Nitrogen mineralisation from amended and unamended intensively managed tropical andisols and inceptisols

Abstract

Intensive vegetable production systems throughout South East Asia are characterised by large nutrient inputs and low nitrogen (N) use efficiencies. In Indonesia, intensive vegetable production is concentrated on volcanic highland soils starting from an altitude of around 700 m above sea level. We measured potential N mineralisation from soil organic matter and from several representative organic materials in Andisols and Inceptisols with andic properties from Central Java, Indonesia. Unamended soils and soils amended with crop residues, animal manures, and compost were incubated during 3-4 months at 25 degrees C in the laboratory, then we monitored N mineralisation. Relative N mineralisation was significantly smaller in the Andisols (average 3.6 +/- 1.0%) than the Inceptisols (7.4 +/- 2.9%), and was negatively related to oxalate-extractable aluminium (Al-ox) (r = -0.749) and soil organic carbon (r = -0.705). This is probably due to the strong protection of organic matter (and organic N) by binding to active Al compounds. Net N mineralisation from the added organic materials was highly variable (ranging from 68.1% for the broccoli residues to 2.6% for tithonia compost), and was best related to the organic N content (r = 0.476). There were no significant correlations between net N mineralisation and biochemical fractions, which we attribute to the large variety of materials used in this study compared with previous studies. The data generated here on N mineralisation potential from soil organic matter, and from a variety of plant materials and animal manures that are commonly used in these intensive vegetable rotations, will allow for the rapid and efficient introduction of N fertiliser advice systems based on balance sheets

Influence of Various Composted Organic Amendments and Their Rates of Application on Nitrogen Mineralization and Soil Productivity Using Chinese Cabbage (Brassica rapa. L. var. Chinensis) as an Indicator Crop

“…These results were in line with the previous findings [45][46][47]. Hence, this strong correlation between the total N and NO3 − -N contents and the N mineralization rate represent the complex mineralization process that is influenced by different parameters and not only the residual added nitrogen [47]. From the calculated correlation between N mineralization rates and total N, it coincides with the finding of Widowati et al [47] who reported that N content of OAs may still be the best factor predicted difference in N mineralization behaviour.…”

“…Correlation studies showed a significant correlation between N mineralization rate and total N (%) and NO3 − -N contents of the OAs. These results were in line with the previous findings [45][46][47]. Hence, this strong correlation between the total N and NO3 − -N contents and the N mineralization rate represent the complex mineralization process that is influenced by different parameters and not only the residual added nitrogen [47].…”

Nitrogen Dynamics and Nitrate Leaching in Intensive Vegetable Rotations in Highlands of Central Java, Indonesia

“…The average excess water (EW) was 2073 mm yr -1 for the Wonosobo sites and 1275 mm yr -1 for the Kopeng sites, respectively. The IP and FP nitrogen balance results were highly positive, as the nitrogen fertilizer was heavily applied (Widowati et al 2012) (Table 4). The average PNC values of IP and FP were significantly different (P < 0.05).…”

“…Excessive N fertilizer application is therefore very common, while N use efficiency is often low. Data gathered from farmers' practices (Widowati et al 2012), revealed an average ANUE value 16% for two consecutive years; therefore, more than 80% of N added is susceptible to loss. Application of N fertilizer in excess of crop requirements can result in the accumulation of NO 3 -N in the soil profile (Gillard et al 1995;Malhi et al 2001).…”

“…This daily NO 3 -N concentration was then diminished by the daily N uptake by the crop (calculated as total N uptake divided by the length of the cropping cycle in days; i.e., assuming a linear crop N uptake pattern) before calculations for that day were continued. The data on N mineralization from soil organic matter and organic materials were taken from Widowati et al 2012, the total crop N uptake was taken from Widowati et al 2011, and the denitrification rates were obtained from Anggria (2007). Data used in the running model were from the first and third planting seasons of the year 2007; i.e., only during the rainy season, as there was no leaching in the second planting season.…”