The Growth and Thatch Accumulation of Kentucky Bluegrasses as Affected by Cutting Management. Varietal Differences under Removing Clipping Residues

예초관리에 따른 Kentucky bluegrass의 품종간의 생육과 Thatch 축적 I. 예초잔여물의 제거 하에서의 품종간의 차이

This experiment was carried out in order to study the changes of morphological characters of the growth and thatch accumulation in :3 varieties of Kentucky bluegrass under removing clipping residues as affected by cutting management. The varieties used were Park, Kenhiuc and Newport.The results obtained are as follows; 1. The dry weight of leaf. stem and number of tiller was highest at 22. June and lowest at 21. Aug in alt varieties. And then the dry weight of rhizome, root and thatch increased with growth progressed) Tabte 3). 2. The relationship of the dry weight of biological yield and number of tillers was quadratic ally increased in the growth stage of spring($R^2$= 0.982**), and linearlly increased in the growth stage of autumn(r 0.944*)(Fig. 1). :3. The dry weight of thatch increased as an exponentially equation in alt :3 varieties of Kentucky blue-grass(Fig. 2). Thatch increased rate(TIR) can used to estimate the specifying a quantity of thatch accumulation from the turf. Thatch increase rate equation as follows. where TH$_2$ is the dry weightof thatch at T$_2$ survey time and TH$_1$ is the dry weight of thatch at $TH_1$ is the dry weight of thatch at $T_1$ survey time. $TIR(mg/cm^2/day)=\frac{Ln\;TH_2 - Ln\; TH_1}{T_2 - T_1}$ 4. Correlation coefficients between the dry weight of thatch and leaf weight was -0.633(P>0.05), and number of tiller of tillers was -0.666(P>0.5), respectively. It means that thatch accumu-lation increased with growth depression of leaf and stem.