Introduction

Land preparation is an important activity for providing favorable condition for crop cultivation. Unlike the other crops, paddy is a major cereal crop, which grows in a standing water conditions. Paddy is predominantly cultivated in fields with higher clay content, and the behavior of clay soil is unpredictable as it becomes pasty in the presence of moisture and forms the huge cracks when it is dry. Providing stagnated water condition for paddy cultivation is challenging. Puddling is an important operation that is carried out to create an impervious layer in the subsurface of soil that reduces the infiltration rate. In puddling, the soil particle is disintegrated or churned in the presence of water and the disturbed soil particles occupy the pore space and thus create an impervious layer which reduces the percolation of water and facilitates the stagnation of water for paddy cultivation. Puddling softens the soil for transplanting.

Behera et al. [2] observed highest puddling index of 30.13% for peg type puddler in two passes and rotary puddler in one pass produced 24.60% of puddling index. Pradhan et al.  [11] evaluated the performance of the power tiller with different cage wheel lug angle and diameter in inceptisol. The cage wheel of 30o lug angle with 73 cm diameter registered the maximum puddling index of 29.25%. Power tiller drawn rotavator produced highest puddling index and lower percolation rate in hilly areas compared to animal drawn traditional country plow, rectangular blade puddler and disk harrow [9]. Saimbhi [12] reported a maximum puddling index of 84%, and an infiltration rate of 0.11 cm h−1 could be achieved by puddling with rotavator. Puddling depth of 12.4 cm was recorded when puddling with pulverizing roller attachment to cultivator and the lowest of 9.4 cm for cultivator and planker combinations. Infiltration rate was decreased (0.85 mm h−1) as the puddling index (71.5%) increased during rotavator puddling. Chandra et al. [3] found that the tractor drawn rotavator had the penetration resistance of 62.92 kPa in experimental fields prepared by rotavator.

Materials and Methods

Initially, a dry soil sample was taken from the trial field. The sample was analyzed using the Robinson pipette method, and the soil was found to be of silty loam in nature. The different conventional puddling techniques (implements) used by the farmers and their combinations were taken for the study. Since the number of passes also influences the puddling index, each technique was analyzed for single pass and double pass [2]. All the evaluation parameters were measured using the standard procedures. The study was conducted in Agricultural Engineering College and Research Institute, Kumulur, Trichy, Tamil Nadu, India, and the total area taken for the study was 900 m2. The treatment details are mentioned in Table 1, and the different puddling techniques are shown in Fig. 1. The treatments were replicated thrice to increase the accuracy. Factorial randomized block design (FRBD) was selected, and AGRES statistical tool was used to analyze the results.

Table 1 Treatment details
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Fig. 1
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Different puddling techniques

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Measurement Procedures

Puddling Index

Sample of 200-ml puddled soil was collected at five different random locations of puddled field using a PVC pipe. PVC pipe was first inserted into the puddled soil after the final lap of each treatment. The inserted pipe was clenched at the top, to hold the sample. Then, the sample was collected in a 250-ml measuring cylinder. The sample was kept undisturbed for 48 h in measuring cylinder. After 48 h, the level of soil and total sample were noted. Using Eq. (1), puddling index is calculated:

$${\text{PI}} = \frac{{P_{\text{s}} }}{{P_{\text{t}} }} \times 100$$
(1)

where PI = puddling index (%), Ps = soil level in the measuring cylinder after 48 h (ml), Pt = total sample level (ml).

Infiltration Rate

A PVC pipe of diameter 200 mm was fitted with a graduated scale on the lengthwise (Fig. 2). The PVC pipe was placed over the soil sample and filled with water. The initial water level inside the PVC pipe was noted as initial value. The water level was noted for every 3-h duration, and then, the infiltration rate for a day was calculated by dividing the reduction in water level within the cylinder of measurement [4].

Fig. 2
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Infiltration rate measurement

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Penetration Resistance

Cone penetrometer was used for measuring the penetration resistance of soil (Fig. 3). According to ASAE standards, the cone base area of 323 mm2 was used for measurement. Readings are taken at different depths (5, 10 and 15 cm) in five different locations of the experimental field randomly. The values were exhibited in digital display, to the accuracy of 0.01 kg.

Fig. 3
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Penetration resistance measurement

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Depth of Puddling

The depth at which the force required to push the cone penetrometer rod increases by 2 kg shall be taken as the depth of puddling [1]. Depth of water was maintained at 5–10 cm from the ground level throughout the field. After secondary tillage, the fields were leveled to maintain the water level same during the puddling process.

Results

Puddling Index and Infiltration Rate

The analysis of variance (ANOVA) for puddling index is presented in Table 2. The puddling techniques were significant at 1% level, and the number of passes recorded its significance at 5% level.

