전국 시군별 마늘 생산성에 관한 취약성 평가를 위한 기후 노출지수, 기후 변화 민감도 지수, 기후 변화 적응 능력 지수를 가중치와 함께 도출하였으며, 각 지수 도출을 위한 변수들도 가중치별로 산정하여 최종적으로 평가하였다. 마늘 생산성의 취약성 지수는 제주시, 고흥군, 창녕군, 서귀포시, 신안군이 각각 취약성 0.92826, 0.92374, 0.85635, 0.82150, 0.81360으로 높았다. 기후변화 민감도 평균지수는 제주도가 가장 높았고, 기후변화 적응능력 평균지수는 경기도, 경상남도, 경상북도, 충청남도 순으로 높았고, 제주도와 강원도가 낮았다. 기후변화 적응능력 지수에 대한 기여도는 GRDP농림어업, 지역내 총생산(GRDP)이 가장 높게 나타났고, 농경지 면적당 농업인구수, 경지면적당 정비사업 관계직원이 가장 낮게 나타났다. 기후노출 변수와 기후노출 지수와의 상관계수를 분석한 결과 파종 및 정식기 마늘이 저온에 의한 피해정도가 심각할 수 있음을 보여주었다. 민감도 변수와 민감도 지수에서는 재배면적과 생산량이 직접적으로 영향을 미치는 것으로 나타났고, 적응능력 변수와 적응능력 지수의 상관관계에서는 재정자립도(%)와 농경지 면적당 농업인구수(명/ha)가 각각 r2 = 0.610과 0.511로 적응능력 지수와 가장 높은 연관성을 지닌 것으로 나타났다. 결론적으로 취약성 지수는 적응능력 지수가 가장 높은 연관성을 보였고(r2 = 0.424), 그 다음이 민감도 지수(r2 = 0.333), 기후노출 지수(r2 = 0.225) 순으로 높은 상관관계를 보여 지자체의 기후변화 적응능력 구비는 취약성을 극복하는 중요한 지수임을 알 수 있었다.

Alfalfa (Medicago sativa L.) plants have been reported to be autotoxic as well as allelopathic. Laboratory and greenhouse experiments through petri-dish and pot test were conducted to determine autotoxic effects of alfalfa leaf and soil extracts on the germination or early seedling growth of alfalfa, and to evaluate allelopathic effects of alfalfa leaf residues on alfalfa, barnyard grass, com, eclipta and soybean. Alfalfa seed germination was delayed depending on aqueous extract concentration, with no difference in final germination after 48 hours. Alfalfa root length was more sensitive to the autotoxic chemicals from leaf extracts than was germination or shoot length. Root growth of alfalfa was significantly inhibited at extract concentration of more than 1 g dry tissue/L (g ~textrmL-1 ). Hypocotyl growth, however, was not affected by all the concentrations of leaf extracts. Soil extracts from 4-yr-old alfalfa stand significantly reduced alfalfa root length by 66%, while soil extracts from 0,1, and 3yr-old stand stimulated root length up to 14-32% over the control. Residue incorporation with dry matters of alfalfa leaf at 100 g ~textrmkg-1 reduced seedling length of several crop and weed species, ranging from 53 to 87% inhibition. Addition of nutrient solution into alfalfa leaf extracts alleviated alfalfa autotoxic effect. This result indicates alfalfa leaf and soil extracts or residues could exert autotoxic as well as allelopathic substances into soil environments during and after establishment.

Greenhouse and laboratory studies were conducted to determine the allelopathic potentials of extracts or residues from sweet potato (Ipomoea batatas L. (Lam). The extracts applied on filter paper in a Petri dish bioassay significantly inhibited root growth of alfalfa. Aqueous leachates at 40g dry tissue ~textrmL-1 (g ~textrmL-1 ) from leaves showed the highest inhibition against alfalfa, and followed by stems and roots. Alfalfa root growth was significantly inhibited by methanol extracts of the same plants as the concentration increased. The effect of residue incorporation into soil on seedling growth of com, soybean, barnyard grass and eclipta was examined in the greenhouse, and results showed that the leaf residues at 200g ~textrmkg-1 by plant parts inhibited shoot dry and root dry weights of test plants by 60-80%. By means of HPLC, causative allelopathic substances present in plant parts of sweet potato "Sinyulmi" were identified as coumarin, trans-cinnamic acid, o-coumaric acid, p-coumaric acid, and chlorogenic acid. Total content of these compounds for leaves extracts were detected as the greatest amount in EtOAc fraction, especially trans-cinnamic acid was the greatest component. These results suggest that sweet potato plants have herbicidal potentials, and that their activities exhibit differently depending on plant parts.ant parts.

The purpose of this study is to investigate the positive or negative effects of 5-aminolevulinic acid(ALA) on the growth of several crops and weeds, by applying a seed soaking treatment, foliar treatment, and application timing, while comparing biological activity between ALA produced by chemical synthesis (Synthetic-ALA) and extracellularly-accumulated ALA by overexpressing the hemeA gene isolated from Bradyrhizobium japonicum(Bio-ALA). Seed soaking treatment of ALA in barley (five cultivars) and wheat (five cultivars) had not shown positive effects at lower concentrations, 0.05 to 0.5 mM as well as negative effects at higher concentrations, 1 to 30 mM. In rice, there also was no positive effect by seed soaking treatment of ALA at lower concentrations, although the rice became damaged by an application of 5 and 10 mM ALA. Growth in barley cultivars, Ganghossalbori, Naehanssalbori, Songhakbori, Saessalbori, and Daehossalbori were increased up to 14%, 19-51 %, 17-64%, 18-23%, and 22-38% by ALA foliar application at lower concentrations, 0.05 to 0.5 mM, respectively. On the other hand, the growth in barley cultivars was inhibited by ALA foliar application at higher concentrations. Barley responded more positively to ALA foliar application than wheat and rice. The growth stimulation caused by ALA seed soaking treatment was less than by ALA foliar treatment. ALA treatment at the 1.5-leaf stage increased growth of barley by 19-58%, while pretreatment to seeds, post-emergence treatment at 3 days after seeding, 3-leaf stages, and 5-leaf stages had not shown positive effects. Thus, the positive effects of ALA on barley were dependent greatly upon the timing of application and its concentration. Monocots weeds were more sensitive to ALA foliar treatment than dicotyledonous weeds. A monocot weed, Setaria viridis L. was the most susceptible plant to ALA while a dicotyledonous weed, Plantago asiatica L. was the most tolerant. No significant difference in biological activity between bio-ALA and synthetic ALA on barley, wheat, rice, and weed, Ixeris dentate tested was observed. Thus, ALA produced by microorganisms would be a potent substance to be used effectively in agricultural production.