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Fluid Journal : Fluid Journal 1999-2001
1 Fluid Journal Winter 2000 he advent of minimum and no-till, the increased occurrence of compacted soils with restricted rooting, earlier planting, and higher yield goals have promoted a renewed interest in starter fertilizer banded at planting. Studies in coarse-textured soils of the coastal plains have shown crop yield increases with NP or NPK handed at planting in addition to broadcast P and K. Similar increases have been experienced with NP banded at planting, compared to NP broadcast before planting. Even though soil P was high in these corn studies, yield increases were attributed to P in the starter when N was not limiting. Past work on the relative effectiveness of granular versus fluid as a source for P has shown that fluids are generally equal to or, in sonic cases, even superior by Dr. James R. Woodruff T Corn/Soybeans R Corn/Soybeans R Corn/Soybeans R Corn/SoybeansR Corn/Soybeans Respond to Star espond to Star espond to Star espond to Star espond to Starter ter ter ter ter Studies show that starters produce optimum responses in coastal plain soils with low Kk- holding c apa city. Summary: Data from South Carolina studies show that positive corn and soybean yield responses were obtained from N, P, K, and B banded near the seed at planting in coastal plain soils with low K-holding capacity. Nutrient deficiency symptoms are commonly observed during early growth of corn or soybeans in the coarse-textured soils of the test sites. The most common nutrient deficiency symptoms observed has been interveinal chlorosis, which resembles Zn and Mg deficiencies. On occasion, yellowing and slow growth associated with N and S deficiencies have been observed. to granular. Maintenance and proper balance of sufficient amounts of available nutrients in the rooting zone are extremely difficult in the coarse-textured soils of the coastal plain. Leaching and limited rooting occur because of less than one percent organic matter in these loamy sands and thick surfaces that restrict vertical roofing. Phosphorus levels are high in the plow layer. High rates of ammonium N increase acidity and accelerate the movement of calcium, magnesium, potassium, sulfur, nitrogen, and boron from the plow layer into the subsoil. Nutrient deficiency symptoms and slow growth are commonly observed during early growth of crops in these soils. Deficiencies are accentuated by cold-wet or cold-dry weather. We have observed that applying nutrients such as N, S, K, and Boron in the inter-row area does not increase leaf concentration of the nutrient elements as effectively as banding or sidedressing close to the plant row. Selected field and greenhouse exper- iments conducted in South Carolina to examine yield response to various nutrients in starters follow below. Blackville Plants not receiving complete starter fertilizer were yellow and stunted, even 120 0 10 gal/A Rate of 9-18-9 + 1% S, 0.1% Zn Figure 1. Corn response to 2 by 2 banded 9-18-9 fluid starter, plus broadcast and side- dressed N (@ 180 lbs/A), P0(@140lbs/A),KO (@ 140 lbs/A) in Dothan loamy sand. 25 2 130 140 150 160 170 180 190 Yield - bu/A 120 0 10 gal/A Rate of 9-18-9 + 1% S, 0.1% Zn Yield - bu/A Figure 2. Corn response to 2 by 2 banded 9-18-9 fluid starter, plus broadcast and side- dressed N ( @ 380 lbs/A), PO(@40lbs/A),KO (@ 340lbs/A), and B (@ 2 lbs/A) in Dothan loamy sand. 25 2 130 140 150 160 170 180 190
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