| Lilium davidii var. unicolor is one of plants with great economic value due to its applications in food, medicine, and gardening. Lilium davidii var. unicolor has more than 150 years cultural history, and it is also local agricultural product and competitive industry in Gansu Province. Aimed at the problems in Lilium davidii var. unicolor planting, this paper studied the effects of mulches and fertilization on growth, niche-fitness and yield of Lilium davidii var. unicolor. Moreover, from the perspective of population ecology, discussed the effects of mulches and fertilization on dynamic of Lilium davidii var. unicolor population. The main results were as follows:1. A 3-year study was conducted to compare the performance of Lilium davidii var. unicolor under different planting patterns, to identify the effect of soil temperature and soil water content, as affected by plastic film mulches, on the growth and yield of Lilium davidii var. unicolor. Three planting patterns were tested in open fields:contour bare ridge (BR), ordinary plastic film mulched contour ridge (OPMR), and water-permeable plastic film mulched ridge (WPMR). The results indicated that plastic-mulched ridge system could increase soil temperature in 10 cm depth and soil water content in 0-100 cm by 1.5-3.2℃and 7.61-19.14%, respectively. Compared with those under OPMR plots, soil temperatures and water content were higher under WPMR plots. The exception was soil temperatures in hot seasons, they were lower under WPMR plots than that under OPMR plots, which could be an advantage for crops under high ambient temperature and high solar radiation. The growth characteristics, i.e., plant height, basal diameter, leaf number and biomass, were also increased under plastic-mulched ridge system, especially under WPMR plots. Mulches improved dry matter accumalation of Lilium davidii var. unicolor, and increased the percentages of bulb in total dry matter. There were significant (P<0.001) differences in the marketable yield and bulblet yield among all three treatments. The highest yield (17268.56 kg ha-1) was obtained under WPMR plots, while the lowest yield (14838.65 kg ha-1) was occurred under BR plots; the bulb yield was 16655.67 kg ha-1 under OPMR plots. Compared with BR plots, the water use efficiency (WUE) under OPMR plots and WPMR plots increased by 12.56% and 19.40% during the whole growth period, respectively.2. The nine fertilization treatments were applied, which consisted of the combinations of three N/P treatment rates and three K treatment rates. The results showed that fertilization improved plant growth. For N/P treatments, seedling height, basal diameter, leaf number and dry matter all reached the highest under (NP)hK0 plots. For K plots, the values of growth characteristics were the highest under (NP)0Kh plots. The mixed fertilizer for N, P, K was more beneficial than single N/P or single K in improving plant growth and dry matter accumulation. The plants of Lilium davidii var. unicolor grow more rapidly and vigorously under (NP)hKh plots. Fertilization increased significantly bulb yield. The bulb yield of Lilium davidii var. unicolor increased with the increase of N/P fertilizer or K fertilizer. The increment of yield between (NP)0K0 and low fertilizer was larger than between high fertilizer and low fertilizer; the effect of K on improving yield was more significant than N/P. The highest bulb yield was obtained under (NP)hKh plots. Fertilization had no regular influence on bulblet yield.3. Introducing the niche theory into the research of crop growth system, this paper studied the meaning of niche-fitness, and also analyzed quantitatively the niche-fitness values of Lilium davidii var. unicolor under different habitat conditions regulated by mulching and fertilizer according to relevant mathematical model. The results showed that film mulching and fertilizer had the effects of increasing of LAI, niche-fitness values and bulb yield. The LAI of Lilium davidii var. unicolor during seedling stage, squaring period and anthesis was increased averagely by 25.90%, and their fitness values and bulb yield were increased by 6.40% and 21.21% under mulching. The LAI, optimum niche values and bulb yield of Lilium davidii var. unicolor tended to increase with the increasing of N, P and K application on the fertilizer gradient under either mulching or flat sowing. Compared with A0B0, the values of LAI with (NP)1K1, (NP)0K1 and (NP)1K0 during seedling stage, squaring period and anthesis were increased by 41.83%,30.07% and 13.73% under flat sowing. Single K application((NP)0K1 relative to (NP)0K0)increased greater in fitness values and bulb yield than single N and P application((NP)1K0 relative to (NP) 0K0) under flat sowing, were 18.32% and 42.65%, respectively. The increments of fitness values and bulb yield with N, P and K application were most significant, and the increments((NP)1K1 relative to (NP)0K0)under mulching condition were larger than that under flat sowing, up to 26.80% and 58.82%, respectively. The marketable bulb yield of Lilium davidii var. unicolor is remarkable quadratic interrelated with the fitness values.4. The study was conducted to determine the effect of K supply regimes and plastic film mulching on the harvest index (HI), reproductive allocation (RA) and the size inequality of Lilium davidii var. unicolor population, and to explore the mechanisms causing them. Compared with K0 treatment, bulb yield, biological yield, HI and RA of Lilium davidii var. unicolor with K fertilizer treatment increased 44.42%,20.60%,14.30% and 5.55%, respectively, under non-mulching control, and 57.21%,13.89%,23.30% and 7.35%, respectively, under mulching condition. Either mulching or non-mulching, size inequality always decreased along the K supply gradient. Compared with the values under non-mulching, the bulb yield and biological yield of Lilium davidii var. unicolor under mulching increased by 15.59% and 13.09%, respectively. However, HI and RA under mulching were lower by 4.19% and 3.20% than that under non-mulching, respectively. Results suggest that the size inequality of Lilium davidii var. unicolor populations are closely correlated with K supply, and that under greater K supply there are relatively larger plants with higher HI. Growth redundancy under mulching conditions occurred in Lilium davidii var. unicolor populations, which may result from the exacerbated interplant competition and greater size inequality. |
PDF Full Text Request