坡瘠地建设高产土土壤养分,作物产量与投肥的关系

新改坡瘠地建高产土是耕作制度改革的重大发展,是粮食生产由提高土地利用率到提高土地生产率的发展过程,是快速培肥土壤、提高农业综合生产力的最好形式。为此,我们在总结农民经验的基础上,采用了适合当地优选的轮作模式,在轮作中应用回归设计的试验方法,研究了新改坡瘠地建高产土土壤养分变化、作物产量水平及效应与投肥的关系,以期为新改坡瘠地稳定持续高产提供科学依据。

高产土壤条件下双季杂交稻施磷效应研究

为完善双季稻超高产栽培技术体系 ,以湖南省醴陵市高产稻田土壤——河沙泥为供试土壤 ,杂交早稻V40 2和杂交晚稻 V6 44为供试作物 ,对不同施磷水平的杂交稻和土壤效应进行了研究 .结果表明 ,在高产土壤条件下 ,施磷仍能促进水稻提早分蘖 ,增大水稻生育前期的干物质积累量和对氮、磷、钾的吸收量 ,但对水稻中、后期的干物质积累和氮、磷、钾的吸收无促进作用 .施磷处理水稻一生中地上部干物质总量和稻谷产量与不施磷处理无明显差异 .施磷的增产效应系数低是高产稻田土壤的重要肥力特性之一 .在这样的土壤条件下水稻施磷量不应依据施磷效应曲线来确定 ,而应依据水稻生产的目标产量和生产单位重量稻谷的需磷量来确定 .依据本试验结果 ,早、晚稻生产 1 0 0 kg稻谷平均吸磷量分别为 0 .32 6 kg和 0 .35 5 kg.比照早、晚稻稻谷产量分别为 7991 .5 kg/hm2 和775 3.9kg/hm2 ,则早、晚稻施磷量应分别为 2 6 .0 5 kg/hm2和 2 7.5 2 kg/hm2 .

除草剂丁草胺对高产水稻土微生物群落功能多样性的影响

采用BIOLOG碳素利用法,研究了模拟条件下不同丁草胺剂量（有效成分质量分数0.15、0.30和1.5 mg.kg-1）对高产水稻土微生物群落功能多样性的影响。AWCD值分析结果表明：各处理均在温育72~120 h期间表现出较强的碳源利用能力,中低浓度对微生物有促生长作用,高浓度有抑制作用,随着培养时间延长,丁草胺对微生物的促进和抑制作用逐渐减缓,直至完全消失。采用温育96 h数据进行群落多样性和碳源利用特征主成分分析,Shannon指数和Simpson指数分析结果表明,施用丁草胺会对高产水稻土微生物群落碳源利用能力产生不利影响,施药浓度是导致微生物群落碳源利用能力集中、可利用碳源种类数减少的直接原因,且浓度越高,发生变化所需时间越短。主成分分析结果表明,施用丁草胺会导致高产水稻土微生物群落碳源利用能力改变,中低浓度改变速度快,高浓度改变速度较慢,随着丁草胺的自然降解,农药对微生物群落碳源利用能力的影响逐渐消退。

江西余江县高产水稻土有机碳和养分含量变化

【目的】研究高产水稻土有机碳和养分含量变化状况,为水稻土的定向培肥和持续利用提供科学参考。【方法】通过田间采样分析并比较第二次土壤普查的背景资料,研究江西省余江县高产水稻土有机碳和养分的含量状况及其近20余年来的变化情况,并分析其环境意义。【结果】江西省余江县高产水稻土表层0～10cm的有机碳、全氮和速效磷含量分别为(20.2±3.88)g·kg-1、(2.09±0.55)g·kg-1、(42.7±32.7)mg·kg-1,均达到非常丰富的水平。近20余年来土壤有机碳库基本保持稳定、处于平衡状态,但全氮和速效磷含量显著增加,而速效钾含量变化不明显。高产水稻土表层0～10cm的磷固定量和固定率分别为(142.7±41.1)mg·kg-1和(36.2±10.4)%,CEC为(7.93±1.32)cmol·kg-1,并不比一般水稻土和旱地红壤高。这使通过施肥进入土壤的磷活动性增加,以致更易进入水体,可能是区域水体富营养化的主因。【结论】经过长期的耕作培肥,高产水稻土的有机质和速效磷含量均达到非常丰富的水平,有机碳库基本处于平衡状态,但磷的固定量并不高。由于该类型土壤的固钾能力较弱,高产水稻土的速效钾含量并不丰富,应当重视钾库的平衡保持和提高。

