bluuebunny/crossref_metadata_2025 huggingface dataset:
Mulch Tillage: Some Effects on Plant and Soil Properties
Authors: Moody J. E. , Lillard J. H. , Edminster T. W.
Published: July 2010

The effects of a “double‐cut plow” method of mulch tillage on fertility, as measured by soil nitrate‐N, soluble nutrients in leaf, grain yields, and nutrient content of the corn plant, and on physical properties of the soil were investigated at Blacksburg, Va. The standard 3‐year rotation of corn, small grain, and clover‐grass with mulch tillage practice during the corn year was compared with a similar rotation using conventional clean tillage practice.

The percentage of N in the corn plant was lower where mulch tillage was used. The differences were significant (5% level) for high yield seasons. Percentage P in the plant was not affected by tillage method. Differences in K content of corn plant between tillage method, although usually large, were inconsistent. In general, soil nitrate‐N and soluble N‐P‐K in leaf tissue were lower during the early part of the growing season under mulch tillage.

Significant reduction in yields (19 bu./A.) were obtained from mulch in 1948. This was apparently due to a similar reduction in stand. In 1949 and 1950, with planter modifications which pushed the mulch from the row, comparable yields and stands were obtained. Three‐year average yields were: mulch 73 bu./A., turn plow 81 bu./A.

The 0–3 inch layer of soil under mulch showed higher aggregation, air space, percent organic matter, and percent total nitrogen than did conventional tillage.

There are a number of factors which may affect the availability of nutrients where this tillage method is used. It is believed that the lower N status under mulch was due chiefly to changes in the soil microflora brought about by this tillage.
The Replacement of Nonexchangeable Potassium by Various Acids and Salts
Authors: Williams D. E. , Jenny H.
Published: July 2010

A large proportion of the potassium absorbed by plants growing on Ramona loam is obtained from the nonexchangeable form. The nonexchangeable potassium may possibly be released to the solution phase before being absorbed by plant roots. This investigation concerns the release of fixed potassium from Ramona loam through the action of various acids and salts. The soil contains 20,000 ppm of potassium of which 78 ppm is exchangeable to neutral, normal ammonium acetate. Rye plants grown by the Neubauer technique removed in addition 112 ppm of nonexchangeable K from the soil. Water saturated with CO2 at pH 4.0 leached through the soil for 50 days removed only 39 ppm of nonexchangeable K. It was noted that equal volumes of CO2 saturated water which passed through the soil removed the same amount of K regardless of the rate of leaching or thickness of the soil column. The final concentration of potassium in the CO2 saturated water leachates was 0.1 ppm K.

Extraction and leaching studies with dilute acid solutions varying in pH from 1 to 7 revealed a correlation between pH and the amount of K replaced from the soil. Potassium replaced with 0.1 N acid solutions with pH ranges between 3 and 7 was mostly from the exchangeable form, whereas that replaced at pH values below 3 included a large proportion of the non‐exchangeable form.

A comparison of leaching and extraction studies demonstrates that for equal volumes and pH values the extraction method is more efficient in releasing nonexchangeable K than the leaching method. This holds even for water saturated with CO2.

In extractions with various chloride salts, ammonium acetate, and hydrochloric acid, it was found that all ions except ammonium replaced nonexchangeable K from the soil. The ions in descending order of effectiveness of replacement of K from the soil are H+ > Na+ > Li+ > Ca++ > Mg++ > NH4+.
The Influence of Soil Moisture Condition on the Uptake of Phosphorus from Calcareous Soils by Sugar Beets
Authors: Haddock Jay L.
Published: July 2010

Field experiments were conducted during 4 years on irrigated calcareous soils in Utah, from which data on the soluble phosphorus content of sugar beet petioles were related to soil moisture condition and fertilizer application. In addition, during 1950, the relationships between fertilizer placement and soil moisture condition upon phosphorus uptake were determined using P32‐tagged superphosphate. On August 20, 1947 sugar beet petioles obtained from beets growing on soils indicating about 1,000, 10,000, and 100,000 ohms resistance contained approximately 13,000, 900, and 500 ppm of phosphorus, respectively. Phosphorus fertilizer placed in bands 6 inches below the soil surface and 4 inches to the side of beets was more readily available to sugar beet plants than broadcast phosphorus at all soil moisture conditions studied, early in the season. High concentration of available soil nitrogen and high soil moisture tension are conditions hindering the uptake of soil phosphorus. It is not clear from the data obtained why low soil moisture tension influences phosphorus uptake by sugar beets favorably. It is probable that indirect effects of soil temperature and carbonic acid concentration in the soil solution of moist soil may promote phosphorus uptake.
Effect of Sodium Ion on Synthetic Water‐stable Aggregates
Authors: Mazurak Andrew P.
Published: July 2010

Particles of diameter <0.15µ were separated from Hesperia sandy loam (micaceous soil) and electrodialyzed. Proper quantities of 0.1 N NaOH were added to the electrodialzed suspensions so that the symmetry‐concentrations, S, of Na+ were 0.0625, 0.125, 0.25, 0.50, 1.0, and 2.0. Each suspension was dried to induce aggregation. The dry synthetic aggregates were then analyzed for their water‐stability by shaking them in water for 2‐, 20‐, 200‐, and 2,000‐minutes. After each shaking period a size distribution of aggregates was obtained.

