Evaluation of the soil penetration resistance along a transect to determine the loosening depth     

H. Domsch  D. Ehlert  A. Giebel  K. Witzke  J. Boess 《Precision Agriculture》2006,7(5):309-326

The objective of this study was to evaluate the distribution of soil strength (measured as cone index, CI) along a 600 m transect and to determine the soil loosening depth necessary to eliminate zones with soil strengths exceeding a threshold value down to a depth of 0.6 m. The transect was located at a site in a glacial drift area which was characterised by sandy deposits overlying boulder clay. A tractor-mounted multi-penetrometer array consisting of four hydraulically driven single vertical penetrometers was used to determine CI at 1-m sampling intervals as a measure of penetration resistance. The spatial fluctuation of the CI readings in general and that of repeatedly averaged readings along the transect was examined. Furthermore, the relationships between the penetration resistance of several soil layers and the relationships between the CI of single penetrometers were identified. Averaged CI values over 5-m intervals were used to determine the depth of soil loosening required. By using various data sub-sets based on the averaged data of the four array mounted penetrometers and simulating several different sampling intervals, treatment intervals and threshold values of soil strength, a sampling interval of about 10 m proved to be sufficiently accurate to determine the loosening depth required.Special Issue: Papers from the 5th European Conference on Precision Agriculture (5ECPA), Uppasala, Sweden, 2005.  相似文献   

An autonomous intelligent gateway infrastructure for in-field processing in precision viticulture     

Emanuel PeresAuthor Vitae  Miguel A. FernandesAuthor VitaeRaul MoraisAuthor Vitae  Carlos R. CunhaAuthor Vitae  Juan A. LópezAuthor VitaeSamuel R. MatosAuthor Vitae  P.J.S.G. FerreiraAuthor VitaeM.J.C.S. ReisAuthor Vitae 《Computers and Electronics in Agriculture》2011,78(2):176-187

Wireless sensor networks have found multiple applications in precision viticulture. Despite the steady progress in sensing devices and wireless technologies, some of the crucial items needed to improve the usability and scalability of the networks, such as gateway infrastructures and in-field processing, have been comparatively neglected. This paper describes the hardware, communication capabilities and software architecture of an intelligent autonomous gateway, designed to provide the necessary middleware between locally deployed sensor networks and a remote location within the whole-farm concept. This solar-powered infrastructure, denoted by iPAGAT (Intelligent Precision Agriculture Gateway), runs an aggregation engine that fills a local database with environmental data gathered by a locally deployed ZigBee wireless sensor network. Aggregated data are then retrieved by external queries over the built-in data integration system. In addition, embedded communication capabilities, including Bluetooth, IEEE 802.11 and GPRS, allow local and remote users to access both gateway and remote data, as well as the Internet, and run site-specific management tools using authenticated smartphones. Field experiments provide convincing evidence that iPAGAT represents an important step forward in the development of distributed service-oriented information systems for precision viticulture applications.  相似文献   

包膜控释尿素对寒地水稻产量与氮肥利用率的影响   总被引：1，自引：0，他引：1  

刘忠新  孙磊  吴英  刘玉林 《北方水稻》2009,39(5):10-12,15

通过2 a田间试验(第二年定位试验),探讨包膜控释尿素(CRU)和普通尿素(PU)不同掺混比例对寒地水稻产量和氮肥利用率的影响。结果表明:与等量养分普通尿素比较,包膜控释尿素可促进水稻分蘖,增加水稻成穗率,产量提高6.0%～31.2%,氮肥利用率提高20.3%～96.5%,搭配比例以控释尿素占总氮量的30%～70%为好。单独施用控释尿素,后效作用不明显。  相似文献   

Site-specific management of limiting nutrients in peanut (Arachis hypogaea) on the Texas High Plains     

Rolf Färe  Chenggang Wang  A. Michael Schubert  Kevin F. Bronson  Jeff Johnson 《Precision Agriculture》2009,10(4):331-341

Nutrient data obtained from soil chemical tests were analyzed in an activity analysis model to identify limiting factors in peanut production on the Texas High Plains. A production function was estimated for the study field, and limiting factors were identified at individual sites where the production function indicated that yield did not respond. The estimated production function also enabled us to conduct a cost-return analysis of variable- and blanket-rate fertilizer applications. The results showed that peanut yields did not respond to most of the nutrients included in the study, which confirmed conclusions from previous studies in the study region. Calcium and nitrogen were the only two limiting factors identified in this study. Significant economic returns could be obtained by site-specific fertilizer application. The average economic return from variable-rate calcium fertilizer application was $27.84 ha⁻¹ and from blanket-rate it was $10.73 ha⁻¹. The return from variable-rate nitrogen fertilizer application was about $20 ha⁻¹ and from a blanket-rate it was about $14 ha⁻¹. There seems to be quite a strong economic incentive to adopt variable-rate application for calcium and nitrogen fertilizer application.

