Abstract
An ordinary paddy variety Hwaseong and a high-yielding variety Samgang were taken under investigation to test the effect of top dressing of newly formulated three compound fertilizers on rice plants for at sprouting heads. The fertilizer formulate used were C. F. I (14-0-14; $NO_3-N$ and $NH_4-N$) and C. F. II (14-0-14; $NH_4-N$ only) and C. F. III (14-0-14 + OM 10%; $NO_3-N$ and $NH_4-N$). A field experiment was conducted on a plot of Gyuam series. The following results were obtained: 1. Effects of compound fertilizers at sprouting heads a. Hwaseong variety exhibited 5-10% yielding increases on the plots with application of 2nd compound fertilizer (I) and (II) compared to straight fertilizer of (I) and (III). Fertilization with 2nd and 3rd compound fertilizers gave the best result when they are done 15 days before heading. A yield increase of 3-5% was achieved when the fertilization was done 20 days before heading in the case of Samgang variety, but no beneficial effect was observed with an application 10 days before heading. b. Rate of barren grains was at the minimum in the compound fertilizer (II) plots of both Hwaseong and Samgang varieties. c. Content of $NO_3-N$ in soils and grain yield appeared to be positively correlated($r=0.618^*$) 2. Effects of heading fertilizers on artificially reduced conditions of soil a. No significant difference in Eh values were measured among reduced paddy soils. The compound fertilizer of (II) presented the best result in yield increases regardless of rice variety. b. Rate of barren grains in both varieties was observed at the minimum on the application of compound fertilizer of (II). c. No great difference of mineral contents was detected among plants from different treatments.
수도(水稻) 수비용(穗肥用)으로 제조(製造)한 2종복비(種複肥)(I)(14-0-14 : $NO_3-N$와 $NH_4-N$함유(含有)), 2종복비(種複肥)(II)(14-0-14:$NH_4-N$함유(含有))와 3종복비(種複肥)(III)(14-0-14+OM10 : $NO_3-N$ $NH_4-N$함유(含有))의 비효(肥效)를 구명(究明)하기 위하여 일반품종(一般品種)인 화성벼와 다수계품종(多收系品種)인 삼강벼를 공시(供試)하여 규암통(窺岩統)에서 포장시험(圃場試驗)을 실시(實施)한 결과(結果) 다음과 같은 결과(結果)를 얻었다. 1. 복합비료(複合肥料)의 수비효과(穗肥效果) 시험(試驗) 가. 수량(收量)에서 화성벼는 단비구(單肥區)에 비하여 2종복비(種複肥)(I) 및 3종복비(種複肥)(III)에서 5~10%의 증수(增收)를 보였고 2종복비(種複肥)(I) 및 3종복비(種複肥)(III)의 수비시용시기(穗肥施用時期)는 출수(出穗) 15일전(日前)이 양호(良好)하였다. 삼강벼의 수비시용시기(穗肥施用時期)는 출수(出穗) 20일전(日前)이 3~5%증수(增收)되었으나 출수(出穗)10일(日) 전(前)은 효과(效果)가 없었다. 나. 처리별(處理別) 부임입비율(不稔粒比率)은 두 품종(品種) 공(共)히 2종복비(種複肥) (I) 시용구(施用區)에서 감소(減少)하였다. 다. 토양중(土壤中) 질산태질소함량(窒酸態窒素含量)과 수량(收量)과는 정(正)의 상관(相關)$(r=0.618^*)$을 보였다. 2. 환원유발토양(還元誘發土壤)의 비종별(肥種別) 수비효과(穗肥效果) 시험(試驗) 가. 환원유발(還元誘發)에 의(依)한 Eh값은 큰 차이(差異)가 없었고 비종별(肥種別) 수량(收量)은 두 품종(品種) 공(共)히 2종복비(種複肥)(I) 시용구(施用區)에서 증수(增收)되었다. 나. 비종별(肥種別) 부임비율(不稔比率)은 2종복비(種複肥)(I)에서 두 품종(品種) 공(共)히 적었다. 다. 식물체중(植物體中) 무기성분함량(無機成分含量)에서 처리간(處理間)에 큰 차이(差異)가 없었다.