Remote sensing for resources development and environmental management: Remote sensing for resources development and environmental management

Damen, M. C. J.

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Multivolume work

Persistent identifier:: 856342815

Title:: Remote sensing for resources development and environmental management

Sub title:: proceedings of the 7th international Symposium, Enschede, 25 - 29 August 1986

Year of publication:: 1986

Place of publication:: Rotterdam; Boston

Publisher of the original:: A. A. Balkema

Identifier (digital):: 856342815

Language:: English

Additional Notes:: Volume 1-3 erschienen von 1986-1988

Editor:: Damen, M. C. J.

Document type:: Multivolume work

Volume

Persistent identifier:: 856343064

Title:: Remote sensing for resources development and environmental management

Sub title:: proceedings of the 7th international Symposium, Enschede, 25 - 29 August 1986

Scope:: XV, 547 Seiten

Year of publication:: 1986

Place of publication:: Rotterdam; Boston

Publisher of the original:: A. A. Balkema

Identifier (digital):: 856343064

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(26,7,1)

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Damen, M. C. J.

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: 3 Spectral signatures of objects. Chairman: G. Guyot, Liaison: N. J. J. Bunnik

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: Spectral components analysis: Rationale and results. C. L. Wiegand & A. J. Richardson

Document type:: Multivolume work

Structure type:: Chapter

348 prevented by predators. e. Unless stresses are extreme, cumulative seasonal light interception relates closely to the phytomass achieved (Monteith, 1981; Steven et al., 1983; Daughtry, et al., 1983; Gallo, et al., 1985; Wanjura and Hatfield, 1985). Cumulative seasonal light interception is, in turn, a function of the seasonal amount and duration of photosynthetically active tissue. f. Seasonal integral VI are. essentially estimates of integral intercepted solar radiation (Wiegand and Richardson, 1984) which Daughtry et al. (1983) and Hatfield, et al. (1984) have shown can be estimated spectrally. Consequently, the VI relate to both APAR and YIELD as shown by the right hand sides of equations [1] and [2]. Likewise, cumulative APAR for the season, or for the reproductive portion of it, and YIELD are related since they each relate to the common variable, VI. 3 MODIFICATIONS IN EDS. [1] and [2] Hie spectral reflectance observations, used to calculate VI, and the PAR transmission and reflectance observations, used to calculate APAR, are, themselves, seasonally and diurnally Sun angle dependent (Anderson, 1971; Colwell, 1974). The path length through the canopy is inversely proportional to the cosine of the solar zenith angle (cos Z) giving light entering the canopy from off nadir angles a better chance of being intercepted. When the same workforce makes both sets of observations, first one set is made on a given day and then the other so that Sun position differs in the data paired for analysis. Differences in solar zenith angle during a growing season are even greater. Consequently, we currently express equations [1] and [2] as /LAI n IcosZ-^ VI 1 X /cosZ^\ APAR72 = APARp^cosZ? [ 1* ] Z1 LAI ) T VI y *j cosZ LAI cosZi 3 ZV VI Z1 ^ LAI YIELD = YTET.D 1 vi z1 [2 ] wherein Z-j is the solar zenith angle at the time the reflectance factor observations were made, and Z? is the solar zenith angle at the time of the light interception measurements. 4 IMPLEMENTING SPECTRAL COMPONENTS ANALYSIS To determine the functional relation between numerator and denominator variables for any term in equation [1 ], the seasonal observations for the involved variables are paired within treatment groups that respond similarly in the experiment and the data are fit by least squares. For equation [2' ], the LAI versus VI data are the same as in equation [1' ]. However, the YIELD/LAI and YIELD/VI terms are best applied to canopies during a time interval after LAI has reached its seasonal plateau when the sinks for the assimilates of photosynthesis are dominated by the plant parts that constitute YIELD. For example, Pinter (1981) used the integral area under the ND versus time curve from 50 percent heading to full senescence for wheat and barley subjected to various irrigation treatments and found a coefficient of determination of 0.88 with grain yield. 