The cumulative weight percentage curves for aggregates with Na+ showed two distinct types of size distribution. Those for aggregates formed with electrodialyzed particles and with Na+ of 0.25‐S and less showed a sigmoid type of size distribution, while those for aggregates formed with Na+ of 0.50‐, 1.0‐, and 2.0‐S showed a bimodal type. The aggregates formed with electrodialyzed particles were more stable in water than any of the aggregates with Na+. The order of water‐stability of aggregates for each of the four shaking periods, as shown by the geometric mean diameters, was: electrodialyzed particles > 0.0625‐S Na+ > 0.125‐S Na+ > 0.25‐S Na+ > 0.50‐S Na+ > 1.0‐S Na+ > 2.0‐S Na+.

The effect of Na+ on the values of geometric mean diameter of water‐stable aggregates was not a linear function, but rather some power function.
The Effect of the Calcium‐Magnesium Ratio on the Solubility and Availability of Plant Nutrients
Authors: Sanik J. , Perkins A. T. , Schrenk W. G.
Published: July 2010

The purpose of the present paper is to determine the effect of the Ca‐Mg ratio in solution and in the soil on the solubility and availability of certain plant nutrients. In recent years many papers have been published on the effect of the Ca‐Mg ratio on crop production. Certain papers and unpublished data have indicated that the Ca‐Mg ratio affects the solubility of other plant nutrients, esepecially phosphorus, including some of the minor or trace elements. Nutrient solutions have been made up and mixed with common soil clay kaolin as an adsorbing component. The solubility of B, Mn, Zn, Cu, K, and P were determined. Soil from the Kingman area which is quite low in Mg was obtained for greenhouse studies. Wheat and sorghum were grown and analyzed for the above elements. Plant uptake of the nutrients was plotted against the Ca‐Mg ratio. The results showed:

A varying Ca:Mg ratio in Kingman soil produced a difference in the weight and height of the plants grown with a maximum plant growth at a Ca‐Mg mol. ratio of 4‐1. All the nutrient elements studied were affected by a varying Ca:Mg ratio in the soil.

The effects observed on the minor elements in wheat and sorghum agree qualitatively with most of the effects observed in nutrient solution studies.

No direct correlation was found between the ratio of Ca:Mg in the soil as compared to the ratio in the plants, but a general correlation occurs.

An overall maximum uptake of the minor elements seems to be provided for both wheat and sorghum at a Ca:Mg ratio of approximately 4:1.

A high magnesium soil favors the uptake of Mn and Zn by sorghum and K, B, and Mn by wheat.
Nitrogen Recoveries from Applications of Ammonium Chloride, Phosphate, and Sulfate and Outgo of Complementary Ions in Rainwater Leachings through a Six‐foot Soil‐subsoil Column
Authors: MacIntire W. H. , Young J. B. , Shaw W. M. , Robinson B.
Published: July 2010

The objectives of the 12‐year lysimeter study were to determine (a) annual recoveries of nitrogen as NH3, NO2, and NO3 from ammonium chloride, phosphate, and sulfate applications to a 1‐foot stratum of Cumberland silt loam underlain by a 5‐foot column of red clay subsoil, and (b) attendant outgo of exchanged Ca, Mg, and K and recoveries of additive CI and SO4.

Quantity of nitrogen input, the soil‐subsoil column used in lysimeter triplicates, and the experimental procedure were those described in a 10‐year study in which nitrates of Na, Ca, and Mg were applied (2).

Leachings of NH4 were nil to meager; nitrites appeared in the leachings throughout the first 3 years. Largest outgo of engendered NO3 occurred in the second, third, and fourth years, in descending order, and respective totals for the initial 6 years were virtually the same as the totals for the 12 years. The applied NH4 was recovered chiefly as engendered NO3, but substantial fractions were lost through reduction processes and/or fixation. Recoveries of N from chloride, phosphate, and sulfate were 79%, 74.8%, and 86%, respectively.

Chlorine recoveries were 73% in the second year, 93% in the second and third years together, 97% after 4 years, and complete in 12 years.

Sulfate recoveries from the (NH4)2SO4 were only 8.3%. The phosphate caused a significant increase in outgo of SO4 from native supplies, but the chloride did not.

Calcium Outgo: That induced by the chloride was largest in the second year;

That induced by the sulfate occurred chiefly in the second and third years;

That induced by the phosphate was highest in the third year and indicated the early development of dicalcium and dimagnesium phosphates in the upper strata of the soil‐subsoil.

The outgo of Ca as chloride was twice the outgo induced by the phosphate and 1.4 that induced by the sulfate.

Magnesium exchange exerted by the three ammonium salts was in the order found for the exchange of calcium, but the mean for Mg exchange was only 52% of the mean for Ca exchange.

Potassium exchange was evidenced by the second year's leachings and by those of the next 3 years; but K‐exchange totals were small in relation to the totals for exchanged Ca and Mg. K‐exchange was largest from the chloride and least from the phosphate.

