Classification of Green Bristle Grass, Yellow Foxtail and Chinese Pennisetum Seeds via HATR-FT-IR Combined with Chemometrics

Fourier transform infrared (FT-IR) and horizontal attenuated total reflectance (HATR) technique are used to obtain the FT-IR spectra of the seed of green bristle grass (the seed fromSetaria viridis(L.) Beauv), yellow foxtail seed (the seed fromSetaria glauca(L.) Beauv), and the Chinese pennisetum seed (the seed fromSetaria faberiiHerrum). In order to extrude the difference among them, cluster analysis is considered to identify the three kinds of plant seeds. Because they belong to the sibling plant seeds, and have similar chemical components and close FT-IR spectra. The result of Cluster analysis is not satisfactory. The discrete wavelet transformation (DWT) and a support vector machine (SVM) were used for further study. The compression detail 3 and 4 in DWT are used to extract the feature vectors, which are used to train SVM. The trained SVM is used to classify seed of green bristle grass, yellow foxtail seed and Chinese pennisetum seed. The seed samples are collected from different places around the country. With 40 testing samples we could effectively identify the sibling plants, seed of green bristle grass, yellow foxtail seed and Chinese pennisetum seed by FT-IR with discrete wavelet feature extraction and SVM classification.

Germination Stimulation Properties of Carbamate Herbicides

Butylate (S-ethyl diisobutylthiocarbamate), EPTC (S-ethyl dipropylthiocarbamate), vernolate (S-propyl dipropylthiocarbamate), diallate [S-(2,3-dichloroallyl)diisopropylthiocarbamate], CDEC (2-chloroallyl diethyldithiocarbamate), and chlorpropham (isopropylm-chlorocarbanilate) at 0.1 kg/ha caused increased velvetleaf (Abutilon theophrastiMedic.) populations in field plots. Butylate caused increased populations of common lambsquarters (Chenopodium albumL.) at rates of up to 1.1 kg/ha. In the laboratory, each of the six herbicides caused increased velvetleaf seed germination, and butylate, EPTC, and CDEC caused increased common lambsquarters germination when seeds were exposed to herbicide vapors prior to germination. Germination of velvetleaf, common lambsquarters, and giant foxtail (Setaria faberiiHerrm.) was also increased by butylate solutions over a wide range of concentrations. Maximum germination stimulation generally occurred between concentrations of 10-5and 10-6M butylate. Seedling injury and death also resulted from these concentrations of butylate. Butylate stimulation of seed germination could not be correlated with light requirements of seeds, but appeared to be an additional promotive factor. Ungerminated common lambsquarters seeds after butylate treatment were viable and responded to KCN and KNO3in the same manner as control seeds which did not initially germinate in water. Butylate in combination with the antidote, R-25788 (N,N-diallyl-2,2-dichloroacetamide) stimulated germination of common lambsquarters.

Effect of Shade on Giant Foxtail

Field studies were conducted with giant foxtail(Setaria faberiiHerrm.) under shade intensities of 0, 30, 60, 70, 80, and 98%. Seed weight, dry weight of plant tops exclusive of seed, and total dry weight per plant decreased linearly with increasing shade intensities. These decreases were due primarily to decreases in number of leaves, number of stems per plant, and number of heads per plant. Height of main culm was less affected than other morphological characteristics. Shading affected the length of internodes but had little influence on number of internodes on the main culm. The amount of shade required to control giant foxtail completely, once it is established, appears to be above 95%. Expressed as 2-year means, plants grew to as much as 135 cm, had as many as 188 leaves, 41 stems, and 31 heads, and produced 73 g of dry matter per plant including 6 g of seed. Maximum number of seeds per head was 1405.

Effect of Weeds on Soybean Yield and Harvesting Efficiency

A reduction in soybean (Glycine max(L.) Merr.) yield of 25% (1968) to 30% (1969) resulted from one smooth pigweed (Amaranthus hybridusL.) per ft in 30-inch rows. A giant foxtail (Setaria faberiiHerrm.) infestation of one plant per ft in 30-inch rows reduced yield 13% in 1969. Harvesting before weeds were desiccated resulted in significant threshing and separating losses as speed was increased from 1 to 2 and 3 mph. Stubble, lodging, and stalk losses were more than double in the pigweed and foxtail plots when compared to the weed-free plots after weeds were desiccated by frost.