丁草胺污染对高产水稻土微生物区系的影响

土壤微生物多样性是表征土壤质量最有潜力的指标,与农田生态系统的稳定性和生产力密切相关。云南永胜涛源乡是保持我国水稻小面积超高产纪录的特殊生态区,常年施用丁草胺作为选择性芽前除草剂,因此,了解丁草胺对其土壤微生物物种多样性的影响意义重大。采用平板菌落计数法,研究了模拟条件下不同丁草胺剂量(有效成分质量分数0.15、0.30和1.5 mg·kg-1)对高产水稻土中好氧细菌(aerobic bacteria)、放线菌(actinobacteria)和真菌(fungi),以及功能微生物自生固氮菌(nitrogen fixing bacteria)、磷酸盐溶解菌(phosphate solubilizing bacteria)和硅酸盐细菌(silicate dissolving bacteria)数量的影响。结果表明:施药7 d,中、高质量分数(0.30和1.50 mg·kg-1)丁草胺处理好氧细菌数量比CK分别高出78.6%和153.8%,而后数量逐渐下降,表现出先刺激生长、后抑制活性的作用,低质量分数(0.15 mg·kg-1)丁草胺对好氧细菌的生长和增殖影响不明显;施药7 d,高质量分数处理放线菌数量超过CK 75.1%,表现出明显的刺激作用;施药15 d,中等质量分数处理放线菌数量比CK高出125.0%,丁草胺浓度越高,刺激作用越迅速,低浓度丁草胺对放线菌则主要表现为抑制作用。低浓度丁草胺对真菌的生长和增殖基本没有影响,中等浓度有先抑制后刺激的作用,施药30 d后其真菌数量超过CK56.9%,高浓度丁草胺则表现为抑制作用,施药7、30和45 d其真菌数量始终显著低于CK;不同浓度处理丁草胺均能刺激自生固氮菌的数量显著增加,施药7 d,低、中、高质量分数处理自生固氮菌数量分别高出CK 237.1%,179.9%和138.1%,刺激作用显著,但随培养时间延长,高浓度开始表现出抑制作用;不同浓度丁草胺均能抑制磷酸盐溶解菌的生长和增殖,低浓度处理抑制作用微弱,中、高浓度处理磷酸盐溶解菌数量则始终显著低于CK,表现为丁草胺浓度越高,抑制作用越明显;低浓度丁草胺对硅酸盐细菌数量影响不明显,中、高浓度则对其有抑制作用,B150在施药7和15 d时分别比CK低60.7%和58.1%,表现为浓度越高抑制作用越明显。

水稻高产的土壤条件

要获得农作物的高产稳产,必须有良好的土壤环境条件,即具备能满足作物生长发育和根系活动所需的营养和环境因素,一般指水、肥、气、热等,但不同作物或同一作物的各个生育期所需的生长条件有所不同。 “水稻,水稻,有水才有稻”,这种说法虽然未必确切,但概括说明了水稻与土壤水分的供求关系。水稻对土壤环境条件的要求与旱作物不同,因水稻属于两栖性植物,防御机构不发达,其生长发育需要近饱和的土壤水分。水稻体内的通气组织,贯穿整个植株。

高产稳产水稻土的培育途径

几年来,由于不断增加化肥、农药和施用量,有机肥料的减少,耕作粗放,基本农田资源环境的破坏,水稻土不同程度存在土质变劣、耕层变浅、养分失调等问题。严重地影响水稻的高产稳产。为此,培育高产稳产水稻土势在必行。

湖南双季稻种植区不同生产力水稻土微生物和生物化学性质的研究

土壤微生物和生物化学性质是农业土壤生产力的重要指标。该文研究了湖南省双季稻种植区不同生产力水稻土微生物种群数量和生物化学性质的差异。不同生产力水稻土样品采自湖南省东部、中部和西北部8个水稻主产县,测定了高产、中产和低产水稻土的微生物种群数量、微生物生物量C(SMBC)、微生物生物量N(SMBN)、土壤呼吸、代谢熵(qCO2)、脲酶、磷酸酶、转化酶、脱氢酶、土壤有机C(SOC)、全N(TN)、全P(TP)、全K(TK)、有效N(AN)、速效P(AP)、速效K(AK)和稻谷与稻草产量。结果表明,高产水稻土的细菌、真菌、放线菌数量和微生物生物量C、N与中产水稻土无明显差异。SMBC、SMBN含量和土壤脲酶、转化酶、脱氢酶活性与细菌、真菌和放线菌的变化规律基本相似。由于湖南省植稻区施用磷肥有近50年历史,土壤磷素含量较高,导致不同生产力水稻土之间的磷酸酶活性没有差异。细菌和放线菌与SOC、TN、TK、AN含量之间相关性最好。脲酶和转化酶活性与土壤SOC、SMBC、SMBN、TN和AN含量之间的相关性最好。高产水稻土与中产水稻土之间在微生物性质上差异很小,中产水稻土只要加强田间管理措施,可以达到高产水稻土的产量目标。目前低产水稻土的微生物性质和生物化学性质较差,应注意有机肥料和无机肥料的合理施用,重视低产水稻土的改良,提升这类土壤的生物质量。