The enhancements in outgo of K, Ca, and Mg were induced by the passage of engendered nitrates.

Sodium outgo was uniform in the first 4 years and was not determined thereafter.

It seems certain that heavy applications of nitrogen as ammonium chloride, phosphate, or sulfate to a heavy soil, in fallow, will not be recovered completely in the rainwater leachings that pass through strata of clay subsoil.
Mineral Characteristics of Some Soils of Puerto Rico
Authors: Jeffries C. D. , Bonnet J. A. , Abruna F.
Published: July 2010

Preliminary data are presented of some of the mineralogical characteristics of 41 soil series of Puerto Rico, which includes soils of three orders, 22 great soil groups occurring in seven physiographic provinces. Study of the constituent minerals of these soils show that there are present quartz, feldspars of the plagioclase series, and the clay minerals kaolin, illite, montmorillonite, and one called provisionally beidellite. The soils can be divided into two general groups, those with abundant feldspar and those where feldspar is absent or occurs only in traces. On the average, those soils which contain feldspar have a lower clay content, a higher total exchange capacity, and a higher productivity rating, where lack of rainfall or extreme slope are not factors, than those soils where feldspars are absent or occur only in traces. This appears to be independent of the great soil group, or province in which the soil series occur. It may be that the presence or abscence of feldspar in a soil is one of the indications of its potential fertility status.
Losses of Nitrogen During Decomposition of Plant Material in the Presence of Inorganic Nitrogen
Authors: Jansson Sven L. , Clark Francis E.
Published: July 2010

Oat straw and alfalfa hay were decomposed in the presence of added inorganic nitrogen under differing conditions of incubation. Changes in organic, ammonium, and oxidized forms of nitrogen were determined. With plant material in shallow (3 mm) layers and at two‐thirds moisture saturation, there was loss of nitrogen in decomposition of alfalfa, but not in decomposition of oat straw. Some influences of pH, moisture content, pore size, added energy‐rich materials, kind of inorganic nitrogen, and of addition of germicidal materials on the occurrence and extent of denitrification are reported. Vigorous bacterial activity and an alkaline reaction were necessary for any extensive denitrification from added nitrate. An active fungus flora was commonly encountered in decompositions in which there were no appreciable losses of nitrogen. Nitrite toxicity appeared to be an important ecological factor in preventing bacterial growth and biological denitrification in acid substrates.
Influence of Cultivation, Mulching, and Fertilizers on Chemical Composition of Pecan Leaves and Their Relation to Yield and Quality of Nuts
Authors: Hunter J. H. , Hammar H. E.
Published: July 2010

Results of previous studies on the chemical composition of pecan leaves indicated a significant relationship between the level of phosphorus and potassium in the leaves and quality of nuts. The objective of the present study was to apply phosphate and potash fertilizers under two systems of culture with the view of increasing the uptake of these fertilizers. A block of trees was selected and the entire block was seeded to blue lupine for the purpose of supplying nitrogen to the trees. The block was divided into plots to accommodate a split‐plot experiment using phosphate and potash singly and in combination. The plots were then divided into two series, one to be cultivated during the summer and the other to have the lupine mowed and left as a mulch. Leaf samples were taken in September of each year and analyzed for N, P, K, Ca, and Mg. Yield records were taken and samples of nuts were examined for quality.

The percentages of nitrogen, potassium, and calcium found in the leaves were not significantly influenced by either cultivation, mulching, or fertilizer. In 1950, the fourth year of treatment, the leaf phosphorus was increased significantly by the application of phosphate and by the summer mulching of the lupine. Leaf magnesium was not significantly influenced by the application of fertilizers, but it was increased significantly by the summer mulching. The mean percentages of leaf N, P, and K were less in 1950 than in 1946 despite the fact that relatively large quantities of these elements were returned to the soil by the cover crop growth and the fertilizer applications. This may have been due to the high utilization of these elements in production of nuts and growth of trees.

Nuts of good quality were produced with a relatively wide range of total nutrients in the leaves. Yield of nuts and quality of the kernels were not highly correlated with the level of any one particular element found in the leaves, but there is evidence that the balance of elements in the leaves was the determining factor in influencing quality.
Water Use by Crops as Determined by Weighing Monolith Lysimeters
Authors: Harrold L. L. , Dreibelbis F. R.
Published: July 2010

The purpose of this study is to present information on water use by crops as determined from evapo‐transpiration data obtained by weighing monolith lysimeters. Additional information on the accretion, depletion, and storage of soil water as influenced by soil type and land use effects is also included. Most of the data presented were obtained during the period 1941–1951.

Water use by crops during the growing season is evaluated in terms of weight of water used to produce one pound of crop. For the corn years (May to September), 438 and 421 pounds of water were consumed in producing one pound of crop (dry matter) on the Muskingum and Keene silt loams, respectively. For the wheat years (April to June 1942, 1946, 1950), consumptive use was 624 and 641 pounds of water respectively; for the first‐year meadow years (April to August) 945 and 1,238 pounds of water per pound of crop were used, respectively, on the same two soil types.