5 METHODS Replicated small plot studies were conducted near Weslaco, TX, with cotton cv. 'McNair 220' in 1983, with hard red spring wheat cv. 'Aim' , 'Nadadores', and 'Yavaros' in the fall 1983 to spring 1984, and with a white field corn cv. 'Asgro 405' in the summer of 1985. Cotton and wheat were planted at optimum dates and recommended configurations and populations, but corn was planted three months late (23 May) to insure water stress in the nonirrigated treatment during the midsimmer period (15 June to 15 August) of normally low rainfall. Also, the corn was not fertilized although N fertilization at 200 kg/ha is recommended for cammerical production. The cotton and wheat experiments were conducted at the South Research Ftarm (lat. 26.16°N and long. 97.96°W) on Raymondville clay loam, a Vertic Calciustolls and the corn was grown on the North Research Farm (lat. 26.22°N, long. 97.99°W) on a Hidalgo sandy clay loam, a Typic Calciustolls. Both soils are inherently fertile. Three cotton treatments were 99,000 plants/ha in north-south rows 1.02 m apart while a fourth was thinned to 52,000 plants/ha. Che densely planted treatment (MC) received a single application of a growth regulator, mepiquat choloride, at the rate of 74 g/ha active ingredient (a.i.) at pinhead-sized squares (21 April). Another of the 99,000 plant/ha treatments received split applications of mepiquat chloride (MC2) at rates of 49 g/ha a.i. and 25 g/ha a.i. at pinhead sized square (21 April) and at first bloom (19 May), respectively. The remaining densely planted treatment (non-thinned, NT) and the treatment thinned to 52,000 plants/ha (<NT) did not receive the growth regulator and were maintained as controls. We designated the four combinations of treatments as <NT, NT, MC, and MC2. The spring wheats were planted 17 Nov. 1983 at the rate of 80 kg/ha with a commerical drill in rows spaced 0.2 m apart. The populations achieved two weeks after emergence were 302, 313, and 197 plants/m^ for Aim (CV1), Nadadores (CV2), and Yavaros (CV3), respectively. Corn was planted in east-west rows 0.66 m apart. Populations achieved averaged 8.2 plants/nr/. Three irrigated (I) and three dryland (D) plots each 30 m x 30 m in size were established. Twelve irrigations were sufficient to insure that the irrigated treatment did not experience significant water stress any time during the season. Rainfall in six events that totaled approximately 100 mm all occurred prior to anthesis (16 July). yhe measurements needed to determine each term in [1 ] and [2 ] were made for each of the three crops. For LAI determinations 1-m row segments of cotton were sampled whereas 0.24 m2 (0.4 x 0.6 m) areas were sampled for wheat, and representative plants from the wet and dry treatments of corn were harvested. LAI was determined at one site per replicate in each crop on the dates listed in Table 1. The vegetation indices were calculated frcm reflectance factor (Robinson and Biehl, 1982) observations made approximately weekly (Table 1) using a Mark II radiometer (Tucker et al., 1981) which has a visible red (RED) band in the 630 to 690 nm wavelength interval and a reflective infrared (RIR) band in the 760 to 900 nm wavelength interval. The radiometer has a 24 degree field of view and was held vertically 1 m above the canopies centered over the crop rows. The spectral band responses plus incident solar radiation and time of observations were electronically logged concurrently for each of four observations per replicate and reduced by the procedures described by Richardson (1981). The vegetation indices employed were the normalized difference (ND) (Tucker, 1979) and perpendicular vegetation index (FVI) (Richardson and Wiegand, 1977). The equations for these respective VI are: ND = (RIR-RED)/(RIR+RED), and PVI = 0.580(RIR) - 0.815(RED) - 0.410 based on the soil line RED = -1.92 + 0.789(RIR) for the Raymondville clay loam, and Photo on (Io) from th< the ban PAR, te: (1-T'-R et al. Io = T = < R = *s For the measurec sensors quantum was ins( rows (wi (corn) measurii 30 cm a) below t) line qu< area in soon afi from pi leveled and I, ■^o electrc taken b the sen The dat, relatioi wherein extinct the pat! the APA] At th< require« sensor ( reflect; impossil the sam< the var experim« merged, the PAR measure data we estimat measure The L abovegr samplirx determi Solar and lorn of year ephimer Equat the dat differe zenith terms o Menti prefere Departan availab

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