No matter what crop is concerned, plowing the soil is the main agricultural practice. Its importance is well known since many centuries ago: suffices to say that the Romans before Christ already had a theory on plowing the land. Thus, the plow, the oldest agricultural implement, has always attracted the attention of farmers, engineers and people engaged on agricultural mechanics. For this reason, its evolution was remarkable. The study of the plow, under both an agricultural and an econcmic point of view, is of great interest to agricultural mechanica, since on such a kind of research is based the best method of application of the plow. The present paper deals with an experiment carried out to obtain data on the use and effect of plowing as related to different depths of doing it. The soil worked out presented the following characteristics: total sand - 75.7%, clay - 13.5%, silt - 10.8%; hence, it is a sandy soil. Plowing was made at the following depths: 5, 10, 15, 20, 25, and 30 cm. in the first two years; in the third year, another depth was included, that is, 40 cm., which corresponds to an under-plowing. The field trial was conducted with four replicates throughout, plots 50 X 20 m. being used. Corn was planted to find out the effects of the depth of plowing on such a crop. The following conclusions can be drawn: 1. on the experimental conditions, yield was directly proportional to the depth of plowing; in other words, the deeper the plow works, the best is the yield therein obtained; 2. it is therefore suggersted that on soils similar to this experiment's it is advisable to plow deeper than usual; a working depth of 252cm. is recommended. | A aradura é a principal das operações agrícolas para o desenvolvimento das diversas culturas. A sua importância é conhecida desde as mais remotas eras. Assim, os romanos já tinham sua teoria sobre aradura. Desta forma o arado, a mais antiga das máquinas agrícolas, foi sempre motivo de atenção dos agricultores, fabricantes e técnicos em mecânica agrícola. A sua evolução foi bastante grande. O estudo do arado sob o ponto de vista agrícola e econômico, para exata aplicação da máquina, nas diversas condições de solo, é de máximo interêsse para a mecânica agrícola. Assim sendo, para orientar a correta aplicação do arado, o que constitui a presente tese, foi experimentado num solo arenoso, de características mecânicas (areia total 75,7%, argila 13,5 e lôdo 10,8%) a diversas profundidades de aração, (5, 10, 15, 20, 25, 30cm), plantando nos mesmos, milho para verificar o efeito na produção. Num terceiro ano de experiência, foi realizada uma experiência a mais, isto é, uma subsolagem a 40 cm. Foi plantado milho nos canteiros assim trabalhados, e que eram repetidos em número de 4, porque o milho é uma cultura muito frequente e de fácil contrôle. As experiências com as diversas profundidades, demostraram que nestas condições de solo, à medida que aumenta a profundidade, aumenta também a produção. Do exposto, conclui-se pela experimentação que para esse solo é aconselhável: fazer o arado trabalhar a maior profundidade em que comumente é empregado até o limite de 25 cm, que foi o valor máximo examinado.

Subsidence of peat and muck soils in the Everglades has been observed and recorded since 1914. An average subsidence rate of approximately 1¼ inches per year was found by periodic survey over 15 profile lines. Water-table test plots showed that loss of peat soil depended directly upon depth of drainage. The relation is expressed by the equation , in which x equals subsidence rate in inches per year and y equals average depth of water table in inches. This rate is about double that found in similar studies by investigators in Indiana. Isopachous charts showing the original depth of the peat soils in 1912, in 1925, and in 1950 are shown for the agricultural area near Lake Okeechobee and projected to the year A.D. 2000. Steps which will minimize soil losses are outlined.

Though surface active agents gain access to soil through agricultural sprays, little is known of their persistence and biological effects. Studies were made with the following surface active agents: (1) Tween 80 (non-ionic); (2) Ceepryn (cationic); (3) Nacconol NRSF (anionic). Tween 80 decomposed rapidly in soil. Ceepryn was also decomposed following an initial lag period. Nacconol NRSF resisted decomposition. Tween 80 had little or no undesirable biological effects in soil. At very high levels, Ceepryn reduced the total number of micro-organisms in soil and inhibited nitrification. Nacconol NRSF was more detrimental than Ceepryn. It is suggested that the toxicity of ionic surface active agents is reduced as a result of adsorption by the colloidal fraction of soil. The cationic compound was adsorbed to a greater extent than the anionic compound.

