Effects of standing culm density and fertilizer regimes on Dendrocalamus brandisii (Munro) Kurz shoot production at Simao District, southwestern China

Abstract

Optimum shoot production in Dendrocalamus brandisii (Munro) Kurz depends on either standing culm density (SCD) or application of fertilizer. However, silvicultural application through the combined effect of SCD and fertilizer regimes is not fully understood. In this study, effects of SCD and fertilizer regimes, relationships between silvicultural treatments and growth parameters and model prediction on shoot production were conducted. A split-plot factorial design was applied in three blocks consisting of two main factors (SCD and fertilizer regimes). These were three SCD levels (2-1, 2-2 and control) and six fertilizer regimes (15 kg clump−1 compost; 0.25 kg clump−1 NPK mixed with 7.5 kg clump−1 compost; 0.5 kg clump−1 NPK; 0.75 kg clump−1 NPK; 1 kg clump−1 NPK; and control). Data collection on culms height, Diameter at breast height (DBH), soil properties and total number of shoots and shoot yield) was conducted from early July to mid-October. A total of 3,380 edible shoots ha−1 and 7.1 ton ha−1 shoot yield were harvested. Higher available nutrients (P and K) and total soil organic carbon (SOC) were associated by favorable soil pH, higher cation exchange capacity (CEC) and lower exchangeable acidity (EA) after fertilizer application. The largest shoot yield (12.04 ton ha−1) was recorded in 2-2 SCD responded to 0.75 kg clump−1 NPK. Shoot production further improved from 0.5 kg clump−1 NPK to 0.75 kg clump−1 and eventually declined to 1 kg. Linear mixed-effects model (LMM) showed that shoot yield had a positive and significant correlation (p<0.05) among D. brandisii silvicultural treatments and culm DBH classes. Our finding indicates that silvicultural application (SCD and fertilizer regimes) in relation to culm DBH classes could be a key factor for higher D. brandisii shoot production.