Daily soil moisture, accumulated daily precipitation, evapotranspiration, and percolation data are presented in graphs for 1951 from three lysimeters each representing a different soil type. Tabular data from these areas were also given showing monthly accretion, depletion, and storage of soil water.

Monthly evapo‐transpiration data are presented for the growing season, April to September for the period 1944–1951. On the lysimeter of Muskingum silt loam the values averaged 23.26, 25.30, and 25.66 inches of water for the corn, wheat, and meadow years, respectively. On the lysimeter of Keene silt loam, values for the same crops averaged 26.42, 28.00, and 26.03 inches, respectively.
The Identification of Clay Minerals in Some Ontario Soils: 1. Parent Materials
Authors: Webber L. R. , Shivas J. A.
Published: July 2010

The colloidal fractions, one micron and less, from the parent materials of nine Ontario soils were examined by the differential thermal method and by chemical analyses. An attempt was made to characterize these fractions in terms of their clay mineral composition by comparing them with reference clay minerals.

The thermal curves suggest that the colloids from the following soil series: Lockport, Haldimand, Caistor, Perth, Peel, Osprey and Guelph, were dominated by an illite‐like clay mineral. Chemical analyses revealed these colloids to have a high content of K2O and an exchange capacity greater than that normally associated with an illite. The Lockport colloid was established as a particular illite and the other soil colloids characterized in terms of the Lockport plus low concentrations of montmorillonite to account for the exchange capacity.

The colloids from a, Northern Ontario soil and the Rideau did not fit into the pattern followed by the other colloids. The thermal curve for the Rideau suggested a micaceous colloid lacking well‐defined thermal curve characteristics. The Northern Ontario soil colloid had a high exchange capacity but lacked the major thermal characteristics of montmorillonite.
The Accumulation of Soil Organic Matter from Wood Chips
Authors: Salomon Milton
Published: July 2010

A study was made in cylinders to measure the effect of incorporating 10 tons of pine and oak chips per acre to a Merrimac sandy loam. The influence of such factors as level of nitrate nitrogen, soil reaction, and size of wood chips, were investigated.

Using nitrate nitrogen depression as a measure of rate of decomposition, it was found that oak chips decomposed more rapidly than pine chips. This was supported by annual sieving experiments. These measurements showed significantly less oak chips remaining at the end of 12 and 24 months than pine chips.

Although 55 to 85% of the wood chips decomposed, organic matter accumulation proved to be meager. No significant differences due to treatments were found. There was some indication that soils at pH 5.0–5.5 accumulated somewhat greater amounts of organic matter than those at pH 6.0–6.5.

The relationship between carbon, as determined by the chromic acid titration method, and total carbon, did not change appreciably after 2 years of wood chips decomposition. There was no significant difference in the amount of chromic acid oxidizable carbon due to treatment.

The effect of various treatments upon total soil nitrogen was small. No constant relationship could be found, in spite of wide differences in the amount of soluble nitrogen added to the soils. Although the carbon‐nitrogen ratios of the soils generally widened, increases were small.

Soil reaction did not change appreciably due to additions of wood chips. Ammonia accumulations were negligible.

After 2 years of decomposition, 150 pounds of nitrogen gave highly significant increases in the yields of beets and spinach. Wood chip residues did not depress plant growth. Small chips resulted in significantly higher yields than treatments containing large chips.

An auxiliary study showed that 100 and 150 pounds of nitrate nitrogen added to beets and spinach, respectively, overcame any depressing effect of additions of 10 tons of small pine chips. With low available nitrogen, wood chips depressed the growth of beets and spinach. This was not true after 12 months of decomposition.
Stubble‐Mulch Tillage in New York
Authors: Free George R.
Published: July 2010

The purpose of this paper is to report on progress made in adapting stubble‐mulch tillage for use under the cool, humid conditions of New York State. Comparisons of stubble‐mulch plowing and disking with turn plowing over a period of 7 years in New York State have been presented and discussed. Over most of the period, and for all crops studied except hay, both kinds of stubble‐mulch tillage resulted in significantly lower yields than those resulting from turn plowing. During the last year of the comparison, however, an improved technique of stubble‐mulch plowing using an improvised plow operating on the tandem and double‐cut principle gave results fully as satisfactory as turn plowing. Soil penetrometer and moisture data showed that the new stubble‐mulch plowing technique produced a seedbed as loose as that obtained by turn plowing and also resulted in moisture conservation through concentration of crop residues on the surface. At the same time, there were indications that disking resulted in a seedbed more difficult to penetrate with the penetrometer and also one from which moisture was used inefficiently for crop production and lost by excessive evaporation regardless of the presence of a residue mulch.
Effect of Potash Fertilization on Yield, Stalk Breakage and Mineral Composition of Corn
Authors: Wittels H. , Seatz L. F.
Published: July 2010

A corn hybrid with known susceptibility to stalk breakage was grown to determine the influence of time and rate of potash fertilization at two rates of nitrogen on yield, amount of stalk breakage, and on the potassium and calcium composition of portions of the plants sampled periodically during the growing season.

Certain of the potash‐treated plots yielded significantly more than the no‐potash plots, but the trend was not consistent.