The American Seed Trade Association photographs contain matted 24"x15" (inc. mat) group photographs from various United States seed trade association meetings. People in photographs are not identified. Seed trade associations represented are as follows: American Seed Trade Association (1924, 1925, 1928, 1932, 1937, 1938, 1940, 1941, 1951, 1952), Atlantic Seedmen's Association (1956), California Seed Association (1949), Pacific Seedmen's Association (1943), and Western Seedmen's Association (1924, 1931, 1932, 1937, 1939, 1941, 1952, 1953).

"This book is not so much a history of agriculture in the past fifty years as a history of the men and women who directly or indirectly built the agricultural structure we know and have today. It is an attempt to look backwards along the road we have traveled and to think with you about some of the astonishing changes that have entirely altered our lives from what they were a few brief years ago. Why write such a book? Because the only way to attack the problems of the present and the future is by studying those of the past. History does repeat itself, not in details but in principles. For human nature never changes, and humans make history. That is why I like to remember the men who made history, particularly the rural history of the past half century. That history has never been written. Because the first 25 years of this century, that is from 1900 to 1925, set the stage and the atmosphere for all the changes that have come since, in the early chapters of thsi book I have tried to give you the feeling and the understanding of what life was like durin gthose first 25 years. Some knowledge of the way rural people worked and lived in those yars written from the personal experience of a country boy and man, may help the reader to an understanding of the great changes that have come since." -- From the introduction.

On behalf of the PEPSU Government I consider it a great privilege to ex- tend to you a most cordial welcome. It must have caused you some inconveniencc to travel all the way to Patiala capital o our tiny State of PEPSU. In particular I have been feeling quite concerned aboui our friends from the South, who, unfor tunately for us, are not accustomed to extremely dry and cold weather of the North I hope that your stay here will be a pleasan• one as we are very proud to have beer afforded the opportunity of arranging fo this session of the Soil Conservation SocietJ of India, and consider it a source of privileg to be in a position to witness the deliberation: of such a representative and distinguishec gathering in Patiala. Such occasions bring to our mind vastness and greatness of our country, and it is always such a source of joy and prid( to see that so many different cultures, lan• guages and traditions are uniting under flag, and trying to serve one common cause — our motherland. Never before in all history has one man paved the way of the united •rogress of such a multitude of humanity as our Nation's Father the Mahatma; and never in history has a leader held such a mass of humanity together as our beloved leader Pandit Nehru.

This paper discusses the technique and the procedure adopted to carry out a systematic survey relating to the deve- lopment and conservation of the water resources of South Bihar and Chota Nagpur in Bihar State, for irrigation, power and soil conservation on the basis of river valley basins. The technique outlined will perhaps be typical of the work which may be done in other States in India for complete assessment and development of the water resources of the country.The total ground area of Bihar State south of the Ganges is about 50,000 sq. miles. It has been divided roughly into three sectors, the north, the middle and the south for the purpose of planning for irrigation, hydro- electric power and soil conservation. The Middle Sector is roughly the area of the Damodar Valley which is drained by the river Damodar and its tributaries. The area of the Damodar Valley is about 7,000 sq. miles. The development of this valley from the point of view of conservation of soil and water is the function of the Damodar Valley Corporation which is an autonomous body. Four major storage reservoirs have been planned in this valley to provide controlled storage of million acre/ft. With this storage, an area of about I million acres in the State of West Bengal will be provided with controlled irrigation, and give flood protection for the lower valley in that State. So far as Bihar State is concerned, no irriga- tion is possible by utilizing the storage of the 4 reservoirs though all the reservoirs are situated in this State. The installed hydro- electric power capacity is 124 Megawatts, which will benefit Bihar State also.