不同水稻品种对硒的吸收转化试验

采用田间试验和仪器分析的方法,研究了不同水稻品种对天然富硒土壤硒的吸收效果,以及不同水稻品种在不同生育期通过外源硒的根施及叶面喷施处理后对硒的吸收转化效果。结果表明:不同的水稻品种对天然富硒土壤中硒的吸收转化存在较大的差异性;外源硒的增施可以普遍提高不同水稻品种硒的含量,有机硒含量均达85%以上;叶面喷施外源硒的效果比根施外源硒的效果更优,且用量小,适合缺硒地区和低硒区生产富硒大米。      

基于深度信念网络的多品种水稻生物量无损检测

提出了基于深度信念网络的多品种生殖生育期水稻生物量无损检测方法。对在正常生长及干旱胁迫两个不同环境下的483个水稻品种,分别于胁迫前、胁迫后和复水后3个时间点进行图像采集。利用HSL颜色空间固定阈值分割法分割图像,并对处理后的图像进行特征提取,共提取57个特征值。对数据进行归一化处理后,构建基于深度信念网络的水稻生物量模型,根据决定系数R2、平均相对误差（MAPE）及相对误差绝对值的标准差（SAPE）选择最优模型,并与逐步线性回归模型进行比较。结果表明,基于深度信念网络的生物量测量模型性能更优,R2为0.9299,MAPE为11.19%,SAPE为18.36%。本研究提供了一种精度高且适用于多品种、不同生殖生育期、不同生长环境的水稻生物量无损检测模型,为水稻研究提供了新的测量工具。     

Submergence risks and farmers’ preferences: Implications for breeding Sub1 rice in Southeast Asia

Rice (Oryza sativa L.) provides a life support system to millions of resource-poor farmers in rainfed environments; however, yields are very low because of various biotic and abiotic stresses. Submergence caused by typhoons and floods is one of the major reasons for production losses. Because of the complexity of these ecosystems, the breeding framework necessitates adequate feedback and a more in-depth understanding of the ecological and socioeconomic conditions in these flood-prone areas. Within this purview, this study validated the performance in farmers’ fields of lines with the SUB1 gene that confers tolerance of submergence for up to two weeks. The SUB1 gene was incorporated through marker-assisted backcrossing, MABC. The evaluation was conducted through participatory approaches to gain understanding of the risks as well as farmers’ preferences for these varieties. A baseline survey of 658 farm households accomplished during 2008, focus group discussions, key informant interviews, and adaptability trials were conducted, with focus on farmers commonly affected by submergence in four Southeast Asian countries: the Philippines, Lao PDR, Indonesia, and Southern Viet Nam. The study further examined farmers’ criteria in evaluating new varieties through the participatory varietal selection (PVS) process. Results showed that varying conditions of submergence can influence farmers’ criteria and preferences for rice cultivars. Depending on the timing of flood with respect to growth stage, shorter duration and shallow flashfloods can result in less than 10% production losses while deeper and stagnant water with two weeks’ duration and >100 cm depth can cause damage ranging from 40% to 77%. Major findings of PVS trials and preference analysis indicated that farmers prefer rice cultivars that are tolerant of submergence, have early to medium maturity relative to their commonly grown varieties, are resistant to pests and diseases, and are resistant to lodging, among other traits. To enhance adoption, male and female farmers should be involved in the evaluation process. The results of this study can contribute to enhancing breeding programs to develop appropriate varieties that reduce production losses, improve income, and ultimately reduce poverty incidence in submergence-prone areas.     

