2. Results
2. Production Efficiency and Land Use Efficiency
2.1. Production Efficiency and Land Use Efficiency
Of the twelve experimental treatments, the crop rotations with PLL combined with autumn- or spring-sown sugarcane had the highest average daily productivity, followed by their counterpart rotations under TLL (
Table 41;
Figure 21). The treatments with late-sown spring sugarcane had the lowest productivity under either laser leveling option. High potato and maize productivity potential, as well as higher bean yields in pea, black gram, and mustard, could explain why these systems are so efficient. Furthermore, as a result of increased output, higher reward was achieved. Potato/maize/mustard/pea/black gram-based systems reported to be productive and profitable than cereal-based systems. T
5 and T
6 showed
[33][13] the highest production efficiency, better water and nutrient availability
[34[14][15],
35], and better soil microbial activities
[36][16] due to PLL.
Figure 21.
Power consumption, electricity cost, and monetary return use efficiency of experimental treatments.
Table 41.
Water use efficiency, employment generation efficiency, productivity, net return, and system profitability of experimental treatments.
Treatments |
WUE (kg Grain m | −3 | ) Water Used) |
EGE (Man dayha | −1 | day | −1 | ) |
Productivity (kg ha | −1 | day |
(7.45 g kg
−1) treatments.
Table 52. After 6 years, changes in soil organic carbon (SOC) concentration (g kg–1) under alternative agricultural systems and precision land levelling procedures.
Soil Depth (cm) |
Inherent (2009) |
T | 1 |
T | 2−1 | ) |
Net Return (INR ha | −1 | ) |
T | 3 | System Profitability (INR ha | −1 | day | −1 | ) |
T | 4 |
T | 5 |
T | 6 |
T | 7 |
T | 8 |
T | 9 |
T | 10 |
T | 11 |
T | 12 |
Mean |
T | 1 |
2.149 |
0.58 |
49.8 |
55,520 |
174.2 |
0–15 |
6.7 ± 0.26 |
7.21 ± 0.74 | d |
4.85 ± 0.23 | c |
7.45 ± 1.40 | d |
4.92 ± 0.23 | a |
8.76 ± 0.21 | c |
5.93 ± 0.28 | a |
7.09 ± 1.09 | b |
3.96 ± 0.18 | b |
8.25 ± 1.16 | b |
5.26 ± 0.2 | b |
8.52 ± 1.40 | c |
5.53 ± 0.26 | a |
6.48 ± 0.62 |
T | 2 |
0.963 |
0.96 |
15–30 |
6.2 ± 0.25 |
6.77 ± 0.30 | d |
3.64 ± 0.18 | c |
6.95 ± 1.16 | b |
4.17 ± 0.21 | b |
8.33 ± 1.15 |
In 2012–13, SOC values were 11% higher under T
5 than T
8, and 10% higher with T
11. By the end of the experiment (i.e., after six years), SOC was 25% higher in T
5 than T
8 and 16% higher with T
11 and 17% higher with T
9 than T
8, respectively. However, the SOC contents was just 7% higher under conventional leveling. Under PLL in the 20–30 cm layer, recorded SOC values were 12% and 19% higher than with T
2 and T
8 treatments, respectively (
Table 52).
2.5. Changes in SOC over Time: Temporal Comparison
6. Changes in SOC over Time: Temporal Comparison
Average SOC stocks in the top 400 kg of soil dropped from 5.92 to 5.41 kg C m
−2 (
Table 63). Between 2009 and 2015, changes in important treatments were −1.88 ± 0.04 kg C m
−2 in T8 (i.e., 5.41 to 4.89 kg C m
−2); −0.68 ± 0.2 kg C m
−2 in T10 (i.e., 5.93 to 5.28 kg C m
−2); −0.82 ± 0.09 kg C m
−2 in T4 (i.e., 5.92 to 5.22 kg C m
−2); and −0.700 ± 0.09 kg C m
−2 in (i.e., 5.48 to 5.05 C m
−2). PLL-treated plants stored larger fractions of atmospheric carbon and, in certain circumstances, established an equilibrium of C imports and exports. SOC stocks decreased after six years in TLL therapy. Over the six-year trial, similar trends in soil C content were seen in lower soil layers (i.e., 400–800 and 800–1200 kg of soil m
−2): the average over all PLL treatments was −0.070 ± 0.06 and −0.020 ± 0.02 kg C m
−2 in the 400–800 and 800–1200 kg of soil
−2 intervals, respectively. This approximates an average yearly rate of change of −6.9 and −5.6 g C m
−2 year
−1 for the mid and lower soil layers, respectively (
Table 63).
