1 Studies on weeds
In experimental field, the problem of weeds (grassy as well as broadleaf) was more in 2017-18 than 2016-17. Farmers also reported that in 2017-18, they faced more problems. Sowing time weather significantly differed in the second year which recorded very low sunshine hours consequently other parameter also turned in the favour to maintain cool and humid weather in second year. This played a major role for higher infestation of weeds and under such situations; the farmers are forced to go for wet seeding or delayed wheat sowing (Chaba and Jagga, 2017; Singh, 2019). Residue burning, an ill-practice prevailing in IGP is also one of the major key factor for unfavorable weather conditions at the onset of winter in north India (Nibber, 2015; Acharya et al., 2016; Singh et al., 2019). Due to this reason during second year, the performance of all herbicidal treatments against grassy as well as broadleaf was also poor than first year.
Weed density was counted at 30, 75 and 120 DAS and given in detail (Tables 2–3). At 30 DAS, only the effect of pre-emergence herbicides (pendimethalin metribuzin and pyroxasulfone) was visible (post-emergence not applied yet) and found that pendimethalin + metribuzin (1500 + 175 g ha− 1) and (1000 + 175 g ha− 1) were most effective against P. minor in both years and recorded lowest density (approximate 90 and 80% reduction in 2016-17 and 2017-18, respectively) followed by pyroxasulfone (105 and 128 g ha− 1) and pendimethalin (1500 g ha− 1) (Table 2). At 30 das performance of pyroxasulfone recorded little bit poor than tank mix application of (pendimethalin + metribuzin) but it gaves complete control of P. minor at later stage. Because it comes under K3 group herbicides those mode of action is Very-long-chain fatty acid elongase (VLCFAE), they allow weed seed to germinate but inhibit further shoot elongation and kill the weeds (Tanetani et al., 2009). Metribuzin (175 and 210 g ha− 1) also found effective but reflected little bit poor performance than pendimethalin and pyroxasulfone. First year performance of the all herbicides against P. minor was far better than second year. In case of broadleaf weeds during both years, pendimethalin (1500 g ha− 1) was not found effective but metribuzin (175 and 210 g ha− 1) and pyroxasulfone (105 and 128 g ha− 1) reduced broadleaf weeds significantly. However, during second year their performance was little bit poor and did not reduce the broadleaf population satisfactorily. During second year, none of the herbicides alone and in combination reduced the broadleaf weeds significantly at 30 DAS.
Performance of pre-emergence application of pendimethalin (1500 g ha− 1) or metribuzin (210 g ha− 1) and POE application clodinafop (60 g ha− 1) or sulfosulfuron (25 g ha− 1) was not much effective against resistant population of P .minor which was clearly evident with only 52–78% control in first year and 33–65% in second year at 75 DAS (Table 3). Tank mix application of pendimethalin + metribuzin (1500 + 175 or 1000 + 175 g ha− 1) increased the P. minor control (79–87% in first year and 66–81% in second year). Punia et al. (2018) conducted experiment in 2017-18 at CCSHAU, Hisar and reported similar results that alone application of pendimethalin or metribuzin was not that effective against resistant population of P. minor with only 33–35% control. Post-emergence application of pinoxaden (50 g ha− 1) or mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) found very effective in first year with 93–95% control, but during second year the performance was poor (only 45–55% control was recorded). Similar results were reported earlier by Punia et al. (2017) indicating that clodinafop (60 g ha− 1) and sulfosulfuron (25 g ha− 1) did not provide satisfactory control of P. minor; however, mesosulfuron + iodosulfuron 14.4 g ha− 1provided better control (85–90%). Pinoxaden (50 g ha− 1) resulted in 80% control of P. minor during first year but it provided only 55% control during second year at farmers’ fields at Kheri Raiwali in Kaithal district of Haryana. P. minor showed high level of resistance to fenoxaprop, isoproturon and clodinafop (resistance factor 1.92–3.89), low level to pinoxaden, sulfosulfuron and mesosulfuron + iodosulfuron (RF 1.06–1.34) (Rasool, 2016).