Evaluation of yield and physiological attributes of high-yielding rice varieties under aerobic and flood-irrigated management practices in mid-hills ecosystem

In the valley land of North-East Hill (NEH) ecosystems of India, about 70% area under rice (Oryza sativa L.) is transplanted. Physiological attributes and yield performance of aerobic rice over conventional flood-irrigated rice need to be assessed while promoting water saving technology. A field experiment was conducted at the experimental farm, ICAR Research Complex for NEH Region, Umiam (950 m msl), Meghalaya during rainy seasons of 2006 and 2007 under aerobic and flooded conditions with aerobic rice variety collected from IRRI, Philippines. Some important high-yielding varieties (HYVs) recommended for the region were also included in the study. The objectives of this study were (i) to evaluate the influence of frequent mid-season drainage as a measure of water saving technique besides inducing the pre-conditioning effect on genotypes to withstand water stress during the subsequent growth period of crop ontogeny, (ii) to compare crop performance between aerobic and flooded rice management practices, and (iii) to identify attributes responsible for the yield gap between aerobic and flooded rice. The results revealed that the yield difference between aerobic (average yield, 1.67 t/ha) and flooded rice (average yield, 2.31 t/ha) ranged from 18.4 to 37.8% (P < 0.05) depending on varieties, highest difference being observed with rice hybrid DRRH 1. Cultivation of rice under aerobic condition resulted in 27.5% yield reduction over flooded rice. Among the yield components assessed, sink size (spikelets per panicle) contributed more to the yield and is considered to be most important factor responsible for yield gap between aerobic and flooded rice. The study suggests that, variety Sahsarang 1 with its moderate values of photosynthesis rate, transpiration rate and water use efficiency (WUE) along with higher grain yield seems to be better choice for both stress (aerobic) as well as normal (flooded) condition. Aerobic rice varieties with minimum yield gap compared to flooded rice is the key for success of aerobic rice cultivation.     

Long-term assessment of nitrogen and variety technologies on attainable maize yields in Nigeria using CERES-maize

Maize simulation models are proposed as tools for assessment of response to nitrogen (N) fertilizer and varieties in order to explore potential target zones for improved maize varieties. The CERES-maize model in the Decision Support System for Agrotechnology Transfer version 2.1 was tested using international testing nurseries at Ibadan, Mokwa, and Kaduna situated, respectively, in the derived savanna, southern guinea savanna, and northern guinea savanna zones in Nigeria during 1992–95. Historical weather data spanning 20 years were used at the target production environments to generate probabilistic estimates of maize yields; nitrogen use efficiency (NUE) associated with fertilizer and variety technologies. Analysis shows with high probability that, under rainfed conditions and N fertilizer input, the 90–110 day varieties (MDV) would yield better than 120–150 day varieties (LDV) at Mokwa and Ibadan, with superior NUE. The risk of crop failure with no N input was, however, substantial. Although response to N varied dramatically from year to year in association with the rainfall, there appears to be no advantage in adjusting N-input strategy for a variety. NUE was predicted to be best at the 60 kg N/ha input strategy, indicating potentials of further yield increase if methods of enhancing NUE at the higher N input levels could be further investigated. The NUE was found to be always lowest at Ibadan, in the derived savanna transition zone where rainfall and cloud cover were higher.     

沈阳市优质高产水稻品种品比试验研究

对引进的14个水稻新品种进行品比试验,鉴定各品种的丰产性、抗逆性及适应条件。试验表明:适合在沈阳地区示范推广的主要品种为辽星1号、千重浪2号、盐粳68、辽优1052和盐丰47;辽优1052相对比较适宜沈阳市以南的中晚熟稻区,并提出了部分品种在推广中应注意的问题,为水稻品种的选用提供参考。     