Table 63. Annual rate of change in multiple soil mass intervals and variations in SOC stocks from (averaged over alternative cropping systems and precision land leveling practices) 2009 and in 2015.
Crop Sequences |
Soil Organic Carbon ( ± Standard Error) |
0–400 kg of Soil m | −2 | (Approx. 0–30 cm) |
SOC Change Rate g of Cm | −2 | year | −1 |
400–800 kg of Soil m | −2 | (Approx. 30–60 cm) |
Annual SOC Change Rate g of C m | −2 | year | −1 |
800–1200 kg of Soil m | −2 | (Approx. 60–90 cm) |
SOC Change Rate g of Cm | −2 | year | −1 |
2009 |
2015 |
Difference |
2009 |
2015 |
Difference |
2009 |
2015 |
Difference |
kg m | −2 |
kg m | −2 |
kg m | −2 |
T | 1 |
8.12 |
9.11 * |
0.99 ± 0.2 |
46.2 |
5.47 |
5.57 |
0.10 ± 0.09 |
7.1 |
3.38 |
3.47 |
0.01 ± 0.11 |
4.4 |
45.1 |
48,410 |
163.9 |
T | 2 |
5.48 | c |
5.52 ± 0.23 | a |
6.44 ± 1.84 | c |
3.47 ± 0.17 | a |
7.84 ± 1.08 | d |
4.83 ± 0.19 | b |
8.06 ± 1.30 | d |
5.23 ± 0.22 | a |
5.055.94 ± 0.67 |
−0.70 ± 0.09 |
−23.3 |
3.85 |
3.18 |
−0.09 ± 0.06 |
−6.1 |
2.92 |
2.57 |
−0.02 ± 0.02 |
−5.4 |
T | 3 |
1.678 |
1.52 |
83.3 |
126,689 |
346.8 |
30–60 |
5.1 ± 0.19 |
6.17 ± 0.12 | a |
T | 2.97 ± 0.15 | c |
3 | 6.44 ± 1.16 | a |
8.813.65 ± 0.18 | c |
8.75 |
0.06 ± 0.05 |
25.7 |
5.827.72 ± 0.34 | a |
5.25 ± 0.21 | b |
5.92 ± 0.35 |
T | 4 |
0.784 |
1.73 |
55.9 |
59,091 |
176.8 |
T | 5 |
2.892 |
1.56 |
89.7 |
154,030 |
388.9 |
T | 6 |
1.058 |
1.95 |
80.3 |
123,933 |
346.2 |
T | 7 |
1.883 |
1.38 |
88.6 |
141,765 |
376.2 |
T | 8 |
0.875 |
1.65 |
79.3 |
119,793 |
328.6 |
T | 9 |
2.216 |
0.64 |
84.2 |
138,050 |
361.4 |
T | 10 |
0.986 |
1.21 |
71.8 |
102,142 |
288.8 |
T | 11 |
1.378 |
1.25 |
81.2 |
131,800 |
359.3 |
T | 12 |
0.635 |
1.41 |
57.4 |
68,600 |
188.7 |
2.2. Production, Monetary, and Employment Efficiencies
3. Production, Monetary, and Employment Efficiencies
Maximum daily cropping system productivity (89.7 kg ha
−1 day
−1), daily monetary return use efficiency (351.6 INR ha
−1 day
−1), and daily cropping scheme profitability (388.9 INR ha
−1 day
−1) were observed in T
5 (
Table 41;
Figure 21). Other treatments that performed well in terms of these metrics were T
7 and T
9; all three cropping systems included a spring-sown sugarcane and PLL. Of the cereal crops, maize has a higher economic value than rice, whereas potato, pea, and mustard are all higher-value vegetable crops: rotations with these crops (rather than those with lower-value crops) achieved higher system productivity and are thus more attractive options for smallholder famers. Thus, there is potential to replace the traditional rice and wheat crops, with which sugarcane is rotated, with other crops with both higher economic value and capacity to improve soil health.
