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作者 Maschmann, Elliot T
書名 Potassium fertilization influence on rice growth, yield and stem rot index
國際標準書號 9781109191349
book jacket
說明 93 p
附註 Source: Masters Abstracts International, Volume: 47-06, page: 3334
Thesis (M.S.)--University of Arkansas, 2009
Plant K nutrition is known to influence disease severity and crop yield. Potassium fertilization practices should be used as a cultural management tool to reduce disease severity. Stem rot (Sclerotium oryzae. Catt.) severity of rice (Oryza sativa L.) has been linked to inadequate K nutrition. Our objectives were to determine how grain yield and stem rot index (SRI) of rice grown on soils low in K were affected by (1) K application time and azoxystrobin fungicide and (2) long-term K fertilization rate. Potassium fertilizer was applied at 0, 56, and 112 kg K ha-1 to rice at preflood (PF), panicle differentiation (PD), or the late-boot (LB) stage. Azoxystrobin was applied at 0 and 0.23 kg ha-1 following the PD K application in six trials. Stem rot was assessed at maturity and expressed as SRI. The effects of long-term K fertilization were evaluated in soil that was cropped and fertilized with 0, 37, 74, 111 and 148 kg K ha -1 yr-1 for at least 5 yr before the stem rot was evaluated. Potassium fertilization increased grain yield by 8 to 11% above rice receiving no K. Within each K application time, grain yield of rice receiving 0.23 kg ha-1 azoxystrobin was 6 to 12% greater than rice receiving no azoxystrobin. Within each azoxystrobin rate, rice yields were lowest when no K was applied, intermediate when K was applied at LB, and greatest when K was applied PF or PD. The average SRI was reduced by K fertilization and azoxystrobin application. The long-term K fertilization trial showed rice grain yields were increased 19 to 73% with the greatest numerical yields always produced by the highest annual K rate. Rice receiving no K had maximum SRI values of 2.8 to 3.7, which indicate mild to moderate stem rot. Compared to rice receiving no K, applying 74 to 111 kg K ha -1 yr-1 always decreased SRI. Potassium fertilizer applied between PD and LB can reduce yield losses from K deficiency, but sufficient K fertilizer should be applied preplant or preflood to prevent yield loss from K-deficiency and minimize stem rot disease
School code: 0011
Host Item Masters Abstracts International 47-06
主題 Agriculture, Agronomy
Agriculture, Soil Science
0285
0481
Alt Author University of Arkansas
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