钝化修复对不同水稻品种镉累积效应及土壤特性的影响

为了探讨坡缕石钝化修复下不同水稻品种(T优272和丰优9号)吸收累积Cd差异,采用盆栽试验,研究了酸性Cd污染稻田土(PL1、PL2和PL3处理)对2种水稻品种重金属Cd累积效应,以及对土壤酶活性、氮磷有效性的影响。结果表明,种植的常规水稻品种T优272稻谷干物质量比低Cd吸收品种丰优9号高7.91%。坡缕石钝化修复下,T优272与丰优9号稻谷干物质量无显著差异,但土壤p H值分别较CK增加了0.33~0.46和0.40~0.53。与CK相比,PL1F、PL2F和PL3F处理土壤有效态Cd质量分数最大降低13.59%,稻米Cd质量分数降幅达20.51%~51.28%,其中PL3F处理的稻米Cd质量分数为0.19 mg/kg,低于食品安全国家标准限量值(0.20 mg/kg);PL1T、PL2T和PL3T处理土壤有效态Cd质量分数最大降低25.08%,糙米Cd质量分数最大降低37.50%,其中PL3T处理糙米Cd质量分数为0.35 mg/kg。土壤酶活性随着坡缕石添加量的增加而逐渐升高,而且种植T优272品种的土壤酶活性总体上高于丰优9号。随着坡缕石添加量的增加,钝化修复各处理间土壤碱解氮质量分数无显著差异,但土壤有效磷质量分数呈逐渐降低趋势;与CK相比,种植丰优9号和T优272品种的土壤有效磷质量分数分别降低了7.08%~18.08%和9.02%~19.59%。研究结果可为重金属Cd污染酸性水稻田土壤坡缕石钝化与低Cd吸收水稻品种联合修复提供一定的科学依据。     

丹东地区玉米及水稻品种的优化选择

品种选择是农作物生产的第1步,不同品种在生育期、抗病性、抗倒性、区域适应性等方面存在较大的差异。选择适合本地区种植条件的优良品种与种子对农业生产和农民增收至关重要。结合丹东地区的实际情况,阐述在玉米、水稻品种的优化选择上应把握的原则和注意的问题,并提出相应的解决措施。     

Bases for farm resource allocation in the traditional farming system: A comparative study of productivity of farm resources in abakaliki area of Anambra State,Nigeria

A study was carried out to determine the returns in utilisation of farm-resources in the production of three crop enterprises. These returns determined the productivity of resources in yam-based crop mixture (YBCM), cassava-based crop mixture (CBCM) and rice enterprises.The results show that of the three crop enterprises considered in the survey year, YBCM received special attention in the resources allocated. Prime land, prime labour and a large proportion of household cash were allocated to the production of YBCM relative to other crop enterprises. Cost-return analysis indicated that all scarce resources such as labour, land and capital were more productive in monetary terms in CBCM and rice enterprises than in YBCM.The cultural value of yam in YBCM transcends the monetary and food security values. It includes intangible value such as social status. The special place of yam in the crop production system militates against practical solutions such as the transfer of farm resources from the less productive (YBCM) to the more productive enterprises. Thus it is that improved management techniques such as the use of higher-yielding yam varieties, increase in cropping densities and the use of fertilizers need to be explored as a means of improving the returns of the resources used in the YBCM enterprises.     

农业机械化水平对中国粮食生产技术效率的空间溢出效应研究——基于农机跨区作业视角

提升农业机械化水平是落实国家“藏粮于技”战略中的重要一环，利用1998—2020年中国31个省(市、区)的面板数据，采用空间杜宾模型，研究农业机械化水平对粮食生产技术效率的直接影响和空间溢出效应。研究发现：第一，农业机械化水平对粮食生产技术效率具有显著的空间溢出效应，在其他影响因素不变的情况下，其他地区粮食生产技术效率加权值每提升1%，本地粮食生产技术效率提升约0.579%；第二，从不同农机类型来看，农业机械化水平对粮食生产技术效率的空间溢出效应主要通过大中型农机实现，影响系数为0.252；第三，农业机械化水平对粮食生产机械效率的空间溢出效应存在于不同经纬度之间，在水稻跨区作业省份中，农业机械化水平对粮食生产技术效率的空间溢出效应为0.027。因此，提出通过进一步优化农机跨区作业机型、改进粮食品种、提升田间管理技术等方式扩大不同地区粮食作物的种植、生长和收获时间差，为农机跨区作业创造条件，实现资源效益最大化。     

Performance of temperate aerobic rice under different water regimes in North China

