Foliage Weight Research Articles

Competition Between Established Tree Roots and Newly Seeded Kentucky Bluegrass1

AbstractLandscape situations frequently are such that trees may be well established when an attempt is made to establish turf. This occurs when renovating an old lawn, changing type of turf, or where new subdivisions are located in areas of established trees. This study was initiated to assess the effects of established silver maple (Acer saccharinum) and honey‐locust (Gleditsia triacanthos L.) roots on newly seeded Kentucky bluegrass (Poa pratensis). A connecting pot technique was used to maintain nearly uniform light intensity over tree‐shaded pots with or without tree roots.Silver maple and honeylocust roots established prior to seeding of common Kentucky bluegrass had a highly significant effect on growth of bluegrass, but the bluegrass had no significant effect on tree roots. Dry weight of foliage, sod and root yields, and root/sod ratios were reduced by presence of tree roots. Penetration of bluegrass roots into the main soil mass was restricted by silver maple roots. A mat of bluegrass roots about 0.95 cm (⅜ inch) thick was easily lifted from the soil containing tree roots.Established tree roots reduced the number of bluegrass plants established from seed, but had no effect on tiller production. It is hypothesized that biochemical inhibition (allelopathy) may be involved.

Variation in nitrogen and mineral composition in populations of prairie grass (Bromus unioloidesH.B.K.)

Abstract Twelve lines of prairie grass (Bromus unioloides H.B.K.), most of them selected for high yield of foliage, were measured for concentrations of 15 major and minor elements in the harvest of foliage taken during spring growth. Significant differences (about twofold) between lines were obtained in the concentrations of sodium, calcium, magnesium, sulphur, phosphorus, iron, manganese, zinc, iodine, and silicon, but not for potassium, chlorine, total nitrogen, nitrate-nitrogen, and copper. A significance test was not obtained for selenium. There were significant negative regressions of element concentration, on dry weight of foliage harvested, for calcium, magnesium, total nitrogen, and phosphorus. When the 12 populations were compared for total amounts of these elements present in the harvested foliage, they differed significantly only for sodium and phosphorus. The organic anion content, as measured by the total cation minus anion content for the major inorganic elements, was very low in all lines. ...

Feeding Habits of the Larch Sawfly Larvae, Pristiphora erichsonii (Hymenoptera: Tenthredinidae) on Japanese Larch in Maryland

Studies on the feeding habits of larch sawfly larvae,Pristiphora erichsonii (Hartig), in Maryland, substantiated previous reports of a feeding preference for spur foliage over elongated shoot foliage. In field examinations on 20 infested Japanese larch trees, significantly greater quantities of foliage were consumed from spurs than from elongated shoots. However, elongated shoots constituted about 1/4 of the total foliage weight consumed. Larvae reared in the laboratory on a constant diet of elongated shoots were more restless, consumed less foliage, and incurred higher mortality than larvae reared on spur foliage. In chemical comparisons, spurs tested quantitatively higher in carbohydrates, proteins, resin, pitch, tar, and photosynthetic pigments than elongated shoots.

