An -farm trial was conducted at three locations under Lumami village covering 1 ha each of jhum fields under the Zunheboto district of Nagaland during 2018-19. For this trial, three locations were selected under jhum fields. Materials used were local variety colocasia @ 800kg ha^-1, paddy straw mulching @ 12t ha^-1 at 3 cm thickness, and FYM@ 10t ha^-1 and irrigation at 1-week interval. The soil status of the fields was pH ranging from 5.5 to 6.5, 0.30 to 0.55% organic carbon, 235 to 245 kg ha^-1 available nitrogen, 17.50 to 18.32 kg ha^-1 available phosphorus, and 135-159 kg ha^-1 of available potassium. The crop was sown in the month of May 2018 and harvested in October. Parameters such as soil temperature were measured at 0-5cm depth @15, 30, and 45 days after planting, soil moisture at 45 days after planting where irrigation was done at one week intervals, yield, B:C ratio, and soil fertility status of the soils after harvest were recorded. The soil temperature, soil moisture, available soil nitrogen, phosphorus, and potassium were analyzed using soil thermometer, Gravimetric method, alkaline KMnO₄ distillation method (Subbiah and Asija 1956), Bray’s No. 1 method (Bray and Kurtz 1945), flame photometer (Jackson 1973). The soil moisture content was determined by digging out soils with the help of an auger from 5 cm depth in the field. The fresh soil is weighed, and then oven-dried at 105^oC for 24 hours. The soil moisture content is then measured using fresh soil samples and oven-dried soil samples by using the formula: Soil moisture content=Fresh weight soil (g) − Dry weight soil (g)Dry weight soil (g)×100

The results shown in table 1 indicate that the soil temperature is reduced and the soil moisture is increased in the trial plots of jhum fields with paddy straw mulch @ 12 t ha^-1 at 3 cm thickness and FYM@ 10 t ha^-1 as compared to the farmers’ practice. The mean temperature at 15, 30 and 45 DAP in the trial plot ranged from 26.2, 30.3 to 31.7^oC. The mean soil moisture at 45 DAP was 28.9 % as compared to the farmers’ practice, where mean temperature was higher, ranging from 27.0, 32.3 and 32.5^oC and mean moisture of 22.2%. Suminarti et al. (2020) reported suppression of the maximum soil temperature of 4.41, 5.17, 5.07 and an increase in soil moisture by 4.9^oC using 10 cm mulch length and 2, 4, 6 and 8cm thickness of paddy straw mulch in beetroot. Mulching also helps insulate the soil by providing a buffer for soil temperatures (Kader et al. 2019). Miyasaka et al. (2001) also reported an increased in soil moisture content due to paddy straw mulching in taro crops under rainfed conditions. This is because of the soil moisture being conserved in the soil through mulching which creates a microclimatic soil condition, controls weeds, reduces evaporation, and increases infiltration of water (Yang et al. 2003). Through mulch decomposition and humus formation, soil water holding capacity can also be improved (Ji et al. 2001). About 34-50 % reduction in soil water evaporation can be achieved through mulching with crop residue (Hatfield et al. 2001).

The mean yield, net income, and B:C ratio per hectare from the trial plots in the jhum fields were found to be higher with the use of paddy straw as mulching and fym in colocasia (Table 2). Its mean yield, net income, and B:C ratio were 3030 kg ha^-1, ₹ 101,033, and 3.00 over farmers practice of 2292 kg ha^-1, ₹ 64,100, and 2.27. This increased yield may be due to the decay of organic mulch adding up soil nutrients, leading to its nutrient availability in the long run (Larentzaki et al. 2008). Ram et al. (2013) also reported an increase in the grain yield of wheat due to straw mulch. A similar observation was also reported in potatoes where yield was 24.04% higher in mulch conditions which might be due to sufficient moisture in the initial growth stage (Begum et al. 2014). Application of straw mulch in wheat which receives five irrigations, gives the highest net return (Brahma et al. 2007). Use of rice straw @ 10 t ha^-1 in rabi-summer tomato found to increase the fruit yield, net income, and B: C ratio and at the same time control weeds and conserve soil moisture (Pandey et al. 2012).

The soil fertility status in the trial plots was also improved. The mean available nitrogen, phosphorus, and potassium were 313.22, 28.03, and 229.31 kg ha^-1 as compared to farmer’s practice i.e. 280.22, 20.95, and 133.49 kg ha^-1 (Table 3). Khan et al. (2002) also reported an increase in soil available nitrogen, phosphorus and potassium due to paddy straw mulching in soil. Application of paddy straw mulch in rape seed-green gram-rice cropping system also increased the N, P, K availability in the soil (Mitra and Mandal 2012). The soil fertility is also improved through mulching over some time due to nutrient cycling through earthworm activity in the soil (Kader et al. 2017 and Qin et al. 2015).

From the trials conducted in jhum fields of Lumami village under Zunheboto district of Nagaland, application of paddy straw @ 12 t ha^-1 at 3 cm thickness and FYM@ 10 t ha^-1 in colocasia crop have shown to decrease the soil temperature and increase the soil moisture in the jhum fields. The yield, net income, B:C ratio, and soil fertility status were also found to increase from the trials compared to farmers’ practice. Thus, from the on-farm trials conducted under rainfed conditions, it was shown that the use of Paddy Straw Mulching and FYM in Colocasia crop in the jhum fields can could help to improve moisture conservation regulate the soil temperature, enhanced soil fertility over some time. Thereby increasing productivity and also enhanced income generation for livelihood.