Using greenhouse pot techniques, 32 drilling mud components were tested to see if, at a high rate of addition, they reduced plant growth. Green beans and sweet corn were the test plants. The excellent black, silt loam, slightly acidic, uncultivated Dagor soil (Cumulic Haploxeroll) was used for most tests. Rates used were considered to be abnormal level (high rate) and usual (low rate) amounts that might be added in commonly used drilling muds. Drilling mud components that caused no observable or statistically significant reductions of plant yield are the following: Super Visbestos, (Asbestos), asphalt, Ben-Ex (a vinyl acetate and maleic anhydride copolymer), bentonite, Cypan (sodium polyacrylate), DME (ethoxylated nonyl phenol), Super Lube Flow (gilsonite), paraformaldehyde, Separan-AP- 273 (Dow-made, Shell-supplied polymer), sodium acid pyrophosphate, and sodium carboxymethyl cellulose. Drilling mud components that barely caused a statistical significant (5 percent level) reduction in yield for only one of the two plant species when added to the soil only and, therefore, is of questionable hazard to plant growth are the following: Barite (BaSO4), Desco (modified tannin), Drillaid 412 (a filming amine), Drillaid 405 (diesel oil replacement), Kelzan-XC (a xanthan gum), Pipe dope, Lingo (lignite), Soltex (sulfonated asphalt?), and Witconnate 1840 (sulfonated tall oil). Drilling mud components causing significant reduction in plant growth mostly at only the high addition rates to soil-mud mixtures are the following: Desco (modified tannin?), Dextrid (a non-fermenting starch), pregelatinized starch, Q-Broxin (an iron chromelignosulfonate), Gendril Thik (guar gum), and Kwik-Seal. The most severe reductions in plant growth were caused by the following materials: Sodium hydroxide at the high rate (which was used in the soil-mud mixture with calcium lignosulfonate and with lignite), diesel oil and potassium chloride at both rates. The latter salt completely inhibited plant germination. Probable causes for plant growth reductions, photographic and visual records, and a discussion of the results is presented in some detail.

The effect of particle size distribution of suspended sediment vii upon a turbidity reading at a known concentration has been relatively quantified for stream bank materials on the Moccasin Basin - North Fork Fish Creek (MB-NFFC) Watershed, located in northwestern Wyoming. As expected, an increase in the median particle size in suspension results in a decrease of turbidity at a given concentration. The relationship derived correlates the particle size distribution of a chemically dispersed stream-bank material sample, with the Coefficient of Fineness for a mechanically dispersed portion of the sample.

A lead sensitive indicator electrode was constructed with a 70 percent lead and 30 percent mercury amalgam billet. Sulfate concentrations in pure solutions, natural waters, and soil saturation extracts were determined potentiometrically using the lead-mercury amalgam indicator electrode and a standard calomel reference electrode. Sulfate concentrations over the range 0.4 to 20 milliequivalents sulfate per liter were determined with an automatic titrator and compared to a turbidimetric method for accuracy and precision. The values obtained by the two methods from twelve saturation extracts and three subsurface drainage waters were not significantly different and the potentiometric method was generally more precise. The automatic sulfate titration method has the advantages of increased sensitivity and speed.

Knowledge of water and salt movement in soils is necessary for development of a management scheme for controlling the quality of irrigation return flow. A computer model was developed to predict the distribution of water and salts in the root zone under varying initial and boundary conditions. The model consists of water flow and salt flow sub-models. The water flow sub-model considers the numerical approximation of the general water flow equation with modification for water loss by evapotranspiration (and thus root extraction). The salt flow sub-model considers the mass flow of salts, chemical exchange, precipitation or dissolution of CaCO3, and CaSO4, and formation of undissociated Ca and Mg sulphate. The model was tested under laboratory and field conditions by comparing predicted values with experimental measurements. Satisfactory agreement was noted for the water content distribution in almost all the experiments. The model yielded approximately correct values of total salt distribution in the field and one of the column experiments. The agreement between the measured and predicted values for the two other column experiments was poor. The poor agreement seems to result from the irregular dissolution of the applied powdered salts. The distribution of individual ions was not accurately predicted by the model. The disagreement between the predicted and measured values was large at high salt concentration. Complex ion formation, insufficient description of exchange and activity coefficients at high salt concentration are suggested for this lack of agreement. Further development and field testing of the model are needed.

Chlorosis of plants from a lack of available iron is one of the most common plant nutrient problems of the calcareous soils of the west. The disease is characterized by a yellowing of the plant leaves and is accompanied, in severe cases, by a partial root death and premature defoliation (3). In addition to reducing growth, the disease greatly reduces the quality and yield of plants. Many types of plants are affected by iron chlorosis. In Hawaii and Porto Rico rice, sugar cane and pineapple are susceptible, while in California and Arizona, citrus trees are seriously affected. In Utah apples, peaches, plums, prunes, apricots, pears, grapes, raspberries and many ornamental plants are affected (27). The problem of iron chlorosis, therefore, is of great importance to agriculture in the west. Chlorosis has been studied for more than one hundred and fifty years, but until recently, little progress has been made toward finding the solution to the problem. Although these past studies have not solved the problem of iron chlorosis, they have shown many factors to be closely related to the occurrence of the disease. These factors include an unbalanced ratio of available manganese to iron in the growth medium (9, 23, 29); chlorotic leaves are high in potassium, nitrogen in the form of ammonia (21), and in ferric iron and are low in total calcium and ferrous iron in comparison with green leaves (12, 13, 14, 17, 25, 26). The climatic factors of light, soil temperature and soil moisture also appear to be of fundamental importance in chlorosis. It is a common observation that fruit trees are more chlorotic during the early spring when the temperature of the soil is low and the moisture level high. Many investigators have noted that chlorosis tends to be most severe in the poorly drained portions of fruit orchards when water tends to accumulate. However, the work on the affect of climatic conditions on chlorosis has been limited largely to observations. The purpose of this investigation was to study, under controlled conditions, the effect of light, soil temperature and soil moisture on a lime-induced chlorosis.