Stalk breakage was reduced by potash applications at the high nitrogen level, but not at the low nitrogen level. At the high nitrogen level up to 40 pounds K2O per acre reduced stalk breakage and higher rates had no further affect.

The potash content of the plants was directly related to the rate of potash applied and for each treatment was approximately the same at the two nitrogen levels. Three methods of potash application showed no difference in their effect on the factors studied. A reciprocal relation was noted between the potassium and calcium content of the plants. A tendency toward cation equivalent constancy at the later stages of growth was observed.
Properties of Soil Aggregates: I. Relation to Size, Water Stability and Mechanical Composition
Authors: Garey C. L.
Published: July 2010

Material from three different soils in Arkansas was sieved through a series of standard screens and material collected from each of the sized aggregates separated. This was collected in two forms: (a) by dry screening, and (b) by wet screening in water. Mechanical analysis, exchange capacity and organic matter were determined for the water‐stable aggregates for each of the sizes separated and related to the same properties of the whole soil.

Results indicate that the properties of the individual waterstable aggregates are somewhat different from those of the whole soil. The smaller aggregates of 0.15 −0.42 mm in diameter tend to contain a larger content of clay and organic matter than do the large aggregates or the whole soil. Also the aggregates larger than 0.42 mm possess lower exchange capacities than does the whole soil. A shielding of the effect of clay inside the aggregates is indicated by the lack of uniform ratio of clay to cation exchange capacity. This ratio is generally larger in the aggregates than in the whole soil.

A theory indicating the formation of aggregates from small secondary particles by cementation with clay and organic matter to account for the differences observed is proposed.
Distribution of Phosphorus in Some Genetically Related Loess‐Derived Soils
Authors: Godfrey Curtis L. , Riecken F. F.
Published: July 2010

The total and organic phosphorus were determined in five virgin‐like loess‐derived soil profiles occurring along a traverse from southwestern Iowa to northern Missouri. The soils studied were representatives of the Prairie (Brunizem)3, Wiesenboden, and Planosol great soil groups. The time of soil weathering was assumed to have been the major soil formation variable affecting the soils investigated. The degree of soil profile development in southwestern Iowa had been found previously to increase maximally in a southeasternly direction from the major source of loessial material at the Missouri River.

The total phosphorus was found to decrease in the profiles along the traverse in relation to the degree of profile development, and the vertical distribution was found to vary in a systematic manner also. The action of soil weathering was found to have reduced the amount of phosphorus in the A horizons of the soils in relation to the amount found in the C horizons. The phosphorus measured on the B horizons was less than in the A or C horizons and decreased along the traverse to a minimum in the Haig profile (maximal Wiesenboden) and then increased slightly in the Planosol soils.

The organic phosphorus was found to decrease also in relation to the degree of soil profile development along the traverse and to decline vertically in the profiles at a progressively greater rate with each succeeding more strongly developed profile.

The data indicate a definite relationship between the amount and distribution of phosphorus and the stage of soil development exhibited in each of the profiles studied.
Changes in the Criteria Used in Soil Classification Since Marbut
Authors: Whiteside E. P.
Published: July 2010

The changes in the criteria used in soil classification since Marbut's time are presented. These changes are of three kinds: additions to the list of properties used, refinements of the properties formerly used, and deletions from the list of properties formerly used. The additional properties now being used are mostly properties of the whole soil body. Most important among these are the properties which are independent variables of the soil system. The introduction of these independently variable properties of the soil body, for use in soil classification, presents the poignant possibility of fusing the genetic and descriptive systems of soil classification without abandoning the premise that soils should be classified on the basis of their properties. The affect of the above changes in soil classification on the definition of the soil individual — the soil type — and its nomenclature are discussed.
Effect of Nitrogen Fertilizer on the Nitrogen, Phosphorus, and Cation Contents of Bromegrass
Authors: Russell J. S. , Bourg C. W. , Rhoades H. F.
Published: July 2010

Heavy applications of nitrogen fertilizer produce large increases in growth of bromegrass on nitrogen deficient soils in eastern Nebraska. Such a marked effect of nitrogen fertilizer upon growth may also be reflected in the composition of the forage according to results obtained on Rokeby soils at Lincoln, Nebr. Rates of 0, 60, 120 and 240 lbs. N/acre were applied to a sodbound field of Lincoln bromegrass. Yields of forage and plant samples were obtained four times during the growing season during one year, and once at the regular time of harvesting hay during other years.