Table 2 ANOVA for puddling index
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The puddling with cage wheel in single pass recorded the lowest puddling index and highest infiltration rate. The puddling index and infiltration rate with cage wheel single pass were observed to be 49.29% and 19 mm d−1, respectively (Fig. 4). The infiltration rate decreased when the puddling index was increased in cage wheel (T1) puddler’s first pass to the second pass (P2).

Fig. 4
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Influence of different puddling techniques on infiltration rate and puddling index

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The analysis of variance for infiltration rate is presented in Table 3. The puddling techniques and the number of passes were significant at individual level at 1% level.

Table 3 ANOVA for infiltration rate
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The single-pass (P1) rotavator (T2) puddling recorded the puddling index as 60.80% and the infiltration rate as 13.5 mm d−1. T2P2 operation recorded higher puddling index of 61.54% and the lowest infiltration rate of 13 mm d−1 compared with T2P1. It might be due to the increased soil disturbance. When the number of passes was increased for rotavator puddling, the puddling index increased by 0.012%. The results of the study were in accordance with the findings of [4]. Chinna [4] reported the puddling index of 71.5% in clay loam soil for rotavator in single pass.

The cage wheel combined with rotavator (T3) registered the lower puddling index of 62.86% in single pass (P1) and the higher puddling index of 64.86% in double pass (P2). Maximum infiltration rate of 12.5 mm d−1 was measured in P1, and the minimum infiltration rate of 12 mm d−1 was recorded for P1 and P2, respectively. Power tiller with rotary tool (T4) resulted in highest puddling index of 70.91% in P2 and the second highest puddling index of 69.61% recorded in T4P1. The above results were in close relation to the authors [4, 9].

Depth of Puddling

The ANOVA for depth of puddling is presented in Table 4. The puddling techniques and the number of passes had the significance effect at 1% level.

Table 4 ANOVA for depth of puddling
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Depth of puddling was higher in T3P2 treatment compared with all the other treatments. The depth of operation reached up to 187.5 mm (Fig. 5). Among all puddling techniques, the lowest depth of puddling of 120 mm was observed in T4P1. In T1P1 and T1P2, the depth of puddling was 125 and 137.7 mm, respectively.

Fig. 5
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Depth of puddling for all the treatments

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Penetration Resistance

Penetration resistance of puddled field was reduced for all puddling techniques. Before puddling, the penetration resistance was 14.729 N cm−2 at 5 cm depth, but after puddling, it was reduced to 4.531 N cm−2, for T1P1 treatment, and further, it was reduced to 3.717 N cm−2 for T1P2 operation (Fig. 6).

Fig. 6
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Penetration resistance of unpuddled field and puddle field

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Penetration resistance was reduced up to 68% and 75% after the first pass and second pass, respectively, for cage wheel operation (Fig. 7). The penetration resistance after the second pass of cage wheel was increased by 7%, but the field had some unpuddled spaces in between.

Fig. 7
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Penetration resistance of cage wheel first pass and second pass

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When rotavator was used, the penetration resistance decreased abruptly in the first pass to 1.658 N cm−2 at 5 cm depth, whereas after second pass of rotavator, it was 1.473 N cm−2, a reduction of 11.15% (Fig. 8). Since the decrease in penetration resistance between the first and second passes of rotavator puddling is negligible, the second pass is not necessary.

Fig. 8
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Penetration resistance of rotavator first pass and second pass

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At 10 cm depth, the penetration resistance for T3P1 (cage wheel + rotavator with single pass) was 2.396 N cm−2. At the same depth of T2P1 operation, the penetration resistance was 2.487 N cm−2 (Fig. 9). In T3P1, the penetration resistance was reduced up to 0.091 N cm−2 compared to T2P1. It was showed that the usage of cage wheel with rotavator (T3) in a single operation does not register a great impact on the penetration resistance compared to rotavator (T2) operation. In the second pass of same puddling techniques, the same trend was achieved.

Fig. 9
figure 9

Penetration resistance for first pass of rotavator (T2P1) and cage wheel + rotavator (T3P1)

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Power tiller operated rotary tool recorded the lowest penetration resistance among all the puddling techniques up to 10 cm depth. Because of its lowest depth of puddling, the penetration resistance was more after 10 cm depth. At the of 5, 10 and 15 cm depth, the penetration resistance was 0.738, 1.109 and 24.670 N cm−2, respectively, after the first pass (Fig. 10).

Fig. 10
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Influence of the number of passes in power tiller operated rotary tool in penetration resistance

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Discussion

Puddling Index

The cage wheel (I1) puddling recorded a puddling index of 49.29 and 52.50% during single pass and double pass, respectively. Puddling index was increased by increasing the number of passes for all treatments, and this might be due to increased manipulation and additional disintegration of the soil. This is well corroborated with the findings of previous researchers [16, 2].

