Study On The Dynamic Changes Of Pecan ’Mahan’ Nutrients

This paper studies on dynamic changes of mineral elements and nutrients during Pecan‘Mahan’s growth and development. The main contents include the dynamic changes of nineelements in its leaves, male and female flowers, fine roots and fruits, the accumulation andtransformation of crude fat, crude protein, soluble sugar and starch in nuts, the dynamic changesof soil pH, organic matter and nine elements. The main results were showed as follows:1、In leaves, the macro-element content of high and low order in turn was N＞K＞Ca＞Mg＞P and the trace element content of high and low order in turn was Mn＞Zn＞Fe＞Cu. Thechanging trend of N and P were the same at the highest content in April, then continued to decline;on the contrary, the lowest content of Ca was in April, then continued to rise; K at first rose afterfalling, and Mg at first fell after rising. The changing trend of Fe and Zn suffered a wavy trend; Cuat first fell, followed by rising and falling again; Mn fell before rising. There was an obviousturning point during June27thto July13th, the concentrations of mineral elements changed moreslowly，it was the best time to pick the samples of leaves for leaf diagnosis.2、The content of K, Zn in male flower increased with growth and development, however, thecontent of Ca, Fe decreased; before the exhibition of leaves, the content of N, P, Cu accumulatedrapidly because of the growth of flower bud. Then the content of N, P decreased gradually exceptCu. Before fertilization, most of the elements including N、P、K、Mg、Cu、Zn increased exceptFe in female flower. During the flowering phase, as can be seen from the correlation analysis，thedemand of N and P were the largest both in male and female flower.3、In fine foots, the macro-element content of high and low order in turn was N＞Ca＞Mg＞P＞K and the trace element content of high and low order in turn was Fe＞Mn＞Zn＞Cu,meanwhile, the trace element content changed more complicated than the macro-elements’ duringthe growing season. Through correlation analysis, there was an extremely significant positivecorrelation between P and K, while other elements were extremely significant negative correlated.4、During the whole growth and development, the macro-element content of high and loworder in turn was K＞P＞N＞Ca＞Mg and the trace element content of high and low order in turnwas Mn＞Zn＞Fe＞Cu in kernel; the macro-element content of high and low order in turn was Ca＞K＞N＞Mg＞P and the trace element content of high and low order in turn was Mn＞Zn＞Cu ＞Fe in shell; the macro-element content of high and low order in turn was K＞Ca＞N＞Mg＞Pand the trace element content of high and low order in turn was Mn＞Zn＞Fe＞Cu in epicarp; thekernel became the center of the whole plant nutrition from late July, other elements all transferredfrom shell to kernel and epicarp, while Ca and Mn traveled the other way around.5、Total soluble sugar and starch decreased while crude fat and crude protein increased duringthe kernel changing process of storage matter in pecan. At harvest, crude fat and crude proteinbecame the main components of the kernel with the content of67.27%and62.04mg/grespectively. During the process of fruit development, the relative contents of UFA and SFA were90.6%and9.4%respectively.6、The average pH of pecan experimental forestland was between5.41to6.64, while theaverage soil organic matter was between2.10%-3.71%in0-20cm soil. pH/organic matter andleaves/fine roots respectively had no significant correlation. The valid macro-element content ofhigh and low order in turn was Ca＞K＞N＞Mg＞P, and the valid trace element content of highand low order in turn was Mn＞Zn＞Cu; the content of P、K、Ca in leaf and the content of Mg, Cu,Fe in fine root and soil available nutrient had a certain correlation. It showed that the relationshipamong soil nutrients, leaf and fine root was complicated. Through correlation analysis, available Pin soil and total K in leaf existed extremely significant negative correlation, while available P insoil and total Mn in leaf or total Cu in fine root existed negative correlation. So we should payattention to use fertilization. Soil and leaf analysis were very complementary in the nutritiondiagnosis. The average pH was between5.41-7.04, while the average soil organic matter wasbetween1.10%-3.17%in20-40cm soil. pH, organic matter and total P in fine roots respectivelyhad significant positive correlation. pH and organic matter existed extremely significant positivecorrelation. Organic matter and total Cu in leaves existed significant negative correlation. Organicmatter and total Zn in fine roots existed extremely significant negative correlation. The availablemacro-element content of high and low order in turn was Ca＞N＞K＞Mg＞P, and the availabletrace element content of high and low order in turn was Mn＞Zn＞Cu.