深翻秸秆还田在我国东北地区已得到了广泛的应用，可以显著增加土壤有机碳储量，改善底层土壤养分循环功能。土壤微生物普遍被认为是这一过程的关键，但其在深层土壤改良中的作用仍研究有限。本研究于2018年开始，以东北地区棕壤为研究对象，以常规耕作（CT，翻耕深度15 cm）为对照，分析了秸秆浅混还田（SCT，翻耕深度15 cm）、深翻处理（IT，翻耕深度35 cm）和深翻秸秆还田（SIT，翻耕深度35 cm）对土壤微生物群落网络和多养分循环功能的影响。结果表明，深翻秸秆还田改善了土壤多养分循环指数，提高了表层和底层土壤有机碳、全氮、有效氮、有效磷和有效钾等养分含量。与传统耕作和秸秆浅混还田相比，深翻秸秆还田通过减少微生物网络平均连通度和节点数，增加平均路径长度和模块化程度，创造了一个结构相对松散但具有高集中度集群的网络结构。同时随机森林分析发现，平均路径长度和聚类系数是影响土壤多养分循环功能的主要因素。综上，深翻秸秆还田将是改善棕壤养分循环和微生物群落结构的一个有效措施，以上结果也为该地区关于微生物驱动秸秆分解策略提供了重要信息。

本研究通过84天的室内培养试验来揭示秸秆和养分（氮(N)、磷(P)和硫(S)）联合供应下土壤新碳生成的潜在微生物机制。结果表明，与对照土壤相比，单独添加秸秆刺激微生物进行养分开采，这与C:N和C:P酶活的比例降低了8-16%相吻合。随着养分补充水平的增提高，公主岭土壤新碳生成量从1155.9增加到1722.4 mg kg^-1，海伦土壤则从725.1增加到1067.5 mg kg^-1。回归树分析表明β-葡萄糖苷酶（BG）、酸性磷酸酶（AP）、微生物量碳（MBC）和酸杆菌对公主岭新碳生成的相对影响分别为27.8、18.5、14.7和8.1%；对海伦新碳生成的相对影响分别为25.9、29.5、10.1和13.9%。路径分析表明酸杆菌通过调节BG、AP和MBC直接或间接对土壤新碳生成产生积极影响，其中MBC的获取更多受到AP的调节。海伦土壤的新碳生成强度低于公主岭土壤，并且海伦土壤的新碳生成与AP活性直接相关，表明土壤属性（例如SOC和pH值）对土壤新碳生成的重要性。综上，本研究揭示了添加秸秆的土壤中新碳生成与NPS养分补充的响应关系，且土壤新碳生成主要依赖于酸杆菌和变形菌的生长代谢及对BG和AP的调控。

了解磷组分特征和影响因素对提高土壤磷利用效率具有重要的意义。基于黑土、潮土和塿土的长期定位试验，选择了五种施肥方式并将其分为三组：无磷肥处理（CK/NK）、平衡施用无机肥处理（NPK/NPKS）和有机无机配施处理（NPKM）。对土壤无机磷组分和土壤性质进行了分析，研究了无机磷组分特征及无机磷组分与土壤性质的关系。结果表明，三种土壤中Ca₁₀-P占总无机磷的比例最高，黑土、潮土和塿土分别为33.5%、48.8%、44.8%。长期施肥导致了土壤无机磷累积或耗竭的周期性变化。NPK/NPKS和NPKM处理下，黑土和潮土在施肥后期（10-20年）的磷累积量高于施肥早期（0-10年），而塿土正好相反。黑土中无机磷的累积发生在全部磷组分中，而潮土主要为Ca₈-P、Fe-P和Ca₁₀-P，塿土主要为Ca₂-P、Ca₈-P和O-P。CK/NK处理下，三种土壤的无机磷耗竭主要发生在施肥早期；除活性无机磷（Ca₂-P）和中活性无机磷（Ca₈-P、Fe-P、Al-P）外，黑土和潮土中的Ca₁₀-P，塿土中的O-P也可被作物利用。冗余分析表明，土壤性质解释了每种土壤90%以上无机磷组分的变化，其中，土壤有机质的解释百分比在黑土、潮土和塿土中分别为43.6%、74.6%、38.2%。总之，在非酸性土壤中施用磷肥时，应考虑磷的累积速率和土壤性质驱动的无机磷组分的变化。