Pyroxasulfone (105 and 128 g ha− 1) provided 100% control of P .minor in first year and 85–94% in second year. Pyroxasulfone has also been reported very effective against P. minor earlier also (Singh, 2015; Punia et al., 2018). Sequential application of metribuzin (175 g ha− 1) followed by clodinafop (60 g ha− 1), sulfosulfuron (25 g ha− 1), pinoxaden (50 g ha− 1) and mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) gave upto 89 to 95% control of P. minor in first year and 82–86% in second year. Advantage of sequential application of pre- and post-emergence herbicides against P. minor was already reported (Yadav et al., 2016). Pendimethalin (1500 g ha− 1) and metribuzin (210 g ha− 1) followed by one hand weeding at 35 DAS was also found effective against P. minor in both years. Pre-emergence application of pendimethalin or metribuzin reduced P. minor population but it was not sufficient to control second flush of weeds which appeared after first irrigation (Punia et al., 2018), and hand weeding at 35 DAS helped to remove such weeds which emerged after first irrigation.
With regard to broadleaf weeds during both years, mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) alone and sequential application of metribuzin (175 g ha− 1) followed by sulfosulfuron (25 g ha− 1) and mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) gave almost complete control (98–100% in 2016-17 and 93 to 97% in 2017-18) at 75 DAS. Sulfosulfuron (25 g ha− 1) alone was also found as good as above mentioned treatments, but it was unable to control Rumex dentatus. Herbicide resistance or poor efficacy in Rumex dentatus against ALS inhibitors already reported in IGP by researchers (Chhokar et al., 2017). In the absence of other weeds, Rumex dentatus grew vigorously in sulfosulfuron treated plots. Pre-emergence herbicides pendimethalin (1500 g ha− 1), metribuzin (210 g ha− 1), pyroxasulfone (105 and 128 g ha− 1) were not found effective against broadleaf weeds in first year (36 to 59% control) and almost no control in second year (20 to 43%). Pendimethalin (1500 g ha− 1 fb HW), metribuzin (210 g ha− 1 fb HW), and pendimethalin + metribuzin (1500 + 175 and 1000 + 175 g ha− 1) provided satisfactory control of broadleaf weeds (75 to 83%) in first year. But in second year, the performance was not up to mark and recorded only 44 to 65% control.
Within pendimethalin (1500 g ha− 1) and metribuzin (210 g ha− 1), performance of pendimethalin was poor in both years as it was unable to control Melilotus spp (alba/indica). This comes at later stage of crop growth and grows profusely in the absence of other weeds (Das, 2011). However, pendimethalin (1500 g ha− 1) was found very effective against Rumex dentatus and gave complete control in both years. Kaur et al 2017 also reported that application of pendimethalin alone and tank-mix