| As one of the main grain crops in China,where rice has a sowing area of 29.1%of the total crop area,and its yield accounts for 43.7%of the total grain production.Rice is the staple food on which our people live.The production of rice will have a great and far-reaching impact on food security in China.At present,rice cultivation in Guizhou Province is mainly single-season rice continuous cropping,there are many problems,for example,the rice field has a large area of winter leisure and a low index of multiple cropping.The long-term continuous cropping system and the excessive use of chemical products such as chemical fertilizers and pesticides can easily lead to the loss of soil nutrient balance,the decrease of soil enzyme activity and the deterioration of the ecological environment of rice fields.As a result,the ability of sustainable use of land decreased,which affected the yield and quality of crops.Rotation of multiple cropping in paddy field can maintain soil strength,improve soil environment,increase soil microbial quantity and enzyme activity,and play a positive role in reducing continuous cropping obstacle.Making crops promote each other to form a virtuous circle is a combination of land and land in agricultural production and can be effectively popularized and applied.In order to understand the changes of crop productivity,soil characteristics and energy flow logistics under different winter planting patterns,and to explore high efficiency and high yield planting patterns,promote the sustainable development of agriculture,increase farmers'income,and provide theoretical basis for the development of circular agriculture in Guizhou Province.Through long-term fixed-point experiment,this study designed five winter planting patterns of winter idling,rape,vegetables,potato and green manure under the condition of multiple cropping rotation in rice fields.The main results of the study are as follows:1.In terms of crop productivity,different winter planting patterns can improve system productivity.?1?The actual yield of rice with winter crops was higher than that in winter field,the C>E>D>B>A,increase was 3.71%?8.48%,among which the actual yield of winter vegetables and green manure increased 8.48%and 7.6%respectively.According to the factors of yield composition,there was no significant difference in the effective spike number,planting setting rate and 1000-grain weight of rice in different winter planting patterns,and the total grain number per ear of winter planting crops was significantly higher than that of winter idle treatment an increase of 6.23%?9.23%,and the total grain number per ear of winter vegetables was the highest,with an increase of 9.23%.?2?The biomass of crops in different winter was different,such as rape>potato>weed>vegetable>green manure,economic yield was rape>potato>vegetable,and harvest coefficient was vegetable>potato>rape.Winter crops can not only increase crop yield and economic yield,but also increase the amount of straw returning to the field,reduce the growth of weeds in winter,improve the utilization rate of farmland,improve soil fertility,affect the growth and development of rice,and increase the yield of rice.In this experiment,the rice yield of vegetable-rice winter was better.2.In terms of soil characteristics,different winter planting patterns have different effects on the physical and chemical properties and enzyme activities of different tillage layers.Except for green manure-rice model,there was no significant difference in bulk density of plough layer in other models.Rape-rice and vegetable-rice models were beneficial to improve the soil capillary porosity,total porosity and capillary water holding capacity of the tillage layer.There was no significant difference in soil organic matter and total phosphorus in different winter planting patterns.All-potassium and available phosphorus in soil 0-21cm in winter crops were higher than those in winter fields,and the effect of vegetable-rice was the best.Rape-rice and vegetable-rice model the content of alkali-hydrolyzed nitrogen and available potassium in soil 0-21cm was higher than that in other treatments.Rape-rice had the lowest total nitrogen in soil 14-21cm.There was no significant difference in soil urease in different winter planting patterns.The soil catalase activity and invertase activity in soil 0-21cm were higher than those of winter treatment,which were 0.58%?0.75%,0.4%?23.81%.Among them,rape-rice soil invertase showed the best performance in soil 0-21cm,with an increase of23.81%.3.For energy flow,the energy input outside the system is mainly non-functional input,accounting for 88.03%?95.28%of the total input,fuel and agricultural machinery account for about half of the non-functional,indicating that the mechanization in this area is relatively high.For system energy output,the total energy output of winter rape was the highest for system energy output,reaching456.92×109 J·hm-2,followed by winter potato and for 327.48×109 J·hm-2.According to the analysis of the production/investment ratio and the returned field/total output of the system,although the production and investment of the treatment B is relatively low and for 2.64,but the returned field/total output is 0.292,which indicates that the cycle utilization ratio of energy is high.4.As for material circulation,the N?P?K input,output and return of different winter modes are different.Fertilizer is the main input of each treatment N?P?K.The N?K output in winter potato was the highest,for 413.62 g·hm-22 and 629.37g·hm-2,and was the highest P in winter rape,for 162.39 g·hm-2.and the N?P?K output of winter purple cloud is the lowest.For N?P?K return,the highest N to deal with A restitution,maximum number of P?K processed B returned.For N?P?K system output/input ratio,Except for winter potato N greater than 1,System input N?P is larger than system output N?P in different winter modes.The results showed that the system N and P were in surplus state,which was beneficial to the virtuous circle of soil N and P.The output/input ratio of the system K is greater than 1 for different winter modes,which indicates that the K output between the treatments is greater than the input,and the system K has a serious loss,so it is necessary to apply more potassium fertilizer to balance the the soil. |
PDF Full Text Request