Plant samples were analyzed for nitrogen, phosphorus, calcium, magnesium, potassium and sodium. There was a general decrease in percentage of all elements throughout the growth period sampled, although the trends varied with the element and with the treatment. Nitrogen percentage was higher for fertilized than nonfertilized bromegrass at all stages of growth. During early stages of growth, phosphorus percentage was greater in the fertilized than the nonfertilized forage, but at final harvest there was a tendency for the reverse to be true. There was a noticeable increase in potassium percentage with some decreases in percentages of calcium and magnesium due to fertilization. The increase in potassium percentage was, however, greater than the decreases in calcium and magnesium percentages so that there was an increase in milliequivalents of total cations.
Solution‐Culture Studies of Nitrite Toxicity to Plants
Authors: Bingham Frank T. , Chapman H. D. , Pugh A. L.
Published: July 2010

Solution‐culture studies of the toxicity of nitrites to plants were undertaken, using several rapidly growing species as indicator plants. Three to four weeks' growth of the test plants in complete nutrient solutions containing graded amounts of nitrous acid (varying nitrite and pH levels) disclosed that growth inhibition in the pH 4.0, 5.0, and 6.0 solutions was related to the undissociated nitrous acid fraction. Experiments with tomato plants suggested that a given concentration of nitrous acid is less injurious to the plant when the nitrogen assimilable by the plant is supplied as nitrate rather than as ammonium.
Factors Affecting the Foliar Absorption of N15 Labeled Urea by Tobacco
Authors: Volk Richard , McAuliffe Clayton
Published: July 2010

Single leaves of Dixie Bright 101 tobacco plants grown in sand culture in the greenhouse were sprayed with N15 labeled urea. Up to 5 mg. of the 15 mg. of nitrogen applied was absorbed by the leaf within 24 hours, and by 6 hours a portion of this nitrogen had been translocated to every plant part. One‐half of the absorbed nitrogen was translocated from the sprayed leaf by 24 hours, chiefly to adjacent leaves, the meristem and root.

The absorption of urea was nearly identical through the upper and lower leaf surfaces. Absorption decreased with increasing vertical leaf position with the exception of the uppermost leaves and irrespective of the leaf area. Leaf maturity had little effect if the relative leaf position was the same. However, very young plants did absorb more nitrogen than more mature plants.

Damaging the epidermal hairs by gentle brushing with a camel's hair brush increased absorption of urea tenfold. Such brushing ruptured the impermeable cutinized layer of the epidermal hairs permitting the urea solution to come into direct contact with the epidermal cell wall.

Absorption of urea over a four hour period was found to be 3 to 10 times greater during the night than during the day. Absorption was also 3 times greater in the morning than in the afternoon. This suggests that internal factors in the leaf which undergo diurnal fluctuations may play an important role in foliar absorption of urea.

The absorption of urea from buffered solutions was a function of both pH and the buffer system used. With phosphate buffer, absorption increased as pH increased from 6 to 8.

Absorption of urea was decreased as the concentration of sucrose in the urea spray solution was increased. A one molar sucrose solution decreased urea absorption by one‐half. It is postulated that sucrose may reduce the absorption of urea by competing with urea during process of absorption, by decreasing the rate of diffusion of urea toward the absorption surface, or by inhibiting urease activity.
Forest Floor in the Piedmont Region of South Carolina
Authors: Metz Louis J.
Published: July 2010

The annual litter fall, weight of forest floor, and organic matter incorporation in the surface foot of mineral soil are reported for three pine, three pine‐hardwood, and three hardwood stands in the South Carolina Piedmont.

The litter fall for the stands averaged 4,400 pounds per acre, of which 3,500 pounds was leaf material. The weight of the forest floor was greatest in the pine stands and least in the hardwoods. The forest floor weight, expressed on a volatile matter basis, ranged from 6,160 pounds per acre in an old hardwood stand to 16,430 pounds in a 40‐year‐old shortleaf pine stand. The organic matter content in the surface foot of mineral soil ranged from 83,550 pounds per acre in the old hardwood stand to 25,780 pounds in a young loblolly pine plantation. The weight of the forest floor and organic matter in the mineral soil show that decomposition is more rapid beneath hardwood stands.

The forest floors are classified as to humus type and the discussion presented shows some practical application of the information to forest management work.
Surface Accumulations of Nitrates and Other Soluble Salts in California Orange Orchards
Authors: Harding Robert B.
Published: July 2010

Information presented shows that in furrow‐irrigated California orange orchards, as much as 3 tons of soluble salts per acre, representing 800 lbs. of nitrogen as well as other necessary plant nutrients, may accumulate in the upper 6 inches of the interfurrow ridges as a result of capillary conduction. These accumulations have little chance of being of benefit to the trees under present cultural practices. Factors controlling the rate of surface concentration of salts are rate of evaporation, amount of irrigation, kind and amount of soluble salts available as source material, type and shape of furrow, and soil texture and profile characteristics. Surface salt concentrations have been shown to be greater in orchards that are not tilled than in those that are tilled.

Laboratory leaching studies indicate that when water is applied to areas of high salt concentration, the initial outflow is not so concentrated as may be suggested by analysis of the saturation extracts. These data also indicate that a considerable amount of water must pass through the soil before any apparent reduction in salinity of the leachate is obtained.

From the information available to date, a number of suggestions are made regarding cultural operations which should be considered in this problem. Further study should be directed toward management practices which will lessen these surface concentrations.
The Effect of Synthetic Conditioners on Some Phases of Soil Structure and Erodibility by Wind
Authors: Chepil W. S.
Published: July 2010

Beginning in 1951, a series of experiments was initiated on several soils for the primary purpose of determining the value of VAMA (a modified vinyl acetate maleic acid compound), and HPAN (a hydrolized polyacrylonitrile), for controlling erosion of soil by wind.

