Root residues

Table 2 Cumulative CO, Evolution from Root Residues (RM), Soil Organic Matter (SOM), and Glucose During 24 Days of Incubation...

The broadleaf weeds responded to tillage in the same general manner when rye root residue was present, however, it does appear that the growth of all the weeds was inhibited by the presence of rye root residue. This can be seen in Table II by comparing results from the tilled treatment with and without rye root residue. In the case of common ragweed, biomass was reduced 34% (178.3 g no rye, till versus 118.3 remove mulch till), but the density increased by 69% (140 plants/2.2 m versus 280 plants/2.2 m ) when rye root... 

It is reported that trimethylamine in combination occurs in large amounts in beet-root residues 2 and can be obtained from them by the action of caustic soda it occurs also in herring brine.3 From both of these sources, however, the substance is obtained in an impure state and can be purified only by rather tedious methods. This is indicated by the fact that trimethylamine has always been an expensive substance. Synthetic methods for its production are by the action of methyl iodide on ammonia 4 by the distillation of tetramethylammo-nium hydroxide 6 by the action of magnesium nitride upon methyl alcohol 6 by the action of zinc upon trimethyloxy-ammonium halides 7 by the action of formaldehyde upon ammonium chloride under pressure 8 by the action of ammonium chloride upon paraformaldehyde.9 Of these syn-... 

A more complex extraction scheme than those of Hewitt, Bowen, and Reilly described above, was used to show that 65Zn is primarily associated with pectin in the root residue (Peterson, 1968). This was modified and used to indicate the association of copper in Armeria maritima (Mill) Willdenow (Farago et al., 1980) and Ni in Hybanthus floribundus (Farago and Mahmoud, 1983). The scheme is shown Fig. 10-1, and some typical results are shown in Table 10-1. In these last two investigations radiotracers were not required, since the plants accumulated Cu and Ni, respectively, and metal determinations were carried out by flame atomic absorption spectrometry on the individual fractions. 

The chief sources of potash i are (1) The deposits of soluble potash minerals at Stassfurt (Germany), Alsace (France), Galicia (Austria), Catalonia (Spain), Punjab (India), and Atacama (Chili). (2) Sea water, brines, and many lake deposits contain appreciable quantities of potash associated with the sodium salts. (3) The ashes o vegetation—e,g, wood ashes, beet-root residues, seaweeds, sunflower stalks, hedge trimmings, etc. (4) The soapy water used for washing the grease from wool. 

Borner (1960) states that soil sickness in fruit culture is a problem of economic importance in Germany. This is a replant problem that involves micro-element depletion and nematodes, but also root residues. As little as 1 g of air-dry root bark of an old apple tree per half liter of nutrient solution reduced root and stem growth of apple seedlings up to 50% within 30 days. Phlorizin, a natural constituent of apple root bark, and its breakdown products, are at least partially responsible for this apple soil sickness. 

All crops add carbon to a soil in the form of root residues even though essentially all of the above-ground portions may be removed. This added carbon may constitute as little as about 5% of the total crop carbon in the case of some vegetable crops, and as much as perhaps 40% in some of the deep-rooted perennial crops. The above-ground carbon that is returned to the soil may be near zero for many crops and perhaps 50 to near 100% for others, depending on the kind of crop and the disposition made of it. 

Root residues (mainly organic compounds) from rice plants produce methane. It is estimated that worldwide rice agriculture contributes 7-20% of the total... 

Pandey DK (1994) Inhibition of Salvinia (Salvinia molesta Mitched) by parthenium Partheniwn hysterophorus L.). II. Relative effect of flower, leaf, stem, and root residue on salvinia and pmldy. J Chem Ecol 20 3123-3131... 

To determine the respective importance of shoot and root residues in regulating early broadleaf weed seedling emergence, and... 

Determine the Respective Importance of Shoot and Root Residues in Regulating Early Broadleaf Weed Seedling Emergence (Blum et al. (2002) Summarized with Permission of International Allelopathy Foundation)... 

Since for the 1992 and 1993 no-till field studies (Blum et al. 1997) both root and shoot residues of rye, wheat, crimson clover, and subterranean clover were present in each no-till plot, the role of shoot or root residues alone on weed seedling emergence could not be determined. Thus for the 1996 and 1997 field studies, sets of no-till plots with only root residue (i.e., shoots removed), only shoot residue (i.e., cut shoots from root plots placed on no-till reference plots), and shoot (uncut and cut but left in place) and root residues were included in the experimental design (Blum et al. 2002). However, to make the 1996 and 1997 field studies more manageable, only one cover crop, wheat, was utilized. 

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