Metabolism of Atrazine by Fall Panicum and Large Crabgrass

Compared to corn (Zea maysL.) (resistant), oats (Avena sativaL.) (susceptible), and giant foxtail (Setaria faberiiHerrm.) (susceptible), fall panicum (Panicum dichotomiflorumMichx.) and large crabgrass (Digitaria sanguinalis(L.) Scop.) metabolized 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) at an intermediate rate. The order of tolerance of these five species (corn > fall panicum and large crabgrass > giant foxtail > oats) is identical to the order of their ability to metabolize atrazine. In 6 hr, corn, fall panicum, large crabgrass, giant foxtail, and oats metabolized 96, 44, 50, 17, and 2%, respectively, of the14C-atrazine absorbed from a 10 ppm solution and translocated to the foliage, leaving concentrations of 2.2, 34.8, 30.1, 59.8, and 66.3 mμ moles, respectively, of atrazine per g of fresh weight of shoots. Hydroxyatrazine [2-hydroxy-4-(ethylamino)-6-(isopropylamino)-s-triazine] was found in the shoots of corn and giant foxtail. Corn shoots also contained a more hydrophilic metabolite, presumably a peptide conjugate. Hydrophilic metabolites found in the shoots of giant foxtail, fall panicum, and large crabgrass were chromatographically identical to the hydrophilic metabolite found in corn.

Influence of Incorporation Depth on Chloramben Activity

Rates of 0, 1.7, and 3.4 kg/ha of 3-amino-2,5-dichlorobenzoic acid (chloramben) were incorporated to 0, 3.8, and 7.6-cm depths in 0.7 by 0.7-m microplots under low, moderate, and high rainfall conditions. Soybean [Glycine max(L.) Merr., var. Amsoy] injury increased with increasing depth of incorporation of 3.4 kg/ha chloramben. Chloramben incorporation under low rainfall conditions significantly improved control of giant foxtail (Setaria faberiiHerrm.), smooth pigweed (Amaranthus hybridusL.), and velvetleaf (Abutilon theophrastiMedic.) compared to surface treatments. Jimsonweed (Datura stramoniumL.) was not controlled well by chloramben regardless of rate or incorporation depth. In larger field plots over a 3-year period, 3.4 kg/ha chloramben incorporated with a disc produced slight but insignificant soybean injury. Giant foxtail, smooth pigweed, common ragweed (Ambrosia artemisiifoliaL.), and velvetleaf control with incorporated chloramben was equal to or better than the control obtained with surface-applied chloramben. Regardless of method of application, control of common cocklebur (Xanthium pensylvanicumWallr.), jimsonweed, and annual morningglory (Ipomoeaspp.) was poor.

Isoparaffinic Oil as a Carrier for Chlorpropham and Terbacil

The herbicides 3-tert-butyl-5-chloro-6-methyluracil (terbacil) and isopropyl m-chlorocarbanilate (chlorpropham) showed greatly enhanced activity on giant foxtail (Setaria faberii Herrm.) and ivyleaf morningglory (Ipomoea hederacea (L.) Jacq.) when applied in an isoparaffinic oil rather than water. The activity of terbacil was enhanced but to a lesser extent when crop oil was added to a water carrier at a concentration of 10%. In field trials, similar enhancement of terbacil and chlorpropham activity was obtained on several weeds. Onions (Allium cepa L., var. Spartan Gem) in the “loop stage” were moderately tolerant and carrots (Daucus carota L., var. Royal Chantenay) were highly tolerant to chlorpropham at 4 lb/A applied in the isoparaffinic oil. Peppermint (Mentha peperita L.) and spearmint (Mentha spicata L.) were tolerant to terbacil applied in the oil at rates sufficient to give good weed control. The oil alone had no injurious effects on onions, carrots, peppermint, or spearmint. This enhancement in activity in greenhouse and field studies appeared to be due to increased penetration as shown by washing, speed of killing plants, and tracer studies. Tracer studies showed that within 2 hr after application, the isoparaffinic oil increased the penetration of chlorpropham more than eightfold in ivyleaf morningglory and more than fourfold in giant foxtail compared to a water carrier. This increase in penetration was even more striking with terbacil. After 4 hr, penetration was increased over 16 times in ivyleaf morningglory and over 18 times in giant foxtail, when applied in the oil rather than acetone. Chlorpropham and terbacil were translocated to the shoot apex of ivyleaf morningglory only when they were applied in the oil.