Anamika Sharma and Kolom Rabi
KVK Dimapur and ICAR Research complex for NEH Region, Medziphema
Pineapple (Ananas comosus) is one of the important fruit crops of Nagaland occupying a total area of 9917 ha with a production of 147384 Mt, with the average productivity of 14.86 Mt/ha. Maximum area is covered under Dimapur district i.e. 2795 ha with average productivity of 11.59 Mt/ha. The state produces the world’s finest quality fruits due to favourable agro-climatic conditions. The fruits weighing nearly1.2-1.7 kg with the TSS of 14-180 brix and acidity 0.9 to1.2% and total sugar 0.7 to 1.75 % depending on the stage of maturity and season. In the district Pineapples are grown in hillocks with a slope of 30-40% as beyond that soil erosion is very high during rainy season and experienced moisture scarcity during winter.
Pineapple crop generally propagated with suckers comes to flowering only after 15-18 months of plantation. Farmers cultivate pineapple as a sole crop and spend a large sum of money and labour on weeding leading to an increased cost of cultivation without any income during the first year of its plantation. So, efforts were made to reduce the expenditure on weeding and to conserve the soil moisture with less soil erosion in this study.
KVK Intervention Initially during 1997-98 the pineapple was cultivated in the district at single row spacing of 1 meter square along the slope for the ease of weeding and harvesting so double row spacing @90 x 60 x 30 cm3 was introduced across the slope to check the soil erosion as pineapple is shallow rooted crop and can hold the soil. The minimum plant population was 44,500/ha. Farmers cultivate pineapple as a sole crop and spend a large sum of money and labour on weeding leading to an increased cost of cultivation without any income during the first year of its plantation. So, black polyethylene mulching with 50 micron thickness, was laid down before pineapple plantation to reduce the expenditure on weeding and to conserve the soil moisture and check the soil erosion. Pineapple was planted in double row spacing @90 x 60 x 30 cm3 with 30-40%. Initially this technology was tested at ICAR Research Complex for NEH region, Jharnapani, Medziphema, Nagaland under wasteland development project and was observed that this technology can reduce the gestation period for fruiting in pineapple and areas with 60 - 80% slopes can be utilised for pineapple cultivation with black polythene mulch technology. Field trials were conducted at Molvom and Dhansiripar villages of the district.
The economy of Molvom village is dependent on pineapple cultivation. Farmers cultivate the pineapple Kew variety across the slope in double row spacing of 90cm x 60cm x 30cm with 44500 plants/ha. Pineapple is being cultivated in an area of 520 ha with the production of 11960 metric ton and 23.0 metric ton/ha as productivity.
Result: Pineapple cultivation with 50 micron black polythene sheet mulching with double row spacing i.e. 90 x 60 x 30cm not only suppresses the weed growth but conserves the soil moisture, which leads to early flowering in mulch plot by 6-7 months i.e. flowering started after 9-10 months of planting in Jan-Feb 2015 where as in control the flowering was observed only after 15 month of planting in September 2015. First year nearly 7.5-10% plants only flowered. Fruit weight and other parameters were recorded. Next season nearly 50% plants flowered.
Soil moisture was conserved by polythene mulch (18%) which could produce the double size fruits whereas in control it was 12.6% only. The impact of mulching on soil moisture content, growth and yield of pineapple (Ananas comosus. L. Merr) was studied by Alwis and Herath (2009) and reported that the highest soil moisture content of 10.9 at 30 cm depth at harvesting was recorded in black polythene, and paddy husk treatments. The highest fruit yield of 24.3 t/ha was recorded in the black polythene treatment.
Mulching with 50 micron poly sheet produces 339.227 MT of Pineapple fruits in the last three years as compared to 112.42 MT in the control with the average production of 37.47 MT per hectare per year whereas in mulching 75.38 MT per hectare per year is recorded with 101.1 % increase over the control. The average fruit weight was recorded 3.5 to 4.25 Kg/fruit with 120.50 brix under polyethylene mulch whereas 1.2 to 1.80 kg/fruit with16.200 brix under control. Das and Hazarika, (1999) in a study conducted in Assam reported that the best quality fruits were obtained in polythene 50 micron thickness mulch treatment throughout the cropping period. Liu et al (2011) reported increased in the total relative content of ester components and decreased the alkene components of pineapple fruits harvested in winter and summer under poly film mulching.
The life span of black polythene mulch is nearly 3-5 years. Second year onwards the cost of cultivation was recovered under mulching demonstrations. Third year onwards harvest was more profitable, whereas in control plot the 3-4 weeding need to be carried out with minimum of Rs. 25,000/ha/year. The net income per hectare per year was Rs. 1, 27,767/- under mulching whereas in the control it was Rs. 69,600/- Pineapple cultivation with polythene mulch was gladly accepted by the farmers as this technology has reduced the cost of weeding in subsequent years although the initial cost of cultivation i.e. laying of black polythene sheet @Rs 1, 85,000/ha was high, which was recovered during second year of cultivation.
Conclusion: Black polythene mulch not only reduces the gestation period but also conserves the soil moisture which almost doubles the fruit size as well as production and productivity. Black polythene film can be boon for pineapple cultivation in undulating hilly terrain with 50 to 100% slopes in double row spacing’s of 90 x 60 x 30 cm across the slopes not only minimize the soil erosion during heavy rains but also increases the plant population by 45500 nos. of suckers with higher production and productivity along with larger fruit sizes as compared to 15000 suckers in the traditional system of planting along the slopes.