As compared to the T
11 system, T
5, T
7, and T
9 gave 1.29, 1.27, and 1.21 times higher productivity, saved 51–69 cm of irrigation water. The T
5 system used 51 cm less water and reported with highest productivity (89.7 kg ha
−1 day
−1) and has productivity margin of 8.5 kgha
−1 day
−1. The T
7 system produced 88.6 kg ha
−1 day
−1 with 132 cm irrigation water (
Table 41), resulting in a 61 cm water savings. T
5 cropping system used 155 cm of irrigation water and produced 84.2 kgha
−1 day
−1, while T
4 cropping system used 38 cm of irrigation water and produced 84.2 kgha
−1 day
−1 (Table 3). This could be due to the black gram pulse crop, which, when compared to the R-W-S-R-W system, reduced water loss due to evaporation, percolation, and seepage
[35,36,37,38][15][16][17][18]. The highest net returns were INR 138,982 ha
−1 annum
−1 in the R-P-S-R-W system, which was 1.39 times greater than the R-W-S-R-W system (
Table 41), followed by INR 130,779 and Rs. 120,096, respectively, in the R-M-S-R-W and R-P-S-R-W sequences. As compared to the R-W-S-R-W system, the R-P-S-R-W, R-M-S-R-W, and M-S-R-W consumed 17.9, 24.8, and 32.1% lesser irrigation water which further resulted in saving electricity consumption by 140, 300, and 460 electricity units’ ha
−1, respectively (
Table 41;
Figure 21). Similar observations were also reported by Bohra et al.
[39][19]; Rathore et al.
[40][20].
2.3. Resource Use Efficiency
4. Resource Use Efficiency
Cropping system profitability ranged from 163.9 (T2) to 388.9 (T5) INR ha
−1 day
−1, with MRUE values ranging from 132.6 (T2) to 351.6 (T5) INR ha
−1 day
−1 (
Table 41). Similar trends of high profitability under PLL and spring-sown sugarcane were reported by Singh et al.
[41][21] and Sharma
[35,42][15][22].
Labor requirements where highest in the T
6 cropping system (1.95 person days ha
−1 day
−1) and lowest in T
1 (0.58 person days ha
−1 da
−1). Overall, in the more profitable spring-sown PLL treatments, labor requirements varied between 0.64 (T
9) and 1.56 (T
5) person days ha
−1 day
−1. Intercropping increased the labor required for weeding by 36% compared to the sole crops. T
8, T
10, and T
12 only hire farmers for 1.73, 1.65, and 1.41 men days ha
−1 day
−1, respectively, but >0.58 men days ha
−1 day
−1 engagement in any order resulted in underemployment, as documented by
[43,44,45,46][23][24][25][26] (
Table 41;
Figure 21).
