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- Author or Editor: Bharat P. Singh x
Abstract
The effect of various amounts of irrigation on vegetative growth and pod yield of bush snap beans (Phaseolus vulgaris L.) was investigated. The field experiments were carried out during 1985 and 1986, years of abundant and limited rainfalls, respectively. Evaporation from a National Weather Service type open pan (Epan) was used to determine the timing and amount of irrigation. Vegetative growth was estimated from the number of leaves, leaf area, and leaf and stem dry weights. Irrigation significantly increased vegetative growth and pod yield. Pod yield/unit of irrigation water was maximum at 60% Epan. Vegetative growth increased linearly from irrigation amounts of 0% to 100% Epan, while pod yield enhancement ceased above 80% Epan. The study suggested an irrigation schedule based on 80% Epan for highest bush snap bean production.
The purpose of this study was to compare the efficacy of winter cover cropping with legumes for replacing synthetic N fertilization in tomato production. The following winter/spring fertility treatments were applied: 1) 0 N winter/ 0 N spring, 2) 0 N winter/90 kg·ha-1 N spring, 3) 0 N winter/180 kg·ha-1 N spring, 4) 0 N winter+rye/0 N spring, 5) 0 N winter+hairy vetch/0 N spring, and 6) 0 N winter+crimson clover/0 N spring. In the spring of 1996, tomato cultivar `Mountain Pride' was planted in all plots. The effects of different treatments on plant dry weight and fresh fruit yields were determined. Tomato following legumes or supplied with 90 kg·ha-1 fertilizer N produced highest plant dry weight, while 0 N winter/0 N spring and 0 N winter+rye/0 N spring produced plants with least dry weights. Treatments differed in a similar fashion also for fresh fruit yields. The results suggested that winter legumes were at par with commercial N fertilizer in supplying needed inorganic N to the succeeding tomato crop soil.
The objective of this study was to determine if winter legume or grain cover could support net photosynthesis (Pn) and plant dry matter production comparable to recommended rate of synthetic N. The following winter/spring fertility treatments were applied: 1) 0 N winter/0 N spring, 2) 0 N winter/90 kg·ha–1 N spring, 3) 0 N winter/180 kg·ha–1 N spring, 4) 0 N winter+abruzi rye/0 N spring, 5) 0 N winter+hairy vetch/0 N spring, and 6) 0 N winter+crimson clover/0 N spring. `Mountain Pride' tomato was planted in all plots in spring. Plant dry weight and Pn were measured at flowering, fruiting and prior to senescence. The highest Pn (22.78 μmol CO2/m2 per s) and leaf dry weight (115.2 g/plant) were obtained at fruiting, while highest branch dry weight (194.5 g/plant) occurred prior to senescence. There was significant increase in plant dry weight during reproductive growth phase. Tomato plants receiving supplemental N from crimson clover or hairy vetch had Pn and plant dry weight comparable to those receiving synthetic N. The results of this study indicated that legume cover crops were as effective as commercial N fertilizer for supporting photosynthesis and vegetative growth of tomato.
Parwal [Trichosanthus dioica (Roxb.)] is a tropical perennial vine producing small fleshy fruits used as a vegetable. It bears male and female flowers on separate plants. During the summer of 1996, a field study was conducted to determine if male and female plants differed in their gas exchange behavior. Three leaves per plant replicated six times for each sex were tagged randomly at initiation of gas exchange measurements. Transpiration (E), stomatal conductance (gs), CO2 exchange rate (CER), and internal leaf CO2 concentration (Ci) were measured when the leaves were 6, 18, 36, 47, 71, and 81 days old. In general, the gas exchange values for both sexes were similar. The leaves of male plants attained highest E, gs, and CER at 18 days of age. In female plants, CER peaked at an early leaf age of 6 days, while the peaks for E and gs were reached 30 days later. The highest Ci for both sexes were observed in 47-day-old leaves. Eighty-four-day-old leaves were no longer actively exchanging gases.
Little is known about the morphology of okra (Abelmoschus esculentus Moench) plant. This information is critical to understanding of plant growth and possible factors limiting yield. Therefore, a field study was conducted during 1989 to determine the changes in leaf number, leaf dry weight and stem dry weight in okra during the fruiting period. Four okra genotypes, PI-178818, PI-211573, Lee and Clemson spineless, were planted in randomized complete block design with four replications. All four genotypes had similar stem dry weight, but differed significantly in leaf number and leaf dry weight. During the reproductive period, 42% of new leaves, 61% of leaf dry weight and 82% of stern dry weight were formed. PI-178818 had highest leaf number and maximum leaf dry weight, but produced lowest fruit yield. The results suggested that since vegetative growth and fruiting proceeds simultaneously in okra, partitioning of dry weight to pod maybe critical for high okra yields.
In literature, amaranth is described as a stress tolerant crop. However, most of the investigations have been concerned with the production of grain crop. The soil moisture regime which promotes maximum vegetative growth is yet to be established. During 1993, the vegetative growth response of amaranth to different soil moisture levels was determined in a greenhouse study. Amaranth cultivar Hin Choy was grown in Dothan sandy loam soil at four soil moisture levels of 6.0, 9.0, 12.0 and 14.0% (w/w) in a randomized complete block experiment with ten replications. Plant height, leaf number, leaf area, leaf fresh and dry weight, stem fresh and dry weight, root fresh and dry weight, leaf-stem ratio, and stem fresh and dry weight were recorded. All parameters gained significantly with each increment in the soil moisture level up to 12%. There was no difference in plant response between 12% and 14% soil moisture. The study indicated that for optimum vegetative growth, amaranth requires a moisture stress free soil environment.
The effects of differing soil moisture levels on the vegetative components of vegetable amaranth, Amaranthus tricolor RRC no. 241, were evaluated. A completely randomized design with 10 replications and 4 treatments (3,6,13, & 18% soil moisture) was followed. Leaf, stem, plant, root fresh weight and leaf area (LFW, SFW, PFW, RFW, and LA, respectively)—were recorded 48 days after planting. For each of the vegetative components the only significant difference (P ≤ 0.05) occurred between 3% versus 6-18% soil moistures, with moisture level of 6-18% showing no significant variation among themselves. The mean ranges for LFW (28.3-32.7 g), STW (6.9-9.2 g), PFW (41.3-48.2 g), RFW (8.6-12.8 g), and LA (1049-1222 cm2) across 6-18% soil moisture were approximately four times greater than the vegetative components of 3% soil moisture. From these preliminary results, it appears that vegetable amaranth has the ability to grow and perform well over a 6-18% soil moisture range, indicating an ability to better adjust and adapt to changing soil moisture environments.