. Efficient use of nitrogen on crop land in the Northeast. Plants; Soils. , ^.^..-te^i^^e-^—-p-^-g^-^r i8Q-CM o p^ 240-GM m».lmAni»,*, dm »ft « ko ^ I W^ 6 8 10 12 2 6 8 10 12 2 MONTHS Figure 13. Distribution of rainfall with time and distribution of nitrate-N concentration with soil depth and time beneath shade tobacco in 1974. (Data of Storr and DeRoo, Connecticut) Turf plots: Nitrate-N movement and losses to ground- water beneath turf grass grown on a Merrimac sandy loam were studied for 3 years at the Valley Lab- oratory (Starr & DeRoo 1979). Field plots, instrumented wit
. Efficient use of nitrogen on crop land in the Northeast. Plants; Soils. , ^.^..-te^i^^e-^—-p-^-g^-^r i8Q-CM o p^ 240-GM m».lmAni»,*, dm »ft « ko ^ I W^ 6 8 10 12 2 6 8 10 12 2 MONTHS Figure 13. Distribution of rainfall with time and distribution of nitrate-N concentration with soil depth and time beneath shade tobacco in 1974. (Data of Storr and DeRoo, Connecticut) Turf plots: Nitrate-N movement and losses to ground- water beneath turf grass grown on a Merrimac sandy loam were studied for 3 years at the Valley Lab- oratory (Starr & DeRoo 1979). Field plots, instrumented with suction lysimeter and neutron probe access pipes, were utilized to study the fate of N fertilizer applied to turf grass. Fertilizer N was applied at an annual rate of 180 kg/ha to each plot in a split application of 90 kg/ha each in May and September for three consecutive years. Grass clip- pings were returned, after subsampling, on two of the four plots. In the third year, the use of ^'N as a tracer in conjunction with management of grass clippings provided the means to quantify the N in the grass derived from fertilizer, soil, current year's grass clippings, and the previous two years of grass clippings. A summary of N uptake showing the relationship of the various sources of N found in the grass is given in Figure 16. In this study, on a low-N soil (, total N) when clippings were not returned, ap- proximately half of the plant-N was derived from the fertilizer and half from the soil. When clippings were returned, yield of grass increased by about one-third, with approximately one-third of the total N in the grass being derived from the cumulative return of the clippings. The rate of fertilizer N uptake was initially high, with 20% of the fertilizer N applied being taken up within 2-3 weeks following both applications. Subse-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - co
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Keywords: ., bookcentury1900, bookpublishernewhavenconnect, booksubjectplants
