不同水肥管理稻田土壤铬生物有效性及吸收富集特征

【目的】探究不同水肥管理对土壤铬生物有效性的影响及水稻吸收富集特征。【方法】试验地为8a长期定位水肥管理水稻田,灌溉处理设常规灌溉（F）、控制灌溉（C）2种灌溉模式,施肥处理设为施用常规化肥（F）、有机肥（OF）2种施肥模式,分析了不同水肥管理下稻田土壤pH值、土壤铬量及形态分布、水稻根系和稻谷铬量的差异。【结果】(1)与常规灌溉处理和常规施肥处理相比,控制灌溉处理和有机肥处理均显著降低了土壤pH值。(2)与FF处理相比,COF处理增加了土壤可交换态、可还原态和可氧化态铬量和比例,各形态铬量分别增加了54.31%、43.06%和39.33%;减少了残渣态铬量和比例,残渣态铬量减少了2.84%;提高了重金属铬从根到稻谷的转运系数;增加了水稻植株根部和稻谷铬量,分别较FF处理增加了46.31%和59.43%。(3)在相同灌溉条件下,不同施肥处理土壤pH值和可交换态、可还原态铬量显著负相关;而在相同施肥条件下,不同灌溉处理间土壤pH值和可交换态、可还原态铬量之间不存在明显相关性。【结论】对比常规肥,施用有机肥给节水灌溉稻田带入了外源重金属铬,并显著增强了土壤铬生物有效性,促进了水稻植株吸收富...     

基于灰色预测模型的温室温湿度系统建模与控制

温室温湿度系统是一个典型的混杂系统(hybrid system,HS),系统的输入包括环境调控设备的开关状态以及可测不可控的外界环境因子扰动输入,包括太阳辐射、室外温度、室外湿度、风速、风向等。针对温室温湿度系统的这种混杂特性,该文提出一种基于切换系统的温室温湿度系统建模与预测控制方法。首先,分别在天窗开启与关闭状态下采用遗忘因子递推最小二乘法(forgetting factor recursive least squares,FFRLS)辨识模型参数,得到系统的2个子系统模型。采用灰色预测GM(1,1)模型预测温室温室度系统中可测不可控的扰动输入。然后,将系统预测控制问题描述为混合整数二次规划问题(mixed integer quadratic problem,MIQP),并通过分支定界法求解。分析了系统在有限时间内的稳定性(finite time stable,FTS)。最后进行了仿真研究,仿真结果表明该文中提出的建模和控制方法是有效的。     

The Box Plot Experiment in Grossbeeren after eight rotations: nitrogen,carbon and energy balances

The Box Plot Experiment in Grossbeeren was set up in 1972 to investigate the efficiency of diverse fertilization strategies within an irrigated vegetable crop rotation system for three different soils. Here, we report on the long-term effects on nitrogen, carbon and energy balances of applying various organic amendments and different amounts of mineral N fertilizer to soils. Fertile soils (sandy loam and clayey silt) were characterized by higher yield and N removal potential by plants, higher acceptable N input amounts, and a higher proportion of total N input recovered by soil N storage and N uptake by plants. After 40 years, organic carbon equilibrium in the soil has not been reached. Rates of change of organic carbon stocks are still affected by the different organic matter levels at the beginning of the experiment. An increasing net N supply increased and organic C input decreased net C gains. Because of the manifold possibilities of producing energy from current or former agricultural land, energetic evaluation of land use needs to become more complex if direct comparisons are to be made. Including the energy contents of organic amendments and soil organic matter in the energy balances would be a first step in this direction.     

Effects of Organic Amendments on Productivity and Profitability of Bell Pepper–French Bean–Garden Pea System and on Soil Properties during Transition to Organic Production

