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ABSTRACT Research has shown that some corn (Zea mays L.) hybrids grown under reduced tillage conditions respond to starter fertilizer containing nitrogen (N) and phosphorus (P), while others do not. This research studied variability of responsiveness among corn hybrids to starter fertilizer containing a more complete complement of nutrients. The experiment was conducted from 1996 to 1998 on a producer's field near Scandia, KS, on a Carr sandy-loam soil (coarse-loamy, mixed, superactive calcareous, mesic Typic Udifluvents). The response of four corn hybrids (Pioneer 3563, Pioneer 3346, DeKalb 591, and DeKalb 646) to starter fertilizer combinations containing N, P, potassium (K), sulfur (S), and zinc (Zn) was evaluated. In all three years of the experiment, starter fertilizer containing N and P consistently increased grain yield, reduced the number of thermal units needed from emergence to maturity, decreased grain-moisture content at harvest, and increased total P uptake (grain plus stover at maturity) of Pioneer 3346 and DeKalb 591, but had no effect on Pioneer 3563 and DeKalb 646. Addition of S to the starter mix produced additional yield increases for Pioneer 3346 and DeKalb 591, whereas addition of K and Zn to the starter did not show any additional yield benefit for these two hybrids. Grain yield of Pioneer 3563 and DeKalb 646 was not improved by starter fertilizer, regardless of the elemental composition. When no starter fertilizer was applied, early-season root development was greater in Pioneer 3563 and DeKalb 646 than in the other two hybrids. However, the addition of starter fertilizer increased numbers of roots and depth of rooting in Pioneer 3346 and DeKalb 591 but had no effect on Pioneer 3563 and DeKalb 636. Results showed starter fertilizer benefited grain yield for two hybrids. Grain yield of the other two hybrids, however, was not influenced by starter, regardless of which nutrients were supplied. This response may be attributed to differences in root-growth characteristics of the hybrids. The two responsive hybrids did, however, yield an average of 0.75 mg ha?1 greater than the two non-responsive hybrids. This result indicates it is unlikely that all of the yield loss from not using a starter can be avoided by hybrid selection. 相似文献
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Effects of Phosphorus Additions on Lead,Cadmium, and Zinc Bioavailabilities in a Metal-Contaminated Soil 总被引：2，自引：0，他引：2
Zwonitzer John C. Pierzynski Gary M. Hettiarachchi Ganga M. 《Water, air, and soil pollution》2003,143(1-4):193-209
The use of phosphorus (P) to reduce lead (Pb)bioavailability is being proposed as an alternative to excavationand disposal as a remedial technology for Pb-contaminated soilsin residential areas. The objective of this study was todetermine the influence of P sources and rates andCaCO3additions on the bioavailabilities of Pb, cadmium (Cd), and zinc(Zn) in a contaminated soil material using plants, a sequentialextraction procedure, and ion activities in equilibrium solutionas indicators. A contaminated soil containing 370 mg kg-1 Cd, 2800 mg kg-1 Pb and 29100 mg kg-1 Zn was amended ina factorial arrangement of CaCO3 (0 or 2000 mg kg-1) and P as rock phosphate or KH2PO4 at 0:1, 2:1 or 4:1P:Pb mole ratios. A pot study was conducted using sorghum-sudangrass (Sorghum bicolor L. Moench). The addition of P did not influence Pb concentrations in plant tissue and had little effect on Cd concentrations. An interaction between P source and level of P addition was found for Zn concentrations in plant tissue; concentrations increased with increasing amounts of P from KH2PO4 anddecreased with increasing amounts of P from rock phosphate. Sequential extraction results suggested a much greater reduction in Pb bioavailability from treatment withKH2PO4 than with rock phosphate and that P influencedthe fractionations of Cd and Zn. Activities of Cd2+,Pb2+, and Zn2+ in equilibrium solutions generally weredecreased by rock phosphate and increased by KH2PO4. Saturation indices suggested the addition ofKH2PO4shifted the soil equilibrium from octavite to hydroxypyromorphite, whereas solid-phase control of Cd2+ andZn2+ was not influenced by soil amendments. A soluble Psource was more effective in reducing Pb bioavailability thanrock phosphate but had variable effects on Cd and Znbioavailabilities. 相似文献