Since the late 1990s, aerobic rice varieties have been released to farmers in the North China Plain to grow rice as a supplementary-irrigated upland crop to cope with water scarcity. Little is known about their yield potential, water use, water productivity (WP), and flood tolerance. In 2001–2002, experiments with aerobic rice varieties HD502 and HD297 and lowland rice variety JD305 were conducted under aerobic and flooded conditions. Under aerobic conditions, five irrigation treatments were implemented. Under flooded conditions, JD305 yielded up to 8.8 t ha⁻¹, HD502 up to 6.8 t ha⁻¹, and HD297 up to 5.4 t ha⁻¹. Under aerobic conditions, the aerobic varieties yielded higher than the lowland variety. HD502 produced 3–3.5 t ha⁻¹ with 450–500 mm total water input and 5.3–5.7 t ha⁻¹ with 650 mm water input and more. HD297 produced 3–3.5 t ha⁻¹ with 450–500 mm total water input and 4.7–5.3 t ha⁻¹ with 650 mm water input and more. The water productivity of aerobic rice under aerobic conditions was higher or on a par with that of the lowland variety under flooded conditions, reaching values of 0.6–0.8 g grain kg⁻¹ water. The relatively high yields of the aerobic varieties under aerobic soil conditions were obtained under “harsh” conditions for growing rice. The soil contained more than 80% sand, was permeable, and held water above field capacity for a few hours after irrigation only. The groundwater table was deeper than 20 m, the soil moisture content in the rootzone was mostly between 50 and 80% of saturation, and soil moisture tension went up to 90 kPa. We conclude that the aerobic rice varieties HD502 and HD297 are suitable for water-scarce environments, and can stand being periodically flooded.     

基于注意力机制和特征融合的葡萄病害识别模型

植物病害是造成农作物减产的主要原因之一。针对传统的人工诊断方法存在成本高、效率低等问题，构建了一个自然复杂环境下的葡萄病害数据集，该数据集中的图像由农民在实际农业生产中拍摄，同时提出了一个新的网络模型MANet,该模型可以准确地识别复杂环境下的葡萄病害。在MANet中嵌入倒残差模块来构建网络，这极大降低了模型参数量和计算成本。同时，将注意力机制SENet模块添加到MANet中，提高了模型对病害特征的表示能力，使模型更加注意关键特征，抑制不必要的特征，从而减少图像中复杂背景的影响。此外，设计了一个多尺度特征融合模块(Multi-scale convolution)用来提取和融合病害图像的多尺度特征，这进一步提高了模型对不同病害的识别精度。实验结果表明，与其他先进模型相比，本文模型表现出了优越的性能，该模型在自建复杂背景病害数据集上的平均识别准确率为87.93%,优于其他模型，模型参数量为2.20×10⁶。同时，为了进一步验证该模型的鲁棒性，还在公开农作物病害数据集上进行了测试，该模型依然表现出较好的识别效果，平均识别准确率为99.65%,高于其他模型。因此，本文模型...     

Water harvesting and supplemental irrigation for improved water productivity of dry farming systems in West Asia and North Africa

In the dry areas, water, not land, is the most limiting resource for improved agricultural production. Maximizing water productivity, and not yield per unit of land, is therefore a better strategy for dry farming systems. Under such conditions, more efficient water management techniques must be adopted. Supplemental irrigation (SI) is a highly efficient practice with great potential for increasing agricultural production and improving livelihoods in the dry rainfed areas. In the drier environments, most of the rainwater is lost by evaporation; therefore the rainwater productivity is extremely low. Water harvesting can improve agriculture by directing and concentrating rainwater through runoff to the plants and other beneficial uses. It was found that over 50% of lost water can be recovered at a very little cost. However, socioeconomic and environmental benefits of this practice are far more important than increasing agricultural water productivity. This paper highlights the major research findings regarding improving water productivity in the dry rainfed region of West Asia and North Africa. It shows that substantial and sustainable improvements in water productivity can only be achieved through integrated farm resources management. On-farm water-productive techniques if coupled with improved irrigation management options, better crop selection and appropriate cultural practices, improved genetic make-up, and timely socioeconomic interventions will help to achieve this objective. Conventional water management guidelines should be revised to ensure maximum water productivity instead of land productivity.     

