土壤微生物在氮转化过程中具有很重要的作用。本实验的目的是研究根际增氧方式处理后水稻根际土壤氮转化功能基因（硝化、反硝化以及固氮基因）丰度和关键酶（脲酶、蛋白酶、氨氧化酶、硝酸还原酶以及亚硝酸还原酶）活性变化。试验设计三种增氧方式（长淹处理：又称厌氧灌溉，水稻整个生育期保持3-5 cm水层；长淹增氧处理：种植方式同长淹。水稻种植之前，在土培盆中埋入打过孔的PVC管并接到增气泵上。首次通气2小时，此后每天间隔2小时通气10分钟（由计时器控制）；干湿交替处理：又称好氧灌溉，自浅水层自然落干到土壤水势达-15 kPa 时，灌水 1~2 cm，再自然落干至土壤水势为-15 kPa，再上浅层水，如此循环），研究水稻主要生育期（分蘖期、齐穗期和成熟期）根际土壤氮转化功能基因丰度和关键酶活性变化，并分析各微生物活性指标间的相关性。结果表明，各处理水稻根际土壤氮转化功能基因丰度和关键酶活性均以齐穗期最高。增氧（长淹增氧和干湿交替处理）后水稻根际土壤硝化功能基因、固氮基因丰度增加、反硝化功能基因丰度降低；脲酶、蛋白酶和氨氧化酶活性提高，硝酸还原酶和亚硝酸还原酶活性降低，干湿交替处理尤其明显。干湿交替处理后水稻整个生育期根际土壤氨氧化古菌（AOA）和氨氧化细菌（AOB）amoA基因以及固氮基因丰度的平均值分别是长淹处理的2.87、5.75和2.97倍，反硝化功能基因nirS, nirK丰度分别比长淹处理减少73.61%和84.41%；脲酶、蛋白酶和氨氧化酶活性分别比长淹处理增加1.13、0.51和0.72倍，硝酸还原酶和亚硝酸还原酶活性分别比长淹处理减少10.30%和36.48%。相关分析结果显示：硝化功能基因和固氮基因丰度与脲酶、蛋白酶和氨氧化酶活性呈极显著正相关；反硝化功能基因丰度与硝酸还原酶活性呈极显著正相关。上述指标和土壤微生物碳、微生物氮含量均呈正相关。综上，水稻根际土壤氮转化相关的微生物活性在齐穗期最高。增氧可以提高大多数氮素转化微生物活性和土壤微生物氮含量，从而促进水稻根际土壤氮素的转化。

土霉素广泛存在于土壤和水体中，可能对农业生态环境构成潜在威胁。含土霉素的粪便作为有机肥施用是土霉素进入土壤和水体的主要途径之一。因此，实现粪便堆肥过程中土霉素的有效去除，并明确土霉素存在下堆肥有机质的转化规律十分重要。本文通过调节不同初始含水率（45%、55%、65%），外源模拟添加土霉素，将鸡粪和小麦秸秆共堆肥，以研究堆肥过程中土霉素降解及有机质变化规律。研究结果表明，堆肥初始含水率对土霉素降解有显著影响，与较低初始含水率相比，初始含水率为65%更有利于土霉素降解（降解率77.4%）和堆肥腐熟，然而，高初始含水率（65%）可能促进堆肥过程的硝化作用，从而增加了氨挥发。此外，增加堆肥初始含水率可以提高堆肥温度。核磁共振结果显示，土霉素的存在可以影响脂肪类物质的内部转化，从而抑制堆肥的腐殖化。55-65%的初始含水率可以缓解粪便堆肥过程中土霉素对腐殖化的影响。

Effects of the heavy metal copper (Cu), the metalloid arsenic (As), and the antibiotic oxytetracycline (OTC) on bacterial community structure and diversity during cow and pig manure composting were investigated.  Eight treatments were applied, four to each manure type, namely cow manure with: (1) no additives (control), (2) addition of heavy metal and metalloid, (3) addition of OTC and (4) addition of OTC with heavy metal and metalloid; and pig manure with: (5) no additives (control), (6) addition of heavy metal and metalloid, (7) addition of OTC and (8) addition of OTC with heavy metal and metalloid.  After 35 days of composting, according to the alpha diversity indices, the combination treatment (OTC with heavy metal and metalloid) in pig manure was less harmful to microbial diversity than the control or heavy metal and metalloid treatments.  In cow manure, the treatment with heavy metal and metalloid was the most harmful to the microbial community, followed by the combination and OTC treatments.  The OTC and combination treatments had negative effects on the relative abundance of microbes in cow manure composts.  The dominant phyla in both manure composts included Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria.  The microbial diversity relative abundance transformation was dependent on the composting time.  Redundancy analysis (RDA) revealed that environmental parameters had the most influence on the bacterial communities.  In conclusion, the composting process is the most sustainable technology for reducing heavy metal and metalloid impacts and antibiotic contamination in cow and pig manure.  The physicochemical property variations in the manures had a significant effect on the microbial community during the composting process.  This study provides an improved understanding of bacterial community composition and its changes during the composting process. 