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It is crucial to know how management factors influence soil test phosphorus (P) since non-point P sources for surface waters are becoming recognized as a problem throughout the USA. Phosphorus fertilizer and crop residue can impact the cycling of P in soils. An eight-year crop residue removal and P fertilization (0, 7.3, 14.7 and 29.4 kg P/ha) as triple superphosphate (TSP) experiment were conducted to determine the effect of P applications on soil P fractions. Significant differences in Bray-l extractable P were observed after only one year of P applications. Extractable P at the highest P rate was significantly higher than all the other rates. For each 5.6 kg P/ha added or removed, Bray-l P changed by 1 mg/kg. Fertilizer P applications did not significantly change the organic P (Po) levels, microbial P (Pm) or soil pH, whereas residue treatments had effects on them except for soil pH. Residue-retained plots had significantly higher Pm in the last two years of study, and Po in the 8th year, compared with residue-removed plots. 相似文献
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Jose G. Guzman Chad B. Godsey Gary M. Pierzynski David A. Whitney Ray E. Lamond 《Soil & Tillage Research》2006,91(1-2):199-206
Long-term tillage and nitrogen (N) management practices can have a profound impact on soil properties and nutrient availability. A great deal of research evaluating tillage and N applications on soil chemical properties has been conducted with continuous corn (Zea Mays L.) throughout the Midwest, but not on continuous grain sorghum (Sorghum bicolor (L.) Moench). The objective of this experiment was to examine the long-term effects of tillage and nitrogen applications on soil physical and chemical properties at different depths after 23 years of continuous sorghum under no-till (NT) and conventional till (CT) (fall chisel-field cultivation prior to planting) systems. Ammonium nitrate (AN), urea, and a slow release form of urea were surface broadcast at rates of 34, 67, and 135 kg N ha−1. Soil samples were taken to a depth of 15 cm and separated into 2.5 cm increments. As a result of lime applied to the soil surface, soil pH in the NT and CT plots decreased with depth, ranging from 6.9 to 5.7 in the NT plots and from 6.5 to 5.9 in the CT plots. Bray-1 extractable P and NH4OAc extractable K was 20 and 49 mg kg−1 higher, respectively, in the surface 2.5 cm of NT compared to CT. Extractable Ca was not greatly influenced by tillage but extractable Mg was higher for CT compared to NT below 2.5 cm. Organic carbon (OC) under NT was significantly higher in the surface 7.5 cm of soil compared to CT. Averaged across N rates, NT had 2.7 Mg ha−1 more C than CT in the surface 7.5 cm of soil. Bulk density (Δb) of the CT was lower at 1.07 g cm−3 while Δb of NT plots was 1.13 g cm−3. This study demonstrated the effect tillage has on the distribution and concentration of certain chemical soil properties. 相似文献
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Physiological responses of plants to ammonium (NH4) versus nitrate (NO3) nutrition can vary considerably. A greenhouse study was conducted to examine the effect of ammonium‐nitrogen/nitrate‐nitrogen (NH4‐N/NO3‐N) ratio on dry matter partitioning and radiation use efficiency in corn (Zea mays L.). The hybrid Funks G 4673A was supplied with nutrient solutions that contained 8:1, 1:1, or 1:8 ratios of NH4‐N/NO3‐N. At each of four harvests, plants were separated into leaf blades, stem + leaf sheaths, and roots. Radiation use efficiency was calculated from these dry matter harvests and measured photosynthetically active radiation. Generally, more dry matter was partitioned to the stem than to leaf tissue when supplied with the 1:8 NH4‐N/NO3‐N ratio than when supplied with the other N treatments. Corn supplied with 8:1 and 1:1 ratios of NH4‐N/NO3‐N resulted in radiation use efficiency values for total dry matter that were significantly higher by 39 and 25%, respectively, than that of corn supplied with the 1:8 ratio indicating that Funks G 4673A was more efficient in converting radiation into dry matter when supplied with high proportions of NH4 than when supplied primarily with NO3. 相似文献
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