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首頁(yè)> 外文學(xué)位 >Identification of optical spectral signatures for detecting cheat and ryegrass in winter wheat, and determination of optimum rate and growth stage of foliar applied phosphorus in corn.
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Identification of optical spectral signatures for detecting cheat and ryegrass in winter wheat, and determination of optimum rate and growth stage of foliar applied phosphorus in corn.

機(jī)譯：確定用于檢測(cè)冬小麥作弊和黑麥草的光譜特征，并確定玉米葉面施用磷的最佳速率和最佳生長(zhǎng)階段。

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Site specific weed management requires the identification of crop and weed species in a mixture. Reflectance spectra were used for the detection of cheat and ryegrass in winter wheat under greenhouse conditions. The three plant species and two nitrogen levels were arranged in a completely randomized design with three replications. Spectral readings were taken at Feekes 3 and 5 wheat growth stages using SD2000 spectrometer. Data were analyzed using a discriminant analysis procedure. The discriminant function with the band combinations 515/675, 555/675 and 805/815 resulted in the best overall correct classification (94%) of observations at Feekes 3 while for spectral data at Feekes 5 the discriminant function with the band combinations 755 and 855/675 resulted in 66.7% overall correct classification of observations. In several instances, ryegrass was classified as either cheat or wheat while cheat was classified as rye. Cheat was not classified as wheat in most of the instances. This suggests that it is possible to identify cheat in wheat using wavelength ratios developed from spectral readings in 10 nm bands between 500 and 860 nm.; Foliar applications of fertilizer phosphorus (P) could improve use efficiency by minimizing soil applications. Nine experiments were conducted at Efaw, Goodwell, Guymon, Lake Carl Blackwell, Perkins and Stillwater, OK in 2002 and 2003 to determine foliar phosphorus rates and appropriate application growth stages. Treatments comprised of ten factorial treatments combinations of three foliar P application timings and four rates of foliar P. Foliar application times were V4, V8 and VT corn growth stages. Foliar P rates were 0, 2, 4 and 8 kg P ha-1. Foliar P applied at VT growth stage improved grain and forage P concentration which was reflected in increased grain yield in some of the experiments. Foliar P rate of 8 kg ha-1 improved to some extent yields and largely forage and grain P concentration of corn more than the smaller rates although phosphorus use efficiency was high only with low foliar P rates. The results suggest that foliar P could be used as efficient P management tool in corn when applied at the appropriate growth stage and rate.
機(jī)譯：特定地點(diǎn)的雜草管理要求鑒定混合物中的作物和雜草種類。反射光譜用于在溫室條件下檢測(cè)冬小麥中的作弊和黑麥草。以完全隨機(jī)的設(shè)計(jì)安排了三種重復(fù)的三個(gè)植物物種和兩個(gè)氮水平。使用SD2000光譜儀在Feekes 3和5小麥生長(zhǎng)階段獲取光譜讀數(shù)。使用判別分析程序分析數(shù)據(jù)。 515 / 675、555 / 675和805/815波段組合的判別函數(shù)在Feekes 3上獲得了最佳的整體正確分類（94％），而對(duì)于Feekes 5的光譜數(shù)據(jù)，波段755和675的判別函數(shù)855/675得出觀察結(jié)果總體正確分類的66.7％。在一些情況下，黑麥草被分類為作弊或小麥，而作弊則被分類為黑麥。在大多數(shù)情況下，作弊沒(méi)有被歸類為小麥。這表明可以使用從500到860 nm之間的10 nm波段的光譜讀數(shù)得出的波長(zhǎng)比率來(lái)識(shí)別小麥中的作弊。葉面噴施磷肥（P）可以通過(guò)減少土壤施用量來(lái)提高利用效率。在2002年和2003年分別在美國(guó)的Efaw，Goodwell，Guymon，Lake Carl Blackwell，Perkins和Stillwater進(jìn)行了9個(gè)實(shí)驗(yàn)，以確定葉面磷的含量和適當(dāng)?shù)氖┯昧?。處理包括三個(gè)葉面施磷時(shí)間和四個(gè)葉面施磷率的十種因子處理組合。葉面施藥時(shí)間為V4，V8和VT玉米生長(zhǎng)階段。葉面磷含量分別為0、2、4和8 kg P ha-1。在VT生長(zhǎng)階段施用葉面磷可以改善谷物和飼料中P的濃度，這在某些實(shí)驗(yàn)中反映為谷物產(chǎn)量的增加。盡管磷的利用效率僅在葉面磷含量低的情況下才高，但8kg ha-1的葉面磷含量在一定程度上提高了玉米的產(chǎn)量，并大大提高了玉米的草料和谷粒中磷的含量。結(jié)果表明，在適當(dāng)?shù)纳L(zhǎng)階段和比例下，葉面磷可以用作玉米中有效的磷管理工具。

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