A Fertility Program for Growing Vegetables - With Information on Soil, Manures and Use of Chemicals , livre ebook

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34 pages

English

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“A Fertility Program for Growing Vegetables” is a classic guide to growing vegetables focusing on fertilisers. It looks at what fertilisers should be used in which circumstances, offering advice and scientific information for the farmer or Gardner. Although old, this volume contains timeless information that will be of considerable utility to anyone with a practical interest in vegetable production. Contents include: “Soil Science”, “Fertility Program”, “Soil Organic Matter”, “Animal Manures”, “Green Manure”, “Use Of Lime”, “Fertilizer Materials”, “Functions Of Fertilizers”, “Complete Fertilizers”, “Typical Fertility Programs”, “Applying Fertilizers”, etc. Many vintage books such as this are increasingly scarce and expensive. It is with this in mind that we are republishing this volume now in an affordable, modern, high-quality edition complete with a specially-commissioned new introduction on soil science.

Sujets

Jardinage

Techniques de jardinage

Potager

Agronomie

Agronomy for Sustainable Development

Agriculture

Engineering

Technology

Agronomy

Sciences et techniques

Soil Science

Informations

Publié par	Read Books Ltd.
Date de parution	26 octobre 2011
Nombre de lectures	0
EAN13	9781447491125
Langue	English
Poids de l'ouvrage	1 Mo

Informations légales : prix de location à la page 0,0350€. Cette information est donnée uniquement à titre indicatif conformément à la législation en vigueur.

