Field study with rock phosphate and superphosphate 1952 to 1990 and dissolution of rock phosphate in silage leachate
Choudhary, Manilal
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/23361
Description
Title
Field study with rock phosphate and superphosphate 1952 to 1990 and dissolution of rock phosphate in silage leachate
Author(s)
Choudhary, Manilal
Issue Date
1991
Doctoral Committee Chair(s)
Peck, Theodore R.
Department of Study
Agronomy
Discipline
Agronomy
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Agriculture, Agronomy
Agriculture, General
Language
eng
Abstract
"In a long term fertility trial conducted in northern Illinois, agronomic and economic effectiveness of rock phosphate (RP) was compared with super phosphate (SP) on crops consisting of oats-alfalfa (hay)-corn-corn (rotation ""A"") and corn-soybean (rotation ""B""). Phosphorus applications ranged from 0 to 80 pounds P$\sb2$O$\sb5$/a. Agronomically, rotation ""B"" responded better than rotation ""A"". Eighty pounds of SP P$\sb2$O$\sb5$/a gave the highest yield in both rotations. In rotation ""A"" alfalfa (hay) and oats produced the highest and lowest yields, respectively. Corn yields were more than twice as high as those for soybeans in rotation ""B"". Corn yields were increased by 800 pounds/a at different P treatments when corn was planted following alfalfa (hay) as compared to continuous corn. In rotation ""B"", corn yields were increased by 2500 pounds/a compared to corn yields in rotation ""A"". Treatments had significant effects on crop yields; a square-root-quadratic model gave the best fit for both rotations. Gross profit was found to be higher for rotation ""B"" than rotation ""A"". By comparing the net present value for 16 years 80 pounds RP P$\sb2$O$\sb5$/a gave the highest value ($1958/a) in rotation ``A'', whereas a combination of 20 pounds RP P$ sb2$O$ sb5$ and 40 pounds SP P$ sb2$O$ sb5$/a brought the highest value (\$2638/a) in rotation ""B"". The optimum economic doses at typical market price ratio ($P$ sb2$O$ sb5$/\$ crop) were found to be 60 and 35 pounds P$\sb2$O$\sb5$/a/year through SP and RP, respectively for corn and 30-35 pounds P$\sb2$O$\sb5$/a/year either through RP or SP for soybean. Soil available P and adsorbed P were found to be higher with SP than RP treatments and were related to amount of P applied. Increase in total P due to RP and SP treatments was accounted for by increase in different inorganic P fractions. Al-P was highly correlated with available P. There was a good agreement between total P obtained by soil test and P calculated as the difference between total P (initial soil total P plus Fertilizer P) and crop removal. Low moisture corn silage leachate effectively dissolved RP because of its high butyric content, but this results in poor quality."
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
