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Author: Jan Ulrich Hermann Eitel
Publisher:
ISBN:
Category : Dry farming
Languages : en
Pages : 216
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Book Description
Growers require pre-harvest information about grain protein to optimize nitrogen (N) fertilizer inputs and grain harvest. The aim of this dissertation was to predict final grain protein of dryland wheat based on mid-seasonal remote sensing data. Grain protein predictions have relied on weather, cultivar and crop N status information. The latter has been remotely sensed by means of spectral indices. These indices generally employ narrow wavebands (40 nm) that are sensitive to chlorophyll a and b content and leaf area index (LAI) both of which usually co-vary with variations in crop N status. However, remote sensing crop N status is complicated by N-independent variations in LAI and soil background reflectance. Chapter 1 shows that N-independent variations in LAI confound remote predictions of crop N status that are based on single indices, but have only a minor effect if combined indices are used. The new combined index derived from the ratio of Modified Chlorophyll Absorption Ratio Index (MCARI) and the second Modified Triangular Vegetation Index (MTVI2) has the lowest sensitivity to variations in LAI (r2 = 0.01) and the highest sensitivity to crop N status (r2 = 0.54). Chapter 2 evaluates the sensitivity of spectral indices to variation in soil reflectance. The results indicate that spectral indices are affected by soil background reflectance when LAI
Author: Jan Ulrich Hermann Eitel
Publisher:
ISBN:
Category : Dry farming
Languages : en
Pages : 216
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Book Description
Growers require pre-harvest information about grain protein to optimize nitrogen (N) fertilizer inputs and grain harvest. The aim of this dissertation was to predict final grain protein of dryland wheat based on mid-seasonal remote sensing data. Grain protein predictions have relied on weather, cultivar and crop N status information. The latter has been remotely sensed by means of spectral indices. These indices generally employ narrow wavebands (40 nm) that are sensitive to chlorophyll a and b content and leaf area index (LAI) both of which usually co-vary with variations in crop N status. However, remote sensing crop N status is complicated by N-independent variations in LAI and soil background reflectance. Chapter 1 shows that N-independent variations in LAI confound remote predictions of crop N status that are based on single indices, but have only a minor effect if combined indices are used. The new combined index derived from the ratio of Modified Chlorophyll Absorption Ratio Index (MCARI) and the second Modified Triangular Vegetation Index (MTVI2) has the lowest sensitivity to variations in LAI (r2 = 0.01) and the highest sensitivity to crop N status (r2 = 0.54). Chapter 2 evaluates the sensitivity of spectral indices to variation in soil reflectance. The results indicate that spectral indices are affected by soil background reflectance when LAI
Author: David J. Bonfil
Publisher:
ISBN:
Category : Soils
Languages : en
Pages : 18
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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The purpose of this research was to improve nitrogen (N) management for soft red winter wheat (Triticum aestivum L.) in North Carolina with three areas of focus: delayed harvest effects on grain quality, explaining grain protein variability caused by management practices, and developing N recommendations at growth stage (GS) 30 using aerial color infrared (CIR) photography. Delayed harvest significantly reduced grain yield and test weight in the majority of trials. Yield reductions were attributed to dry, warm environments, possibly due to shattering. Test weight reductions were attributed to the negative effects of wetting and drying cycles. Of the 20 quality parameters investigated, flour falling number, clear flour, and farinograph breakdown times were significantly reduced due to delayed harvest, while grain deoxynivalenol (DON) levels increased with a delayed harvest. Environment contributed to grain protein variability (23%), though the majority of that variability was attributed to N management (52%). It was found that as grain protein levels increased at higher N rates and with the majority of N applied at GS 30, the overall grain protein variability increased. The recommendations to reduce grain protein variability are; to reduce the range in N fertilizer rates used, to avoid over application of N beyond what is required to optimize yields, and to apply spring N at GS 25. Relationships between derived agronomic optimum N rates and three spectral bands and 39 indexes were weak, but after separating the data into two biomass classes (low 1000 kg ha-1 and high 1000 kg ha-1), the relationships of optimum N rates with a relative Red and Green bands (relative to a high N-status reference plot) had the best (quadratic) relationships (R2 = 0.80 and 0.81, respectively) for the high biomass class. These results indicate that agronomic optimum N rates at GS 30 can be estimated using aerial CIR photographs if areas of low and high biomass can be determined.
Author: Dianne Carter Farrer
Publisher:
ISBN:
Category :
Languages : en
Pages : 177
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Book Description
Keywords: protein variability, delayed harvest, grain quality, winter wheat, remote sensing.