小麦叶锈病是危害小麦最严重的病害之一，该病由小麦叶锈菌（Puccinia recondite f. sp. tritici）引起，侵染小麦叶片，严重影响小麦光合作用从而造成减产，培育和利用小麦抗叶锈病品种是最为经济有效的防治措施。为鉴定国内外普通小麦材料中所携带的抗病基因并了解其组成背景，发掘新的抗叶锈病基因，本研究结合基因推导、分子标记检测等方法对66个来自世界不同国家的普通小麦品种（系）进行了抗叶锈病基因鉴定。在苗期接种17个不同毒力的小麦叶锈菌生理小种，通过与36个含有单个已知抗病基因的载体品种抗性比较进行基因推导。同时，利用12个与已知抗病基因紧密连锁的分子标记对供试品种（系）进行基因标记检测，以验证基因推导结果。在河南周口（2016-2017年度）、河北保定（2017-2018年度）两地对66个供试品种（系）进行小麦叶锈病田间叶锈抗性调查，利用SAS软件对鉴定数据进行分析，以筛选出具有成株慢锈性的品种。结果表明，在66个供试品种（系）中，12个品种（系）含有Lr1，4个品种（系）含有Lr26，3个品种含有Lr10，2个品种含有Lr20，2个品种含有Lr17。通过成株抗病基因分子标记检测发现，14个品种（系）含有Lr34，5个品种含有Lr46，3个品种（系）含有Lr37。结合田间调查结果发现，有17个品种（系）具有成株慢锈性。这些含有已知抗病基因的品种及慢锈性品种将丰富我国现有的小麦种质资源，有利于培育抗病品种，同时为利用基因布局防治小麦叶锈病提供遗传学依据。

草地贪夜蛾又名秋行军虫，严重危害玉米和水稻等农作物，目前已经入侵我国。昆虫病毒作为生物农药，在控制害虫过程中具有重要的作用。昆虫浓核病毒具有环境友好和高效杀虫等优点，是一种潜在的生物杀虫剂。我们采用多种昆虫细胞系和鳞翅目昆虫幼虫从鹿眼蛱蝶浓核病毒全基因组感染性克隆成功拯救了病毒粒子。采用感染性克隆质粒转染的昆虫细胞系的匀浆物饲喂二龄草地贪夜蛾幼虫，具有致死效应。该浓核病毒感染致死的斜纹夜蛾的匀浆物对二龄草地贪夜蛾的半致死剂量是1.76×10⁸ 病毒基因组拷贝， 高于斜纹夜蛾（7.39×10⁷ 病毒基因组拷贝）和棉铃虫（9.71×10⁷ 病毒基因组拷贝）。这种匀浆物对草地贪夜蛾的半致死时间是6.96 d， 高于斜纹夜蛾（6.18）和棉铃虫（5.94 d）。该病毒能够感染棉铃虫的脂肪体，但是不能感染草地贪夜蛾和斜纹夜蛾的脂肪体。虽然这三种昆虫都对该病毒敏感，但是毒力大小具有差异。鹿眼蛱蝶浓核病毒可以作为控制草地贪夜蛾的潜在的生物杀虫剂。

    Organic pollutants, such as polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), antibiotics, herbicides, and bisphenol A (BPA), are commonly found in agricultural environments. They are released into the environment as a result of their use for human health purposes and farm management activities, and are often discharged as waste-water effluents. Most of these organic pollutants are taken up by plants through roots and leaves, and when they enter the tissue, they cause serious damage to the plants. Although the toxicity of organic pollutants to plants, especially to plant cells, has been intensively studied, a systematic review of these studies is lacking. Here we review researches on the toxicity of organic pollutants, their uptake, and translocation in plants. Our objective is to assemble existing knowledge concerning the interaction of organic pollutants with plants, which should be useful for the development of plant-based systems for removing pollutants from aquatic and agricultural environments.

