Effects of interspecific competition on crop yield and nitrogen utilisation in maize-soybean intercropping system

Intercropping system plays a crucial role in improving crop yield, nitrogen utilisation efficiency (NUE) and economic benefit. The difference in crop yield and interspecific relationship under different bandwidth and row ratio allocation patterns are still unclear. A field experiment was carried out to explore change regularities between crop yield and interspecific relationships under maize soybean intercropping with different bandwidths and row ratios. The results showed that the yield of intercropped crops was lower than that of the sole crop. The nitrogen accumulation (NA), NUE and nitrogen competition ratio was the highest under the intercropping mode with a bandwidth of 2.0 m, which indicated that this mode was more conducive to the N uptake and utilisation in crops. In all intercropping systems, nitrogen equivalent ratio (NER) and land equivalent ratio (LER) were all greater than one, indicating that intercropping systems were conducive to improving land utilisation efficiency and NUE. Under the same bandwidth pattern, expanding the maize soybean row ratio from 2 : 4 to 3 : 4 was beneficial to the improvement of LER, NER, NUE, crop group yield. In conclusion, it was preferable in the NA, NUE, crop group yield under the system of bandwidth 2.0 m and row ratio 2 : 2, which could be a reference for maize soybean intercropping system.

Photo-Crosslinking of Copolymeric Methacrylates Bearing Stilbene Chromophores

Radical polymerization of methyl methacrylate (2) as major component and the methacrylates 1a or 1b, which contain an (E)-stilbene unit fixed by a tether to the ester group, yield easily soluble copolymers 3a, b. Whereas the dominant photoreactions in solution are (E)⇄Z) isomerizations and intra-chain [2π +2π] cycloadditions, cast films of 3a, b give an inter-chain photo-crosslinking on irradiation. Compared to homopolymers, the copolymers are not only better soluble and more easily processible, their films show less undesired light scattering. The cross-linked material is completely insoluble in organic solvents. Thus, it represents the basis for negative photoresists and the corresponding imaging techniques.

Quality of carcass sides, yield and distribution of certain tissues in carcasses from pigs fattened in conventional way and on deep litter

Objective of this research was to present and compare results of the research of the effect of two fattening methods, on deep litter and conventional method (without litter). Slaughter properties have been determined with special focus on distribution of certain tissues in pig carcasses fattened in two different ways. Research was carried out on meat, fattening pig breeds - Swedish landrace. Research included 115 fatteners from single farm in Vojvodina. Depending on the housing conditions, two groups were formed: first group - group I (60 heads in group) was housed on deep litter, and the second - group II (55 heads in group), without litter. At the end of the trial, pigs were slaughtered and dissection was performed on cooled (+4?C) left carcass sides and meat yield determined using the method of partial dissection (Walstra and Merkus, 1996). Carcass sides were cut in 12 parts. Based on the meat quantity in four main carcass parts: leg, shoulder, back-loin part (BLP) and belly-rib part (BRP), which contain 75% of total musculature mass and mass of tenderloin of carcass side, meat percentage in carcass sides was calculated according to formulation (Manojlovic Danica et al., 1999). Fatteners housed on deep litter had statistically significantly (**p<0.01) lower mass of cool carcass sides (38.38 kg) compared to fatteners housed without litter (40.90 kg). Higher absolute and relative shares of leg (10.22 kg and 25.02%) were established and higher absolute yield of shoulder (5.35 kg ) in fatteners housed in boxes without litter (II group). Yield of muscle tissue in leg, shoulder, BLP and BRP was higher in fatteners of the II group (without litter) compared to pigs fattened on deep litter, and also statistically highly significant differences were established in share of muscle tissue in shoulder (**p<0.01) and considerable differences in regard to share of muscle tissue in BRP (*p<0.05). Meat yield of pig carcass sides was determined by method of partial dissection, for fatteners housed on deep litter it was 47,92%, and in case of fatteners housed without litter it was 53.89%. Established differences were very significant (**p<0.01).

U–Pb age constraints on arenaceous and volcanic rocks of the Wakeham Group, eastern Grenville Province

Combined sensitive high-resolution ion microprobe (SHRIMP) and thermal ionization mass spectrometry (TIMS) U–Pb zircon data from a tightly constrained stratigraphic context of the Wakeham Group provide a precise depositional age for sedimentation within this extensive basin of the Grenville Province. Metavolcanic rocks at the eastern exposure of the Wakeham Group yield ages of 1511 ± 13, 1506 ± 11, 1502 ± 9, and 1491 ± 7 Ma. A crosscutting 1493 ± 10 Ma porphyry vein marks the end of volcanism. The older two volcanic rocks rest stratigraphically above metasediments, with a 1517 ± 20 Ma maximum age of sedimentation derived from the youngest detrital zircons of an arenite. Five 1.61–1.55 Ga inherited zircons in the volcanics, reinforced by coeval inheritance in nearby plutons, indicate a Labradorian basement source to the supracrustals. The predominant arenite detrital zircons dates are in the 1.95–1.75 Ga range, however, and feature both trace element and morphological evidence for metamorphism in the source terrane. Together with zircons as old as 2.95 Ga, the detrital age spectrum is consistent with a circum-Superior provenance. The ages obtained imply that Wakeham Group volcanism and sedimentation were, at least in part, coeval with the onset of 1.52–1.46 Ga Pinwarian plutonism along the southeastern margin of Laurentia. U–Pb zircon analyses record a late Grenvillian metamorphic event around 1019 Ma. U–Pb monazite analyses from one sample yield 1010–1000 Ma ages, and the end of Grenvillian metamorphism is marked by 990 Ma U–Pb titanite ages.

