Effects of cutting interval and nitrogen fertilizer rate on the yield and nutritive value of Brachiaria brizantha and Chloris gayana.

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Date

1990

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Volume Title

Publisher

Sokoine University of Agriculture

Abstract

The effects of three cutting intervals (20, 40 and 60 days ) and four levels of N application (0, 100, 200 and 400 kg N/ha) on the dry matter yield, dry matter content, tiller height, CP content, CP yield, N utilization efficiency, in vitro dry matter digestibility and in vitro digestible dry matter yield were studied in Chloris gayana and Brachiaria brizantha over a period of 120 days in 1987 in a field experiment at Sokoine University of Agriculture farm in Tanzania. The dry matter yield of the grasses increased with extension of the cutting interval up to 40 days and then declined thereafter. dry matter yield of the grasses increased with increasing N rate.The dry matter content increased with increasing cutting interval decreased with increasing N rate.The green leaf and stem dry matter yields increased with increasing N rate.Extended period between successive cuts slightly reduced green leaf dry matter yield and slightly increased the the stem dry matter yield. Leaf:stem ratio was not significant!;. ( P > 0.05) affected by extension of the cutting interval. Tiller height increased significantly (P < 0.01) with increasing N rate and cutting interval.The CP concent of the herbage decreased with extension of the cutting interval. The 'CP yield increased with increasing N rate and extension of the cutting interval to 40 days and declined thereafter.The recovery of applied N increased with increasing N rate up to 200 kg N/ha then declined thereafter.yield response in terms of kg DM Dry matter per kg of applied N decreased with increasing N rate.In vitro dry matter digestibility of the grasses increased with increasing N rate and decreased with extension of the cutting interval.Brachiaria brizantha had a significantly (P < 0.01) higher in vitro dry matter digestibility than Chloris gayana at all cutting intervals.The in vitro digestible dry matter yield of the grasses increased with nitrogen rate. It also increased with extension of the cutting interval up to 40 days and then declined thereafter. The results of this experiment support the view that, the producti­vity of grasses can be improved by N fertilization. In this study it has been shown that B. brizantha and C. gayana should be harvested every 40 days during the period of favourable growth in order to balance the productivity and the quality of the produced herbage.

Description

Dissertation

Keywords

Nitrogen fertilizer, Green leaf, Brachiaria brizantha, Chloris gayana

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