Jeff JohnsonEmail:

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Spatial variation of fiber quality and associated loan rate in a dryland cotton field     

Yufeng Ge  J. Alex Thomasson  Ruixiu Sui  Cristine L. Morgan  Stephen W. Searcy  Calvin B. Parnell 《Precision Agriculture》2008,9(4):181-194

A field study was conducted in 2006 in a dryland cotton field in Texas, USA, to explore the spatial variation of cotton fiber quality and the loan rate associated with it. A total of 66 cotton samples were hand-harvested, and the fiber quality properties investigated included the High Volume Instrument measurements of micronaire, length, uniformity, strength, elongation, reflectance (Rd) and yellowness (+b). Conventional statistics showed a generally low level of variation in fiber quality with coefficients of variation <10%. Variogram analysis showed that all fiber quality properties were spatially correlated. Contour maps of individual fiber quality properties were produced from block kriged estimates. Fiber length, uniformity, strength and Rd were positively correlated, and all of these were negatively correlated with +b. The spatial distribution of most fiber quality properties was similar to that of soil apparent electrical conductivity, suggesting that water holding capacity could be a limiting factor for cotton fiber quality. Maps of individual fiber quality properties were combined with the United State Department of Agriculture—Commodity Credit Corporation Loan Schedule for Upland Cotton to create a loan rate map that is associated with fiber quality. A loan rate difference of 20 cents kg^–1 was observed within the field. This level of difference indicated that fiber quality at the field level can have a large impact on producers’ revenue. A site-specific management system encompassing both lint yields and fiber quality is strongly recommended for cotton production.  相似文献   

实地氮肥管理对氮肥利用率及稻米品质的影响   总被引：1，自引：0，他引：1  

姜龙 《北方水稻》2010,40(5)

以牡丹江地区代表性品种牡丹江28和空育131为材料,研究了水稻实地氮肥管理(SSNM)的氮肥利用效率及其对稻米品质的影响。结果表明,SSNM的施氮量较常规施肥方法(FFP)降低了54.2%～61.5%,产量提高了1.6%～8.6%。SSNM的氮肥吸收利用率和农学利用率分别较FFP提高了42.7%～72.9%和132.1%～242.5%。此外,实地氮肥管理提高了稻米的加工品质,还明显降低了直链淀粉含量,提高了胶稠度,降低了糊化温度和蛋白质含量,改善了稻米的食味品质。  相似文献   

Spatial econometric analysis of a field-scale site-specific nitrogen fertilizer experiment on wheat (Triticum aestuvum L.) yield and quality     

Andreas Meyer-Aurich  Terry W. Griffin  Antje Giebel 《Computers and Electronics in Agriculture》2010,74(1):73-79

Knowledge of site-specific response may help farmers to tailor their management decisions with the help of precision farming technologies. However, farmers often have only a vague idea of the economic potential for site-specific management of their fields, which is important for investment decisions on precision farming technologies. This study presents an on-farm experimental approach to identify the economic potential of site-specific fertilization strategies at low costs. A strip trial with winter wheat (Triticum aestivum, L.) was established with precision farming technologies. Twelve different nitrogen fertilizer rates split in two applications were applied to 30 plots over a total strip length of 1.5 km. Geo-referenced yield was recorded with the harvester. Furthermore, electrical conductivity of the soil was measured and grain quality was surveyed with hand selected samples. With the help of advanced spatial statistical methods, within-field site-specific response was modeled with sufficient accuracy at comparably low costs. Electrical conductivity of the soil, elevation above sea level, and derivates of a digital elevation model were used as covariates to identify a possible economic potential for site-specific fertilization. Yield and protein response was best predicted with spatially adjusted regression models with site-characteristics or their interaction with management variables. Protein content was essential for achieving best economic results. The economic potential for site-specific fertilization strategies for the analyzed field was below 2 €/ha. However, the approach to identify the potential may be transferred to other locations with greater potential for site-specific farming.  相似文献   

Current status and future directions of precision aerial application for site-specific crop management in the USA   总被引：2，自引：0，他引：2  

Yubin Lan  Steven J. Thomson  W. Clint Hoffmann 《Computers and Electronics in Agriculture》2010,74(1):34-38

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Modification of Cre Gene by PCR Method     

WANG Yong  LUO Hong  XU Yaying  LV Tao  CHEN Dian 《东北农业大学学报(英文版)》2010,17(2)

Cre/LoxP site-specified recombination system is mainly used for excision,inversion and integration of target gene.Therefore,this system can be used for plant marker free genetic transformation,site-specific transgene expression and so on.However,the application of this system was limited due to its low expression and excision efficiency.In this study,an intron,which can enhance gene expression in plants,was inserted into Cre by using PCR method.And a modified Cre gene,named Crein,was obtained.This gene was ...  相似文献   

Prospects for multifunctionality of paddy rice cultivation in Japan and other countries in monsoon Asia     

Y. Matsuno  K. Nakamura  T. Masumoto  H. Matsui  T. Kato  Y. Sato 《Paddy and Water Environment》2006,4(4):189-197

This paper presents a study carried out by a group of Japanese researchers to critically review past researches and discussions on the multifunctionality of paddy rice cultivation, with the aim of describing the current status of the subject and providing options and potentials for future research and practices. The review was of over 200 documented articles on the major external functions. The results of this study revealed that the importance of multifunctionality is well perceived in Japan. The methodologies to measure and estimate the magnitude have been established for most functions. However, there is a need for more cases, to integrate all the functions at the local or regional scale to represent site-specific characteristics of multifunctionality. There is also a need to develop management practices to sustain and enhance the positive multifunctionality of paddy rice cultivation while minimizing negative effects to the environment, which may be brought into the agricultural policies. Except for Korea, Taiwan, and Japan, there are slightly different notions on multifunctionality in other monsoon Asia countries, but the gap in this notion is reducing following recent international activities.  相似文献