Effects of Long-term Site-specific Fertilization on Soil Physical and Chemical Properties and Nutrients in Dry Farmland

In order to investigate the variation in soil physical and chemical properties and nutrients in the mountainous areas in southern Ningxia, and to provide a theoretical basis for fertilization management in local farmland, the soil p H, total salt content,crop root length, root weight, soil organic matter, available nitrogen, total nitrogen, total phosphorous and total potassium in different fertilization treatments were measured from 2010 to 2016. Multiple comparisons of the data were performed using Duncan's new multiple range test. The results indicated that in the 0-20 cm soil layer, soil p H value and total salt content changed in different patterns, and varied greatly from 2010 to 2016(P<0.05). The changes of both root length and root weight of millet over time fitted S-shaped curves. The root length and root weight in the four fertilization treatments(Treatment 2 to Treatment5) increased faster than those in the control(Treatment 1). The soil organic matter content in all the five treatments gradually increased from 2010 to 2016. The content of alkaline hydrolyzable nitrogen in soil rapidly increased in the first two to three years of the experiment, followed by a slow increase or decrease in 2013, and then raised rapidly again from 2014 to 2016.The soil total nitrogen content varied significantly from 2010 to 2016. The total phosphorus content in soil changed in a different pattern from that of total nitrogen content. The seven-year field trails revealed that soil p H, total salt content, root length, root weight and soil nutrient all changed with the increase of fertilizer level, and that long-term fertilization is of significance for maintaining soil fertility, improving soil quality and reducing soil salinization.

Diversity Evaluation of Proso Millet Germplasm Resources in Dryland

[Objective] This study was to provide a theoretical basis for the selection of the parents of proso millet breeding in dry land of south Ningxia, with the aim to improve the production of hilly proso millet in Ningxia hilly area. [Method] The genetic diversity of 46 accessions of dryland proso millet germplasm at 11 agronomic traits were analyzed by using principal component analysis, Shannon-weaver diversity index and non-weighted matching arithmetic average clustering method （UPGMA）. Cluster analysis was also performed. [Result] The proso millet resources mainly had green inflorescence color, panicle spikes, and yellow grain color. The maximum diversity index of proso millet was 2.03. The variation coefficient of grain weight per plant was 19.23. In all the principal components, the main information concentrated on the first 4 principal components with the cumulative contribution rate reaching 83.34%. The tested materials were clustered into 3 categories at euclidean distance of 0.984 4. The first category contained 41 germplasm resources, the second contained 2, and the third category contained 3. [Conclusion] This study could provide references for the targeted use of drought-resistant parents to select hybrid combinations of proso millet in Ningxia.