合肥市郊县“稻改菜”的土壤培肥途径

分别对合肥市近郊高产菜园土土壤和肥东县长乐乡水稻土土壤的理化性状和土壤酶活性等进行分析 ,阐述并比较了合肥郊区高产菜园土和肥东县水稻土土壤的肥力特征 ,提出了“稻改菜”的土壤培肥途径。

夏玉米“一增四改”高产栽培技术

介绍了襄汾县夏玉米"一增四收"高产栽培技术的主要内容、操作要求,以及其他配套技术。生产实践证明,该技术操作简单、方便,切实可行。

日本农业现代化中一些土壤肥料问题

中国科学院农业科学考察团,于三月二十二日至四月十二日在日本进行了参观访问。回国以后又陪日本农业科学工作者在湖南桃源县做了五天考察。这里就考察所见,以及日本朋友提供的文献资料,对日本农业现代化中的一些土壤、肥料方面的工作,扼要介绍于下。

Supporting of Potential Forage Production to the Herbivore-based Pastoral Farming Industry on the Loess Plateau

For the purpose of contributing to the establishment of optimized eco-productive paradigm, a new layout of land use of the Loess Plateau was carried out and the associated forage potential was estimated. Results indicated that the percentages of the area of grassland, woodland, basic farmland and orchard to the total productive land area were 44%, 22%, 20% and 14% respectively according to this new land use scenario. Based on the datasets of 197 counties in the Loess Plateau, the estimated forage potential would amount to 104 881 028 ton/a (hay), which can raise 104 881 028 productivity sheep unit/ a. According to the unchanged price in 1999, pastoral gross product value would amount to 52 440.51 million yuan RMB/a, which is as much as 5.3 times of that in 1999 and exceeds the agricultural gross product in 1999 by 14%. In addition, there are ca. 59% of counties whose mean pastoral product value per person would be more than 1 000 yuan RMB/a, while ca. 41% of counties whose mean pastoral product value per person would be less than 1 000 yuan RMB/a. On the other hand, the estimated agricultural gross product on the Loess Plateau would amount to 11 472 2.34 million yuan RMB/a and ca. 46% of the total would come from pastoral industry, 27% from orchid industry, 14% from forestry and 13% from farmland. From the perspective both ecologically and economically, this paper holds that the herbi-vore-based pastoral industry is a promising industry bolstering the ecological improvement and economical development on the Loess Plateau.

Nitrogen Recoveries and Yields Improvement in Cowpea sorghum and Fallow sorghum Rotations in West Africa Savannah

The effects of previous cowpea （Vignaunguiculata） and annual fallow on N recoveries, succeeding sorghum yields and soil properties were studied using a 5-year-old （1995-1999） field experiment at Kouar6 （11°59′ North, 0°19′ West and 850 m altitude） in Burkina Faso. A 3 4 factorial design in a split plot arrangement with three rotation treatments and four fertilizer treatments was used. Total N uptake by succeeding sorghum increased from 26 kg N ha~ in mono cropping of sorghum to 31 and 48 kg N ha~ when sorghum was rotated with fallow or cowpea respectively. Nitrogen derived from fertilizer increased from 10% in mono cropping of sorghum to 22% and 26% when sorghum was rotated with fallow or cowpea respectively. While fallow did not increase N derived from soil, cowpea doubled the quantity of N derived from soil （Ndfs）. Sorghum grain yields increased from 75% and 100% when sorghum was rotated with fallow or cowpea respectively. All rotations treatments decreased soil organic C and N but soil organic C was the highest in fallow-sorghum rotation. It was concluded that cowpea-sorghum rotation was more effective than fallow-sorghum rotation and five management options were suggested to improve traditional system productivity.

