Scheme of Weather-Based Indemnity Indices for Insuring Against Freeze Damage to Citrus Orchards in Zhejiang,China

We design a weather-based indemnity index for the insurance against freeze damage to citrus orchards so as to provide technological support for the development of policy-based agriculture. The indices are prepared by separating a relative meteorological yield from the yield that is dependent on tree age, high-yield and low-yield years, and environmental factors, and then using a risk assessment scheme to determine the percentage yield reduction due to the meteorological hazard. We thus develop a set of indices associated with cold temperature damage with which to construct more severe weather indices in conjunction with the yield percentage decrease. We then combine the insured regional citrus yield index with the insured meteorological counterpart to obtain a weather-based indemnity index for the varying degree of freeze damage to crops. When the freeze damage index （FDI） is greater than -7.0℃ for the coastal belt of Zhejiang Province, China, or greater than -9.0℃ for other regions of Zhejiang, weather-based indemnity index （WBII） is zero, meaning there is no compensation; when the FDI is from -7.0 to -7.9℃ for the coastal belt or from -9.0 to -9.9℃ for other regions, the WBII is 1 with 50% compensation; when the FDI is from -8.0 to -8.9℃ for the coastal belt or from -10.0 to -10.9℃ for other regions, the WBII is 2 with 70% compensation; and when the FDI is less than -9.0℃ for the coastal belt or less than -11.0℃ for other regions, the WBII is 3 with 90% compensation. The weather indemnity indices of insured orchards are developed in the interest of owners, thereby eliminating adverse selection and moral hazard issues and providing timely recompense from the insurer, and resolving the problem of high indemnity cost in agricultural insurance.

Production Mode and Economic Benefit of Improved No-tillage Intercropping with Potato in New Mode Citrus Orchard

[Objectives]In terms of increasing the utilization of land in agriculture and the per unit area yield,intercropping is the most popular farming method.[Methods]Based on the climate and soil conditions in Zhaoqing,this experiment explored the improved mode of no-tillage intercropping winter potato with citrus in the new high-ridge,wide-row and dense-plant cultivation mode citrus orchard.Taking the conventional tillage and film-mulched intercropping as the control,it studied the adaptability of intercropping,evaluated the quality,and analyzed its economic benefits.[Results]The early emergence rate of improved no-tillage intercropping cultivation was slightly higher than that of conventional tillage and film-mulched intercropping,but the difference of final emergence rate was not significant,indicating that improved no-tillage intercropping cultivation could provide excellent potato emergence environment.Under the conventional tillage and improved no-tillage intercropping cultivation mode,the change trend of the potato's plant height,main stem thickness,crown diameter and number of leaflet is the same.The change rule of the crown diameter of the film-mulched intercropping cultivation method is similar to that of the plant height,both have a large increase in the late growth stage.The potato yield of improved no-tillage intercropping cultivation were 22747.5 kg/ha,and the proportions of potatoes of each grade were 11.85%,35.61%,37.63%and 14.91%,respectively.The content of dry matter,Vc,soluble protein,starch and amino acid in the main nutrients of the potato under the improved no-tillage intercropping mode is not significantly different from that of the film-mulched intercropping cultivation.The changing trend of reducing sugar content showed that the reducing sugar content of no-tillage intercropping cultivation was the highest(0.466%).Through evaluating the eating characteristics of potatoes from the flavor,taste,texture and appearance after chewing,the three cultivation methods have little difference.In the no-tillage intercropping cultivation technology,the growth of potatoes consumes part of the nutrients in the soil between the rows of the citrus orchard,but it does not exerts a significant impact on the surrounding citrus trees.Compared with the film-mulched intercropping cultivation,the improved no-tillage intercropping cultivation method does not require the expense of mulched,the cost of fertilizer is low,and labor costs are saved,so a net income of 27075 yuan/ha can be obtained.[Conclusions]From the perspective of orchard intercropping,it has achieved the effect of improving soil utilization and increasing output without reducing the edible quality of potatoes.

Changes in Soil Moisture Content and Characteristics ofWater Movement in Citrus Orchards under Different Mulching Methods

[Objectives]The paper was to explore the effects of different mulching methods on soil moisture content and water movement in citrus orchards,and to provide the theoretical basis for improving water and weed management level in orchards.[Methods]Three ground mulching treatments including spraying herbicide(CK),grass-proof cloth cover(GPC)and natural grass mowing(NGM)were set up to analyze the soil moisture content and water flux characteristics of soil profile in the soil layers of 5,20,40 and 60 cm under different mulching methods.[Results]The GPC and NGM treatments significantly increased the soil moisture content in the soil layer of 0-60 cm at the young fruit stage and fruit expansion stage,which inhibited soil water evaporation and effectively improved soil water holding capacity,thus reducing irrigation water consumption and saving water resources.During the expansion stage of citrus fruits,the soil water flux in the soil layer of 0-60 cm in NGM and CK treatments was upward,and the upward soil water flux in NGM treatment was larger,which could mobilize more upward movement of deep soil moisture for uptake by citrus roots.However,the soil water flux in the soil layer of 0-60 cm in GPC treatment was downward,and the soil moisture conditions in the upper and middle layers were already sufficient for citrus growth.[Conclusions]Both GPC and NGM treatments can increase the overall soil moisture content.In the dry season,the soil moisture content in the upper layer treated by GPC is always relatively high,while more soil water in the lower layer move to the upper layer in NGM treatment,which has met the water requirements for citrus growth.

Effects of Intelligent Irrigation on Photosynthetic Characteristics of Citrus Leaves and Fruit Quality

[Objectives]This study was conducted to improve the water use efficiency and fruit quality of citrus,and realize the automatic irrigation and standardized production in citrus orchards.[Methods]With Orah as the research object,the effects of intelligent irrigation management in citrus orchards on citrus leaf chlorophyll content,photosynthetic characteristics and fruit quality were investigated by comparing with conventional farmer management.[Results]The smart irrigation measure in citrus orchards significantly increased the SPAD value of leaves at the maturation stage of citrus,and simultaneously significantly improved the photosynthetic rate,transpiration rate and stomatal conductance at the flower bud differentiation stage,as well as the photosynthetic rate,transpiration rate,stomatal conductance and intercellular CO_(2) concentration at the maturation stage.However,the effects on the photosynthetic characteristic indexes in the rainy season were not significant.Compared with conventional experience management,the smart irrigation management measure of citrus orchards increased the edible rate and juice rate of citrus by 4.53 and 3.69 percentage points,respectively,and increased soluble solids,total sugar,vitamin C and sugar-acid ratio by 16.75%,20.86%,24.10%and 13.17%,respectively.[Conclusions]The smart irrigation management fully met the water demand for citrus growth due to timely irrigation,significantly improved the photosynthesis indicators of citrus leaves during drought,and significantly improved the quality of citrus.