In:
Agronomy Journal, Wiley, Vol. 77, No. 4 ( 1985-07), p. 616-621
Abstract:
Nitrogen fertilizer applications, for maximum fertilizer efficiencies and crop yields, should be based on the N required by the crop during its various growth stages. The objectives of this paper were to identify the N requirements of the potato plant ( Solanum tuberosum L.) during growth and to evaluate selected soil and plant tissue tests as indicators of the plant's N status. Growth analysis data and soil and petiole NO 3 ‐N concentrations were obtained at predetermined time intervals from N fertilization treatments in replicated field studies on a coarse‐silty mixed, mesic Durixerollic Calciorthrid soil. Maximum early tuber growth occurred when leaf area index was between 2.5 and 3.2 and the tops contained between 79 and 100 kg N ha −1 at the start of linear tuber growth. A preplant N fertilizer application between 67 and 134 kg ha −1 gave these characteristics under the experimental conditions. The maximum dry matter production rate per day (approx. 250 kg ha −1 ) occurred when there was between 80 and 140 kg N ha −1 in the plant tops and roots. An average tuber growth rate of 0.75 Mg ha −1 day −1 required a N uptake rate of 3.7 kg ha −1 day −1 to prevent the loss of N and dry matter from the tops and roots. Sufficient N was available for this rate when the soil NO 3 ‐N concentration was 〉 7.5 mg kg −1 (0.46‐m soil depth), corresponding to 15 000 mg kg −1 NO 3 ‐N in the fourth petiole. Soil and petiole NO 3 ‐N concentrations may be used to adjust the N fertilization rates during the growing season. This practice has the potential of increasing the overall N fertilizer use efficiency and final tuber yields within the climatic, disease, and variety limitations.
Type of Medium:
Online Resource
ISSN:
0002-1962
,
1435-0645
DOI:
10.2134/agronj1985.00021962007700040024x
Language:
English
Publisher:
Wiley
Publication Date:
1985
detail.hit.zdb_id:
1471598-3
