Browse on keywords: fertility wheat residue
Search results on 03/24/19
9569. Cochran, V.L., L.F. Elliott and R.I. Papendick. 1980. Carbon and nitrogen movement from surface-applied wheat straw.. Soil Science Soc. Am. J. 44:978-982..
The N immobilization potential of surface-applied wheat straw as compared with incorporated straw was evaluated in the laboratotory with soil columns. The columns were leached weekly and C and N content of the leachate was determined. Leachate C/N ratios for straw alone exceeded 20:1 on several occasions and reached a maximum of 56, indicating a potential for N immobilization. Less than 5% of the total C in the straw was recovered in the leachates, providing an inmobilizatoin potential of <5 kg N//ha. Leachate C/N ratios from 1-, 2-, and 4-cm deep soil columns with surface-applied wheaat straw and no ferilizer N ranged up to 55:1; 30:1 and 22:1, respectively, while the highest leachate C/N ratio from the 4-cm mixed straw treatment was 30:1. A significant percentage of mineralized N was immobilized in the 1 and 2 cm of soil by surface residues. Much less N was immobilized in the 4-cm soil columns. Thus, placement of fertilizer N several centimenters below the soil surface would alleviate possible N immobilization from organic C leached from surface crop residues. The amount of applied N recovered in the leachate during 9 weeks of incubation ranged from 60 to 70% for all soil column treatments with or without surface straw. There was no significant difference between treatments. In contrast, the recovery of applied N from the mixed straw treatment was only 36% indicating a much greater potential for N immobilization with mixed than with surface straw. The quantity of the fertilizer N added probably masked the immobilization potential of surface residues. Fertilizer N stimulated early release of C from the straw alone treatment. But after 9 weeks of incubation the overall C loss from both fertilized and unfertilized straw was about 30%.
9732. Smika, D.E. and R. Ellis Jr.. 1971. Soil temperature and wheat straw mulch effects on wheat plant development and nutrient concentration.. Agronomy J. 63:388-391.
Hard red winter wheat was grown with and without wheat straw mulch on the soil surface both in a growth chamber with controlled soil temperatures and in the field where soil temperatures were measured at the crown depth. Concentrations of N, P, K, Ca, Mg, Fe, Zn, Mn, and Cu in the plant were determined at the end of tillering and at heading.