2.4. Soil Organic Carbon Patterns
5. Soil Organic Carbon Patterns
The treatment T
5 had the greatest soil organic carbon concentration in the surface layer (0–15 cm) at 8.76 g kg
−1, followed by T
11 (8.52 g kg
−1) (
Table 52). Treatments with PLL achieved maximum soil organic carbon concentrations in the surface and lower soil layers than were observed in treatments with TLL. Across all treatments, the mean SOC concentration varied from 2.69 inT
8 to 6.91 g kg
−1 in T
5 and with almost nil improvements in T
2 emphasizing the role of laser levelling
[47][27]. The greatest improvement in SOC concentration was observed in the T
9 (8.25 g kg
−1) and T
3
2.75 ± 0.13 |
a |
7.62 ± 0.33 | b |
3.62 ± 0.18 | c |
6.99 ± 0.34 | b |
4.76 ± 0.19 | b |
5.32 ± 0.31 |
5.31 * |
0.51 ± 0.2 |
4.5 |
2.93 |
2.67 |
0.26 ± 0.02 |
5.7 |
60–90 |
4.3 ± 0.13 |
4.52 ± 0.14 | c |
2.18 ± 0.11 | a |
4.76 ± 0.21 |
T | 4 |
5.92 | c |
5.22 | 2.74 ± 0.14 | a |
−0.82 ± 0.095.88 ± 0.09 | a |
−21.43.61 ± 0.19 | c |
4.054.71 ± 0.22 | d |
3.981.92 ± 0.11 | a |
−0.07 ± 0.095.09 ± 0.09 | b |
−5.52.98 ± 0.15 | c |
2.425.66 ± 0.12 | a |
2.95 ± 0.15 | a |
3.92 ± 0.14 |
2.37 |
−0.05 ± 0.02 |
−4.2 |
90–120 |
3.4 ± 0.09 |
2.53 ± 0.18 | a |
1.53 ± 0.07 | b |
2.88 ± 0.09 | a |
1.66 ± 0.09 | b |
3.87 ± 0.12 | b |
T | 5 | 2.46 ± 0.13 | d |
9.18 * | 2.47 ± 0.23 | b |
9.87 | 1.36 ± 0.07 |
−0.69 ± 0.2 |
82.1 |
7.62 |
7.64 |
0.02 ± 0.2 | d |
3.13 ± 0.23 | a |
1.74 ± 0.10 | b |
3.62 ± 0.33 | b |
1.92 ± 0.12 | b |
8.8 |
5.04 |
5.082.43 ± 0.15 |
0.04 ± 0.01 |
7.2 |
Mean |
5.14 ± 0.18 |
5.00 ± 0.29 |
3.03 ± 0.15 |
5.69 ± 0.80 |
3.43 ± 0.17 |
6.91 ± 0.38 |
4.55 ± 0.21 |
5.33 ± 0.75 |
2.69 ± 0.13 |
−4.86.39 ± 0.58 |
3.69 ± 0.17 |
6.57 ± 0.69 |
4.08 ± 0.19 |
- |
T |
6 |
6.62 |
6.18 |
−0.79 ± 0.2 |
−13.6 |
5.36 |
5.27 |
−0.46 ± 0.07 |
3.56 |
3.28 |
−0.18 ± 0.02 |
−1.8 |
T | 7 |
7.46 |
7.15 * |
0.31 ± 0.03 |
28.2 |
5.39 |
5.65 |
0.26 ± 0.09 |
3.9 |
4.14 |
4.12 |
0.02 ± 0.01 |
1.8 |
T | 8 |
5.41 |
4.89 |
−1.88 ± 0.04 |
−67.8 |
3.35 |
3.08 |
−0.07 ± 0.06 |
−6.9 |
2.72 |
2.37 |
−0.02 ± 0.02 |
−5.6 |
T | 9 |
8.98 * |
9.77 |
0.79 ± 0.2 |
57.4 |
7.03 |
7.11 |
0.08 ± 0.2 |
1.5 |
3.72 |
3.81 |
0.09 ± 0.11 |
5.1 |
T | 10 |
5.93 |
5.28 |
−0.68 ± 0.2 |
−19.2 |
4.05 |
3.98 |
−0.07 ± 0.09 |
−5.5 |
2.42 |
2.37 |
−0.05 ± 0.02 |
−3.9 |
T | 11 |
9.15 |
9.29 |
0.14 ± 0.9 |
19.6 |
5.72 |
5.88 |
0.16 ± 0.09 |
7.3 |
4.57 |
4.58 |
0.01 ± 0.01 |
0.6 |
T | 12 |
6.01 |
5.75 |
−0.70 ± 0.09 |
−16.3 |
4.85 |
4.18 |
−0.31 ± 0.09 |
−5.1 |
3.42 |
3.37 |
−0.15 ± 0.02 |
−2.4 |
Due to associated errors during its calculation, SOC estimates in the 400–800 and 800–1200 kg m
−2 layers were small. Over the entire 0 to 1200 kg m
−2 soil depth, SOC stocks did not vary greatly under different land leveling treatments (
Table 63), although superficial differences were observed during 2015 between rotations
(Table 7).