recorded 98–100% control of Rumex dentatus. So it is alternate option in those areas which are facing problem of herbicide resistance in Rumex dentatus against ALS inhibitors herbicides. Pyroxasulfone (105 and 128 g ha− 1) also behaved like pendimethalin and was unable to control Melilotus spp (alba/indica) in both years but gave complete control of Rumex dentatus. Clodinafop (60 g ha− 1) and pinoxaden (50 g ha− 1) did not provide any control of broadleaf weeds and were at par with weedy plot in both years. Sequential application of metribuzin (175 g ha− 1) followed by clodinafop (60 g ha− 1) and pinoxaden (50 g ha− 1) reduced the broadleaf weeds and their effect was synergetic with metribuzin against broadleaf. Clodinafop and pinoxaden did not control broadleaf weed and continuous use of grass killing herbicides, besides resulting into resistance development, also led to a shift in the weed flora (Chancellor, 1979; Chhoker et al., 2012; Yadav et al., 2016). Weed density in all treatments also followed similar trend at 120 DAS, but there was sharp reduction in broadleaf weeds density as their population was 2.80 and 3.05 times at 75 DAS in 2016-17 and 2017-18, respectively. P. minor was only 1.0 and 1.22 times (Table 3). Broadleaf weeds are less aggressive in nature and pose fewer problems than grassy weeds (Chhoker et al., 2012). (Insert Table 2 & 3 Here)
Table 2
Effect of different weed control treatments on weed density (No. m− 2) at 30 DAS
Treatment
|
Dose (g ha− 1)
|
P. minor
|
Broadleaf weeds
|
2016-17
|
2017-18
|
2016-17
|
2017-18
|
PMN, PRE
|
1500
|
2.7(8.0)
|
4.6(24.0)
|
5.2(26.0)
|
8.5(71.3)
|
MBZ, PRE
|
210
|
4.6(20.0)
|
5.5(29.3)
|
4.4(18.7)
|
7.2(54)
|
CDF, POE
|
60
|
8.1(65.3)
|
8.3(68.7)
|
5.7(32.0)
|
8.7(74.7)
|
SSN, POE
|
25
|
8.0(63.3)
|
8.3(67.3)
|
5.9(33.3)
|
8.8(76.7)
|
PDN, POE
|
50
|
8.4(70.0)
|
8.2(66.0)
|
5.9(34.0)
|
8.6(73.3)
|
MSN + ISN, POE
|
14.4
|
8.3(68.0)
|
8.1(65.3)
|
6.0(34.7)
|
8.5(72.0)
|
MBZ fb CDF, PRE-POE
|
175 fb 60
|
4.9(22.7)
|
5.7(32.0)
|
3.6(12.0)
|
7.6(58.0)
|
MBZ fb SSN, PRE-POE
|
175 fb 25
|
5.0(24.7)
|
5.7(32.7)
|
3.8(13.3)
|
7.1(50.7)
|
MBZ fb PDN, PRE-POE
|
175 fb 50
|
4.9(23.3)
|
5.8(33.3)
|
4.5(19.3)
|
7.9(62.7)
|
MBZ fb MSN + ISN, PRE-POE
|
175 fb 14.4
|
6.0(37.3)
|
5.8(32.7)
|
4.3(17.3)
|
6.8(46.0)
|
PMN + MBZ, PRE
|
1500 + 175
|
2.2(5.3)
|
3.8(15.3)
|
3.8(14.0)
|
6.1(38.0)
|
PMN + MBZ, PRE
|
1000 + 175
|
2.8(7.3)
|
3.9(16.7)
|
4.2(17.3)
|
6.6(44.0)
|
PSF, PRE
|
105
|
4.2(16.7)
|
4.2(16.7)
|
3.9(15.3)
|
7.9(66.7)
|
PSF, PRE
|
128
|
3.6(12.0)
|
4.2(18.0)
|
4.2(17.3)
|
6.2(40.7)
|
PMN fb HW, PRE-POE
|
1500
|
3.0(8.7)
|
4.8(22.0)
|
5.0(24.7)
|
8.5(76.0)
|
MBZ fb HW, PRE-POE
|
210
|
4.7(21.3)
|
5.6(30.7)
|
4.0(15.3)
|
7.1(53.3)
|
WF
|
|
1.0(0.0)
|
1.0(0.0)
|
1.0(0.0)
|
1.0(0.0)
|
WC
|
|
8.2(70.7)
|
8.5(71.3)
|
6.2(37.3)
|
8.5(76.7)
|
SEm±
|
|
0.6
|
0.6
|
