Soil physicochemical properties, tree growth, and fruit production in a non-astringent organic persimmon (Diospyros x kaki Thunb.) orchard affected by mowing frequency

摘要

The physical and chemical properties of the soil and the growth and fruit yields of mature 'Fuyu' persimmon (Diospyros x kaki Thunb.) trees were measured as responses to the frequency of mowing in an organic orchard from 2011 to 2013. Treatments included zero, two, three, or four mowings per annum of the natural vegetation in the orchard to which organic fertiliser was applied annually. The four-fold mowing treatment increased the biomass of the cut vegetation to 8.4 metric tonnes (MT) ha(-1) year(-1), followed by the three-fold (6.4 MT ha(-1) year(-1)), two-fold (5.7 MT ha(-1) year(-1)), and zero mowings (3.4 MT ha(-1) year(-1)) and the corresponding supply of macro-nutrients from the biomass. The four-fold mowing treatment reduced the bulk density of the soil from 1.3 kg m(-3) to 1.1 kg m(-3) and increased soil porosity to 59% (measured as air-filled space) as well as increasing the soil organic matter content to 25 -30 mg kg(-1) in March and September 2011 and 2012. Foliar macro-nutrient concentrations, except for foliar P, increased in the two-, three-, and four-fold mowing treatments in 2012. An increased mowing frequency stimulated the number of water-sprout shoots, and reduced light transmission into the tree canopy in 2012 and in 2013. The three-and four-fold mowing treatments increased average fruit yields by 28.1 - 29.4 MT ha(-1) and average fruit fresh weights (FWs) to 209 - 211 g compared to zero mowing (23.3 MT ha(-1) fruit yield and 197 g fruit FW) over the 3 years. The estimated average gross income from fruit sales increased by 183% in the three- and four-fold mowing treatments compared to the zero-mowing treatment over the 3 years.