Effect of fertigation schedules and mulching on growth, yield and profitability of Bt cotton (Gossypium hirsutum L.)
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Date
2022-12-30
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Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani
Abstract
The present investigation entitled “Effect of fertigation schedules and mulching on growth, yield and profitability of Bt. cotton (Gossypium hirsutum L.)” was undertaken during kharif season, 2020 and 2021 at experimental farm, Department of Agronomy, V.N.M.K.V., Parbhani. The fertility status of the soil in the experimental plot reveals that it has a clayey texture, a slightly alkaline reaction, low levels of organic carbon, low levels of nitrogen that is readily available, medium levels of phosphorus and high levels of potassium that are readily available.
Treatments consists of sixteen combinations comprising four different fertigation schedules (S1: 80:40:40 NPK kg ha-1, S2: 100:50:50 NPK kg ha-1, S3: 120:60:60 NPK kg ha-1 and S4: 140:70:70 NPK kg ha-1) in main plot and four mulching treatments (M1: No mulch, M2: Organic mulch, M3: Black polyethylene mulch and M4: Silver polyethylene mulch) as sub plot treatment were assigned in a split plot design with three replications.
After land preparation, beds were prepared and mulching was applied as per the treatment. The cotton crop was sown on 04/07/2020 and 18/06/2021 by dibbling method during 2020-2021 and 2021-2022, respectively. Fertilizers were applied through drip to different plots as per the treatments and biometric observations on growth parameters, yield attributes and yield were recorded periodically. Inter-culture operations were also carried out as per the schedule. The climatic conditions were favourable during 2020-2021 and 2021-2022 for the growth and development of Bt . cotton which ultimately resulted in more accumulation of photosynthate in both seasons. Plant growth analysis, post-harvest studies, nutrient uptake, available soil fertility status after harvest of Bt. cotton and economics of Bt. cotton were also estimated during 2020-2021 and 2021-2022.
Fertigation scheduling with higher fertilizer level of 140:70:70 NPK kg ha-1 has recorded higher growth attributes, dry matter accumulation and growth functions over 80:40:40 NPK kg ha-1.
Fertigation scheduling with highest fertilizer level of 140:70:70 NPK kg ha-1 has increased seed cotton yield (2867 kg ha-1), GMR (1,31,882 D ha-1), NMR (58,149 D ha-1) and B:C ratio (1.79) significantly over fertigation scheduling with 80:40:40 NPK kg ha-1 and was comparable with fertigation scheduling with 120:60:60 NPK kg ha-1 and 100:50:50 NPK kg ha-1 for seed cotton yield and profitability. Harvest index was increased with increase in fertilizer level.
The lint yield (kg ha-1) was significantly higher in fertigation scheduling with 140:70:70 NPK kg ha-1 over fertigation scheduling with lower levels. Fertigation scheduling with different fertilizer levels didn’t affect the major fiber parameters of Bt. cotton.
Total uptake of nitrogen, phosphorus and potassium by crop were significantly increased with fertigation scheduling with higher fertilizer level i.e., 140:70:70 NPK kg ha-1 (S4) over fertigation scheduling with lower fertilizer level (S1). The available status of soil nitrogen, phosphorus and potassium after harvest of Bt. cotton crop was not influenced by fertigation scheduling with different fertilizer levels.
Highest values of growth attributes (plant height, number of functional leaves, dry matter accumulation per plant, leaf area, number of monopodia, number of sympodia etc.) were recorded when cotton crop was sown on silver polyethylene mulch as compared to no mulching. Sowing of cotton crop on silver polyethylene mulch also recorded highest values of yield attributes (number of picked bolls per plant, boll weight, seed cotton yield plant-1 etc.) seed cotton yield, lint yield, stalk yield and biological yield (kg ha-1) etc. as compared to no mulch treatment.
Sowing of cotton crop with polyethylene mulch was not profitable in terms of NMR and B:C ratio. Fertigation scheduling with fertilizer level of 100:50:50 NPK kg ha-1 was found remunerative as it was on par with fertigation scheduling with higher fertilizer levels for monetary returns.
Application of polyethylene mulch either silver or black has increased nutrient uptake over no mulch treatment. The soil NPK status after harvest of Bt. cotton crop was not influenced by mulching treatments.