Abstract:
Objective The aim was to explore the contribution of purple-leaf rape to soil fertility and provide theoretical support for the promotion of new variety of rape green manure.
Method Indoor cultivation experiments were conducted using purple-leaf rape and green-leaf rape as test materials. Different treatments were applied to different types of soil (yellow red soil, red soil), including CK (control, no addition of rape), T1 (low-dose rape addition), T2 (high-dose rape addition), and so on. The differences in soil pH, physical clay (PC), physical sand (PS), soil organic matter (SOM), available nitrogen (AN), available phosphorus (AP), available potassium (AK), as well as bacteria, fungus and actinomycete populations were analyzed after the addition of different rape green manures.
Result The results revealed that the soil pH in all treatment groups decreased after the addition of rape, and significant differences in yellow red soil (reductions ranging 3.70%-5.29%). The SOM, AN, AP and AK in yellow red soil all significantly increased with 10.35%-14.40%, 258.58%-277.88%, 135.06%-143.31%, 41.83%-49.92%, respectively. And they increased in red soil with 8.41%-20.76%, 52.27%-70.99%, 56.06%-83.05%, 39.50%-50.54%, respectively. Soil bacteria, fungi and actinomycetes also significantly increased in yellow red soil with 0.82%-16.35%, 12.71%-37.46% and 5.56%-19.01%, respectively ; And they increased in red soil with 547.44%-2592.31%, 2652.29%-3468.81% and 208.57%-629.52%, respectively. All these indicators showed the highest increase in T2. Purple-leaf rape and green-leaf rape had the same improvement effects on SOM, AP, AK, bacteria, fungi, and actinomycetes, but high added amounts of purple-leaf rape were more conducive to increasing soil AN content than that of green-leaf rape.
Conclusion Therefore, T2 is more conducive to improving soil physicochemical indicators and increasing microbial populations, making it the most effective fertilization method. Under equal conditions, purple-leaf rape has the same fertilization effect as green-leaf rape. The high added amounts of purple-leaf rape has an advantage in improving available nitrogen compared with green-leaf rape.