Soil conservation approaches and agroforestry systems can play an important role in controlling erosion from tropical hillside cropping systems. Experimental testing of their potential application domain and design, however, is costly and time consuming. We, therefore, tested the ability of the Water, Nutrient and Light Capture in Agroforestry Systems (WaNuLCAS) model. The specific objectives of the study were: (i) to evaluate the WaNuLCAS model for predicting water induced erosion under different soil conservation strategies, (ii) to use the model for a better understanding of various soil conservation measures in controlling erosion, and (iii) to assess the magnitude and dynamics of key processes influencing the efficiency of soil conservation measures. A 3-year-data set (2003–2005) from a field experiment from the Loei province in Northeast Thailand on the impact of soil conservation (Leucaena hedgerow, Jack bean relay cropping) under minimum tillage on runoff and soil loss was tested. Results indicated thatWaNuLCAS was able to predict soil loss and runoff well at the test site; i.e. R2 = 0.80 and 0.82, respectively. In the calibration procedure a sub data set was used, where adjusting crop development parameters was an important step for improving simulated soil loss (R2 = 0.75) and runoff (R2 = 0.89). Soilconservation measures such as Leucaena hedges were effective techniques to control runoff and soil loss. Implementing a dynamic soil structure module in combination with minimum tillage reduced runoff and soil loss via an increase in available macropores and hence drainage over time which improved simulation results. Relay cropping with Jack bean played an important role in the control treatment in reducing soil loss during the third year due to its additional soil cover and positive impact on soil fertility as suggested by the model. Hence, the WaNuLCAS model is a valuable tool to study and understand processes and to explore management options for improving tropical hillside cropping threatened by soil degradation.
Tag: cropping
Growth, yield and economic potential of Strobilanthes cusia (Nees) Kuntze in underutilized bamboo stands in Indonesia
Strobilanthes cusia is a herb species of the Acanthaceae family. This plant is a well-known dye crop. A participatory experiment was conducted regarding S. cusia cultivation under bamboo stands. Strobilanthes cusia seedlings were planted in split plot design consisting of two treatments, with bamboo canopy cover (dense canopy, moderate canopy, sparse canopy, open area) as the main plots and the use of fertiliser (control, swine manure, NPK 16-16-16, NPK plus swine manure) as the sub plots, with each plot being 10 m2. Strobilanthes cusia seedling performance was best under sparse canopy, where on average shoot length was 22.80 cm, the number of leaves was 45.3, and leaf yield at the edge and middle of plot were 1.90 kg/plot and 1.86 kg/plot, respectively. Wet paste yield was best from S. cusia cultivated under the sparse canopy with NPK plus manure (337 g m−2) resulting in dried paste at 0.71 g m−2. Financial feasibility showed that intercropping S. cusia under a natural bamboo stand of Dendrocalamus asper delivered net present value of Indonesian Rupiah 28,951,568 (USD 1,587) with benefit cost ratio of 1.58.