Nitrification suppression and spinach growth in alkaline soil

1976 Spring.Covers not scanned.Includes bibliographical references.A single at-planting application of (NH4)2SO4 with and without nitrapyrin, [2-chloro-6-(trichloromethyl) pyridine], was evaluated on spinach in alkaline soil in 2 field experiments and 1 greenhouse experiment. Parameters measured were soil NH4 -N and NO3 -N, spinach yield, leaf color and leaf P, Fe and Zn. Nitrapyrin was adsorbed onto (NH4)2SO4 crystals then applied in a band at planting in the field experiments. The first field experiment consisted of N application rates of 87. 8 and 157.5 kg/ha and nitrapyrin rates of 0, 280 and 560 g/ha while the second field experiment included N application rates of 0, 45 and 90 kg/ha and nitrapyrin rates of 0, 140, 280 and 420 g/ha. Nitrapyrin (1.5 ppm - dry soil weight basis) was adsorbed onto (NH4)2SO4 crystals and incorporated with soil in the greenhouse at N rates of 0, 400 and 800 mg/2 kg dry soil. Drainage was prevented in this greenhouse experiment. Spinach yields were measured and leaf and soil samples were taken at harvest from the first field experiment and the greenhouse experiment. Yields were measured and leaf and soil samples were taken 28, 42, 48 and 56 days from planting in the second field experiment. Apparently little leaching occurred in the first field experiment and final yield was greatest when N applications included 280 g nitrapyrin/ha. This resulted in high soil concentrations of both NH4 and NO3 at harvest. Concentrated soil NH4 resulting from prolonged nitrification suppression with as much as 560 g nitrapyrin/ha produced good plant growth on this alkaline soil. Leaching had apparently occurred in the second field experiment and increased yields with nitrapyrin 56 days from planting were attributed to increased soil N retention. Prolonged nitrification suppression from 1.5 ppm nitrapyrin in the greenhouse resulted in severely stunted plant growth along with other NH4 toxicity symptoms. Leaf color, which is important in determining market and nutritional quality of spinach, was darker green when (NH4)2SO4 adsorbed with nitrapyrin was applied. This was measured during all 3 experiments. The dark green leaf color was measured and/or observed well before observed yield differences. Leaf P, Fe and Zn concentrations were generally increased when NH4 applications included nitrapyrin in this study. Leaf P concentrations increased the most while leaf Zn concentrations increased the least. Increase in leaf P, Fe and Zn concentrations due to the addition of small amounts of nitrapyrin to NH4 fertilizer may be an important consideration with regard to alkaline soils where P, Fe and Zn are often limiting

Profile of the circulating DNA in apparently healthy individuals

BACKGROUND: Circulating nucleic acids (CNAs) have been shown to have diagnostic utility in human diseases. The aim of this study was to sequence and organize CNAs to document typical profiles of circulating DNA in apparently healthy individuals. METHODS: Serum DNA from 51 apparently healthy humans was extracted, amplified, sequenced via pyrosequencing (454 Life Sciences/Roche Diagnostics), and categorized by (a) origin (human vs xenogeneic), (b) functionality (repeats, genes, coding or noncoding), and (c) chromosomal localization. CNA results were compared with genomic DNA controls (n = 4) that were subjected to the identical procedure. RESULTS: We obtained 4.5 x 10(5) sequences (7.5 x 10(7) nucleotides), of which 87% were attributable to known database sequences. Of these sequences, 97% were genomic, and 3% were xenogeneic. CNAs and genomic DNA did not differ with respect to sequences attributable to repeats, genes, RNA, and protein-coding DNA sequences. CNA tended to have a higher proportion of short interspersed nuclear element sequences (P = 0.1), of which Alu sequences were significant (P < 0.01). CNAs had a significantly lower proportion of L1 and L2 long interspersed nuclear element sequences (P < 0.01). In addition, hepatitis B virus (HBV) genotype F sequences were found in an individual accidentally evaluated as a healthy control. CONCLUSIONS: Comparison of CNAs with genomic DNA suggests that nonspecific DNA release is not the sole origin for CNAs. The CNA profiling of healthy individuals we have described, together with the detailed biometric analysis, provides the basis for future studies of patients with specific diseases. Furthermore, the detection of previously unknown HBV infection suggests the capability of this method to uncover occult infections