PhD

Cowpea is an important legume vegetable crop known as vegetable meat because of high protein content (24.8 %). The average productivity of cowpea in India is 607 kg/ha (ICAR, 2020) which is considered to be low. Productivity of the crop can be enhanced through selection of appropriate varieties and advanced technologies in management of nutrients and water. Since the research work on cowpea under open precision farming in Kerala is meagre, an attempt was made to standardise the agro techniques for enhancing the yield and profit to the growers.
The research work on the topic “Agro techniques for bush type vegetable cowpea (Vigna unguiculata (L.) Walp.) under open precision farming” was undertaken in the Department of Agronomy, College of Horticulture, Vellanikkara during 2017- 2019. The project was aimed to standardize optimum spacing and irrigation requirement of bush type cowpea for enhanced growth and yield under open precision farming. It also aimed to develop a fertigation schedule and to study the response of biofertilisers and foliar nutrition on bush type vegetable cowpea.
The first experiment on “Evaluation of genotypes and optimization of spacing for enhanced growth and yield of bush type vegetable cowpea under open precision farming” was laid out with five genotypes viz. Lalita, VU-5, Bhagyalakshmi, Kashi Kanchan, Pusa Komal and Anaswara and three spacings viz. 60 cm x 30 cm, 45 cm x 30 cm and 30 cm x 15 cm, replicated thrice. Among the genotypes Lalita performed better in terms of growth characters and yield and the poor performance was recorded by genotype VU-5. The wider row spacing of 60 cm x 30 cm had a significant superior effect on growth characters and yield of cowpea. The best treatment of genotype Lalita and wider spacing of 60 x 30 cm were selected for the subsequent experiments.
The second experiment on “Standardization of source of nutrients and levels of fertigation in bush type vegetable cowpea under open precision farming” was carried out with four levels of fertilizers and three sources of nutrients replicated thrice under open precision farming. The levels of fertilizers were arrived based on the nutrient uptake pattern. The fertigation was given at twenty equal splits doses with conventional and water soluble fertilizers and their combination. The results revealed that there was no significant difference between the levels of fertilizers with respect to growth and yield of cowpea and the application of 20:30:10 kg N, P2O5, K2O per hectare was found to be sufficient for the comparable performance of cowpea with other levels. Fertigation through conventional fertilizers viz. urea, diammonium phosphate and muriate of potash had comparable effect with water soluble fertilizers and their combination in terms of growth and yield of cowpea.
The third experiment on “Standardization of irrigation schedule and response of biofertilisers on bush type vegetable cowpea under open precision farming” was conducted to standardize the schedule of drip irrigation and to study the response of biofertilisers and foliar nutrition on bush type vegetable cowpea under open precision farming. Drip irrigation at 100 per cent Ep recorded higher fresh pod yield which was on par with 80 per cent Ep. Water productivity was significantly influenced by irrigation levels and higher water productivity was recorded with drip irrigation at 80 per cent Ep. Combined application of 60 per cent of the recommended dose of fertilizers (20:30:10 kg N, P2O5, K2O / ha) through fertigation as conventional fertilizers and 40 per cent through foliar application using water soluble fertilizers recoded higher fresh pod yield as well as quality characteristics compared to fertigation alone.
It is concluded that genotype Lalita at wider spacing of 60 cm x 30 cm was found promising for enhanced growth and yield of bush type vegetable cowpea under open precision farming. Fertigation with conventional fertilizers viz. urea, diammonium phosphate and muriate of potash at the rate of 20:30:10 kg N, P2O5, K2O per hectare found optimum in term of growth and yield under open precision farming. Combined application of 60 per cent of the recommended dose of fertilizers (20:30:10 kg N, P2O5, K2O /ha) through fertigation with conventional fertilizers viz. urea, diammonium phosphate and muriate of potash and 40 per cent through foliar nutrition using water soluble fertilizers with drip irrigation schedule at 80 per cent Ep was found superior for maximum water productivity, yield and profit of bush type cowpea under open precision farming.