Nitrogen nutritional studies with flower-bulb crops

Studies have carried out for the effect of nitrogen nutrient on some flower-bulb crops which are important in the Tottori region.This paper presents the effect of nitrogen supply and omission at the various stages of growth on the absorption of nutrient, the growth and the yield of Dutch iris by using 5.5±0.2g bulbs of cv.‘Wedg-Wood’in sand culture. Growth period was divided into the following four stages; I, Stage of advance growth (Oct.-Nov.); II, Stage of retardative growth (Dec.-Jan.); III, Stage of later growth (Feb.-Mar.); and IV, Stage of bulb weight increase and maturity (Apr.-mid Jun.). Secondary adventitious roots grew up at the beginning of February. Blooming time was mid-April. Treatments were designed as Fig. 1.1. Fresh weight, dry weight and dry weight rate of foliage were the highest in nitrogen omission group (C and J) at the end of March when the foliage weight was maximum of the entire growth period of normal plants.2. Nitrogen supply or omission at stage III dominates the nitrogen level at the end of March when the nitrogen level in the foliage was maximum of the entire growth period of normal plants, in spite of the plants have had nitrogen supply or omission at stage I and II.3. Nitrogen supply was necessary till the end of stage II for the muximum nitrogen level in the roots at the end of January when nitrogen level of roots was maximum in the entire growth period of normal plants. The nitrogen level of roots increased after stage II if nitrogen supply was not done till stage II but was done at the following stages.4. Nitrogen omission at stage I and II resulted the decrease of much amount of nitrogen level in the mother bulb. In this case, there was high negative correlation between the nitrogen level and the weight of mother bulb at the end of January. (Correlation coefficient r=-0.979). It was suggested that absorbed nitrogen has close relation with consumption of reserve substance in the mother bulb.5. Absorbed nitrogen content (Table 12) was little at stage II and paticulary abundant at stage IV. Nitrogen absorption was synergistic with potassium absorption (Table 11).6. The correlation coefficient of nitrogen concentration among foliage, roots and mother bulb varied largely each other depending upon the stage of growth (Table 4). Its value was especially small between foliage and roots at the end of January (Stage II). It was guessed that absorbed nitrogen content of foliage was so little at stage II that nitrogen removed from top to roots in this stage.7. The effects of absorbed nitrogen of each stages on the production of the bulbs were shown in Tables 5 and 6, i.e., stage I, non-effective or rather decrease the yield; stage II, the greatest increase in the yield with an ideal quality of either main or lateral bulbs; stage III, decrease the main bulb yield, but tend to increase the lateral bulbs yield. If nitrogen was applied at stage IV, omission in this stage causes maximum yield (J), and stage IV, decrease the main bulb yield, but tend to increase the lateral bulbs yield. (At this period moisture content sensitively increased in connection with the absorbed nitrogen.)8. The moisture content in the produced bulbs had close relation with the nitrogen concentration (Fig. 5).9. Relation between the nitrogen concentration in the foliage and the bulbs became higher after stage III (Table 10).10. From the above investigation it was considered that suitable nitrogen supply for an ideal bulbs production are as follows: 1) Supply it at stages II and III, and omission it at stages I and IV, or 2) supply it at stages I, II and till mid-May of stage IV, and omission it at stage III and after mid-May of stage IV (Table 13).

Effect of Root/Leaf Temperature Differentials on Root/Shoot Ratios in Some Pasture Grasses and Clover

Twelve pasture species were grown in the same aerial environment, but with five constant soil temperatures ranging from 5 to 35 °C, to determine the influence of root temperature on the weight of roots per unit weight of foliage (R/S ratio). This ratio varied by a factor of 2 to 8 within species. Using maximum yield of foliage to indicate the optimum soil temperature for each species, it was found that the R/S ratio was lowest at the optimum soil temperature, and was progressively higher at soil temperatures above and below the optimum with only slight exceptions. This experimental manipulation of R/S ratios suggests that the partitioning of photosynthate is controlled by the relative rates of photosynthesis and root absorption, by inverse proportion: Root mass x rate(akSOrption) a Leaf mass x rate (photosynthesis)'

Comparative photosynthesis of red alder, Douglas-fir, Sitka spruce, and western hemlock seedlings

More rapid growth by red alder than by coastal conifer species may be explained by alder's greater foliage surface per unit foliage weight, greater total foliage area per seedling, and higher photosynthetic rate at high light intensities. Net photosynthetic rates per unit foliage area were similar for red alder and the three conifers up to saturating light intensity for the conifers. Relative weight of photosynthetic and nonphotosynthetic tissue was also similar for the four species. Average maximum photosynthetic rates measured for these conifers are comparable to reported rates for woody broad-leaved species.