金融扶贫是2020年中国脱贫攻坚决胜战的重要举措，厘清以政府主导的正规金融对农户家庭收入的影响及其作用机制显得尤为重要。本文基于课题组2012年、2015年和2018年对中国西部贫困地区贵州、云南和陕西3省6个国家级贫困县592户农户家庭跟踪调查数据，评估了正规金融贷款对农户家庭收入及其作用机制做了深入研究。结果表明：第一，正规金融借贷能够显著提高西部贫困地区农户家庭收入。第二，正规金融借贷使得西部贫困地区农户家庭通过调整从事非农产业的劳动力资源配置和改变家庭“生产投资-消费”决策行为路径影响了农户收入水平和收入结构。第三，以政府为主导的正规金融贷款可能会拉大西部贫困地区农户内部的收入差距，农户本身的特征，如物质资本、人力资本和社会资本在内的资本禀赋状况是导致农户群体内部出现正规金融贷款引起增收差异的重要影响因素。本文研究结论为理解中国西部贫困地区金融扶贫效果与作用机制提供了理论依据，对中国政府完善相关政策提供了重要参考。

Certain agricultural management practices are known to affect the soil microbial community structure; however, knowledge of the response of the fungal community structure to the long-term continuous cropping and rotation of soybean, maize and wheat in the same agroecosystem is limited.  We assessed the fungal abundance, composition and diversity among soybean rotation, maize rotation and wheat rotation systems and among long-term continuous cropping systems of soybean, maize and wheat as the effect of crop types on fungal community structure.  We compared these fungal parameters of same crop between long-term crop rotation and continuous cropping systems as the effect of cropping systems on fungal community structure.  The fungal abundance and composition were measured by quantitative real-time PCR and Illumina MiSeq sequencing.  The results revealed that long-term continuous soybean cropping increased the soil fungal abundance compared with soybean rotation, and the fungal abundance was decreased in long-term continuous maize cropping compared with maize rotation.  The long-term continuous soybean cropping also exhibited increased soil fungal diversity.  The variation in the fungal community structure among the three crops was greater than that between long-term continuous cropping and rotation cropping.  Mortierella, Guehomyces and Alternaria were the most important contributors to the dissimilarity of the fungal communities between the continuous cropping and rotation cropping of soybean, maize and wheat.  There were 11 potential pathogen and 11 potential biocontrol fungi identified, and the relative abundance of most of the potential pathogenic fungi increased during the long-term continuous cropping of all three crops.  The relative abundance of most biocontrol fungi increased in long-term continuous soybean cropping but decreased in long-term continuous maize and wheat cropping.  Our results indicate that the response of the soil fungal community structure to long-term continuous cropping varies based upon crop types.