A transition period of at least 2 years is required for annual crops before the produce may be certified as organically grown. There is a need to better understand the various management options for a smooth transition from conventional to organic production. The purpose of this study was to evaluate the effects of different organic amendments and biofertilizers (BFs) on productivity and profitability of a bell pepper–french bean–garden pea system as well as soil fertility and enzymatic activities during conversion to organic production. For this, the following six treatments were established in fixed plots: composted farmyard manure (FYMC, T₁); vermicompost (VC, T₂); poultry manure (PM, T₃) along with biofertilizers (BF) [Rhizobium/Azotobacter + phosphorus solubilizing bacteria (Pseudomonas striata)]; mix of three amendments (FYMC + PM + VC + BF, T₄); integrated nutrient management (FYMC + NPK, T₅); and unamended control (T₆). The yields of bell pepper and french bean under organic nutrient management were markedly lower (25.2–45.9% and 29.5–46.2%, respectively) than with the integrated nutrient management (INM). Among the organic treatments, T₄ and T₁ produced greater yields of both bell pepper (27.96 Mg ha^?1) and french bean (3.87 Mg ha^?1) compared with other treatments. In garden pea, however, T₄ gave the greatest pod yield (7.27 Mg ha^?1) and was significantly superior to other treatments except T₅ and T₁. The latter treatment resulted in the lowest soil bulk density (1.19 Mg m^?3) compared with other treatments. Similarly, soil organic C was significantly greater in all the treatments (1.21–1.30%) except T₂ compared to T₆ (1.06%). Plots under INM, however, had greater levels of available nitrogen–phosphorus–potassium (NPK) than those under organic amendments. T₁ plots showed greater dehydrogenase and acid phosphatase activities compared with other treatments. However, T₄ and T₅ plots had greater activities of β-glucosidase and urease activities, respectively. The cost of cultivation was greater under organic nutrient management (except T₂) compared with INM. The latter treatment gave greater gross margin and benefit/cost (B/C) ratio for all vegetables, except that T₂ gave greater B/C ratio in garden pea compared with other treatments. We conclude that T₁ and T₄ were more suitable for enhancing the productivity of bell pepper–french bean–garden pea system, through improved soil properties, during transition to organic production.     

Survey of Underutilized Grain Legume Production Systems in the Southwest Agricultural Zone of Nigeria

ABSTRACT

A socio-economic survey of production systems was carried out in four out of the eight states that make up the southwest agricultural zone of Nigeria. A total of 157 minor grain legume farmers selected by multi-stage sampling were interviewed using structured questionnaires. The study shows that lima bean, pigeon pea, African yam bean, and bambara groundnut are the prominent minor grain legumes grown on less than 10% of the total cultivated land area. The minor grain legumes are grown on an average land size ranging from 0.2 to 0.4ha and predominantly in mixture with crops like cassava, maize, yam, sorghum, cocoyam, etc. The use of modern inputs like herbicides, pesticides, fertilizers, and improved varieties is uncommon in minor legume production systems. The cultivation of these legumes is more popular among the older members of the farming communities, about 78% of which are above 40 years of age. The average yield of the legumes on farms is considerably low, estimated at 271kg/ha, 265kg/ha, 174kg/ha, and 275kg/ha for lima bean, pigeon pea, African yambean, and bambara groundnut, respectively. Major constraints identified by the farmers include low market demand, inadequate seed supply, high cost of labour, and low yield. Research work is therefore needed in agronomy and breeding for improved yield and utilization for expanded market and, consequently, increased production.     

沉积物中生物活性磷赋存形态对耗氧有机物的响应

[目的] 本研究为验证耗氧有机物影响沉积物中生物活性磷的赋存形态的假说。[方法]以葡萄糖代替耗氧有机物,将沉积物暴露于耗氧有机物30天。[结果表明] 不充气时,葡萄糖浓度0、2、4、8 mg/L下的表层沉积物Ex-P含量为0.02±0.01、0.02±0.01、0.03±0.01、0.02±0.01 μmol/g;充气时,相应葡萄糖浓度下的表层沉积物Ex-P含量为0.03±0.00、0.03±0.01、0.03±0.01和0.06±0.02μmol/g,葡萄糖浓度8mg/L下的Ex-P含量高于葡萄糖浓度0mg/L下的（P< 5%）。不充气时,葡萄糖浓度0、2、4和8mg/L 下的表层沉积物IP含量为0.96±0.42、0.74±0.29、0.97±0.78和0.88±0.22μmol/g;充气时,相应葡萄糖浓度下的表层沉积物IP含量为0.37±0.10、0.46±0.16、0.41±0.06和0.69±0.05μmol/g,葡萄糖浓度8mg/L下的IP含量高于葡萄糖浓度0mg/L下的（P< 5%）。[结论]耗氧有机物对沉积物中生物活性磷有双重阈值作用。     