0.4
|
0.9
|
LSD (p = 0.05)
|
|
1.8
|
1.6
|
1.2
|
2.7
|
Original values in parenthesis were subjected to square root transformation (√x + 1) before statistical analysis |
PMN, pendimethalin; MBZ, metribuzin; CDF, clodinafop; SSN, sulfosulfuron; PDN, pinoxaden; MSN + ISN, mesosulfuron + iodosulfuron (ready mix), PSF- pyroxasulfone, WF-weed free, WC-weedy check, PRE-pre-emergence, POE-post-emergence |
Table 3
Effect of different weed control treatments on weed density (No. m− 2) at 75 and 120 DAS
Treatment
|
Dose (g ha− 1)
|
75 DAS
|
120 DAS
|
P. minor
|
Broadleaf weeds
|
P. minor
|
Broadleaf weeds
|
2016-17
|
2017-18
|
2016-17
|
2017-18
|
2016-17
|
2017-18
|
2016-17
|
2017-18
|
PMN, PRE
|
1500
|
3.4(10.3)
|
4.5(19.3)
|
7.5(55.3)
|
9.6(92.7)
|
3.1(8.7)
|
3.8(14.0)
|
5.1(24.7)
|
6.1(37.3)
|
MBZ, PRE
|
210
|
4.3(17.7)
|
6.6(42.7)
|
6.2(38.0)
|
8.9(79.3)
|
3.4(10.7)
|
4.9(24.7)
|
3.4(10.7)
|
5.2(26.7)
|
CDF, POE
|
60
|
4.0(15.3)
|
6.2(37.3)
|
9.1(82.7)
|
9.9(98.0)
|
3.3(10.0)
|
4.3(18.0)
|
5.1(25.3)
|
6.2(38.0)
|
SSN, POE
|
25
|
3.9(14.0)
|
5.0(24.7)
|
4.0(14.7)
|
4.5(20.7)
|
3.2(9.7)
|
4.3(17.3)
|
3.0(10.0)
|
4.3(18.0)
|
PDN, POE
|
50
|
1.7(2.0)
|
6.0(35.3)
|
8.6(74.6)
|
8.8(76.7)
|
2.5(5.3)
|
4.6(20.7)
|
4.8(22.0)
|
5.5(30.3)
|
MSN + ISN, POE
|
14.4
|
1.7(2.6)
|
5.6(30.7)
|
1.0(0.0)
|
2.8(7.3)
|
2.4(4.7)
|
4.3(17.3)
|
1.0(0.0)
|
2.4(7.3)
|
MBZ fb CDF, PRE-POE
|
175 fb 60
|
1.7(2.0)
|
3.1(8.7)
|
5.4(28.0)
|
8.7(76.0)
|
1.5(1.3)
|
3.3(10.0)
|
3.6(12.0)
|
5.1(25.3)
|
MBZ fb SSN, PRE-POE
|
175 fb 25
|
2.1(4.0)
|
3.2(9.3)
|
1.5(1.3)
|
3.0(8.0)
|
1.7(2.0)
|
2.8(6.7)
|
2.1(4.0)
|
1.4(1.3)
|
MBZ fb PDN, PRE-POE
|
175 fb 50
|
1.7(2.0)
|
3.0(8.0)
|
5.5(30.0)
|
7.7(59.3)
|
1.7(2.0)
|
2.2(4.0)
|
3.8(14.0)
|
4.9(24.7)
|
MBZ fb MSN + ISN, PRE-POE
|
175 fb 14.4
|
2.2(4.0)
|
3.2(9.7)
|
1.4(1.3)
|
2.0(3.3)
|
1.9(2.7)
|
2.4(4.7)
|
1.5(1.3)
|
1.5(2.0)
|
PMN + MBZ, PRE
|
1500 + 175
|
2.4(4.7)
|
3.4(10.7)
|
4.0(15.3)
|
7.2(50.7)
|
1.7(2.0)
|
2.4(5.3)
|
3.0(8.0)
|
4.7(22.0)
|
PMN + MBZ, PRE
|
1000 + 175
|
2.9(7.7)
|
4.4(18.7)
|
4.7(21.3)
|
8.0(64.7)
|
2.4(4.7)
|
3.5(12.0)
|
3.2(9.3)
|
5.2(28.0)
|
PSF, PRE
|
105
|
1(0.0)
|
2.9(8.0)
|
6.3(38.7)
|
8.7(75.3)
|
1(0.0)
|
2.0(4.0)
|
4.1(16.7)
|
5.5(30.0)
|
PSF, PRE
|
128
|
1(0.0)
|
1.9(3.3)
|
6.0(35.3)
|
8.1(66.0)
|
1(0.0)
|
1.7(2.7)
|
3.6(12.0)
|
5.2(28.0)
|
PMN fb HW, PRE-POE
|
1500
|
1.7(2.0)
|
3.7(12.7)
|
4.7(21.3)
|
7.6(61.3)
|
2.5(5.3)
|
2.9(7.3)
|
2.4(6.0)
|
4.5(22.0)
|
MBZ fb HW, PRE-POE
|
210
|
2.0(3.4)
|
4.2(16.7)
|
3.8(14.7)
|
6.2(40.7)
|
2.8(7.3)
|
2.9(8.0)
|
1.7(2.7)
|
4.1(16.0)
|
WF
|
|
1.0(0.0)
|
1.0(0.0)
|
1.0(0.0)
|
1.0(0.0)
|
1(0.0)
|
1(0.0)
|
1.0(0.0)
|
1.0(0.0)
|
WC
|
|
6.1(36.7)
|
7.4(55.3)
|
9.3(86.0)
|
10.8(116.0)
|
6.1(36.7)
|
6.8(45.3)
|
5.6(30.7)
|
6.3(38.0)
|
SEm±
|
|
0.3
|
0.4
|
0.5
|
0.7
|
0.2
|
0.4
|
0.4
|
0.6
|
LSD (p = 0.05)
|
|
0.9
|
1.2
|
1.3
|
1.9
|
0.6
