Investigations were carried out on the micronutrient contents,of major citrus orchard soils (involving seven soil great groups in 8 provinces and an autonomous region of southern China),and an evaluation on the abunda...Investigations were carried out on the micronutrient contents,of major citrus orchard soils (involving seven soil great groups in 8 provinces and an autonomous region of southern China),and an evaluation on the abundance and deficiency of available micronutrients in these soils was made in this paper.In southern China,citrus orchard soils derived from sandstone,sandy shale,Quaternary red clay,diluvial deposit,granite gneiss and neritic deposit were deficient in available Mo and B and low in Zn.Those developed on purple sandy shale,limestone and slope deposit were all in short supply of available Zn,B and Mo.Coastal solonchak was fairly abundant in B,but its available Fe,Zn and Mo contents were rather low.展开更多
By using nutritional diagnosis of citrus leaves and determining soil micronutrients,the relationship between soil micronutrients and citrus growth in southern China has been studied.Studies showed that there was a sig...By using nutritional diagnosis of citrus leaves and determining soil micronutrients,the relationship between soil micronutrients and citrus growth in southern China has been studied.Studies showed that there was a significant positive correlation between available micronutrients (such as Zn,Mo,Cu)in the soil and the corresponding nutrients in citrus leaves.Thus,one can roughly learn of the sufficiency or deficiency of certain nutrients in soils by analyzing citrus leaves.Rational spray of Zn B or Mo fertilizer not only improved citrus yields but also increased the total sugar of Satsuma mandarin and of Xinhui orange by 2.9 and 17.2% respectively compared with the control.Spraying Mo fertilizer increased the vitamin C content of Satsuma mandarin juice by 4.7%-8.4%,maturated fruits 7-10 days earlier and gave the peel a brighter color.The ultramicroscopic characteristics of Zn-deficient citrus leaves were investigated under an electron microscope.Results showed that the Zn-deficient leaf cell was characterized mainly by poor cytoplasm,endoplasmic reticula and ribosomes and by big starch grains in the chloroplast.As a result of spraying Zn fertilizer the structure of the cell returned to normal,the cytoplasm became rich and the amount of chloroplast increased.There also appeared a great deal of multiform endoplasmic reticula,thus promoting the photosynthesis of Zn-deficient plants.This provides a cytologico-theoretical basis for fertilization of high-yielding citrus trees.展开更多
Soil capacity to support life and to produce economic goods and services is strongly linked to the maintenance of good soil physical quality(SPQ). In this study, the SPQ of citrus orchards was assessed under three dif...Soil capacity to support life and to produce economic goods and services is strongly linked to the maintenance of good soil physical quality(SPQ). In this study, the SPQ of citrus orchards was assessed under three different soil managements, namely no-tillage using herbicides, tillage under chemical farming, and no-tillage under organic farming. Commonly used indicators, such as soil bulk density,organic carbon content, and structural stability index, were considered in conjunction with capacitive indicators estimated by the Beerkan estimation of soil transfer parameter(BEST) method. The measurements taken at the L'Alcoleja Experimental Station in Spain yielded optimal values for soil bulk density and organic carbon content in 100% and 70% of cases for organic farming. The values of structural stability index indicated that the soil was stable in 90% of cases. Differences between the soil management practices were particularly clear in terms of plant-available water capacity and saturated hydraulic conductivity. Under organic farming, the soil had the greatest ability to store and provide water to plant roots, and to quickly drain excess water and facilitate root proliferation.Management practices adopted under organic farming(such as vegetation cover between the trees, chipping after pruning, and spreading the chips on the soil surface) improved the SPQ. Conversely, the conventional management strategies unequivocally led to soil degradation owing to the loss of organic matter, soil compaction, and reduced structural stability. The results in this study show that organic farming has a clear positive impact on the SPQ, suggesting that tillage and herbicide treatments should be avoided.展开更多
文摘Investigations were carried out on the micronutrient contents,of major citrus orchard soils (involving seven soil great groups in 8 provinces and an autonomous region of southern China),and an evaluation on the abundance and deficiency of available micronutrients in these soils was made in this paper.In southern China,citrus orchard soils derived from sandstone,sandy shale,Quaternary red clay,diluvial deposit,granite gneiss and neritic deposit were deficient in available Mo and B and low in Zn.Those developed on purple sandy shale,limestone and slope deposit were all in short supply of available Zn,B and Mo.Coastal solonchak was fairly abundant in B,but its available Fe,Zn and Mo contents were rather low.
文摘By using nutritional diagnosis of citrus leaves and determining soil micronutrients,the relationship between soil micronutrients and citrus growth in southern China has been studied.Studies showed that there was a significant positive correlation between available micronutrients (such as Zn,Mo,Cu)in the soil and the corresponding nutrients in citrus leaves.Thus,one can roughly learn of the sufficiency or deficiency of certain nutrients in soils by analyzing citrus leaves.Rational spray of Zn B or Mo fertilizer not only improved citrus yields but also increased the total sugar of Satsuma mandarin and of Xinhui orange by 2.9 and 17.2% respectively compared with the control.Spraying Mo fertilizer increased the vitamin C content of Satsuma mandarin juice by 4.7%-8.4%,maturated fruits 7-10 days earlier and gave the peel a brighter color.The ultramicroscopic characteristics of Zn-deficient citrus leaves were investigated under an electron microscope.Results showed that the Zn-deficient leaf cell was characterized mainly by poor cytoplasm,endoplasmic reticula and ribosomes and by big starch grains in the chloroplast.As a result of spraying Zn fertilizer the structure of the cell returned to normal,the cytoplasm became rich and the amount of chloroplast increased.There also appeared a great deal of multiform endoplasmic reticula,thus promoting the photosynthesis of Zn-deficient plants.This provides a cytologico-theoretical basis for fertilization of high-yielding citrus trees.
基金supported by the RECARE Project from the European Union Seventh Framework Programme (FP7/2007-2013) (No. 603498)COST actions 1306
文摘Soil capacity to support life and to produce economic goods and services is strongly linked to the maintenance of good soil physical quality(SPQ). In this study, the SPQ of citrus orchards was assessed under three different soil managements, namely no-tillage using herbicides, tillage under chemical farming, and no-tillage under organic farming. Commonly used indicators, such as soil bulk density,organic carbon content, and structural stability index, were considered in conjunction with capacitive indicators estimated by the Beerkan estimation of soil transfer parameter(BEST) method. The measurements taken at the L'Alcoleja Experimental Station in Spain yielded optimal values for soil bulk density and organic carbon content in 100% and 70% of cases for organic farming. The values of structural stability index indicated that the soil was stable in 90% of cases. Differences between the soil management practices were particularly clear in terms of plant-available water capacity and saturated hydraulic conductivity. Under organic farming, the soil had the greatest ability to store and provide water to plant roots, and to quickly drain excess water and facilitate root proliferation.Management practices adopted under organic farming(such as vegetation cover between the trees, chipping after pruning, and spreading the chips on the soil surface) improved the SPQ. Conversely, the conventional management strategies unequivocally led to soil degradation owing to the loss of organic matter, soil compaction, and reduced structural stability. The results in this study show that organic farming has a clear positive impact on the SPQ, suggesting that tillage and herbicide treatments should be avoided.