The concentration of soil Olsen-P is rapidly increasing in many parts of China, where P budget (P input minus P output) is the main factor influencing soil Olsen-P.  Understanding the relationship between soil Olsen-P and P budget is useful in estimating soil Olsen-P content and conducting P management strategies.  To address this, a long-term experiment (1991–2011) was performed on a fluvo-aquic soil in Beijing, China, where seven fertilization treatments were used to study the response of soil Olsen-P to P budget.  The results showed that the relationship between the decrease in soil Olsen-P and P deficit could be simulated by a simple linear model.  In treatments without P fertilization (CK, N, and NK), soil Olsen-P decreased by 2.4, 1.9, and 1.4 mg kg^–1 for every 100 kg ha^–1 of P deficit, respectively.  Under conditions of P addition, the relationship between the increase in soil Olsen-P and P surplus could be divided into two stages.  When P surplus was lower than the range of 729–884 kg ha^–1, soil Olsen-P fluctuated over the course of the experimental period with chemical fertilizers (NP and NPK), and increased by 5.0 and 2.0 mg kg^–1, respectively, when treated with chemical fertilizers combined with manure (NPKM and 1.5NPKM) for every 100 kg ha^–1 of P surplus.  When P surplus was higher than the range of 729–884 kg ha^–1, soil Olsen-P increased by 49.0 and 37.0 mg kg^–1 in NPKM and 1.5NPKM treatments, respectively, for every 100 kg ha^–1 P surplus.  The relationship between the increase in soil Olsen-P and P surplus could be simulated by two-segment linear models.  The cumulative P budget at the turning point was defined as the “storage threshold” of a fluvo-aquic soil in Beijing, and the storage thresholds under NPKM and 1.5NPKM were 729 and 884 kg ha^–1 P for more adsorption sites.  According to the critical soil P values (CPVs) and the relationship between soil Olsen-P and P budget, the quantity of P fertilizers for winter wheat could be increased and that of summer maize could be decreased based on the results of treatments in chemical fertilization.  Additionally, when chemical fertilizers are combined with manures (NPKM and 1.5NPKM), it could take approximately 9–11 years for soil Olsen-P to decrease to the critical soil P values of crops grown in the absence of P fertilizer. 

Black soil is one of the most precious soil resources on earth because it has abundant carbon stocks and a relatively high production capacity.  However, decreasing organic matter after land reclamation, and the effects of long-term inputs of organic carbon have made it less fertile black soil in Northeast China.  Straw return could be an effective method for improving soil organic carbon (SOC) sequestration in black soils.  The objective of this study was to evaluate whether straw return effectively increases SOC sequestration.  Long-term field experiments were conducted at three sites in Northeast China with varying latitudes and SOC densities.  Study plots were subjected to three treatments: no fertilization (CK); inorganic fertilization (NPK); and NPK plus straw return (NPKS).  The results showed that the SOC stocks resulting from NPKS treatment were 4.0 and 5.7% higher than those from NPK treatment at two sites, but straw return did not significantly affect the SOC stocks at the third site.  Furthermore, at higher SOC densities, the NPKS treatment resulted in significantly higher soil carbon sequestration rates (CSR) than the NPK treatment.  The equilibrium value of the CSR for the NPKS treatment equated to cultivation times of 17, 11, and 8 years at the different sites.  Straw return did not significantly increase the SOC stocks in regions with low SOC densities, but did enhance the C pool in regions with high SOC densities.  These results show that there is strong regional variation in the effects of straw return on the SOC stocks in black soil in Northeast China.  Additional cultivations and fertilization practices should be used when straw return is considered as an approach for the long-term improvement of the soil organic carbon pool.

    The efficiency of hybrid rice seed production can be improved by increasing the percentage of exserted stigmas. To identify quantitative trait loci (QTLs) for this trait, we conducted QTL mapping using 75 chromosome segment substitution lines (CSSLs) developed from a cross between the donor parent, Xieqingzao B (XQZB), a maintainer line which has high stigma exsertion and the recurrent parent, Zhonghui 9308 (ZH9308), a restorer line which has low stigma exsertion. A total of nine QTLs (qSSE5, qSSE10, qSSE11, qDSE10, qDSE11, qTSE5, qTSE6, qTSE10, and qTSE11) for single stigma exsertion (SSE), dual stigma exsertion (DSE) and total stigma exsertion (TSE) were assessed in two environments (Hainan and Zhejiang). Six of these QTLs (qSSE10, qSSE11, qDSE10, qDSE11, qTSE10, and qTSE11) were found in both environments, while one QTL (qTSE6) was found in only Hainan, and two QTLs (qSSE5 and qTSE5) were found in only Zhejiang. The qSSE10, qSSE11, qDSE10, qDSE11, qTSE6, qTSE10, and qTSE11 alleles, which are derived from the parent XQZB, exhibited a positive additive effect. In contrast, the qSSE5 and qTSE5 alleles, which are derived from the parent ZH9308, exhibited a negative additive effect. The SSE, DSE and TSE traits were significantly correlated with each other in an environmentally dependent manner. These results indicated that the lines showing higher values for SSE were more likely to exhibit increased values for DSE, which would ultimately increase TSE. To evaluate the advantage of exserted stigmas for cross-pollination, single, dual and total stigma exsertion should be considered separately in future attempts at genetic improvement to achieve increased production of rice hybrid seeds. This study also provides information for fine mapping, gene cloning and particularly marker-assisted selection (MAS), on the latter and with an emphasis the phenotypic effects and implications of the QTLs for practical use in hybrid rice breeding.

