| 【Objective】 The experiment was conducted to explore the changes of soil nutrient contents and enzyme
activities after different years of banana-sugarcane rotation and to explore the mechanism of banana-sugarcane rotation
mode to alleviate continuous cropping obstacles from soil nutrient level.【Method】Two field trials were conducted to determine a total of 24 indicators(including contents of nutrients and soil enzyme activities etc.) of different years. One was the
experiment of sugarcane rotation in banana fields. There were four treatments:continuous cropping bananas for many years(CK),
bananas monocropping-1 year of sugarcane rotation(GZ1), bananas monocropping-2 years of sugarcane rotation (GZ2), bananas
monocropping-3 years of sugarcane rotation(GZ3). The other was the experiment of replanting bananas after sugarcane rotation.
Four treatments were designed as follows 2 years of rotation(GZ2), GZ2-1 year of banana replanting(XJ1), GZ2-2 years of
banana replanting(XJ2), GZ2-3 years of banana replanting(XJ3). 【Result】The soil pH value showed a decreasing trend with
the increase of sugarcane rotation years , and an increasing trend with the increase of banana replanting years. The soil enzyme
activities such as soil invertase(Inv), urease(Ure), polyphenol oxidase (PPO), cellulose(Cel), and the available phosphorus(P),
available potassium(K), available sulphur(S) and available boron(B) tended to increase with the increase of sugarcane
rotation years, and tended to decreased with the increase of bananare planting years. These indicators could better reflect
the changes of soil quality during banana-sugarcane rotation. The incidence of banana wilt was positively correlated with soil
pH, and negatively correlated with Cel activity, contents of NO3
--N, K, S and B in the soil. Sugarcane Rotation could improve
soil quality better. Comparing with the CK, the soil invertase, urease, polyphenol oxidase and cellulose activities increased
significantly in GZ2, and the contents of NO3
--N, P, K,S, B and Ca/Mg increased by 146.13%, 18.61%, 22.70%, 45.48%,
214.63% and 37.64%, respectively. After 2 years of rotation and 3 years of replanting banana, however, soil quality deteriorates
severely. Comparing with the GZ2, the activities of Inv，Ure，PPO and Cel were significantly decreased in XJ3, the contents of
NO3
--N，S，Zn and B decreased by 45.18%, 38.97%, 19.05% and 72.09%, respectively. Except for Cel activity, AA content
and Ca/Mg, other indicators were lower or close to those of CK. 【Conclusion】Sugarcane rotation of sugarcane in continuous
cropping banana in fields can increase soil enzyme activity and nutrient contents and improve soil physical and chemical
properties. Therefore, banana continuous cropping obstacles can be alleviated. The soil physical and chemical properties can be
effectively improved after continuous cropping of sugarcane for 2 years. After sugarcane rotation for 2 years, then it is advisable
to plant bananas for 3 years. |