Diurnal and Seasonal Patterns of Net Assimilation in Douglas‐Fir, Pseudotsuga Menziesii (Mirb). Franco, as Influenced by Environment

A 2—year study on net assimilation was carried out in a 38—year—old natural stand of Douglas—fir. Five trees in each of the dominant, co—dominant, and suppressed crown classes were studied using the cuvette method on intact branches and measuring the CO2 exchange with an infrared gas analyzer. Light intensity, air temperature, and relative humidity were monitored using selenium photocells, thermocouples, and a 2—mv, 24—line recorder. The net gain in photosynthesis in 1962 was found to be two to three times that in the drier year of 1961. Expressed per unit weight of dry foliage per hour, suppressed foliage possessed higher photosynthetic efficiency than co—dominants, which in turn were slightly more efficient than dominants. Douglas—fir could photosynthesize at low light intensities. The CO2 compensation point was commonly as low as 10 ft—c, and maximum rates of net assimilation were attained at 800 ft—c. Net assimilation could not be predicted from specific levels of air temperature, light intensity, or relative humidity, but not found to be directly related to light intensities below 750 ft—c and to air temperatures above 30°C. Apart from these extreme situations, net assimilation under natural conditions is apparently limited by the interaction of many internal and external factors. Diurnal patterns of net assimilation differed in trees of different crown class. The rates of photosynthesis and nocturnal respiration commonly fluctuated within each diurnal pattern despite apparently stable environmental conditions. The causes of midday depressions are complex as depressed patterns occurred under hot conditions in summer and under cool, foggy conditions in autumn. Bursts of CO2 evolution immediately after sundown, lasting up to 2 hours, were commonly observed in summer and autumn.

Effects of defoliation and reduction of stand on yield of sugar beets in southern Alberta

In southern Alberta insect pests often cause serious damage to roots or Eol iage of sugar beets. Prior to til inning, fiea beetles, Phyllotreta spp., may cause serious defoliation. After beets are thinned the sugar beet webworm, Loxostege sticliealis (L.), the beet leaf miner, P egomya iJetae Curtis, and the spinach carrion beetle, Silpha bitu berosa Lee., may cause extensive damage to the leaves. The sugar beet root maggot, Tetanol)s myopaeformis (Roder), the red-backed cutworm, Eux oa ochrogaster (Cuen.) , and the three wireworms Limoni'lls californicu.s (Mann.), Cten­ icera destructor (Brown), and HY!Jolithlls bieolor Esch. attack the root and may kill young bee ts . There is little information con­ cerning the amount of damage the plants can withstand or the level of protection required, and therefore the value of treating with insecticides cannot be adequately estimated beforehand. In England, Jones et al. (5) 3 found that 50, 75, and 100% defoliation of sugar beets in the 4- and 8-l eaf stages reduced yields by 5, 10, and 270;0) respectively. In Montana, Morris (6) found that complete defoliation of sugar beets in late June or early July reduced yi eld by Yl and 50% defoliation reduced yield by 1/ 6. Afanasiev et aZ. (I), work­ ing in the same area, reported that up to 75% defoliation reduced yield of roots by amounts not exceeding 6% and yield of tops by amounts not exceeding 20%. Complete defoliation resulted in reductions in foliage weight of up to 80% and a 23 to 270;0 reduction in beet yield. The greatest loss of: top weight occurred when plants 'were injured late in. the season. The following experiments were conducted to determine the effects of defoliation and of reduction of stand on the yields of sugar beets grown in southern Alberta so that the economic sig­ nificance of damage caused by sugar beet insects could be assessed. Materials and MethodsIn 1960 and 1961 experiments were carried ol!t on irrigated land near Lethbridge. The soil was a sil ty clay loam with a pH of 7.7. Plots had been summer fallowed the previous year and each had received an application of ammonium phosphate (11­ 48-0) at 100 pounds per acre prior to seeding. The sugar beets 1 Contribution from the Entomology Section, Canada Agriculture Resea rch Station.

Population and Mortality Assessment During the Egg and Larval Stages of the Larch Sawfly, Pristiphora erichsonii (Htg.)