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A Fertility Program for Growing Vegetables
With Information on Soil, Manures and Use of Chemicals
By
Ralph L. Watts
Copyright 2011 Read Books Ltd.
This book is copyright and may not be reproduced or copied in any way without the express permission of the publisher in writing
British Library Cataloguing-in-Publication Data
A catalogue record for this book is available from the British Library
Contents
Soil Organic Matter
Animal Manures
Green Manures
Use of Lime
Functions of Fertilizers
Fertilizer Materials
Complete Fertilizers
Applying Fertilizers
Typical Fertility Programs
FERTILITY PROGRAM
C ONSIDERING the vegetable farm as a factory the soil is the machine most likely to limit or expand the output. The cost of producing a bushel or ton may be doubled or halved with ordinary-not extreme-decreases or increases in yields. Fortunately the soil is exceedingly responsive. The grower who keeps it working at a high level of efficiency is practically assured of larger, more economical yields than the average, often with little or no increase in expenditure of money or labor to the acre. No other factor is so effective as large yields in securing a profit under the competitive market conditions that usually prevail.
The dependence of low unit costs on good crops, the naturally intricate relationships of soil management, and the particular problems involved in the intensive cropping and lavish fertilization common to the vegetable growing business justify rather detailed consideration of the fertility program.
The three main phases of soil management are systematic replenishment of organic matter, suitable liming, and balanced fertilization. Good drainage and proper tillage are assumed.
SOIL ORGANIC MATTER
From ancient times observing farmers have recognized the important benefits of an abundance of organic matter in the soil. Regular and frequent addition of organic matter to the soil is the foundation of the fertility program. This is especially true in vegetable growing because intensive tillage accelerates the decomposition and depletion of organic matter; and most vegetable crops are very sensitive to the unfavorable soil conditions usually associated with its deficiency. Failure to supply adequate amounts of organic matter is certain to result in reduced yields and invites crop failures.
Effects of soil organic matter. -In simple language, soil organic matter may be said to have four general effects: (1) to increase the absorptive capacity; (2) to improve the physical condition; (3) to stimulate biochemical activity; (4) to supply nutrients.
Important increases in the absorptive capacity of mineral soils may be accomplished by incorporating liberal quantities of organic matter. Great reserves of moisture are required for uninterrupted growth and large yields of high quality vegetables. Well decomposed organic matter has a very high absorptive capacity, will hold approximately seven or eight times as much water as an equal weight of sand and four times as much as a typical clay. The important benefits of high absorptive capacity include also the ability to retain relatively large quantities of nutrient materials and to decrease thereby the losses that occur by leaching.
The effect of organic matter in improving the physical condition of the soil is particularly notable on heavy loam or clay types. With plenty of organic matter these soils are less plastic; they more readily assume and maintain a granulated structure, tillage operations require less power and labor, the soil remains friable under greater extremes of moisture, and there is less packing, baking, or crusting when dashing or prolonged rains occur or crops must be harvested during wet seasons. Greater permeability of such soils is conducive to rapid absorption of rainfall with consequent reduction in run-off and erosion.
In sandy soils organic matter serves as a binder and supplies more body. Erosion from wind or water is reduced by the presence of fibrous material. Through its combined influences on absorptive capacity and physical condition, organic matter in abundance ameliorates the effects of excessive rainfall as well as drought on all types of soils. Organic matter darkens the color of soil and enables it to warm quickly and absorb more heat.
Readily decomposable organic matter stimulates favorable activities of bacteria, other soil organisms, and chemical processes. Vast amounts of organic matter are required to furnish energy and food for the work of the various soil organisms; it also promotes their activity by improving the aeration of the soil and providing conditions favorable for rapid percolation or distribution of water. In consequence decay rapidly breaks down animal manures or plant residues in the soil and from these releases essential food elements that become available to the growing crops. In addition, the unavailable reserves of minerals in the soil are attacked and progressively converted into available forms, by the action of organic acids that are most abundant in the soil solution when decomposition processes are active. At the same time carbon dioxide escapes to the atmosphere where some of it is used by the new generation of plants. In short, active organic matter in the soil feeds the growing crops by decomposing old plant and animal substances and by converting some of the raw materials to available forms.
Certain valuable constituents of fertilizers are converted to unavailable forms less rapidly in soils that are well supplied with organic matter. Such soils are characterized by greater resistance to factors which may increase acidity, and by ability to produce good crops within a wider range of reaction than is possible on highly mineral soils. There is less tendency toward injury from fertilizers placed very near to roots or seeds.
The effects of active organic matter in supplying nutrients, as indicated in the preceding paragraph, occur directly by decomposition of organic residues and indirectly by reaction of certain byproducts upon raw materials. The grower s problem is to supply adequate amounts of suitable organic matter so that decomposition, as the growing season advances, may progressively evolve available nutrients more or less in accordance with needs of the developing crop. Source of the material, provided its amount and character are suitable, is of secondary importance, a matter of convenience and economy. The principal available sources are animal manures, green manures, and crop residues. The effect of any particular application of organic matter, however, is determined mainly by the nitrogen-carbon ratio of the material and also by the fertility level of the soil.
The nitrogen-carbon ratio .-Experienced growers know that good stable manure or a succulent green manure usually produces flourishing, dark-green plants, whereas the same soil with much strawy material plowed under near the time of planting is likely to support only weak, yellow growth for some time, unless fertilizer nitrogen is supplied.
In the first case, the organic material is relatively rich in nitrogen, the ratio being one to about 20 or 30 of carbon. Decomposition proceeds rapidly with comparatively slight demand for additional nitrogen, and nitrogen soon becomes available for the crop.
With the strawy material-mature green manure, dry fodder or straw-the nitrogen-carbon ratio may be as wide as one to 40, one to 80 or more. Carbon, the energy factor, is added to the soil in great excess, creating an enormous microbial demand for nitrogen. With the supply insufficient, decomposition proceeds slowly, excess carbon is gradually converted to carbon dioxide, and the supply of nitrogen available for the crop remains depressed until the ratio has been narrowed. In practice this can be accomplished by allowing considerable time before planting the next crop, or by applying fertilizer nitrogen with the highly carbonaceous materials, or to the crop, or to both as circumstances may indicate.
It may be emphasized that the food requirements of soil microorganisms and higher plants are similar and sometimes come into direct competition. In such cases microbial demand definitely and successfully asserts priority, occasionally with detriment to the crop. The grower s interest is to arrange for the needs of both, either by avoiding conflict or by providing nutrients.
The nitrogen-carbon relationships of the soil are of practical interest to the vegetable grower in another connection. Inasmuch as microbial activity strongly tends to reduce the nitrogen-carbon ratio to the normal status of one to about 10 or 12 it is apparent that the amount of humus finally remaining in the soil must be in rather direct proportion to the supply of nitrogen. Thus inclusion of fertilizer nitrogen with strawy materials which are added to the soil not only overcomes the difficulties of nitrate depression but also secures less wasteful utilization of the carbon, a larger building-up of humus. By such means the grower may overcome some of the objectionable effects of returning resistant material to the soil, whether it is done intentionally to secure greater and more prolonged loosening effect or on account of unavoidable overgrowth of a green manure crop. Rates of application are considered later (p. 89).
It may be added that calcium, lime, is second only to nitrogen in probability of deficiency for the most active decomposition. It should be included with the application of nitrogen unless the supply in the soil is known to be at a good level.
ANIMAL MANURES
Importance of manures .-It is well known that successful vegetable growers in all parts of the world, with all kinds of crops and soils, have in many cases placed their entire dependence upon animal manures. Market gardeners with limited acreage are especially dependent upon animal manure, because intensive planting schedules leave little or no interval between crops for t