Effects of Method of Harvest on Flue‐cured Tobacco. I. Agronomic Factors¹

Abstract

The optimum in mechanized harvesting of flue‐cured tobacco (Nicotiana tabacum L.) may involve the removal of all leaves in one operation. Field experiments were conducted during the 1968 and 1969 growing seasons to evaluate 12, 16, and 20 leaf topping heights and normal and once‐over harvesting methods for yield, value, and price of flue‐cured tobacco. A separate analysis was utilized to determine stalk position effects within the three topping heights. A significant year effect and its interactions, probably resulting from excess water received in 1968, were noted. The tobacco from the normal harvest method had a greater yield, value, and price than that harvested by the once‐over method, resulting from overmature bottom and immature top leaves, both of which cause lower dry matter yields and a lower price/45.2 kg. The high‐topped plants produced the greatest yield but the lowest price, reflecting greater amounts of lowervalued tobacco from the bottom and top leaves. Yield was lowest at the lower stalk positions, increased to a maximum near the middle stalk positions, and then decreased at the upper stalk positions. Price was at a maximum at the lower‐middle stalk position and decreased in both directions. Leaves harvested by the once‐over method were lower in yield and price at the lower and upper stalk positions as compared to leaves harvested by the normal method. Disregarding the extreme lower and upper stalk positions, the once‐over harvest method resulted in leaves that were comparable to those harvested by the normal method.

Effects of plant density and fertilization on the yield and quality of flue-cured tobacco in the Kenana area of the Sudan

“…12° 44' N, long. 34° 07' E in 1971 and1972. In the plant density experiment (Expt 1) inter-and intra-row spacings of 60, 80 and 100 cm were tested during three periods, July 1971 and July and September 1972. In the fertilizer experiment (Expt 2) three rates of N application 42-8, 85-6 and 128-4 kgN/ha (Nj, N 2 , N 3 , respectively) and four rates of K, 0, 85-6, 171-2 and 256-8 kg K 2 O/ha (K o , K 2 , K 4 and K 6 , respectively) were also tested during three periods, i.e.…”

“…Excessive rainfall may result in loss of plant nutrients in light soils and drowning of plants in heavy clays. Brown & Terrill (1972) concluded that seasonal variation in the yield of flue-cured tobacco was due to excessive rainfall following irrigation which resulted in leaching of N from the soil.…”

Effects of Method of Harvest on Flue‐Cured Tobacco Part II. Chemical Components1

“…Experimental design, cultural practices, and treatment descriptions were presented in "Part I. Agronomic Factors" (Brown and Terrill, 1972).…”

“…Significant interactions were also detected ior most of the chemical factors measured, which reflects the complexity of evaluating relationshpis among planned variability, individual chemical characters, and among the eight chemical characters observed (Table I). Excess water (discussed in "Part I. Agronomic Factors", Brown and Terrill, 1972) during the 1968 growing season probably leached some of the applied nitrogen fertilizer from the soil, resulting in less total N, soluble N, and a lower pH in plants produced in 1968 than those grown in 1969 (Table 2). Higher reducing sugars and water-soluble acids were evident in the 1968 crop reflecting a lesser amount of nitrogen in the plant.…”

Response of rice yields to irrigation and drainage at two phases of growth

“…Pande & Adak (1971) reported that the N losses from rice plots were three times greater under flooded conditions than when the soil moisture ranged from 0 to 0-1 atm. In an adjacent tobacco experiment (Farah, 1975) there was also this association of lower yields with high rainfall, presumably due to leaching of N from the soil, as was suggested by Brown & Terrill (1972).…”