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Fertilizer Placement and Tillage Effects on Grain Sorghum Growth and Nutrient Uptake
Author(s) -
Sweeney Daniel W.
Publication year - 1993
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1993.03615995005700020039x
Subject(s) - loam , tillage , sorghum , nutrient , fertilizer , dry matter , agronomy , growing season , human fertilization , zoology , mathematics , chemistry , biology , soil water , ecology
Because fertilizer placement may be important with conservation tillage, this study was conducted to examine the effect of N‐P‐K suspension placement methods on grain sorghum [ Sorghum bicolor (L.) Moench] growth and N, P, and K uptake in reduced‐, ridge‐, and no‐tillage systems. Fertilizer treatments were (i) check; (ii) check‐knife; (iii) broadcast; (iv) dribble; (v) knife; (vi) broadcast‐split N; (vii) dribble‐split N; and (viii) knife‐split N. The experiment was conducted in 1985 and 1986 on a low P and K, Parsons silt loam soil (fine, mixed, thermic Mollic Albaqualf). Tillage primarily affected plant growth and nutrient uptake at the nine‐leaf stage, with minimal effects later in the growing season. General fertilization and placement method produced consistent dry matter and nutrient uptake responses at each measured growth stage. Cubic functions described dry matter accumulation and N, P, and K uptake with time. Nutrient uptake generally followed a sigmoid pattern, with knifing resulting in greatest N, P, and K uptake during the season. First derivative rate functions showed that knifing increased N, P, and K maximum uptake rates and shifted P and K uptake rate maxima to 1 to 2 wk earlier in the season, which may be partially explained by accelerated maturity. The response to knifing appeared to be more related to placement of P and K. Maximum nutrient accumulation preceded the maximum dry matter growth rate, suggesting the importance of positional availability of early‐season soil P and K, which appeared to be improved by knifing of the N‐P‐K suspension.