Comparisons of laboratory and greenhouse indexes of nutrient availability in soils

Accurate indexes of the availability to plants of nutrients in soils are needed for comparisons of different chemical tests to determine which tests should be used in the laboratory for any given group of soils. This study was conducted to develop and improve techniques for obtaining such standard indexes of nutrient availability to plants. Emphasis was placed on: (a) treating the soil similarly (or uniformly) before testing in the greenhouse and laboratory and (b) avoiding treatments during the greenhouse cropping that might influence the availability of the soil nutrient being tested. The greenhouse technique involved growing plants on undried samples of 24 different soils. Water was added directly to the soils during plant growth, but nutrients other than the one being tested were added by a method which minimized contact with the soil

Comparisons of laboratory and greenhouse indexes of nutrient availability in soils

Accurate indexes of the availability to plants of nutrients in soils are needed for comparisons of different chemical tests to determine which tests should be used in the laboratory for any given group of soils. This study was conducted to develop and improve techniques for obtaining such standard indexes of nutrient availability to plants. Emphasis was placed on: (a) treating the soil similarly (or uniformly) before testing in the greenhouse and laboratory and (b) avoiding treatments during the greenhouse cropping that might influence the availability of the soil nutrient being tested. The greenhouse technique involved growing plants on undried samples of 24 different soils. Water was added directly to the soils during plant growth, but nutrients other than the one being tested were added by a method which minimized contact with the soil.</p

Agricultural Research Bulletins, Nos. 522-555

Volume 35, Bulletins 522-555. (522) Role of Nitrogen, Phosphorus and Potassium Fertilizers in Continuous Corn Culture on Nicollet and Webster Soils; (523) Solving Tile Drainage Problems by Using Model Data; (524) Soybean Yields and Plant Composition as Affected by Phosphorus and Potassium Fertilizers; (525) Conservation Reserve in South-Central Iowa; (526) Application of Distributed Lag and Autocorrelated Error Models to Short-Run Demand Analysis; (527) Cost Functions in Relation to Farm Size and Machinery Technology in Southern Iowa; (528) Family Decision-Making and Role Patterns Among Iowa Farm and Nonfarm Families; (529) Milk Production Functions in Relation to Feed Inputs, Cow Characteristics and Environmental Conditions; (530) Regional Intersectoral Relations and Demand Projections with Emphasis on the Feed-Livestock Economy of the North Central States; (531) Effect of Feed-Grain Output Controls on Resource Uses and Values in Northern and Southern Iowa; (532) Influence of Nitrogen and Phosphorus Fertilization on Nutrient Status and Profitability of Bromegrass on Ida Soils: I. Effect on Yields and Economics of Use, II. Effect on Chemical Composition of Bromegrass; (533) Experiments with Autoregressive Error Estimation; (534) Farm Migrants to the City: A Comparison of the Status, Achievement, Community and Family Relations of Farm Migrants with Urban Migrants and Urban Natives in Des Moines, Iowa; (535) Relationship of Tree Survival and Yield to Coal-Spoil Characteristics; (536) Effects of Migration on the Open-Country Population of Iowa, 1950-61; (537) Normative Supply Functions and Optimum Farm Plans for Northeaster Iowa; (538) Programming Analysis of Interregional Competition and Surplus Capacity of American Agriculture; (538) Projections of U. S. Agricultural Capacity and Interregional Adjustments in Production and Land Use with Spatial Programming Models; (539) Yield Response of Corn in a Planosol Soil to Subsurface Drainage with Variable Tile Spacings; (541) Evaluation of Alternative market Organizations in a Simulated Livestock-Meat Economy; (542) Exploratory Econometric Study of Dairy Bargaining Cooperatives; (543) Fertilizer Production Functions from Experimental Data with Associated Supply and Demand Relationships; (544) Comparisons of Laboratory and Greenhouse Indexes of Nutrient Availability in Soils; (545) Aggregate Investment Demand for Farm Buildings: A National, Regional and State Time-Series Analysis; (546) Characteristics of Operator Entry Into Iowa Farming, 1959-60; (547) Coordinated Egg Production and marketing in the North Central States: V. Least-Cost Egg Marketing Organization Under Alternative Production Patterns; (548) Simulation of Regional Product and Income with Emphasis on Iowa, 1954-1974; (549) Postglacial Environments in Relation to Landscape and Soils on the Cary Drift, Iowa; (550) Analysis of Ranking of Dairy Bargaining Cooperative Objectives; (551) Hyperactivity, Blood Lactic Acid and Mortality in Channel Catfish; (552) Selection in Zea mays L. by Inbred Line Appearance and Testcross Performance in Low and High Plant Densities; (553) Dissemination of Farm Market News and Its Importance in Decision-Making; (554) Fertilizer Production Functions in Relation to Weather, Location, Soil and Crop Variables; (555) Acreage Response and Production Supply Functions for Soybeans</p