Breeding for improved abiotic stress tolerance in maize adapted to southern Africa

The difficulty of choosing appropriate selection environments has restricted breeding progress for abiotic stress tolerance in highly variable target environments. Genotype-by-environment interactions in southern African maize growing environments result from factors related to maximum temperature, season rainfall, season length, within-season drought, subsoil pH and socio-economic factors that result in sub-optimal input application. In 1997, CIMMYT initiated a product-oriented breeding program targeted at improving maize for the drought-prone mid-altitudes of southern Africa. Maize varieties were selected in Zimbabwe using simultaneous selection in three types of environments, (i) recommended agronomic management/high rainfall conditions, (ii) low N stress, and (iii) managed drought. Between 2000 and 2002, 41 hybrids from this approach were compared with 42 released and pre-released hybrids produced by private seed companies in 36–65 trials across eastern and southern Africa. Average trial yields ranged from less than 1 t/ha to above 10 t/ha. Hybrids from CIMMYT's stress breeding program showed a consistent advantage over private company check hybrids at all yield levels. Selection differentials were largest between 2 and 5 t/ha and they became less significant at higher yield levels. An Eberhart–Russell stability analysis estimated a 40% yield advantage at the 1-t yield level which decreased to 2.5% at the 10-t yield level. We conclude that including selection under carefully managed high-priority abiotic stresses, including drought, in a breeding program and with adequate weighing can significantly increase maize yields in a highly variable drought-prone environment and particularly at lower yield levels.     

Combining hydrological modeling and GIS approaches to determine the spatial distribution of groundwater recharge in an arid irrigation scheme

Accurate quantification of the rate of groundwater (GW) recharge, a pre-requisite for the sustainable management of GW resources, needs to capture complex processes, such as the upward flow of water under shallow GW conditions, which are often disregarded when estimating recharge at a larger scale. This paper provides (1) a method to determine GW recharge at the field level, (2) a consequent procedure for up-scaling these findings from field to irrigation scheme level and (3) an assessment of the impacts of improved irrigation efficiency on the rate of GW recharge. The study is based on field data from the 2007 growing season in a Water Users Association (WUA Shomakhulum) in Khorezm district of Uzbekistan, Central Asia, an arid region that is characterized by a predominance of cotton, wheat and rice under irrigation. Previous qualitative studies in the region reported irrigation water supplies far above the crop water requirements, which cause GW recharge. A field water balance model was adapted to the local irrigation scheme; recharge was considered to be a fraction of the irrigation water losses, determined as the difference between net and gross irrigation requirements. Capillary rise contribution from shallow GW levels was determined with the HYDRUS-1D model. Six hydrological response units (HRUs) were created based on GW levels and soil texture using GIS and remote sensing techniques. Recharge calculated at the field level was up-scaled first to these HRUs and then to the whole WUA. To quantify the impact of improved irrigation efficiency on recharge rates, four improved irrigation efficiency scenarios were developed. The area under cotton had the second highest recharge (895 mm) in the peak irrigation period, after rice with 2,514 mm. But with a low area share of rice in the WUA of <1 %, rice impacted the total recharge only marginally. Due to the higher recharge rates of cotton, which is grown on about 40 % of the cropped area, HRUs with a higher share of cotton showed higher recharge (9.6 mm day^?1 during August) than those with a lower share of cotton (4.4 mm day^?1). The high recharge rates in the cotton fields were caused by its water requirements and the special treatment given to this crop by water management planners due to its strategic importance in the country. The scenario simulations showed that seasonal recharge under improved irrigation efficiency could potentially be reduced from 4 mm day^?1 (business-as-usual scenario) to 1.4 mm day^?1 (scenario with maximum achievable efficiency). The combination of field-level modeling/monitoring and GIS approaches improved recharge estimates because spatial variability was accounted for, which can assist water managers to assess the impact of improved irrigation efficiencies on groundwater recharge. This impact assessment enables managers to identify options for a recharge policy, which is an important component of integrated management of surface and groundwater resources.     

