Premium
The Effect of Straw and Nitrogen on the Yield and Quantity of Nitrogen Fixed by Soybeans 1
Author(s) -
Pinck L. A.,
Allison F. E.,
Gaddy V. L.
Publication year - 1946
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1946.00021962003800050005x
Subject(s) - chemist , straw , yield (engineering) , nitrogen , mathematics , chemistry , library science , computer science , materials science , organic chemistry , metallurgy , inorganic chemistry
O of the most practical methods of utilizing undecomposed carbonaceous crop residues for the maintenance of soil organic matter is to seed the soil to legumes after returning the plant residues to the soil. Properly inoculated leguminous plants usually make about the same amount of growth when grown on a nitr6gen-free medium as when abundantly supplied with combined nitrogen. An exception occurs in case nitrogen fixation fails to start promptly in the young seedlings. This "hunger condition" is likely to occur in soybeans and cowpeas, especially under conditions of high light intensity, but is less often observed with other legumes. In spite of the obvious advantages of planting legumes subsequent to the addition of straw and similar materials to a soil, this practice has not been especially emphasized, and very few quantitative data have been published that show to what extent the crop yields and nitrogen fixation are affected by the presence of the nitrogen-deficient plant materials. Under greenhouse conditions, Thornton (5) a observed that the addition of fresh chaff to soil increased the number of nodules on soybeans and broad beans. In the absence of nodules, the chaff depressed plant growth but well-nodulated plants showed no such effect. In field experiments, uhdecomposed chaff increased the growth of broad beans and of wheat grown the following year. Demidenko and Timofeieva (2) obtained similar results with soybeans and p6as. Straw increased the weight of the nodules and the crop, and also the nitrogen content. In greenhouse xperiments with peas, Vandecaveye and Puller (6) observed that ~o tons of straw per acre had no harmful effect upon germination, nodulation, or yields of dry matter. Jensen (3), on the other hand, obtained almost no growth of lucerne in sand cultures following an application of 5 tons of straw even though the sand was well inocul~ited with Rhizobium. Greenhouse studies designed to furnish practical information on the best method of utilizing crop residues in a legume cropping system are reported below. It was not only desired to determine the effect of straw upon yields and nitrogen fixation by legumes, but also the effect of simultaneous additions of various quantities of commercial nitrogen with the straw.