In soil science we shall always be confronted with reactions in soils that involve Ca. Early recognition of this led to experimentation in this area. Due to the fact that Ca deficiency is most common in acid soils, the majority of the experimentation has in the past been largely confined to acid soils and their soil-Ca-plant relationships. There has been relatively little research done with Ca and its availability problems associated with alkaline or sodic soils.

High bicarbonate-soluble phosphorus (P) in some Utah subsoils may affect the validity of fertilizer recommendations based on plow layer samples. The primary objective of this experiment was to determine the proportion of plant P derived from subsoils at typical Utah soil P levels and soil temperatures. A calcareous soil very low in bicarbonate-soluble P was treated with various amounts of P and packed into deep pots to provide 24 centimeters of "topsoil" and 27 centimeters of "subsoil". Water baths in a growth chamber were used to control soil temperatures at 14 centigrade and 20 centigrade. Light, air temperature and humidity were varied. The treated soils were analyzed for NaHCO3-P before and after cropping, and changes were related to plant P uptake. At a topsoil NaHCO3-P level of 17 parts per million, subsoil apparently contributed no more than ten percent of the plant P in the harvested tops unless subsoil P was greater than five parts per million. At lower levels of topsoil P, subsoil P became more important. When topsoil P was five parts per million or less, 20 to 67 percent of the plant P came from the subsoils.

A model has been developed that predicts spring wheat grain and dry matter yield. Preliminary tests show very favorable results when predicting grain yield in two different climatic regimes, one being a dryland and another being an irrigated area. The strenghts of the model lie in its simplicity, relatively available input data, and low computer processing time cost. Weakness of the model stem from the assumptions that allow its simplicity. The basic assumption in the model is that grain and dry matter yield can be related to the ratio of actual to potential transpiration, computed for each of five phenological stages. Actual and potential evapotranspiration, transpiration, and soil evaporation are obtained in the model by numerical operations on a potential evapotranspiration/potential soil evaporation array obtained by empirical formulae or pan data, and a modified crop coefficient. Soil water status is monitored in the model by taking into account the balance of irrigation, drainage, precipitation, soil water storage and evapotranspiration. Phenological data is computed by a simple numerical formula utilizing maximum and minimum temperatures during the season. Good agreement was found in comparing predicted versus actual heading date for four varieties over four different years. A field study was carried out to aid in model calibration and testing. A continuous variable plot design, with two replications of each of five spring wheat varieties (two soft whit spring wheats and three hard red spring wheats)> This allowed a large number of data points to be measured that related yield to many water levels within the soil. Although this design leads to difficulties in classical statistical analysis, it was shown to be especially useful in calibration of a model of the type shown herein.

Many factors that influence the growth and quality of sugar beets behave in one way under one set of conditions and in quite another under other conditions. Consequently, these factors should be considered together under a dynamic situation to find their interrelations and their influence on sugar beet yield. This study is a statistical analysis of the interaction of fertilizer and soil moisture potential with the yield of sugar beets grown in a crop rotation under different regimes of irrigation conducted over a period of seven years. The data are available for the years 1949 through 1956, from an intensive field experiment conducted under Western Regional Research Project W-29, entitled Soil-Water-Plant Relations under Irrigation. There is need of a complete statistical analysis of third order interaction for the whole cultural rotation. This third order interaction has been examined for the sugar beet crop grown in the seven years of the general cultural rotation, which includes peas, first year alfalfa, second year alfalfa, potatoes, and sugar beets.

This era has been termed the atomic or space age. The greatest concern of most people seems to be centered around survival from the destruction and suffering that might be caused by atomic and nuclear weapons. However, along with this, the world is confronted with perhaps a greater disaster--a potential calamity seldom realized by most people, yet a problem which grows more serious in the world each year--a tragedy which would probably be worse than destruction from nuclear weapons. This encroaching catastrophe is starvation. Even today the majority of the people in the world do not have enough food. Each year the acreage of fertile, productive land decreases because of expanding populations, misuse and the extinsive cropping of many years. As time proceeds, agriculturalists will be required to produce more food with less land resources. Undoubtedly, agricultural scientists will be confronted with greater challenges. Many of these problems will require extensive "basic" research. Now, while food in America is plentiful, seems the proper time to perform this basic research and prepare for the challenges that are going to come. Since much of the world land area is semi-arid, the limiting factor in food production is water. There is an urgent need to use irrigation water more efficiently. In order to do this, more basic information concerning water-growth relations in the soil-plant-atmosphere system is needed. Water movement in the plant element of the system is perhaps the least understood. This classical problem has been extensively studied, yet many important problems still exist. The knowledge in many areas is a scarce and contradictory. Basic research and investigation must be continued. this investigation was a plant-water relations study with the purpose of obtaining basic knowledge about the processes and phenomena involved in water transport through plants. The location and magnitude of the resistance to water flow in plants and the effect of temperature on water movement in plant tissue were the two aspects of water flow investigated. Other more minor subjects of study included: (a) water transport and the effect of mechanical suction, and (b) the correlation of water movement in plants with various measurements of plant response.