Table 7. Efficiencies of energy use and its dynamics and SOC stocks (0–90 cm) under alternative cropping systems and precision land leveling practices.
Under T
5, SOC increased from 22.33 to 24.31 kg C m
−2 between 2009 and 2015. Changes were also observed in T
11 (20.89 to 21.86 kg C m
−2), T
7 (14.96 to 14.13 kg C m
−2), and T
8 (13.08 to 12.35 kg C m
−2). Archived samples exposed that decomposition degree of SOC under T
5, T
8, and T
7 was 1.5 times greater, and significantly higher than that of R-W-S-R-W
PLL with PLL (
Table 7) and hence to evaluate the effect of applied treatments on SOC, previous year samples are certainly important
[48][28].
Between 2009 and 2015, the average SOC in 0–1200 kg m
−2 of soil (i.e., around 1 m soil depth) in T
8 treatments declined by −1.97+0.06 kg m
−2, from 13.08 to 12.35 kg C m
−2. SOC stocks in 0–1200 kg m
−2 of soil grew by +1.98 kg m
−2 (i.e., from 22.33 to 14.13 kg m
−2) in T
5 (i.e., from 22.33 to 24.31 kg m
−2) and +0.83 ± 0.3 kg m
−2 in T
7 (i.e., from 14.96 to 14.13 kg m
−2) in T
5 (i.e., from 22.33 to 24.31 kg m
−2. Between 2009 and 2015, C was removed from the soil rather than absorbed from the environment in the TLL treatments.
2.6. SOC and Tillage Practices
7. SOC and Tillage Practices
Under T
7, SOC in the first 400 kg m
−2 soil (about the top 30 cm) had higher profile than under T
5. While SOC stocks were higher (+10%) in precision land levelling (T
5) than in T
7, they were marginally lower (−5.6%) and (−1.8 %) in T
8 than in T
6, respectively (
Table 52). SOC stocks, on the other hand, were consistently lower under T
12 than they were under T
5 or T
7. (
Table 63). There were no significant variations in SOC stocks between T
7 and T
12 when the 0–400 kg of soil m
−2 under R-M-S-R-W and R-P-S-R-W with or without land levelling was investigated, whereas T
12 had 16% less SOC (
Table 63). T
12’s soil disturbance in the top 400 kg of soil m
−2 may have accelerated the rate of SOC loss compared to T
11.
Traditional field levelling has been shown to destabilize aggregates, lowering physical protection and exposing previously inaccessible SOC to microbial destruction
[49][29]. When compared to archival soil samples, six years of treatment demonstrated a decrease in SOC stocks in the first 400 kg of soil m
−2 for all TLL treatments (
Table 63). This shows that six years were insufficient to produce detectable differences in SOC across the T
7, T
5, and T
11 plots. Long-term studies are necessary to determine the differences in the effect of management practices, according to several studies
[50,51][30][31]. Given the high SOC background in the entire soil profile and small annual changes, long-term studies are essential to determine differences in the effect of management practices. When SOC stocks were examined over time in the soil layer immediately below the plough layer (400–800 kg m
−2), it was clear that during the period between soil samplings (2009–2015), SOC levels had fallen significantly under T8 plots while remaining virtually unaltered under T
7 or T
5 plots (
Table 63). Under T
7 and T
5, there was no difference in SOC stocks between 2009 and 2015. (
Table 52). Under R-M-S-R-WTLL (T
8), the yearly rate of SOC loss in the 400–800 kg of soil m
−2 interval was −6.9 g C m
−2 year
−1, while the rate of SOC change in the T
1 and T
5 plots was +7.1 and +8.8 g C m
−2 year
−1, respectively (
Table 63). SOC stocks under T
1 and T
5 were assumed unaffected by land levelling at this soil mass interval due to the estimation error. As a result, compared to T
1 or less intrusive PLL as T
5 cropping system, significant soil disturbance with T
8 could have resulted in a quick rise in soil aeration (as well as changes in soil temperature and moisture) at larger depths. SOM decomposition would be accelerated if exposed to higher oxidative conditions at deep
[52][32], and this could be the source of SOC depletion at the 400–800 kg of soil m
−2 interval in T
8 plots. SOC was unaffected by management techniques in the 800–1200 kg of soil m
−2 interval (about 60–90 cm) and remained constant under all of the examined treatments, as expected (
Table 63).