This contribution is the eighth in a series of papers on sampling techniques used in population studies of the larch sawfly (Ives, 1955; Ives and Prentice, 1958; Buckner, 1959; Ives, 1959; Ives and Prentice, 1959; Ives and Turnock, 1959; and Turnock, 1960). Although the greatest proportionate mortality usually occurs in the cocoon stage of this insect, the largest amount of mortality in terms of absolute numbers occurs between oviposition and the completion of larval feeding. This paper presents a method for estimating seasonal increments to the egg and larval populations and alternative methods for estimating mortality during these stages. Examples are also provided of the integration of these methods with previously developed techniques for estimating egg populations and foliage weight.

Effects of Soil Insecticides and Absorbents on Plant Sugars and Resulting Effect on Mite Nutrition1

The effects of DDT and various absorbent materials as soil additives on the composition of Black Valentine beans and Clark soybeans and on the Tetranychus telarius (L.) populations developing thereon were investigated in the greenhouse. Treatments included DDT only at 800 or 1,600 pounds per acre and DDT at both levels in combination with six levels of the absorbent material as well as an untreated check. Mite development was measured by counting the progeny developing over a period of 8 days from five young adult female mites introduced to a detached leaf disk, each disk being one of four replicates. Dry weight of foliage was calculated and foliage was analyzed for total and reducing sugar, total nitrogen, phosphorus, and potassium. Analyses for correlation coefficient (r) were made on populations with the results of the foliage analyses. In Black Valentine beans DDT added to the soil at both 800 and 1,600 pounds per acre increased total and reducing sugars, nitrogen and T. telarius populations over the untreated check, while decreasing phosphorus, potassium, and dry weight of foliage. Addition of Hydrodarco B, Aqua Nuchar A, and Nuchar C-115-A generally restored the chemical components of the beans and also the mite populations to the levels of the untreated check. Mite populations were thus correlated positively with reducing sugar and nitrogen, in some cases total sugar, and negatively with per cent phosphorus, potassium, and dry weight of foliage. Peat moss, calcium hydroxide, and Fisher activated charcoal pellets did not function effectively as absorbents; Norit-A and Mallinckrodt activated charcoal alleviated the phytotoxic effects of DDT but did not influence mite populations consistently. Clark soybeans were not as sensitive to DDT as Black Valentine beans. The percentages of reducing and total sugar were elevated much less and lower concentrations of absorbent were required to reduce these values to the original levels. Hydrodarco B was the only absorbent to affect the chemical composition and mite populations as consistently as in Black Valentine beans although similar trends were noted with Aqua Nuchar A and Nuchar C-115-A. These studies demonstrated that at least one organic constituent of the plant, reducing sugar, has been markedly influenced in the plant by the addition of high levels of DDT to the soil. Also it has been shown that these plant sugars can be related to the development of a plant feeding mite such as T. telarius.

A Technique for Estimating Tamarack Foliage Production, A Basis for Detailed Population Studies of the Larch Sawfly

This paper is one in a series on sampling techniques used in population studies of the larch sawfly (Ives, 1955; Ives and Prentice, 1958). The technique has been developed to provide bases for comparing the intensity of sawfly infestations in stands of different compositions, and for studying the effect of the insect upon its host. A preliminary study demonstrated the feasibility of developing a sampling method for estimating foliage weight, but also indicated that the foliage weight increased as the season progressed (Ives, 1958). Foliage sampling in stands infested by the larch sawfly must be completed before defoliation becomes prevalent, and the foliage weight may increase considerably after sampling. In 1956 an intensive sampling program was carried out on tamarack in the Whiteshell Forest Reserve, Manitoba, to determine the sample size needed to obtain statistically acceptable estimates of foliage production and to study the nature of changes in foliage weight during the season.