基于蚁群算法与人工势场法的移动机器人路径规划

针对复杂环境下移动机器人路径规划困难的问题,提出了一种将全局路径规划蚁群算法与局部路径规划人工势场法相融合的混合型算法。首先,采用多因素启发函数和新的蚂蚁行进机制来解决传统蚁群算法路径质量差且易陷入对角障碍的问题;其次,针对传统蚁群算法收敛速度慢的情况,设计了自适应挥发系数和动态权重系数;接着,通过引入虚拟目标点、相对距离和安全距离的概念,解决了传统人工势场法易陷入局部极小值、目标不可达以及过度避障的问题;最后,将改进蚁群算法规划路径的转折点作为局部子目标点来调用改进的人工势场法进行二次规划。仿真表明改进蚁群算法较传统算法以及其他算法在路径长度方面优化了9.9%和2.0%,在路径转折次数方面优化了81.8%和63.6%,在收敛速度方面优化了94.2%和63.6%;改进人工势场法有效解决了自身问题;而以二者为基础的混合型算法则充分地结合了二者的优势,在复杂的静态和动态环境中具有极高的环境适应性和路径规划效率。     

基于人工势场法的移动机器人路径规划研究现状与展望

路径规划是移动机器人领域的热点研究方向，人工势场法已在工业机器人路径规划中得到广泛应用，近年来正逐步应用于农业工程的路径规划问题中。首先对路径规划中人工势场法的原理及传统人工势场法存在的缺陷进行分析，针对人工势场法中的局部极小值和目标不可达问题的多重改进方法进行原理分析和方法总结，并根据人工势场法在工业机器人中的应用对已有的算法融合方法进行分类综述。最后通过对多种改进方法的比较，对农业机器人路径规划所需满足的实时性以及障碍物的多变性进行应用展望，可以利用现有的算法融合研究，结合农业生产的实际情况，对不同农业生产应用场合的融合算法选择机制进行深入研究，以满足现代农业生产中对机器人路径规划的需求。     

计算机视觉在水稻大面积制种中的应用研究

水稻是我国最主要的粮食作物,在农业经济中占有重要的地位。水稻种植环境多样,高产稳产在很大程度上依赖于优良品种。制种是杂交稻生产的关键环节,种子质量对产量有着决定性的影响。随着科学技术的发展,无人机、物联网和计算机视觉等新技术在农业中得到了应用,推动了农业现代化进程。为此,将计算机视觉用于水稻大面积制种,实现对田间的空行和杂草杂株的识别,以及对父母本抽穗期的监测。试验表明:计算机视觉能够有效识别水稻空行,对杂株杂草的识别较为准确,没有出现误检的情况。计算机视觉监测的父母本抽穗期与实际接近,最大差异仅为1天,可以提高杂交种产量和纯度,推动水稻制种技术的发展。     

早熟玉米高密度不同施肥量栽培试验

探索早熟玉米品种垦沃2号、德美亚2号在不同施肥因素、不同密度的产量潜力。试验发现,不同施肥量,大肥区的长势明显好于小肥区,叶面积指数大肥区高于小肥区7.6%。两个品种不同处理产量:垦沃2号大肥区比小肥区增产11.4%,德美亚2号大肥区比小肥区增产12.5%;不同密度产量增产12.7%。用碧护拌种、喷施叶面肥对防除前茬大豆残留药害效果明显,喷施福田佳利、彩特美等叶面肥有增加苗期抗逆性的功效。      

水分胁迫对不同生长类型桃叶片水分利用效率和羧化效率的影响

以盆栽短枝型桃品种超红短枝和普通型品种早红珠为试材,研究了水分胁迫对不同生长类型桃树新梢增长率、叶片水分利用效率和羧化效率的影响。结果表明,在水分胁迫条件下,短枝型品种超红短枝的新梢增长率、叶片水分利用效率和羧化效率均显著高于普通型品种早红珠。表明桃短枝型品种对干旱有较高的生理适应性。