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Effect of Fertilizer‐N and Herbicides on the Growth and N Content of Soybeans and Cowpeas 1
Author(s) -
Behran Sh.,
Maftoun M.,
Sheibany B.,
Hojjati S. M.
Publication year - 1979
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1979.00021962007100040003x
Subject(s) - trifluralin , chlorophyll , chemistry , fertilizer , agronomy , vigna , dry matter , horticulture , biology , pesticide
Little is known about herbicide‐N fertilizer interaction with respect to the growth and N content of soybeans ( Glycine max (L.) Merr.) and cowpeas ( Vigna unguiculata ). This study was undertaken to evaluate the effect of added N and trifluralin (α, α, α‐trifluoro‐2, 6‐dinitro‐N, N‐dipropyl‐ρ‐toluidine), nitralin [4‐(methylsulfonyl)‐2, 6‐dinitro‐N, Ndipropylaniline] and diphenamid (N, Ndimethyl‐2, 2‐diphenylacetamide) on the growth and N uptake by these two crops. Soybeans and cowpeas were grown in greenhouse for 74 days in soil treated with various levels of N (0, 25, and 50 ppm) and herbicide (0, 1, 2, and 3 ppm). Leaf chlorophyll, dry matter yields, N concentration and N uptake were determined. All N‐treated soybean and cowpea plants had greater chlorophyll content, produced more growth and contained higher N than untreated check. An increase in growth and N uptake suggests that symbiotic N fixation probably failed to supply all of N required for optimum growth. Application of 1 ppm trifluralin slightly increased growth and N content of cowpea and enhanced chlorophyll content, N concentration and root dry weights of soybean. However, higher concentrations exhibited strong phytotoxic effects. Soybeans treated with 3 ppm of herbicide developed stunted and chlorotic leaves and had fewer nodules than untreated seedlings. Soil amended with nitralin and diphenamid reduced leaf chlorophyll, growth and N uptake of soybeans and cowpeas. Moreover, nitralin exhibited a stronger inhibitory effects in roots than tops and was slightly less phytotoxic than trifluralin. Diphenamid‐treated plants developed chlorotic leaf margins, followed by necrosis at the leaf edge. N addition to trifluralin treatment only affected N content of soybeans significantly, whereas there was increased chlorophyll content, N concentration and top dry weights of cowpea. On the other hand, N applied to nitralin and/or diphenamid‐treated soybeans and cowpeas resulted in an increase in dry weight and N content of tops, probably due to better nutrient and water supply to plants.