基于农作制分区的1985—2015年中国小麦生产时空变化

Comparing spatio-temporal variation characteristics of China’s wheat production, yield, sown area and yield-area-contribution in different farming zones in the past 30 years could help improving wheat planting layout and adjusting planting structure. Concentration index, rate of change, moving of gravity and resolution of yield-area-contribution were used to analyze spatio-temporal changes of China’s wheat production and yield-area-contribution based on county wheat production statistics including sown area, production and yield from 1985 to 2015. The wheat sown area decreased obviously in Northeast farming region, Northwest farming region and South farming region and increased rapidly in Huang-Huai-Hai farming region and Yangtze Plain farming region. In Huang-Huai-Hai farming region, the concentration indexes of Haihe Plain farming region, Huang-huai Plain farming region and Fenwei Basin farming region reached to 20.64%, 25.77%, and 21.65% respectively in 2015. Wheat production increased significantly by more than 48 milliontons in Huang-Huai-Hai farming region, and nearly 8 million tons Yangtze Plain farming region but decreased by more than 2.6 million tons in Northeast farming region. In Huang-Huai-Hai farming region, wheat production was concentrated in Haihe Plain farming region, Huang-huai Plain farming region and Yuxi Hill farming region. The average wheat yield continuously improved during the study period, Huang-Huai-Hai farming region and Northwest farming region had the yield increase up to 103.5 kg hm ^-2 and 92.9 kg hm ^-2 each year. Wheat yield in Yuxi Hill farming region, Fenwei Basin farming region and Haihe Plain farming region was relatively high in Huang-Huai-Hai farming region. The yield-reduced area was mainly caused by the decreasing of sown area, while the yield-area-contribution rate was different in yield-increased area. Yield-dominant counties were reduced, area-dominant counties were increased and yield-area-dominant counties were relatively steady. In production increased area, yield-dominant and yield-area-dominant counties were the main types in Huang-Huai-Hai Farming region, area-dominant and yield-area-dominant counties were the main types in Yangtze Plain farming region. Chinese wheat production was increasingly concentrated in Huang-Huai-Hai farming region which has high and rapid increase of wheat yield over the past three decades. Haihe Plain farming region, Huang-huai Plain farming region and Fenwei Basin farming region were the most concentrated areas in Huang-Huai-Hai farming region for wheat production during this period. Wheat yield and sown area jointly promoted the increase of wheat production in Huang-Huai-Hai farming region, wheat sown area was the crucial factor to increase wheat production in Yangtze Plain farming region, especially in the north of Jiangsu, Anhui province and greater part of Xinjiang.     

配施矿物质质有机肥及化肥减量对玉米水肥资源利用率的影响

采用单因素试验设计,在大田栽培条件下研究了配施矿物质有机肥及化肥减量对玉米产量构成及水、肥资源利用率的影响。结果表明,配施矿物质有机肥可以显著的提高玉米的产量、水分利用效率和氮肥、磷肥利用率。在配施矿物质有机肥的条件下,化肥施量较当地最佳施肥水平减量15%和30%时,玉米产量分别达到13948 kg/hm2 、12782 kg/hm2,水分利用效率分别达到1.74 kg/m3、1.62 kg/m3,氮肥利用率分别达到35.97%、30.04%,磷肥利用率分别达到25.93%、21.55%。其中,在当地最佳施肥水平下减量15%并配施矿物质有机肥与当地最佳施肥水平处理的玉米产量没有显著性差异。表明在合理配施矿物质有机肥的条件下,将当前的化肥施量降低15%以内在生产实践中是可行的。     

The tyranny of taste: the case of organic rice in Cambodia

Fair-trade and organic products are often sold at price premiums justified by smaller production volumes that are associated with greater social and environmental responsibility. The consumption of these products confers on the consumer a greater sense of morality – and usually a claim to better taste. This paper tells the story of attempts to promote organic/fair-trade rice production by de facto organic Cambodian farmers for export to North American and European markets in order to assist poor farmers to trade their way out of poverty. It demonstrates that instead of promoting sustainable agriculture and fair trade between developed and developing markets, organic/fair-trade projects may impose First World consumer ideals and tastes that are out of step with the larger realities of agrarian transition in Cambodia and the wider region of developing Southeast Asia.     

Experimental Study of Multifunctional Acid to Deliquesce Stratum-jam

Aiming at the oneness of acid to deliquesce stratum-jam applied in scene at the present time,which is incapable of deliquescing complex dirty simultaneously,this article confects a new multifunctional O/W acid.This acid is an emulsified mixture containing 15% hydrochloric acid as its extro-posture,high dissolved oil as its internal state under the function of some proper exterior active reagent.It is composed of 0.5%OP-10,0.5%Span80,0.2%Tween80,0.06%imidazole and 0.01%twelve-alcohol,and the content of oil is equal to the acid content.It can be indicated that this acid has good ability of resolving mineral(CaCO_3,MgCO_3) and organic compound(mainly colloidal bitumen) when it was poured into the stratum,so that it can deliquesce oleic stratum-jam,resume and improve the penetrability of stratum,boost the ability of liquid flowing up.