    In this study the transfer characteristics of mercury (Hg) from a wide range of Chinese soils to corn grain (cultivar Zhengdan 958) were investigated. Prediction models were developed for determining the Hg bioconcentration factor (BCF) of Zhengdan 958 from soil, including the soil properties, such as pH, organic matter (OM) concentration, cation exchange capacity (CEC), total nitrogen concentration (TN), total phosphorus concentration (TP), total potassium concentration (TK), and total Hg concentration (THg), using multiple stepwise regression analysis. These prediction models were applied to other non-model corn cultivars using a cross-species extrapolation approach. The results indicated that the soil pH was the most important factor associated with the transfer of Hg from soil to corn grain. Hg bioaccumulation in corn grain increased with the decreasing pH. No significant differences were found between two prediction models derived from different rates of Hg applied to the soil as HgCl₂. The prediction models established in this study can be applied to other non-model corn cultivars and are useful for predicting Hg bioconcentration in corn grain and assessing the ecological risk of Hg in different soils.

The irrigation method used in winter wheat fields affects micro-environment factors, such as relative humidity (RH) within canopy, soil temperature, topsoil bulk density, soil matric potential, and soil nutrients, and these changes may affect plant root growth. An experiment was carried out to explore the effects of irrigation method on micro-environments and root distribution in a winter wheat field in the 2007–2008 and 2008–2009 growing seasons. The results showed that border irrigation (BI), sprinkler irrigation (SI), and surface drip irrigation (SDI) had no significant effects on soil temperature. Topsoil bulk density, RH within the canopy, soil available N distribution, and soil matric potential were significantly affected by the three treatments. The change in soil matric potential was the key reason for the altered root profile distribution patterns. Additionally, more fine roots were produced in the BI treatment when soil water content was low and topsoil bulk density was high. Root growth was most stimulated in the top soil layers and inhibited in the deep layers in the SDI treatment, followed by SI and BI, which was due to the different water application frequencies. As a result, the root profile distribution differed, depending on the irrigation method used. The root distribution pattern changes could be described by the power level variation in the exponential function. A good knowledge of root distribution patterns is important when attempting to model water and nutrient movements and when studying soil-plant interactions.

The essential and toxic element concentrations in buckwheat were analyzed by inductively coupled plasma optical emission spectrometer (ICP-OES). The concentration data were subjected to common chemometrics analyses, including correlation analysis (CA), principal component analysis (PCA) and hierarchical cluster analysis (HCA), to gain better understanding of the differences among the tested samples. Our results indicated that the essential and toxic element concentrations were not different between Fagopyrum tataricum (L.) Gaertn and F. esculentum Moench. The element concentrations varied among buckwheat samples from different sources. Commercial tartary buckwheat tea contained several essential elements, thus, could be used as the source of essential elements. The detection of toxic heavy metals in commercial tartary buckwheat tea suggested that safety issue of such buckwheat products should be seriously concerned. Our results also revealed that the place of origin and the processing protocol of tartary buckwheat affected the element concentrations of the commercial form. The implications to the quality control and safety evaluation of buckwheat were extensively discussed.

Understanding the relationship between the timing of N fertilizer applications and crop primary production is crucial for achieving high yield and N use efficiency in agriculture. This study investigated the effects of starting-N plus topdressing N applications (as compared to the common practice of all basal application) on soybean photosynthetic capacity under different planting densities. A field experiment was conducted in two growing seasons (2011 and 2012), and the soybean (Glycine max L. Merrill) cultivar was Dongnong 52, three planting densities (20, 25 and 30 plants m-2), and four N fertilizer application patterns (all N fertilizer of 6 g N m-2 as basal fertilizer, all N fertilizer as topdressing at beginning pod stage (R3), 1.8 g N m-2 as basal fertilizer and 4.2 g N m-2 as topdressing at stage R3 and full pod stage (R4), respectively). The results indicated that under the same planting density, compared to applying all N as basal fertilizer, the application of starter-N plus topdressing N substantially reduced the rate of pod abscission, and enhanced leaf area index (LAI) significantly at beginning seed stage (R5) (P<0.05), net assimilation rate (NAR) during stages R4-full seed stage (R6) (P<0.05), contribution rate of post-seed filling assimilate to seed (CPA) (P<0.05), and yield (P<0.05). Applying topdressing N at stage R4 resulted in higher net primary production and yield than applying topdressing N at stage R3. When applying starter-N plus topdressing N at planting density of 25 plants m-2, LAI after stage R5 and NAR after stage R4 were increased by 5.92-16.3% (P<0.05) and 13.7-26.6% (P<0.05) with the planting density of 20 plants m-2, respectively, and yield was 8.46-14.0% (P<0.05) higher than that under 20 plants m-2. When planting density increased to 30 plants m-2, only LAI during stages R4-R5 and NAR during stages R4-R5 increased by applying starter-N plus topdressing N, while the other indexes declined. Overall, results of this study demonstrated that applying starter-N plus topdressing N could significantly enhance soybean photosynthetic capacity after stage R5 at planting density of 25 plants m-2.