Estimation of Red Clover Yield Losses Caused by the Clover Root Borer

Reductions in second cutting red clover hay yields caused by the clover root borer, Hylastinus obscurus (Marsham), were estimated by multiple regression analyses. Variables included were number of borers, crown diameter of the root, the square of crown diameter, and foliage weight. Both foliage weight and number of borers per root were found to increase as crown diameter increased, the relationships being curvilinear. Regression of foliage weight on borers, independent of crown diameter, showed an increase in number of borers to result in a decrease in foliage weight. Calculations indicated that an average of 1.5 borers per root resulted in a 5.5 %reduction in yield in Ohio in 1950.

Taproot-problems in the breeding of root vegetables

1. In most breeding programs of root vegetables the thickness of the taproot is an important but somewhat confusing factor. The reason is that there is not a clear idea of how genetic and physiological influences interact. Here a report is given of the results of a series of field experiments on this interaction in red garden beet. 2. It is shown that, as a rule, there is a close correlation between the foliage weight per plant and the size of the taproot. This means that a variety with a large top also has a relatively thick taproot. There may be genetic factors influencing the differences in the ratios of the taproot diameter to the foliage weight. Usually the influence of these factors is rather small. 3. The opinion is forwarded that there are two different activities in the beet plant, which may operate at the same time as long as the plant grows. But under the influence of the age of the plant and of the growth conditions one of them may dominate over the other. The first is the growth activity of the primary axis (leaf rosette + taproot). The second is the activity of root thickening. When the plants are very young the growth activity of the primary axis dominates. Later on there is a changeable equilibrium between the two activities. 4. Low germination capacity of the seeds, short day length or an acid soil retard both activities. Under these conditions root thickening is slow but also the growth of the primary axis. Consequently, reduction of the growth rate in these cases does not result in an uncommonly heavy taproot. 5. Relatively low temperature and (or) a relatively dry soil retard root thickening more than the growth of the primary axis. The result is a thick taproot. 6. Relatively high temperatures and a satisfactory water content of the soil favour a quick root thickening. The result is an early root thickening and a small primary axis. The taproot becomes thin and the top will be relatively small. 7. This explains why large top types of beet are more popular in areas with a warm, continental climate, and short top types in areas with a cool marine climate.

Magnesium Deficiency of Some Northeastern Pines

AbstractMagnesium deficiency of Pinus resinosa, P. strobus and P. banksiana was studied in young forest plantations on light textured soils bordering the western and southwestern margins of the Adirondack province of New York.The most conspicuous symptom of deficiency was a bright yellow discoloration of the tips of the current season's needles, appearing in the fall and affecting the upper part of the tree most strongly. When the deficiency was severe the chlorosis was followed by death of the needle tips or premature loss of foliage. Gross reductions in shoot growth and needle length occurred only under extreme deficiency or when lack of magnesium was accompanied by potassium deficiency.In P. resinosa the appearance of deficiency symptoms was usually associated with magnesium contents less than .16% of the oven dry weight of mature first year foliage; with less than about .13% symptoms were severe. Fertilization with magnesium sulfate at rates of 20 to 50 lbs. Mg/acre eliminated or reduced the symptoms after a lapse of at least a year.Fertilization of deficient trees with magnesium sulfate resulted in increased height growth over a period of at least three years. In two instances this increase was shown to be additive to that due to potassium, without evidence of significant interaction.

Influence of nitrogen, phosphorus, potassium and calcium on tuber and foliage weight of potatoes

Following dry seasons in which much of the applied nitrogen is not utilized by the plant but prevented from leaching by green manure cropping, a reduction in the amount of nitrogen applied for potatoes is not only justifiable but highly desirable. On acid soils large quantities of phosphate in potato fertilizers are apparently necessary, regardless of previous weather conditions, until the phosphate-fixing capacity of the soil is adequately satisfied. Tuber yields are not necessarily correlated with plant growth, as high tuber yields were produced on plots with both low and high plant weights and low tuber yields were also produced on plots with both low and high plant weights. In view of the above results a 5-10-5 analysis is probably at least as well suited to most soils on the Eastern Shore of Virginia as the 6-8-6 analysis and high analysis phosphatic materials may suitably be used in its formulation.