When the number of passes was increased from single to double, the puddling index was increased by 6.51, 1.21, 3.02 and 1.86% in T1, T2, T3 and T4, respectively. The cage wheel puddling (T1) resulted in appreciable increase in puddling index, whereas other puddling techniques could register negligible increase with increasing the number of passes. The power tiller operation had the highest puddling index among all puddling techniques, but the depth of puddling was up to 13.38 cm.

Infiltration Rate

Infiltration rate was decreased by 0.5 mm d−1 during the second pass in rotavator puddling. Reduction in infiltration rate could be observed for all treatments with an increase in the number of passes. It is because the effective creation of impervious layer and due to additional churning in second passes. Puddling with cage wheel (T1) in single pass recorded the higher infiltration rate, and the power tiller operated rotary tool (T4) registered the lowest. The infiltration rate was decreased by 7.63, 3.70, 4.00 and 38.10% for T1, T2, T3 and T4, respectively, with the increase in the number of passes. The infiltration rate was minimum in treatment T4P2 compared with other treatments.

The experiments showed an inverse relation between puddling index and infiltration rate for all treatments. This might be due to the reason that the higher degree of churning of soil in standing water resulted in higher puddling index, which permits the small soil particle to occupy the pore space of the underneath soil layer and creating effective impervious layer [10]. This was in relation with the findings of [7, 16, 5].

Depth of Puddling

Depth of puddling was increased with an increase in the number of passes, irrespective of the puddling techniques. This could be because an increase in softness of puddled soil in the first pass allowed the prime mover to utilize the available energy for further manipulation of soil below the puddled soil. This corroborates the observations of [14]. The variation in depth of puddling for rotavator with cage wheel (T3) and rotavator (T3) could be observed as 10 mm during single pass.

The increase in the number of passes resulted in 1% significance on depth of puddling. Insignificance was observed in the interactive effect of puddling technique and the number of passes. The increase in the number of passes from one to two increased the depth of puddling by 10.04, 4.28, 1.35 and 11.5% for T1, T2, T3 and T4, respectively. Dhiman et al. [6] stated that the puddling depth of rotavator operation was more than the power tiller operation. The same result was observed in this study. Most of the paddy roots (56%) were implanted at 0–12 cm depth, 32% of roots were rooted in between 12 and 22 cm depth and 12% was deep rooted below 22 cm depth [8]. So the power tiller operated rotary tool puddling was not up to the mark. Rotavator (T2) puddling registered 175 mm of depth of puddling which is more than the power tiller operated rotary tool in single pass (P1).

Penetration Resistance

Paddy root extends it root growth in soil where its penetration resistance is less than 100 N cm−2 [13]. Penetration resistance for all the puddling techniques recorded well below 100 N cm−2, so puddling with any of the implements could ease the root growth. The penetration resistance for power tiller operated rotary tool (I4) technique recorded the lowest value of 0.738 N cm−2 and the highest value of 4.531 N cm−2 for cage wheel (I1) puddling. Rotavator with cage wheel (I3) and rotavator (I2) ranked second and third, respectively, with the penetration resistance of 1.014 and 1.658 N cm−2 at 5 cm depth. Similar trend was observed at 10 and 15 cm for all the puddling techniques and in second pass. Valera et al. [15] observed that the first pass caused most of the soil change when compared to following passes. The penetration resistance was lowest in the case of power tiller operated rotary tool (I4) puddling. But due to the lesser weight of power tiller, it could not manipulate the soil below 120 and 127.30 mm during the first and second passes, respectively, which is not favorable for paddy cultivation.

The cage wheel with rotavator (I3) ranked the second lowest in terms of penetration resistance, and rotavator (I2) puddling ranked the third. The difference in penetration resistance was 0.644, 0.091 and 2.226 N cm−2 at 5, 10 and 15 cm, respectively, (Table 5). In terms of field capacity, the rotavator (I2) puddling is covered 2990 m2 h−1, and the cage wheel with rotavator (I3) is 2740 m2 h−1. It was concluded that the rotavator (I2) covered more area than cage wheel with rotavator (I3) puddling.

Table 5 Penetration resistance of different implements during first pass
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Conclusions

Cage wheel with double passes created the puddling index not equal to rotavator operation. Hence, the rotavator puddling can be an optimum treatment. Power tiller operated rotary tiller had the highest paddling index compared to other puddling techniques, but the depth of puddling was 120 mm only. It was the lowest value compared to other puddling techniques. Rotavator puddling with single-pass operation had the puddling index of 60.80% and depth of puddling of 175 mm. Infiltration rate for cage wheel, rotavator, cage wheel + rotavator and power tiller operated rotary tiller in single pass was 19, 13.5, 12.5 and 10.5 mm d−1, respectively. In silty loam soil, infiltration rate increased with a decrease in puddling index for all puddling techniques used in puddling operation. Penetration resistance was increased with an increase in depth. Highest depth of puddling was observed as 187.50 mm in cage wheel with rotavator second pass puddling operation.