Browse on keywords: fertility organic matter nitrogen
Search results on 10/17/18
690. Bear, F.E.. 1931. Soil management.. J. Wiley, N.Y..
A fairly complete text on soil management - fertility, tillage, organic matter, fertilizers; describes proper plow, moisture content, and depth to improve soil tilth; describes weeds as a potential cover crop; field study in England - free living N fixers input ~44 lb/ac/yr (est.). Azotobacter critical pH = 6.4.
1077. Broadbent, F.E. and F.J. Stevenson. 1966. Organic matter interactions.. Agricultural anhydrous ammonia: technology and use. p. 169-197..
1657. Doughty, J.L., F.D. Cook, and F.G. Warder. 1954. Effect of cultivation on the organic matter and nitrogen of brown soils.. Canadian J. Agr. Sci. 34:406-411.
Over 14 yr of cropping, soils lost 26% of OM and 33% of total N. Only part of the N loss is accounted for by crop removal. Some N is lost by leaching, also some gaseous loss of N other than as ammonia.
2617. Hill, K.W.. 1954. Wheat yields and soil fertility on the Canadian prairies after a half century of farming.. Soil Sci. Soc. Am. Proc. 18:182-184.
T: soil properties X rotation; wheat yields X time
5065. Patten, A.G.. 1982. Comparison of nitrogen and phosphorous flows on an organic and conventional farm.. M.S. Thesis, Dept. of Agronomy and Soils, WSU, Pullman, WA.
Two adjacent farms, one organically managed and the other conventionally managed, located in the Palouse region of eastern WA, were studied for 2 years. Soil organic matter, total N, extractable P, and extractable K tended to be higher in the top 30 cm of soil from the organic farm. Mineral nitrogen in the top 30 cm of soil from the conventional farm was higher than or equal to that of the organic farm. Average long-term changes calculated in soil N and P pools resulted in substantial deficits of 44 and 14 kg/ha/yr, respectively, for the organic farm and 23 and 5 kg/ha/yr for the conventional farm. However, nutrients deficits were not reflected in lower soil N and P levels in the plot area tested on the organic farm as compared to the plot area on the conventional farm.
5632. Ramig, R.E., P.E. Rassmussen, R.R. Allmaras and C.M. Smith.. 1975. Nitrogen - sulfur relations in soft winter wheat. I. Yield response to fertilizer and residual sulfur.. Agronomy J. 67(2):219-223.
This study measured yield response of wheat to S applied with a range of N for the first crop and monitored residual S effects on yields of 3 subsequent crops. Significant N to S relationships were found. The first crop did not respond to S when N was deficient or optimal. Residual S increased straw yield in all crops and grain yield in 1 of 4 trials for the second crop, 3 of 3 trials for the third crop, and 2 of 2 trials for the fourth crop. Wheat response to residual S was influenced by N rates applied to the first wheat crop. High N and S fertilization resulted in early drought and lower yelds. Gradual release of residual S from recent organic matter apparently provided S at a rate adequate for efficient water use and maximum yield. T: Grain and straw yield response to S and N in first through fourth wheat crop following fertilization. The initial and residual effects of S on grain yield of wheat receiving optimum N.
5744. Rasmussen, P.E., R.E. Ramig, R.R. Allmaras and C.M. Smith.. 1975. Nitrogen - sulfur relations in soft white winter wheat. II. Initial and residual effects of sulfur application on nutrient uptake and N/S ratio.. Agronomy J. 67(2):224-228.
This study determined S and N uptake and distribution in soft white winter wheat fertilized with S in combination with deficient, optimum, and excessive N. Residual uptake from 17, 34, and 68 kg of applied S/ha was evaluated in 3 subsequent wheat crops receiving optimum N fertilization. S uptake and concentration in the first crop was proportional to the rate applied, but accumulated primarily in vegetative tissue when present in excess of the amount required for grain protein. Uptake from residual S was lower than from applied S. Grain yield responses to S were poorly correlated with S concentration or N/S ratios in tissue, because of inconsistancy of S accumulation in plant parts and the dominant effect of N on yield. T: Effect of N and S fertilization on S concentration and uptake at 3 stages of growth in a first wheat crop. Effect of residual S on grain yield and S concentration in grain and straw of second, third, and fourth crops. Relationship between S concentration in mature whole plants and grain yield receiving optimum N fertilization.
6001. Russell, J.S. and C.H. Williams. 1982. Biogeochemical interactions of carbon, nitrogen, sulfur, and phosphorus in Australian agroecosystems.. IN: J.R. Freney and I.E. Galbally (eds.). Cycling of C,N,S, and P in terrestrial/aquatic ecosystems..
An excellent review article looking at nutrient cycling and gains and losses over time under different agricultural management. Estimates that over 3 million tons C are tied up in soil organic matter additions each year in Australian farmland. SOM levels are higher now than the native condition under systems that have used a legume pasture in the rotation. There was a generally downward trend in the soil C:N over the first 25 yr of OM accumulation. A WWPP rotation slightly increased SOM, while WWWP decreased it slightly, and fallow systems decreased it significantly. Increases in SOM increased the water-stable aggregates in the soil and improved infiltration. Leguminous pastures had an acidifying effect on the underlying soil.
6028. Salter, R.M. and T.C. Green. 1933. Factors affecting the accumulation and loss of nitrogen and carbon in cropped soils.. J. Am. Soc. of Agron. (now Agronomy J.), 25(9):622-630.
Data show changes in N and C of soils under continuous and rotation cropping at the Ohio Expt. Sta. Study attempts to show differences due to cultural practices vs. crop residues. In a single year, organic carbon changed by: corn - 3.12%, wheat - 1.44%, oats - 1.41%, hay (timothy) in 5 yr rotation - +1.36%, hay (clover) in 3 yr rotation - 3.25%. Corresponding values are given for N, which are relative to OM values. The amount of OM and N on the 5 yr rotation plots after 32 yrs were positively correlated to the total crop production of the plot. Residues from corn were not effective in conserving soil OM and N, wheat was moderate, and oats better. T: Calculated changes in OM of unfertilized soils. Calculated changes in N of unfertilized soils. Relative changes in production in unfertilized soils. Effects of hay crops in two rotations. Effects of manure.