Finally, there were differences across tillage treatments when evaluating soil C changes in the entire 1200 kg of soil m
−2 (about 90 cm depth) in 2009, but they grew wider to become significant in 2015. Over the last 06 years of the trial, soil C stocks increased by 4.4, 5.1, 5.7, and 7.2, 0.74, 0.76, 0.97, and 1.98 kg C m
−2 under T
1, T
9, T
3, and T
5 treatments, respectively (
Table 52). T
8 twice the rate of SOC change under T
9 or T
5, 57.4, 63.3, 82.1, and 99.2 g C m
−2 year
−1, respectively, assuming a constant rate of change in SOC stocks for the last 06 years (
Table 6 and Table 73). Despite the observed differences between treatments, the differences were statistically significant when C changes for each treatment were evaluated over time (
Table 6 and Table 73).
After six years, more SOC stores were discovered in the surface 400 kg of soil m
−2 under T
9 or T
5 compared to T
8. T
8 lost more SOC than T
9 or T
5 with PLL, despite the fact that the temporal difference was not judged significant. Given the parameters of this experiment, it is likely that more than 06 years will be necessary to identify variations between the examined cropping systems and land levelling procedures in the surface 400 kg of soil m
−2 (approx. 30 cm). SOC stores in the 400–800 kg soil m
−2 range were found to diminish after only 06 years under T
8, but remained constant under T
9 and T
5. Leveling choices have no effect on SOC stores in the 800–1200 kg of soil m
−2 range. Comparison between old and fresh soil samples revealed that higher fraction of carbon was recorded in the T
9 and T
5 plots where PLL followed than T
8 plots where TLL was practiced. Further, plots under TLL with time lost the SOC. The yearly SOC change rate (g of cm
−2 year
−1) under both alternative cropping systems and precision land leveling practices indicated that rice-black gram-autumn sugarcane-ratoon sugarcane-wheat, maize-autumn sugarcane-ratoon sugarcane-wheat, rice-potato-spring sugarcane-ratoon sugarcane-wheat, rice-mustard-spring sugarcane-ratoon sugarcane-wheat, rice-pea-spring sugarcane-ratoon sugarcane-wheat, and rice-wheat-late spring sugarcane-ratoon sugarcane-wheat under precision laser leveling showed the positive SOC than traditional laser leveling (
Figure 32)
Figure 32.
Yearly SOC change rate (g of cm
−2
year
−1
) under alternative cropping systems and precision land leveling practices.
38. ConclusionsFuture
Cropping systems that used PLL had higher total SOC stocks compared to their counterparts with TLL which might be due to inherent low C status of the experimental site. Under R-P-S-R-WPLL, M-S-R-WPLL, R-M-S-R-WPLL, and R-B-S-R-WPLL plots, SOC concentrations and storage were maximum in the upper 0.3 m soil depth. The active C and N pools in the conventional rice-wheat-sugarcane cropping system decreased as system productivity grew with the addition of P to N, and then increased even more with the addition of N, P, and K. In a cropping system, the administration of N fertilizer at the recommended dose to each crop is suggested, as is the careful adjustment of P fertilizer doses, taking into account the type of fertilizer, soil features and yield levels, the extent of P removal, and the growing environment. The active C and N pools in the conventional rice-wheat-sugarcane cropping system decreased as system productivity grew with the addition of P to N, and increased even more with the addition of N, P, and K. In a cropping system, the administration of N fertilizer at the required dose to each crop is suggested, as is the careful adjustment of P fertilizer dose, taking into account the type of fertilizer, soil features and yield levels, the extent of P removal, and the growing environment. Relative to conventional TLL practices, PLL improves carbon sequestration, cropping system energy requirements, water productivity, and system productivity and profitability.