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The uptake of 15 N‐labelled fertiliser by winter wheat and its immobilisation in a clay soil after direct drilling or ploughing
Author(s) -
Dowdell Rodney J.,
Crees Rachel
Publication year - 1980
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740311004
Subject(s) - plough , calcareous , agronomy , nitrogen , crop , clay soil , chemistry , organic matter , nitrate , environmental science , soil water , soil science , biology , botany , organic chemistry
Abstract The uptake of fertiliser nitrogen (N) by winter wheat was measured using 15 N‐labelled calcium nitrate applied at 80 kg N ha‐ 1 rate in May to the soil in microplots contained by sections of rigid PVC tube (30 cm diameter, 20 cm long), inserted into a calcareous clay soil (Evesham series). The microplots and surrounding plots had been subjected to either 5 or 6 years of continuous ploughing or direct drilling or 1 and 2 years of direct drilling after 4 years of deep‐tined cultivation. The recovery of fertiliser N labelled with 15 N in the crop plants at harvest was in the range 60–67% of that applied in the first year and 0.5–0.7% in the second year; there were no significant treatment differences. The ‘apparent’ recovery of fertiliser based on a comparison of plots with and without fertiliser N was greater and ranged from 77–111 % of that applied. Estimates of the contribution of non‐fertiliser N to the crop by means of 15 N analysis suggest that if this N had been utilised with the same efficiency as that of fertiliser N about 120 kg N ha‐ 1 was available to the plants. This represents about 1% of the total N in the soil to 80 cm depth. Soil analysis (0–15 cm) showed that about 8% of the applied 15 N was retained in the upper layers of the soil; there were no treatment differences. Any changes due to mineralisation of the soil organic matter during the 2 years of the experiment were within the errors of the experiment.