Effects Of Cropping Patterns Research Articles

Long-Term Impacts of Different Cropping Patterns on Soil Physico-Chemical Properties and Enzyme Activities in the Low Land Plain of North China

Various cropping patterns are extensively used on the North China Plain, which greatly alter various soil properties. Although these soil properties respond differently to the different cropping patterns, little is known about the possible effects of cropping patterns on desalinized soils. To assess the effects of the different cropping patterns on soil properties and enzyme activities, a long-term field experiment was conducted at the Nanpi Agro-Ecological Station in Hebei Province, China. The cropping patterns under study were the single-cropping patterns of winter wheat (Triticum aestivum L.), spring maize (Zea mays), and spring cotton (Gossypium hirsutum), and the double-cropping pattern of winter wheat–summer maize (WW–SM), which is the predominant cropping pattern on the North China Plain. Soil samples were collected at a depth of 0–100 cm, depending on the soil properties. Our results indicated that soil available phosphorous (P) and available potassium (K) concentrations at 0–20 cm were greater than those of the subsurfaces. Soil organic matter declined with depth, and WW–SM had the highest amount in the deep levels. The WW–SM cropping pattern also generally showed greater levels of enzyme activities than did the single-cropping patterns, proving that diverse crops can enhance enzyme activities. Soil pH generally increased with depth despite there being no significant differences between the cropping patterns. No significant effects were observed on soil electrical conductivity (EC). However, EC generally increased with depth in spring cotton and winter wheat and declined in spring maize and WW–SM. Winter wheat had a significant aggregate size (<0.053 mm) at 20–40 cm depth and generally showed the lowest amount of nutrients. This study suggests that a fallow period allows the soil to regenerate its structure, whereas WW–SM enhances high soil organic matter in the deep soil layers and promotes increased soil enzyme activities. This indicates that crop rotation could sustainably exploit soil resources without reducing fertility over a long period. There is a need to incorporate different soil management practices for single-cropping patterns to increase their productivity, especially in spring maize, whose organic matter declined the most. Our results also show a need to diversify to different crop rotations to utilize their benefits and enhance soil productivity while increasing crop output.

Effect of cropping patterns onbacterial community diversity and metabolic function in rhizosphere soil of Angelica sinensis

The sustainable development of Angelica sinensis industry is seriously restricted by continuous cropping obstacles. In order to explore an efficient cultivation technique for A. sinensis, an experiment with five cropping patterns [A: Pisum sativum (Ps)-A. sinensis (As)-As, control); B: Ps-Triticum aestivum (Ta)-As; C: Ps-Mongolia astragalus (Ma)-As; D: Ps-Solanum tuberosum (St)-As); E: Ps-Fallow (F)-As)] were conducted in major A. sinensis producing areas located in Weiyuan County, Gansu Province. The physicochemical properties and relative abundance of bacterial genomic DNA in rhizosphere soil under different cropping patterns were measured during A. sinensis harvest period to investigate the effects of different cropping patterns on physicochemical properties, bacterial community diversity, and metabolic pathways. The results showed that: 1) the physicochemical properties in A. sinensis rhizosphere soil varied among different cropping patterns. Compared with the control, soil electrical conductivity under C pattern was significantly higher, and lower under B, D and E, CO2 respiration rate for B, C, D and E were significantly increased. 2) Soil bacteria of A. sinensis rhizosphere soil in the five cropping patterns belonged to 26 phyla and 368 genera. The dominant genera were Gemmatimonas from Gemmatimonadetes, Sphingomonas from Proteobacteria, and Subgroup_6 from Acidobacteria. Compared with the control, the relative abundance of Proteobacteria and Actinobacteria under B and C patterns was significantly higher, Acidobacteria in D pattern was significantly lower, while Proteobacteria, Acidobacteria, and Actinobacteria in E pattern was significantly higher. 3) There were significantly negative relations between soil pH, electrical conductivity, contents of organic matter, available nitrogen, phosphorus and potassium with the relative abundance of Proteobacteria in A. sinensis rhizosphere soil across the five cropping patterns. 4) There was significant difference in relative abundance for bacteria of six metabolic pathways under the five cropping patterns. In conclusion, C pattern had a regulating effect on physicochemical properties and bacterial communities in A.sinensis rhizosphere soil, which could be taken as a major practice to overcome the continuous cropping obstacles.