자운영 지속재배시 토양에 매몰된 종자의 휴면 및 발아특
성을 조사하여 토양속 종자 동태를 구명하기 위해 자운영
종자와 꼬투리의 토양매몰 깊이 및 기간별 휴면성과 종자활
력 변화를 조사하고 또한 자운영 지속재배 포장에서 낙수후
자운영 종자의 토양속 분포 개수, 발아율 및 종자활력기간
을 조사한 결과는 다음과 같다.
1. 자운영 종자 회수율은 종자 매몰 한달후부터 활력이
잃기 시작하여 낙수전 9월까지 52~65%, 낙수후 10월에는
급격히 떨어져 종자와 꼬투리 모두 30% 이하를 나타내었
고, 꼬투리 매몰의 경우는 낙수전 9월까지 활력소실이 되지
않고 100%를 보였다.
2. 자운영 종자의 휴면은 수확당시는 95%로 높았으나 시
간이 경과함에 따라 점차 파괴되어 9월에는 휴면율(경실율)
이 종자는 12~22%, 꼬투리는 31~33%로 급격히 낮아졌
고, 낙수후 10월에는 경실율이 종자는 2~8%, 꼬투리는
5~12%로 보다 더 낮아졌다.
3. 발아율은 토양 매몰전 종자는 4%로 낮았으나 토양에
120일간 매몰후 종자 및 꼬투리속 종자 발아율은 휴면이 타
파되어 각각 21%~31%, 49~51%로 증가하였다.
4. 자운영 지속포장에서 9월 낙수후 토양속 잔존 자운영
종자는 로터리 부분경운이앙은 경운이앙보다 2.3~2.6배가
많았고, 자운영 종자분포 깊이는 로터리 경운은 0~15 cm
깊이에 고르게 분포되었으나 부분경운 이앙은 대부분의 종
자가 5cm 이하 깊이에 분포하고 있었다.
5. 자운영 종자의 출아기간을 기준으로 한 토양 속에서
활력유지기간은 매몰 후 2년정도 인 것으로 조사되었다.Experiments were conducted to investigate
seed persistence of Chinese milk vetch(CMV) in naturally
reseeded rice field in 2007~2009. The seed and pods with
seeds were buried in rice field at 0, 5 and 10 cm depths
and retrieved from the field at one to three month intervals
from July to the following year March and determined
change of seed dormancy and viability. In the second
experiment, persistence of the CMV seeds in the naturally
reseeded rice field at different tillage methods and soil
depths were also investigated after rice harvest in autumn.
Burial depths and durations affected recovery rate, dormancy
and viability of CMV seed. The viability loss was faster
and greater in the seed than the pod with seeds and on the
soil surface than the 5 or 10 cm burial depths. The recovery
rate of CMV seed was decreased starting from one month
as seed burial and it was significantly decreased to 52~
65% for the seed in September. However, unlike the seed
burial, the nearly 100% CMV seeds were recovered for
burial as pod with seeds even after four months burial in
both 0 and 5 cm depths. However, the recovery rate was
sharply declined to below 30% at October in 2007 in both
seed and pods with seeds and in the 2008/2009 experiment.
the 15~47% of CMV seeds still remained even after
October. The CMV had high seed dormancy of 95%,
showing only 4~5% germination at the beginning in June
but the seed germination increased to 25 to 35% in seed
and 55 to 61% in pod with seeds in September due to
breakage of hard seed dormancy. The viability loss was
faster in the seed than in the pod with seeds regardless of
depths of placement in the soil base on decayed seeds.
Also the seed placed on the soil surface lost viability faster
than the 5~10 burial depths. On the other hand, field
observation in the naturally reseeded CMV rice field
showed that as many as 917~2,185 CMV seeds m2 were
from the 0~15 cm soil depth in the rotary tillage and 25
0~10,105 CMV seeds in minimum tillage treatmints. The
recovered seed germinated 25~33%, 23~43% but still
had high percentage of hard seed having 64~72% and 5
1~77% even after rice harvest in autumn. These results
indicate that freshly harvested CMV seeds had high level
of primary dormancy and the dormancy was gradually
broken in soil with time during rice cultivation periods and
appreciable number of CMV seeds remained even 4 month
after burial in soil. CMV plant regenerated naturally from
the remained seed bank at rice harvest time in autumn. The
CMV seedling still emerged even after 2 years of continuous
destructive killing of emerged CMV plant by rotary tillage
in naturally reseeded CMV plant in rice field, indicating
that CMV seeds do persistent as least two years in soil.