VAMA increased substantially the proportion of water‐stable aggregates in all soils tested and decreased the proportion of fine water‐dispersible particles < 0.02 mm. in diameter. From this standpoint VAMA may be considered a very effective soil aggregating agent. However, the great majority of the water‐stable aggregates formed by VAMA were of the size erodible by wind.

VAMA applied to the surface of the ground, or mixed with the soil, generally increased the crodibility by wind. The soils treated with VAMA were loose and friable and had a granular surface. The untreated soils were more or less cemented together and had a distinctly developed surface crust. The crust was resistant to wind erosion despite its unfavorable characteristics otherwise.

VAMA was beneficial for producing good soil tilth and for increasing soil permeability. Both of these characteristics tend to reduce erosion by water and increase crop yields.

VAMA was incorporated into the soil more conveniently as dust than as spray.

HPAN applied on top of the ground was ineffective in controlling erosion of soil by wind as early as one week after the application. Erosion, in fact, was increased in some cases due to the application of HPAN.
Effect of Rate and Placement of Superphosphate on the Yield and Phosphorus Absorption of Legume Hay
Authors: Lawton K. , Tesar M. B. , Kawin B.
Published: July 2010

A study was undertaken to determine the effect of superphosphate topdressing on the yield and phosphorus content of legume and legume‐grass hay. Radioactive superphosphate containing 20% P2O5 was broadcast in the early spring on established meadows at five locations in central Michigan.

A significant yield response of first cutting hay was obtained on all fields as a result of topdressed applications of 80 and 120 pounds of P2O5per acre. The hay which was thus treated contained appreciably more phosphorus than did that which was grown on untreated plots or where only 40 pounds of P2O5 was applied.

The absorption of fertilizer phosphorus was low in hay grown on two soils and relatively high in hay from the remaining locations. As the rate of broadcast superphosphate increased, the percentage of plant phosphorus derived from fertilizer in forage plants also increased. The recovery of fertilizer phosphorus by first‐cutting hay from two locations was low, but was as high as 15% in hay from the other areas. As the rate of broadcast superphosphate increased, the percentage of recovery of applied phosphorus decreased.

The percentage of phosphorus in hay derived from superphosphate placed at various depths in two soils was related to depth of fertilizer placement. Absorption of fertilizer phosphorus was highest at the surface or 3‐inch depth; intermediate at the 6‐inch depth; and low for the 12‐, 24‐, and 36‐inch placement. In an alfalfa‐bromegrass meadow where the fertilizer was applied broadcast, the bromegrass obtained a greater percentage of its phosphorus from the fertilizer than did alfalfa. However, at the 3‐ and 6‐inch depths, the alfalfa absorbed two to three times as much phosphorus as did the bromegrass.
Characterization of Some Halomorphic Soils and Their Normal Associates in the Yakima Valley
Authors: Anderson James U.
Published: July 2010

A study was made of four soils—Naches, a Brown; Fiander, a Solonetz; and Umapine and Ahtanum, Solonchak soils. These occur in close association in the Yakima River Valley of south central Washington in poorly defined zones which parallel the lower edge of the alluvial fan on which the soils are found. Areas of pure soil types are extremely small. Studies made of transects across soil boundaries indicate that materials from which these soils were formed were heterogeneous, and that soil morphology has been greatly influenced by parent material differences.

Resalinization has occurred to varying degrees since the beginning of irrigation in the Yakima Valley. The concentrations of soluble and exchangeable cations in the soils vary not only between series but also within a series, chiefly as a function of positions on the alluvial fan.
The Physical and Mineralogical Properties of Related Minnesota Prairie Soils
Authors: Arneman Harold F. , McMiller P. R.
Published: July 2010

The morphological, chemical and mineralogical characteristics of soils are to a considerable extent attributable to the amount of water that enters the soil. The Clarion, Nicollet, and Webster soils in south central Minnesota were investigated. These soils are members of a catena developed on calcareous glacial till of Wisconsin age (Mankato substage). Three profiles of each series from widely scattered areas were studied.

The study revealed that the (1) color of the soil is directly related to drainage; (2) there was little or no accumulation of clay in the B horizons of any of the soils; (3) the surface soil of the Clarion series is the most highly weathered horizon as indicated by a relatively low content of apatite and orthoclase, a high content of garnet, and the presence of kaolinite in the coarse clay fraction; (4) the high cation exchange capacity of all soils is not attributed entirely to organic matter but more particularly to the high montmorillonite content of the clay fraction; and (5) the observable and distinguishable properties of the soils of the three series are chiefly morphological rather than chemical or mineralogical.
Transformations of Sawdust in the Course of its Decomposition Under the Influence of Coprinus ephemerus
Authors: Davey Charles B.
Published: July 2010

Sawdusts of jack pine, sugar maple, and red oak were treated with anhydrous ammonia, neutralized with H3PO4, enriched with K2SO4, and inoculated with Coprinus ephemerus. Compost mixtures were prepared in earthenware jars in greenhouse cultures at 2‐week intervals to permit simultaneous analysis of composts at various stages of decomposition.