During meiosis in flowering plants, degradation of the callose wall in tetrads releases newly produced microspores, which develop into mature pollen grains. In this study, we identified zbs1, a male-sterile mutant of naked oat (Avena nuda L.) that displayed complete spikelet sterility due to inviable mature pollen. The abnormal pollen grains originated from microspores with a defective callose wall and cell plate during meiosis. The defective callose wall and cell plate of the zbs1 mutant were detected by the labeling of cell wall epitopes (β-1,3-glucan) with immunogold during meiosis, and an abnormal chromosome configuration was observed by propidium iodide staining. The mature pollen grains of the zbs1 mutant were irregular in shape, and abnormal germination was observed by scanning electron microscopy. Together, our results indicate that the cause of male sterility in zbs1 is abnormal meiosis.

Long-term continuous cropping of soybean (Glycine max), spring wheat (Triticum aesativum) and maize (Zea mays) is widely practiced by local farmers in northeast China. A field experiment (started in 1991) was used to investigate the differences in soil carbon dioxide (CO2) emissions under continuous cropping of the three major crops and to evaluate the relationships between CO2 fluxes and soil temperature and moisture for Mollisols in northeast China. Soil CO2 emissions were measured using a closed-chamber method during the growing season in 2011. No remarkable differences in soil organic carbon were found among the cropping systems (P>0.05). However, significant differences in CO2 emissions from soils were observed among the three cropping systems (P<0.05). Over the course of the entire growing season, cumulative soil CO2 emissions under different cropping systems were in the following order: continuous maize ((829±10) g CO2 m-2)>continuous wheat ((629±22) g CO2 m-2)>continuous soybean ((474±30) g CO2 m-2). Soil temperature explained 42-65% of the seasonal variations in soil CO2 flux, with a Q10 between 1.63 and 2.31; water-filled pore space explained 25-47% of the seasonal variations in soil CO2 flux. A multiple regression model including both soil temperature (T, °C) and water-filled pore space (W, %), log(f)=a+bT log(W), was established, accounting for 51-66% of the seasonal variations in soil CO2 flux. The results suggest that soil CO2 emissions and their Q10 values under a continuous cropping system largely depend on crop types in Mollisols of Northeast China.