Allium discoloration: the nature of onion pinking and garlic greening

Precursors involved in the formation of pink and green-blue pigments during onion and garlic processing, respectively, have been studied. It has been confirmed that the formation of both pigments is of a very similar nature, with (E)-S-(1-propenyl)cysteine sulfoxide (isoalliin) serving as the primary precursor. Upon disruption of the tissue, isoalliin and other S-alk(en)ylcysteine sulfoxides are enzymatically cleaved, yielding prop-1-enylcontaining thiosulfinates [CH₃CH = CHS(O)SR; R = methyl, allyl, propyl, 1-propenyl], among others. The latter compounds subsequently react with amino acids to produce the pigments. Whereas the onion and leek-related propyl, prop-1-enyl and methyl derivatives can form pink, pink-red and magenta compounds, those containing the allyl group yield dark blue products after reacting with glycine at pH 5.0.

Broccoli Production in Cowpea, Soybean, and Velvetbean Cover Crop Mulches

Fall transplanted `Commander' broccoli (Brassica oleracea Botrytis group) yield in mulches formed from the residues of killed cowpea (Vigna unquiculata), soybean (Glycine max), and velvetbean (Mucuna pruriens) cover crops was compared to yield in conventional production on bare soil. Average aboveground biomass production was 6.9, 7.7, and 5.9 t·ha-1 (3.08, 3.43, and 2.63 tons/acre) and total nitrogen content of the aboveground tissues was 2.9%, 2.8%, and 2.7% of the dry weight for cowpea, soybean, and velvetbean, respectively. Within each cover crop mulch main plot, subplots received different nitrogen rates, [0, 84.1, or 168.1 kg·ha-1 (0, 75, or 150 lb/acre)]. For several nitrogen level × year comparisons, broccoli grown in mulched plots yielded higher than broccoli grown on bare soil plots. Cowpea and soybean mulches promoted broccoli growth more than velvetbean mulch. The mulches of all three species persisted through the growing season and suppressed annual weeds.

A NEW CLASS OF RIGID COXETER GROUPS

A Coxeter group is said to be rigid if any two systems for that group yield isomorphic Coxeter diagrams. A Coxeter group is said to be strongly rigid if moreover the generating sets of any two systems are conjugate. We determine a new class of Coxeter groups which are rigid, and introduce the notion of reflection independence, a generalization of strong rigidity.

The chronology of speleothem deposition in northern Yukon and its relationships to permafrost

In the northern Yukon there is a significant group of limestone caves in an area that was not glaciated during the Quaternary. Permafrost appears to have played an important role in restricting calcite speleothem deposition in the caves. U/Th dating and stable isotopic studies indicate that the deposits form two distinct groups, a first group younger than 350 ka, and a second group older than the 350 ka BP limit of the conventional U/Th alpha spectrometric dating method. Two large samples from the second group yield sequences of magnetic declinations and inclinations with reversed and normal polarity, perhaps from the Tertiary. The pollen content of five speleothems, the modes of calcite deposition, and stable isotopic analyses indicate that the speleothems were deposited under a cold regime. It is suggested that the ancient speleothems were deposited at a time when permafrost was absent, during the later Tertiary or at the beginning of the Quaternary period. The establishment and maintenance of permafrost throughout the Quaternary has prevented the formation of younger speleothems, except at a few cave entrances where the active layer may have deepened during interglacials.

Impact of Insecticide Schedule, N and K Rates, and Transplant Container Size on Cabbage Yield

The impact of two insecticide spray application schedules (weekly or on demand), three N and K rates [1x, 1.5x, and 2x; 1x = (kg·ha-1) 130N-149K], and two transplant container cell sizes [small, 21 mm wide × 51 mm deep (7.5 cm 3), and large, 38 mm wide × 70 mm deep (33.7 cm”)] on `Market Prize' cabbage (Brassica oleracea L. Capitata group) yield was investigated in Fall and Winter 1982-83 and Spring 1983. Fenvalerate was sprayed at 0.112 kg·ha-1. For the weekly schedule, 10 sprays were applied in fall and winter and nine in spring; for the on-demand schedule, two sprays were applied in both seasons. There were more insect-damaged heads in both seasons in the plots sprayed on demand than in those sprayed weekly. In fall and winter, the combination of a weekly schedule with 1.5x and 2x N and K rates increased marketable yields over those of the on-demand schedule. Marketable yields at the 1.5x and 2x N and K rates were similar for plants in small or large transplant container cells, but the lx N and K rate applied to plants in small cells reduced yields. In spring, both application schedules produced similar yields, but yield increased with increasing N and K rates and large transplant container cells. Insecticide application schedule and cell size did not affect leaf nutrient concentration significantly, but increasing N and K rates resulted in higher N, P, and K leaf concentrations. Concentrations of N and K in the soil at 42 days after transplanting (DAT) were higher with increasing N and K rates. At harvest (86 DAT), only K concentrations had increased with N and K rates. Chemical name used: cyano (3-phenoxyphenyl) methyl 1-4 chloro-alpha-(1-methylethyl benzeneacetate) (fenvalerate).