The results of chromatographic analysis indicated that C. ephemerus is not selective in its sugar utilization, although it consumes hemicellulose somewhat earlier than alpha‐cellulose. A chromatogram of the hydrolysate of C. ephemerus showed almost exclusively glucose.

The course of fermentation of pine and maple sawdust was characterized by a decrease in the cold water extractables and the alcohol‐benzene solubles. Oak sawdust, however, gained in alcohol‐benzene solubles. Both oak and maple sawdust showed an appreciable loss of holocellulose and lignin methoxyls, but a considerable increase in lignin and base exchange capacity. Pine sawdust attained a nearly 100% increase in base exchange capacity but failed to reveal a clear picture of transformations in its structural building blocks. The consistent increase in the base exchange capacity in decomposed sawdust of all types investigated assures the values of the organism in the preparation of soil‐improving organic fertilizers.
Lateral Flow Above a Sloping Water Table
Authors: Luthin James N. , Day Paul R.
Published: July 2010

The lateral movement of water above a water table has been studied under steady‐state conditions. The dependence of the capillary conductivity on soil moisture tension has been considered in making a theoretical analysis of the problem.

Lateral flow was induced in a sand‐filled tank by maintaining a small difference in head between constant reservoirs located on either side of the sand‐filled tank. The experimentally determined values of hydraulic head and quantity of flow were then compared to the theory which considered the variations of capillary conductivity with soil moisture tension. The hydraulic head determined at various points of the flow section in the steady state experiment agreed approximately with values calculated from theory. The flow calculated from knowledge of the capillary and hydraulic conductivities agreed with the measured flow.

The methods of numerical analysis which were used to develop the theory can be applied to other steady‐state flow problems involving variable conductivities.
Laboratory Determination of Infiltration Rates of Disturbed Soil Samples
Authors: Peele T. C. , Beale O. W.
Published: July 2010

A procedure for determining infiltration rates of disturbed soil samples in the laboratory, using simulated rainfall, is described. Data showing the relation of laboratory infiltration rates to those measured on cultivated areas in the field are presented. Comparisons of runoff from natural storms with infiltration rates determined in the laboratory and the field are given for several soil types. The laboratory infiltrometer, the type F field infiltrometer, and infiltration during natural storms placed the different soils in the same order. The usefulness of the laboratory infiltrometer for evaluating the effects of rotations, chemical soil conditioners, and inherent soil properties on infiltration in the surface soil of clean‐cultivated areas is briefly discussed.
The Chemistry of Zinc Added to Soils and Clays
Authors: Nelson J. L. , Melsted S. W.
Published: July 2010

The chemical forms which zinc assumes when added to soils and clays have been investigated, using the isotope dilution technique (with Zn65 as a tracer). After equilibrium, the added zinc was extracted by successive leaching with neutral normal NH4Ac, 2.5% HAc, and 0.1 N HCl. Variables were: (1) time of equilibrium, (2) calcium saturation, (3) amount of zinc added, (4) rate of extraction, and (5) type of clay mineral.

With symmetry additions of zinc and a hydrogen soil system, practically all of the zinc taken up by the soil was replaceable with NH4Ac, whereas in a calcium soil system a part of the zinc could not be replaced with NH4Ac. The portion of the zinc not removed with NH4Ac could be extracted by repeated leaching with dilute HCl. This acid‐soluble form of zinc increased with increasing length of time of contact between the soil and the zinc solution. It apparently did not occupy exchange sites in the soils, since there was no reduction in the base‐exchange capacity of the soil with the formation of the acid‐soluble form. As smaller quantities of zinc were added to these soils and as the amount of time following the addition increased, a higher proportion of the zinc was found in the acid‐soluble form.
Uptake of Molybdenum from Everglades Peat by Several Grasses and by White Clover
Authors: Gammon Nathan , Fiskel J. G. A. , Mourkides G. A.
Published: July 2010

The problem of molybdenum toxicity to livestock in forage grown on Everglades peat, in practice, is met by application of copper to the soil, by copper in the mineral supplement fed to cattle and by copper drenching of severely affected cattle. The present study reports the molybdenum content of several grasses and clover that are grown in the area. Samples of clover from several fields are found to have about the same molybdenum content as the grass herbages. There is considerable variability in the molybdenum content of the different grasses tested on the Everglades peat. Kentucky 31 fescue, Pensacola Bahia, St. Augustine, Pangola and Coastal Bermuda grass, and white clover contained about 0.1 to 0.3 ppm. Mo in pot studies on unlimed peat, and 0.4 to 0.8 ppm. Mo on limed peats under greenhouse conditions. Under field conditions, the molybdenum content of these same herbages was considerably greater. Species taken from corresponding locations showed small variation in molybdenum content during the growing season when the pasture was well established, but initial samples taken at the time of the establishment of the pasture were much higher. On sandy soils, both Pangola grass and clovers showed a much higher molybdenum content for considerable periods after molybdenum fertilization, but no increase in yields. The molybdenum content of clover appears adequate where the soil has been limed. High fertilization of the pastures on peats and mucks high in molybdenum, followed by removal of the hay, and feeding the cattle on low molybdenum areas is suggested both to provide drier forage and to prevent return of the molybdenum to the pasture by manure and urine.