Author: Salim Lamine
Publisher: Elsevier
ISBN: 0323914640
Category : Technology & Engineering
Languages : en
Pages : 555
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Book Description
Remote Sensing in Precision Agriculture: Transforming Scientific Advancement into Innovation compiles the latest applications of remote sensing in agriculture using spaceborne, airborne and drones' geospatial data. The book presents case studies, new algorithms and the latest methods surrounding crop sown area estimation, determining crop health status, assessment of vegetation dynamics, crop diseases identification, crop yield estimation, soil properties, drone image analysis for crop damage assessment, and other issues in precision agriculture. This book is ideal for those seeking to explore and implement remote sensing in an effective and efficient manner with its compendium of scientifically and technologically sound information. - Presents a well-integrated collection of chapters, with quality, consistency and continuity - Provides the latest RS techniques in Precision Agriculture that are addressed by leading experts - Includes detailed, yet geographically global case studies that can be easily understood, reproduced or implemented - Covers geospatial data, with codes available through shared links
Author: Daniel Robert Jepsen
Publisher:
ISBN:
Category : Fertilizers
Languages : en
Pages : 194
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Book Description
Proper nitrogen (N) management and variety selection are important for profitable hard red winter (HRW) wheat production in the dryland growing regions of northeastern Oregon. In these dryland systems, N management for grain yield and grain protein concentration (GPC) is challenging due to climatic and year-to-year variation in production environments. However, current fertilizer guides make little distinction between locations and incorporate relatively little data from HRW production. Identifying adequate N management practices and scenarios suitable for HRW production will help producers reduce risk and enhance profits. This study investigates the effects of fertilizer N rate, N application timing, variety and location over six site-years in northeastern Oregon from 2007-2009. Whole plant tissue nitrogen (TN) concentration at Zadoks growth stage (GS) 30 and flag leaf nitrogen (FLN) were also evaluated as decision making tools for N management in this region. Three sites representing low and intermediate precipitation zones were chosen for this study. A site at Pendleton, Oregon represented an intermediate precipitation zone (420 mm), while sites at Lexington and Arlington, Oregon were in a low precipitation (250-300 mm) zone. Study sites were minimally responsive to N treatments in terms of yield. Spring N was less detrimental to yield than fall application when N was excessive at Lexington and Arlington. Grain protein concentration response to fertilizer N was significant and varied by site-year. Some site-years proved favorable for efficient production of high GPC HRW wheat, whereas acceptable GPC was very difficult to achieve in others, underscoring the difficulty of consistently producing high GPC HRW wheat in these regions. Fertilizer N use efficiency was 18-39% at Pendleton, but generally less than 20% at Lexington and Arlington, dropping to zero in some circumstances. At all sites the soil N pool was used more efficiently than fertilizer N, indicating that HRW production is best suited where only minimal fertilizer N is required to complement crop N requirements. Spring N application improved GPC one year at Pendleton following above average late spring rainfall, and may therefore be a useful N management strategy in that environment. In contrast, spring N had a neutral or negative impact on GPC at Lexington and Arlington. Overall, current recommendations did not adequately describe N requirements observed in this study. However, requirements for achieving target GPC were generally lower and more stable at Pendleton, indicating that this and similar environments may be more suitable for HRW production than low yield, high stress environments such as Lexington and Arlington. Varieties showed similar response to N treatments regardless of site. Grain yield of HRW varieties were generally competitive with the soft white winter (SWW) variety 'Stephens'. Among tested HRW varieties, 'Norwest 553' expressed the best combination of yield and GPC performance. The relationship of tissue N (TN) concentration at Zadoks growth stage 30 to GPC was stable across site-years. A critical TN level of 41 g kg-1 corresponded to 126 g kg-1 GPC. This level could be used to indicate when additional N is required to achieve desired GPC, but it remains uncertain how useful this test would be at high stress, low rainfall sites considering the poor response to spring N at Lexington and Arlington. Flag leaf N also showed promise for predicting GPC, but additional research is necessary to clarify this relationship.
Author: United States. Congress. House. Committee on Appropriations. Subcommittee on Agriculture, Rural Development, Food and Drug Administration, and Related Agencies
Publisher:
ISBN:
Category : Rural development
Languages : en
Pages : 680
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Author: United States-Israel Binational Agricultural Research and Development Fund
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Ruixiu Sui
Publisher:
ISBN:
Category :
Languages : en
Pages : 246
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Author: Elizabeth Johanna Botha
Publisher:
ISBN:
Category : Crops and soils
Languages : en
Pages : 260
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