Study on Maize-water Model for Supplemental Irrigation in Loess Plateau

The Loess Plateau has a typical semi-arid climate, and the area suffers from very harsh ecological environment, severe soil erosion and water runoff, and uneven distributed precipitation. Due to the relatively low holding capacity, current rainwater-collecting and conservation facilities can only supplement a maximum of18 mm of water for crop production in each irrigation. In this study, mathematical models were constructed to identify the water requirement critical period of maize crop by evaluating response of each individual developmental stage to supplemental irrigation with harvested rainwater. In the transformed Jensen model, ETmin/Eta was used as the index of relative evapotranspiration. The use of relative yield and relative crop evapotranspiration was able to eliminate influences from unintended environmental factors. A BP neural network crop-water model for extreme water deficit condition was constructed using the index of relative evapotranspiration as the input and the index of relative yield as the output after iterative training and adjustment of weight values. Comparison of measured maize yields to those predicted by the two models confirmed that the BP neural network crop-water model is more accurate than the transformed Jensen model in predicting the sensitivity index to waterdeficit at various growth stages and maize yield when provided with supplemental irrigation with harvested rainwater.

Total Integration of Renewable and Fossil Energy Aiming to a Clean and Sustainable Energy System

This paper presents a new concept of TIRFE （total integration of renewable and fossil energies）, represented by an octagonal structure of all sources, vectors of transmission and optimization of consumption, aiming to a clean and sustainable energy system. The main TIRFE technologies are： cogeneration of H2 and EE （electric energy） by H2-BGSCW/TEU （biomass gasification in supercritical water integrated with a thermoelectric unit）; use of H2 from biomass in oil refinery processes for production of light and clean derivatives; supply of 1-12 deficiency for methanol production from coal; carbon sequestration by a basket of technologies （exhausted petroleum and gas） wells, underground saline aquifers, forests and stockpile of cellulignin-CL-produced from forest residues）; use of H2-BGSCW/TEU as district CHP （combined heat and power） with photovoltaic panels for EE, including electric car battery recharge; optimization of energy consumption by verticalization of the cities replacing low strength materials （bricks and common cement） by high performance concrete with addition of silica from rice husk. TIRFE helps to solve key problems of H2-BGSCW/TEU, such as materials, energy recovery, plugging, corrosion, economics and energy security for the first generation of plants, and organizes the development for the second generation. TIRFE can be incrementally implanted in existent and new cities.

Estimation of New Wheat Genotypes for Salt Tolerance Which Induced through Plant Breeding Programs

Salinity of soils or water poses an increasing threat to food production due to climate change. Plant breeding programs were applied to improve salt tolerance in new wheat genotypes to overcome this problem. The aim of this research work is to estimate the realized improvement in salt tolerance of the selected genotypes through plant breeding programs. The comparison experiments were conducted in salinized soils at two locations for two years as compared with two local cultivars. All the selected genotypes derived from F2 populations after six cycles of exposure to high salinity level were tested for salt tolerance during all growth stage. At harvest stage, seed yield and its components were studied for the comparison. Results showed that there were significant differences between all selected genotypes and local eultivars in their overall sensitivities to soil salinity. All selected genotypes were superior in seed yield and its components at maturity to those of the local cultivars at the two location and years. Clearly, all the selected genotypes exhibited more than twice seed yield/m2 compared with that obtained from local cultivars. The results also indicated that there were differences among selected genotypes in their responses to soil salinity between locations and years, but not significant. Important thing is significant improvement in selected genotypes was achieved in their salt tolerance through six cycles of screening and selection to high salinity level. The conclusion is a strong possibility to improve salt tolerant genotypes of wheat with high salt tolerance through plant breeding programs.

Herbage Production and Species Richness in Sub-alpine Grasslands of Different Soil Parent Material in Northern Greece

Several abiotic and biotic factors were investigated as possible predictors of local species richness in two sub-alpine grasslands of Jenna and Belles Mountains in Northern Greece.For species richness modelling a hierarchical modelling framework based on generalized additive models was adopted.The two sub-alpine grasslands differed in aspect,altitude and soil parent material(volcanic origin,mostly trachyte,and andesite(TA) for Jenna and metamorphic rocks,mostly gneiss(G) for Belles).12 fenced squared plots,16 m2 each,were used per grassland,where soil properties,herbage production,species presence and cover of grasses,legumes and forbs were estimated.Mean herbage production was significantly affected by slope and altitude,soil K content and floristic composition as expressed by an ordination axis.Soil p H,floristic composition and average herbage production were significant predictors of forbs and total species richness.For the former,soil N content and for the latter the occurrence of Agrostis capillaris,were also included as significant terms in the predictive model.Thepredictors for grasses species richness were N content,having a positive effect,and average herbage production.In all cases higher species richness was predicted for intermediate values of average herbage production.Differential responses were found between forbs and grasses.The predictors of their species richness were different while for the case of the common predictor(N) the responses of the two groups were also different(grasses species numbers increase and forbs species numbers decreased with increasing N).Maximum species richness of grasses was observed at relatively low production levels while forbs species richness maximized at relatively high production levels.