MSc

The research project titled “Studies on fertigation in bitter gourd (Momordica charantia L.)” was undertaken in the farmer’s field at Pirappancode, Thiruvananthapuram district, during March 2015 to June 2015, to standardize the fertigation schedule for precision farming in bitter gourd, to assess the impact of precision farming practices on growth and yield of the crop and to work out the economics.
The experiment was laid out in split plot design with four replications. The main plot treatments included four fertigation levels (l), viz., l1- 75 per cent recommended dose (RD) of N and K, l2- 100 per cent RD of N and K, l3- 150 per cent RD of N and K and l4- 200 per cent RD of N and K. Fertigation intervals (i) (i1- fertigation at 4 days interval and i2- fertigation at 8 days interval) formed the sub plot treatments. Two controls were included in the study, viz., control 1- Kerala Agricultural University (KAU) ad hoc recommendation for precision farming and control 2- KAU Package of Practices (POP) recommendation. Uniform application of P @ 25 kg ha-1 in all treatments except control 1.
The results revealed that the growth attributes like number of leaves at 35 days after sowing (DAS), leaf area index (LAI) and days to first female flower appearance were influenced by fertigation levels and vine length (20 and 35 DAS) and leaf production (20 DAS) were influenced by fertigation intervals. The number of leaves (35 DAS) was the highest in l2, while l3 produced the highest LAI (55 DAS). The female flower appearance was early in l1 and late in l4.
Fertigation with l2 recorded the highest fruit yield (4.26 kg plant-1 and 21.30 t ha-1) fruit number (31.76), number of harvests (5.74), total dry matter yield (636.92 g plant-1) and ascorbic acid content (54.05 mg 100 g-1), while the same level of nutrient through conventional method of application (control 2) gave a comparable fruit yield (3.41 kg plant-1 and 17.05 t ha-1) and protein content (23.18 per cent) as that of fertigation treatment and also registered the highest content of TSS (3.250 Brix) and K (4.19 per cent).
Water use efficiency (WUE) and water productivity were found to be influenced by fertigation levels with l2 recording the highest (24.41 and 3.65 kg ha mm-1 respectively).
The uptake of nutrients particularly P and K were the highest in l2. Also K uptake was the highest in both the controls than in fertigation treatments. Fertigation at 8 days interval recorded the highest N uptake.
Fertigation treatments and control 1 improved the N and K status of soil, while N status improved and K decreased in control 2.
Economic analysis revealed the superiority of fertigation treatments over both the controls and within fertigation levels, the level l2 as reflected in the respective B:C ratios. The mean B:C ratio in fertigation was 4.29 and in l2, it was 4.94. The B:C ratio recorded in the two controls were 2.74 and 3.21 respectively. Similarly the net income was the highest in l2i1 ( 6,90,488 ha-1), the lowest in control 2 ( 4,69,412 ha-1), and though control 1 gave a comparable fruit yield, its economics in respect of B: C ratio and net income were the lowest.
The results of the study revealed that the current nutrient recommendation of KAU (70:25:25 kg N, P2O5 and K2O ha-1) is sufficient for bitter gourd, but giving it through fertigation, the yield can be further increased.
Based on the results, a fertigation schedule of 152 kg ha-1 urea and 53 kg ha-1 MOP at 4 days interval along with a basal dose of 100 kg ha-1 rajphos (equivalent to 70:20:32 kg N, P2O5 and K2O ha-1 modified from KAU recommendation of 70:25:25 kg N, P2O5 and K2O ha-1 as per soil test) can be given as a recommendation for precision farming in bitter gourd for high yield, quality produce and the highest net income and B:C ratio