ISSN:0010-3624    

DOI:10.1080/00103629809370034

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103629809370035

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103629809370036

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103629809370037

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103629809370038

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0010-3624    

DOI:10.1080/00103629809370039

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The basis for fertilizer recommendations has progressed from trial and error in the 1940s to an almost total dependence on soil testing at the present. Fertilizer recommendations have progressed over time from small amounts of compound fertilizers to an amount of a nutrient based on a soil test value. Research activity on development of soil testing and fertilizer recommendations was greatest in the 1950s and 1960s and has declined steadily since that time. Because the research was conducted by land grant universities in the individual states, the recommendation philosophies and recommendations varied among many states. This condition still exists although there presently is more agreement among some states. A national survey of land grant universities which have conducted the research supporting fertilizer recommendations, strongly suggests a need to update the soil test calibration data supporting the recommendations. The greatest recent improvement in fertilizer recommendations in many states has been the calibration of a soil nitrate test on which to base fertilizer nitrogen (N) recommendations for corn(Zea maysL.). A regional research approach using current and potential precision ag technology could provide a large and up‐to‐date data base on which to base nutrient recommendations across a wide spectrum of soils and crops.

ISSN:0010-3624    

DOI:10.1080/00103629809370040

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The wide scale adoption of site specific management (SSM) and variable rate fertilizer application (VRA) in the next 5 to 10 years portends changes in soil testing and plant analysis. To develop site specific nutrient recommendations, more detailed information about the soil's fertility status will be required which could mean greatly increased samples numbers for soil or plant analysis. Discussions of initial research on the large numbers of samples required to produce quality maps for SSM and VRA among scientists, agricultural industry and producers, however, indicates that this may only be a short phase as the expectation of using remote sensing (RS) to replace or compliment limited soil and plant analysis is already occurring. Soil and plant analysis numbers may increase during the next 5 to 10 years as there is a slow transition to SSM and VRA. During this time, however, there will be research to related RS imagery to soil and crop management problems. After 10 years of this transition, there may be more adoption of RS for primary diagnosis and management with limited soil and plant analysis done from ‘reference’ areas to assure the accuracy of remotely sensed image interpretation.

ISSN:0010-3624    

DOI:10.1080/00103629809370041

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Fertile soils are one of the most important resources on earth. Sustainable agriculture should use this resource in such a way that the present and future human needs for food or other agricultural goods are warranted whereas the quality of the environment and the natural resources remain preserved. Plant production needs resources of different origins and most of them are maintained according to certain soil parameters. But as soils are neither static, nor homogenous in space and time, the standard approach of uniform application rates always results in a side by side of over and under supply. Precision Agriculture aims at addressing this spatial variability but for this task physico‐chemical images [Digital Agro Resource Maps (DARM)] of the land are required. Efforts in acquiring these maps are actually one of the major bottlenecks for the exploitation of Precision Agriculture at the farm level. Most recent developments in strategies for reducing sampling efforts without loosing information are in “self surveying”;. This is a method by which basic spatial information of soil texture, organic matter content and geomorphology for instance are gathered just by human skills and “directed”;, or, “smart”; sampling which uses already existing spatial information of a site to guide sampling to representative plots. Optical sensors for major important soil information like soil texture and plant available nutrients are far away from being realized. Already existing approaches for on‐the‐go measurements of soil features are still soil invasive and therefore slow and ineffective as far as human labor is concerned. However, these methods might benefit a lot from developments in robot techniques. Remote sensing is a promising method for gathering spatial information of soils, but will always need a certain amount of work on the ground to allow interpretation and calibration of images. In so far it fits well with the strategy of “directed”; sampling. Temporal availability and visibility are major problems for remote sensing which might be solved by new technological approaches like unmanned air vehicles (UAV) or stationary “surf‐eyes”;. New approaches are also required for the interpretation of spatially distributed soil and plant analysis data and how fertilizer recommendations are derived to be from this information. It is obvious from the first experiences with Precision Agriculture under practical farming conditions that the standard approach of fertilizer recommendation does not provide the best basis in the sense of sustainable farming for a successful implementation of Precision Agriculture.

ISSN:0010-3624    

DOI:10.1080/00103629809370042

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Introduction of new and improved technologies will speed adoption of site‐specific management practices. Integrated production systems of the future will likely include more sophisticated monitoring and control devices, remote sensing, greater use of consultants and field scouts, and interactive data management systems. Professional managers and consultants will play a major role in helping producers organize data and make management decisions. Technologies that save time, result in greater profitability, and reduce environmental risks will be rapidly adopted by producers. Future opportunities will include harvesting and marketing schemes to preserve the identify of products that have special characteristics. Remote sensing will undoubtedly play a major role in helping make site‐specific management decisions and in assessing world‐wide marketing opportunities.

ISSN:0010-3624    

DOI:10.1080/00103629809370043

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor