ENERGY AND ECONOMIC ASSESMENT IN TILLAGE AND SOWING FOR ROTAVATORS, CONVENTIONAL AND NO-TILL WHEAT ESTABLISHMENT

Rice-wheat is major crop of IGP covering around 10 Mha areas and contributing about 40% to national food grain production. Rice residue management in combine harvested fields, for wheat sowing, is performed primarily through intensive tillage. This demands more energy input leading to higher production cost and lesser benefit-cost ratio. Indian government is promoting rotavators for speedy seedbed preparation in rice-wheat system. Notill wheat sowing is also quite popular amongst the farmers. This study compares energy input and benefit-cost ratio of six treatments viz. T1 (RM1 x 2 + sowing), T2 (RM2 x 2 + sowing), T3 (RM3 x 2 + sowing), T4 (RM4 x 2 + sowing), T5 (Notill sowing) and T6 (Disc harrow x 6 + Planking x 2 + sowing). Result revealed maximum time and fuel consumed in T6 (10.13 h/ha and 59.85 l/ha) and minimum for treatment T5 (1.39 h/ha and 6.19 l/ha). Energy saving was maximum (89.57%) in no-till wheat sowing (T5) followed by rotavator treatments (47.08-62.65%) compared to treatment T6. The energy productivity was highest (13.06 kg/MJ) for no-till sowing (T5). It ranged from 2.73-4.20 kg/MJ for rotavator treatments (T1-T4) and was minimum (1.59 kg/MJ) for T6. The benefitcost ratio was found 2.99 for treatment T6 and 6.35% higher for no-till wheat sowing (T5). It ranged from 2.91-3.53 for treatments (T1-T4). Based on the results, T5 was found most energy efficient treatment followed by T3, T4, T2 and T1. Conventional method (T6) was found to be most energy intensive method of wheat establishment.


INTRODUCTION
Agriculture has been the life line of Indian economy and provides livelihood to about 65% of the total population. It has largest arable land (160 Mha) sharing 11.2 percent arable land of the world. Rice-wheat are major crops grown in Indo-Gangetic Plains (IGP) covering around 10 Mha area and contributing about 40% of the country's total food grain production. 2014-15, these two crops together contributed more than 76% to the total food grain production of the country (Anonymous, 2016). In regions where lowland rice is cultivated during the rainy season, tillage operation for preparing seedbed for wheat sowing, in combine harvested rice fields, is considered most difficult and time-consuming. Conventionally farmers, in tarai region of Uttarakhand, use 6-8 operations, sometimes even more, of disc harrow followed by planking twice to prepare the seedbed for wheat sowing in combine harvested rice fields. This not only increases cost of cultivation but also results in delayed sowing and marginalize benefit-cost ratio. No-till technique or reduced tillage could help the farmers in earning more profit from the same land by reducing the cost of cultivation. No-till wheat sowing, introduced during 1995 (Singh and Singh, 1995), is now limited to progressive farmers of this region. It has been reported to save operational energy and cost of cultivation over traditional method (Sharma et al., 2007).
Rotavators (rotary tillers) have been reported to produce smaller clodmean-weight diameter, better residue incorporation as well as most energy and cost effective for seedbed preparation (Singh, et al., 2006;Prasad, 1996). These are being promoted by Indian government by providing 50% subsidy to the farmers on its purchase. Due to government support and demand by the farmers, a large number of manufacturers are manufacturing and supplying various sizes of rotavators. However, the data on energy requirement by various sizes of rotavator is lacking. Considering this in view, study was undertaken to assess energy input and economics for various sizes of rotavators, conventional and notill system of wheat establishment.

MATERIAL AND METHODS
The experiment was conducted at University Farm in combine harvested rice field for consecutive two years (2013-14 and 2014-15). Four sizes of rotavators with rotor lengths as 115, 148, 172 and 195 cm fitted with L-shape blades were selected for seedbed preparation whose technical details are presented in Table 1. On an average, the initial residue load was 6.03 t/ha with average height of stubbles as 36.19 cm. The initial soil moisture ranged from 23.2-25.8%. An area of 1.25 ha was selected and was divided into 18 equal plots (size 60 m x 10 m) to accommodate all the 6 treatments (Table 2) with three replications. In conventional method of seedbed preparation (T6), double action trailed type disc harrow (8 x 8 disc) with disc diameter as 610 mm and weighing 500 kg was used. A wooden plank, 300 cm long weighing about 65 kg, was used for clod crushing and levelling of the field. No-till ferti-seed drill (11 rows) was used to sow wheat, at 110 kg/ha seed rate, in all the treatments including T5. A tractor of 37.3 kW was used for operating the various implements. Other cultural practices, after sowing, were performed similar in all the treatments to minimize experimental variation. The data related to soil, machine and crop parameters were determined as per the standard procedures. Energy as well as economic analysis was made by adopting the standard methods and energy equivalences (Kumar, 2013;Asodiya, 2014 andAnonymous, 1970). The data was analyzed using Completely Randomized Design (CRD). RM 4 x 2 + sowing 3 T 5 No-till sowing 3 T 6 -control Disc harrow x 6 + Planking x 2 + sowing 3 RM1…4 represents the four sizes of the rotavators

RESULTS AND DISCUSSION
The results of clod size and residue incorporation has been presented in Table 3 which revealed minimum clod mean-weight-diameter (CMWD) of 14.9 mm in treatment T1 followed by 15.8, 16.7 and 17.2 mm in treatments T4, T3 and T2. Largest clod size of 17.6 mm was observed in case of treatment T6 (control). Smaller size of clods in treatments T1-T4 may be due to better slicing action by the rotavator blades as compared to discs of disc harrow. The clod size for all the treatments varied significantly from each other at 5% level of significance. Maximum residue incorporation (87.56%) was found for T1 followed by 87.40% (T4), 86.40 (T2) and 85.74% (T3). Treatment T6 showed minimum, 80.63%, residue incorporation (Table 3). Higher residue incorporation in treatments T1-T4 might be due to better cutting (because of higher peripheral velocity of rotavators blades in case of active tillage tools) and mixing of residue by the rotavators blades. Another reason could be the blade orientation with respect to direction of travel that might have helped in cutting the residues into smaller pieces consequently better mixing with soil. In treatment T6, the peripheral speed of disc cutting edge remains same, as in case of passive tillage tools, as that of tractor forward speed resulting in poor slicing action and hence poor residue incorporation. The percentage residue incorporation in all the treatments was found to vary significantly from each other at 5% significance level. Machine parameters namely speed of operation for rotavators, treatment t1-t4, was found in the range of 4.14 -4.36 km/h showing very little variation (table 3). This was due to the fact that the tractor was operated at the same forward speed to minimize the experimental variations. The speed of operation for disc harrow and planker in treatment t6 was comparatively higher which was probably due to lesser draft requirement. However, all the implements were operated within their recommended speed of operation. The field capacity, amongst the treatments t1-t4, was found maximum for t4 and minimum for treatment t1 which is obvious (table 3) as known that field capacity is a function of width of cut and speed of operation of an implement. Similarly field capacity was found more for disc harrow (0.81 ha/h) and planker (1.48 ha/h) which was again due to higher width and speed of operation.
Time required in various treatments revealed maximum time requirement of 10.13 h/ha (table 3) for conventional method of tillage and sowing (t6). This was due to more number of disking and planking operation. No-till method of wheat sowing (t5) recorded minimum time of 1.39 h/ha which was due to elimination of seedbed preparation. In treatments t1-t4, the minimum time requirement of 3.91 h/ha was recorded for treatment t4 in which largest size of rotavators was used. It was followed by treatments t3, t2 and t1 respectively. This was due to the fact that smaller rotavator would require more time to till a given area than a larger size of rotavator. Also the field capacity, ha/h, is inversely proportional to time requirement (h/ha). Almost similar pattern was observed for cumulative fuel consumption, l/ha, in various treatments. This was again due to lesser time requirement by a larger size of implement and vice-versa. Statistical analysis indicated significant variation in total time requirement for various treatments at 5% significance level.
The fuel consumption for each treatment was determined (table 4) which revealed minimum fuel consumption of 6.19 l/ha in t5 which is due to elimination of seedbed preparation. Treatment t6 consumed maximum diesel fuel which is due to repeated operation of disc harrow and planker. Among rotavator treatments, treatment t1 consumed more fuel followed by t2, t4 and t3 which is due to more time required in seedbed preparation. Statistical analysis shows that fuel consumption in each treatment vary significantly from each other at 5 percent significance level. Table 4: mean values of soil, machine and crop parameters for various treatments Fuel consumption for various sizes of rotavators (T 1 -T 4 ) was also determined on the basis of per meter rotor length and unit volume of soil worked and same is presented in Fig. 1 which indicated minimum fuel consumption (3.08 l/h) for treatment T 3 followed by T 4 (3.28 l/ha), T 2 (3.93 l/ha) and T 4 (4.90 l/ha). Fuel consumption, on the basis of unit volume of soil worked, also followed the similar trend. This indicated superiority of the rotavator used in treatment T 3 over other rotavators. In other words, rotavator with rotor size of 172 cm performed better than other three rotavators in respect of fuel consumption. This may also be due to the fact that the rotavator with rotor length of 172 cm was a better match, as compared to other rotavator size, for the size of tractor being used for operating it.
Wheat yield and its attributes has been presented in Table 4 which revealed that number of plants/ m 2 was observed highest (369) for treatment T 4 followed by treatments T 2 , T 1 , T 6 and T 5 . The same was found minimum (308) for T 3 treatment. The plant height ranged between 48 and 51 cm for all the treatments under the experiment. The result also indicated maximum wheat yield of 54.09 q/ha under treatment T 6 . It was observed as 53.20, 51.24, 49.09, 46.76 and 46.25 q/ha for treatments T 4 , T 2 , T 1 , T 3 and T 5 respectively. The yield result for various treatments was found to vary significantly from each other at 5% significance level, however, yields of treatments T 3 and T 5 did not vary significantly. The higher yield in T 6 may be due to the higher weight of grains per ear head. The straw yield was observed maximum as 84.59 q/ha for treatment T 4 followed by treatments T 6 , T 2 , T 1 , T 5 and T 3 respectively.

Figure 1. Fuel consumed by various sizes of rotavators
Energy analysis was performed for all the treatments and same has been presented in Table 5 that showed minimum total direct input energy (tillage +sowing operation) of 0.35 GJ/ha for treatment T 5 indicating as most energy efficient treatment. Amongst the rotavator treatments (T 1 -T 4 ), input energy was observed minimum for treatment T 3 as 1.24 GJ/ha. Treatments T 4 , T 2 and T 1 consumed 2.34, 27.45 and 45% more energy respectively compared to T 3 which was due to more time and fuel requirements in tillage operation because of comparatively smaller rotor length. Conventional method (T 6 ) recorded maximum, 174% higher, input energy as compared to treatment T 3 . The energy saving, in terms of treatments T 6 , was observed highest (89.57%) for treatment T 5 followed by treatments T 3 , T 4 , T 2 . Minimum saving in input energy (47.08%) was observed for treatment T 1 . The energy output to input ratio revealed minimum (45.95) for treatment T 6 and maximum 373.80 for treatment T 5 (no-till sowing). The total energy input and energy input-output ratio varied significantly for all the treatments at 5% level of significance. The energy productivity was also observed maximum (13.06 kg/MJ) for treatment T 5 followed by treatments T 4 , T 3 , T 2 and T 1 . Treatment T 6 recorded lowest energy productivity of 1.59 kg/MJ. The statistical analysis indicated significant difference among the values of various treatments, however, treatment T 1 , T 2 and T 2 , T 3 and T 4 did not vary significantly among themselves at 5% level of significance. Economic analysis was performed for all the treatments included in the experiment (Table 4). The cost of cultivation was observed highest (451.57 USD/ha) for treatment T 6 which is 23.04% higher compared to T 5 which recorded minimum (367.01 USD/ha) input cost for cultivation. Amongst rotavator treatments (T 1 -T 4 ), T 4 and T 3 were having almost same cost of cultivation. Treatments T 1 and T 2 recorded marginally higher, 4.32 and 2.54%, cultivation cost compared to treatment T 3 . Cost of cultivation for treatment T 4 was found 14.64% less compared to T 6 . This was mainly due to more time and fuel consumption per unit area basis. The net profit was observed highest for treatment T 4 followed by T 6 , T 2 , T 1 , T 5 and T 3 respectively.
The statistical analysis indicated significant variation for all the treatments at 5% significance level. The benefit-cost ratio was found maximum (3.53) for treatment T 4 followed by T 2 (3.20), T 5 (3.18), T 6 (2.99), T 1 (2.96) and T 3 (2.91) respectively. Treatment T 4 resulted in 18.06% and 11.01% higher benefit-cost (B: C) ratio compared to treatment T 6 and T 5 respectively.
The statistical analysis indicated significant difference between the treatments T 1 , T 2 , T 4 and T 5 , however, it did not vary significantly for rest of the treatments at 5% significance level.

CONCLUSIONS
In terms of direct energy requirement, T5 (no-till sowing) was found most energy efficient treatment for wheat establishment. Among rotavator treatments (T1-T4), treatment T3 and T4 showed similar result and were found energy efficient next to T5. The energy productivity was found again higher for T5, T4 and minimum for treatments T1, T6. B:C ratio was found higher for T4 followed by T2 and T5 treatments. Based on study, it is concluded that larger size of rotavator (195 cm rotor length) could be used as a substitute to conventional method of wheat establishment. Amongst all the treatments, no-till is most energy efficient method of wheat cultivation.