‐sodic soils. Based on the results of this study, we propose that SSW could be used to reclaim saline‐sodic soils by using a rice–wheat rotation and a site‐specific combination of soil amendments and water application strategies.     

Philosophy and mechanics of how we arrive at fertilizer and lime recommendationsx

Abstract

Three rates of the synthetic, hydrophylic substance Permabsorb (1.6, 3.2, and 6.4 gm/1) were tested by growing ryegrass, azalea, and impatiens in a greenhouse mix, consisting of 1 part Spagnum peat moss, 1 part vermiculite and 1 part perlite by volume.

The increased water holding capacity furnished by the Permabsorb at 6.4 gm/1 significantly decreased the watering frequency of rye‐grass without affecting yield. All Permabsorb treatments reduced azalea yield because of decreased aeration or toxicity. Impatiens grew poorly in treatments and control.

As the Permabsorb treatments and the control were put through wetting and drying cycles, all held less water unless saturated for long periods of time. Nevertheless, the treatments generally held more water and had lower watering frequencies than the control throughout the 5 to 6 month duration of the experiment.