TITLE:
Potential for Increasing Soil Nutrient Availability via Soil Organic Matter Improvement Using Pseudo Panel Data
AUTHORS:
María Daniela Chavez, Paulus Bernardus Maria Berentsen, Oene Oenema, Alfons Gerard Joseph Maria Oude Lansink
KEYWORDS:
Soil Degradation, Fixed and Random Effects, SOM Improvement Benefits and Costs, Green Manure
JOURNAL NAME:
Agricultural Sciences,
Vol.5 No.8,
July
28,
2014
ABSTRACT:
Fixed and random
effect models were applied to a pseudo-panel data built of soil analysis
reports from tobacco farms to analyze relationships between soil
characteristics like soil organic matter (SOM) and soil nitrogen (N),
phosphorous (P) and potassium (K) and to explore the potential for improving
nutrients availability by increasing SOM content. These econometric models may
account for unobserved specific characteristics such as location-specific
characteristics, management strategies, farmers’ skills and preferences and
environmental heterogeneity. Positive relationships were found between N, P and
K availability and SOM. The random effect model reports a highly significant
elasticity of N with respect to SOM of 0.75, meaning that an increase of 1% of
SOM will increase soil N by 0.75%. Using this elasticity, the required SOM
improvement of green manure was calculated at which costs of green manure would
exactly equal benefits in terms of reduced N fertilizer use. Costs and benefits are equal if the SOM increases
from 1.55% to 3.61%, which is barely achieved according to the literature.
Hence, growing green manure crops to increase SOM and thereby N availability is
not economically attractive. However, additional benefits may arise from SOM
improvement and growing green manure crops.