Search Results

You are looking at 1 - 10 of 35 items for

  • Author or Editor: Bharat P. Singh x
Clear All Modify Search
Author:

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.

Open Access

The effect of in-row plant densities on gas exchange, chlorophyll content and leaf area index of okra (Abelmoschus esculentus (L.) Moench) was studied. The six in-row plant densities ranged from 8 cm to 48 cm (D1 - D6). On 11 and 27 July 1990, the photosynthetically active radiation (PAR), transpiration (E), net photosynthesis (Pn) and chlorophyll content (Chl) at top- and mid-canopy levels and leaf area index (LAI) were measured. Mid-canopy PAR was 86 ± 6% less than that of the top-canopy and E, Pn and Chl at mid-canopy were respectively 55, 90 and 10% lower than those of the top-canopy. The interaction of plant density with canopy position was significant for E and Pn. The highest E and Pn, (12.28 mmol m-2 s-1 and 22.01 μmol CO2 m-2 s-1, respectively) were recorded at the D5 top-canopy. In-contrast, the lowest E and Pn, (4.17 mmol m-2 s-l and 1.23 μmol CO2 m-2 s-1, respectively) at the D6 mid-canopy were recorded. The LAI also exhibited significant variation among plant densities with a range of 4.65 to 4.97 for D5 and D3, respectively. These results indicate that 40 cm in-row density was the most suited for gas exchange of okra.

Free access

This study was conducted over 3 years for the purpose of determining how tomato yield, fruit number, and vegetative dry matter are affected by winter cover crop and recommended fertilizer N rates. The following winter-spring fertility treatments were applied using randomized complete-block design with four replications: 1) 0 N winter–0 N spring, 2) 0 N winter–90 kg N/ha spring, 3) 0 N winter–180 kg N/ha 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. In Spring of 1996, 1997, and 1999 `Mountain Pride' tomatoes were transplanted in all plots. Total yield was compiled over 6 weeks, while seasonal fruit number and plant dry matter were measured at final harvest. In 1999, highest plant dry matter (350.5 g/plant) was produced by vetch and highest fruit number (36/plant) by 180 kg N/ha. Total yield were highest (85.8 Mg/ha) at 90 kg N/ha in 1996 and lowest (35.3 Mg/ha) for control during 1997. Organic nitrogen from hairy vetch and crimson clover affected plant dry weight, tomato number and yield comparable to those receiving synthetic N. Results over three years for this study indicate that legume cover crops can be an effective N fertilizer in supporting plant dry matter, fruit number and fruit yield of tomato.

Free access

The purpose of this study was to evaluate the tillage method effects of N sources on gas exchange (GE) at the flowering, fruiting, and pre-senescence in tomato. Measurements of transpiration (E), stomatal conductance (gs), photosynthesis (Pn), and internal leaf CO2 concentration (Ci) were reported. The following fall/spring tillage and fertility treatments were applied: 1) fall-fallow/spring-moldboard, 2) fall-fallow/spring-moldboard + 90 kg·ha–1 N, 3) fall-moldboard + hairy vetch/spring-chisel, 4) fall-moldboard + hairy vetch/springchisel + 90 kg·ha–1 N, 5) fall-minimum till+hairy vetch/spring-chisel, and 6) fall-minimum till + hairy vetch/spring-chisel + 90 kg·ha–1 N. During the 2nd week of Apr. 1995, `Mountain Pride' tomato was transplanted in all plots. Maximum E (11.9 mmol·m–2·s–1), gs (1465.1 mmol·m–2·s–1), and Pn (22.23 μmolCO2/m2 per s) occurred at the fruiting and highest Ci (301.2 μL·L–1) at the flowering. Throughout the growing seaon, treatments 5 and 3 affected GE rates the most, while treatments 1 and 3 at flowering affected Ci the most. Results indicate that fall moldboard or minimum-till + hairy vetch/spring chisel had greatest influence on GE of tomato.

Free access

Reduced tillage saves energy and safeguards soil against erosion. While it is widely used for these reasons in producing agronomic crops, it has yet to find acceptance in vegetable cultivation. The main obstacle is the lack of knowledge of the growth and developmental responses of intensively managed vegetable crops to reduced tillage operations. Therefore, this study was performed to determine the effect of different tillage levels on vegetative growth and flowering and fruiting of tomatoes. The following tillage treatments were applied in a randomized complete-block design to a field that was cover cropped with vetch during winter T2 produced maximum vegetative dry weight/plant: 1) fall mold-board + spring no-till (T1), 2) fall mold-board + spring chisel (T2), and 3) fall chisel + spring chisel (T3). The number of flowers/plant were highest in T1, followed by T2 and T3, respectively. There was a 14: 1 ratio between the number of flowers and fruit set. The number of fruit in T1 and T2 were similar, and significantly greater than in T3. The fruit weight of T1 was similar to T2 but significantly greater than T3.

Free access

The purpose of this 3-year study was to compare organic and inorganic N sources for promoting gas exchange (GE) in tomato at fruiting. Measurements of transpiration (E), photosynthesis (Pn) and internal leaf CO2 concentration (Ci) are reported. The following winter–spring fertility treatments were applied using randomized complete block design with four replications: 1) 0 N winter–0 N spring, 2) 0 N winter–90 kg N/ha spring, 3) 0 N winter–180 kg N/ha 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. In spring of 1996, 1997, and 1999, `Mountain Pride' tomatoes were transplanted in all plots. Maximum E (14.3 μmol·m–2·s–1), Pn (22.8 μmol CO2/m2 per s), and Ci (352.2 μL·L–1) occurred in 1997, 1996, and 1999, respectively. In general, E was affected mostly by treatments 2, 3, 5, and 6 and Pn by treatments 2 and 5, while treatments 1 and 4 affected Ci the most. Results indicate that N from both legumes and synthetic fertilizer enhanced GE of tomato similarly.

Free access

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.

Free access