Optimization of nitrogen fertilizer application in lowland rice production system of agricultural resource system research station using tailored farm-plot database

Abstract

© 2020 Chiang Mai University. The objectives of this study were to monitor the effects of nitrogen and phosphorus from input sources on rice production system by using 3-year-plot database and to optimize application rates of nitrogen fertilizer of 4 rice varieties. Tailored farm-plot database was applied to manipulate crop production data in farming system of Agricultural Resource System Research Station, Chiang Mai University, Thailand during July, 2014 and December, 2016. Nitrogen and phosphorus amount from input sources were quantified by referent nutrient contents in crop residues and fertilizer materials. Stepwise multiple regression was used for selective monitoring input crop nutrients on above ground weight and grain yield. The multiple regression models could explain 77 and 37% of variations on above ground weight and grain yield, respectively. The average harvest indexes and average yield of above 75th percentile of rice yield records of Khao Dowk Mali 105 (KDML), Mali Dang (MD), Sangyod (SY), and Hom Nin (HN) varieties were used to quantify the expected above ground weight. The results from baseline scenario indicated that application of 14.6, 4.0, 0 and 8.9 kg N.ha-1 with incorporated green manure were sufficient to supply the expected yield as 5,120.0, 5,597.5, 5,030.0 and 6,735.0 kg.ha-1 of KDML, MD, SY and HN, respectively. In case of without incorporated green manure, application of 35.6, 24.3, 16.1 and 22.2 kg N.ha-1 were required in comparison with site-usual application rate as 69.8 ± 24.6 kg N.ha-1. The results of this study may guide for site-specific crop nutrientmanagement, which relied on site-database.