Super high-yielding soybean cultivar Liaodou 14, soybean cultivars from Ohio in the United States, and the common soybean cultivars from Liaoning Province, China, with similar geographic latitudes and identical pod-bearing habits were used as the study materials for a comparison of morphological traits and production characteristics to provide a theoretical basis for the breeding of improved super high-yielding soybean cultivars. Using a randomized block design, different soybean cultivars from the same latitude were compared under conventional and unconventional treatments for their production characteristics, including morphological traits, leaf area index (LAI), net photosynthesis rate, and dry matter accumulation. The specific characteristics of the super high-yielding soybean cultivar Liaodou 14 were analyzed. The results showed that the plant height of Liaodou 14 was significantly lower than that of the common cultivars from Liaoning, whereas the number of its main-stem nodes was higher than that of the cultivars from Ohio or Liaoning. A high pod density was observed in Liaodou 14 under conventional treatments. Under both conventional and unconventional treatments, the branch number of Liaodou 14 was markedly higher than that of the common cultivars from Liaoning, and its branch length and leaf inclination angle were significantly higher than those of common cultivars from Liaoning or Ohio. Only small changes in the leaf inclination angle were observed in Liaodou 14 treated with conventional or unconventional methods. Under each treatment, Liaodou 14 exhibited the lowest amplitude of reduction in SPAD values and net photosynthesis rates from the grain-filling to ripening stages; the cultivars from Ohio and the common cultivars from Liaoning exhibited more significant reductions. Liaodou 14 reached its peak LAI later than the other cultivars but maintained its LAI at a higher level for a longer duration. Under both conventional and unconventional treatments, Liaodou 14 produced a higher yield than the other two cultivars, with significant differences from the Ohio cultivars. In summary, super high-yielding soybean cultivars have several main features: suitable plant height, high pod density, good leaf structure with strong functionality, and slow leaf senescence at the late reproductive stage, which is conducive to the accumulation of dry matter and improved yield.

The effects of different levels of CaCl2 on photosynthesis under low night temperature (8°C) stress in peanuts were studied in order to find out the appropriate concentration of Ca2+ through the artificial climate chamber potted culture test. The results indicated that Ca2+, by means of improving the stomatal conductivity of peanut leaves under low night temperature stress, may mitigate the decline of photosynthetic rate in the peanut leaves. The regulation with 15 mmol L-1 CaCl2 (Ca15) was the most effective, compared with other treatments. Subsequently, the improvement of Ca2+ on peanut photosynthesis under low night temperature stress was validated further through spraying with Ca15, Ca2+ chelator (ethylene glycol bis(2-aminoethyl) tetraacetic acid; EGTA) and calmodulin antagonists (trifluonerazine; TFP). And CaM (Ca2+-modulin) played an important role in the nutritional signal transduction for Ca2+ mitigating photosynthesis limitations in peanuts under low night temperature stress.

The effects of active modified atmosphere packaging (MAP) on the postharvest quality of shiitake mushrooms stored at cold temperature (4°C) were investigated. The gas components were 2% O2+7% CO2 (MAP1), 2% O2+10% CO2 (MAP2) and 2% O2+13% CO2 (MAP3), respectively. The results showed that active MAP could extend the shelf-life of shiitake mushrooms to 17 d and the concentration of carbon dioxide could influence the postharvest quality of shiitake mushrooms. MAP2 treatment inhibited the increase in respiration rate and malondinaldehyde (MDA) contents, delayed the decrease in firmness, soluble sugar and vitamin C, and obviously reduced the activity of polyphenol oxidase (PPO) and the degree of browning, therefore maintaining better quality.

Mature-green tomato fruit (Solanum lycopersicum cv. Zhenfen 202) were exposed to different UV-C irradiation at 2, 4, 8, and 16 kJ m-2 and then stored under the dark at 14°C and 95% relative humidity (RH) for 35 d. Of these four doses, UV-C irradiation at 4 and 8 kJ m-2 significantly increased total phenolic contents in present tomato fruit by 21.2 and 20.2%, respectively. Furthermore, UV-C irradiation at 4 or 8 kJ m-2 promoted the accumulation of total flavonoids and increased the antioxidant activity. 2 or 16 kJ m-2 UV-C irradiation also enhanced antioxidant activity, but to a lesser extent. Seven phenolic compounds, viz., gallic acid, (+)-catechin, chlorogenic acid, cafferic acid, syringic acid, p-coumaric acid, and quercetin in tomato fruit were identified and quantified by HPLC. Gallic acid was the major phenolic compound in tomato fruit and significantly correlated with antioxidant activity. 4 or 8 kJ m-2 UV-C irradiation significantly increased the contents of gallic acid, chlorogenic acid, syringic acid, p-coumaric acid, and quercetin. The optimum dose of UV-C irradiation in terms of increased phenolic compound content and enhanced Antioxidant activity was determined to be 4 or 8 kJ m-2.