|
1.1
|
1.2
|
1.8
|
Original values in parenthesis were subjected to square root transformation (√x + 1) before statistical analysis |
PMN, pendimethalin; MBZ, metribuzin; CDF, clodinafop; SSN, sulfosulfuron; PDN, pinoxaden; MSN + ISN, mesosulfuron + iodosulfuron (ready mix), PSF- pyroxasulfone, WF-weed free, WC-weedy check, PRE-pre-emergence, POE-post-emergence |
In 2016-17 at 75 DAS, P. minor biomass was nil in pyroxasulfone (105 and 128 g ha− 1) treated plots as no P. minor recorded (Table 4). Except pendimethalin (1500 g ha− 1), metribuzin (210 g ha− 1), clodinafop (60 g ha− 1) and sulfosulfuron (25 g ha− 1), all other treatments were found quite good with 83 to 98% biomass reduction. During second year, pyroxasulfone (128 g ha− 1) caused highest P. minor biomass reduction (97%) which was at par with weed free plot. Pyroxasulfone (105 g ha− 1) and sequential application of metribuzin (175 g ha− 1) followed by clodinafop (60 g ha− 1), sulfosulfuron (25 g ha− 1), pinoxaden (50 g ha− 1) and mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) gave up to 90 to 95% reduction of P. minor biomass. Pendimethalin + metribuzin (1500 + 175 g ha− 1), pendimethalin + metribuzin (1000 + 175 g ha− 1), pendimethalin (1500 g ha− 1 fb HW), metribuzin (210 g ha− 1 fb HW), sulfosulfuron (25 g ha− 1), pinoxaden (50 g ha− 1) and mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) reduced P. minor biomass significantly but efficacy was little bit lower (77 to 87%). Pendimethalin (1500 g ha− 1), metribuzin (210 g ha− 1) and clodinafop (60 g ha− 1) were not found so effective in second year also and recorded only 66 to 71% reduction in P. minor biomass.
In case of broadleaf weeds during both years, mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) alone and sequential application of metribuzin (175 g ha− 1) followed by sulfosulfuron (25 g ha− 1) and mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) gave best results which were as good as weed free treatment and recorded broadleaf weeds biomass reduction to the tunes of 94–100% in 2016-17 and 90 to 98% in 2017-18 at 75 DAS. Except pendimethalin (1500 g ha− 1), metribuzin (210 g ha− 1), clodinafop (60 g ha− 1), pinoxaden (50 g ha− 1) and pyroxasulfone (105 and 128 g ha− 1), all other treatments were found quite good against broadleaf weeds and provided 66 to 82% biomass reduction in first year. But in second year, only sulfosulfuron (25 g ha− 1) was found effective and all other treatments did not perform so well and provided only 33 to 63% reduction. Similar trend was observed at 120 DAS. In general, combination of herbicides resulted into better control of complex weed flora. (Insert table Figs. 1 & 4 Here)
Table 4
Effect of different weed control treatments on dry matter of weeds (group wise) (g m− 2) at 75 and 120 DAS
Treatment
|
Dose (g ha− 1)
|
75 DAS
|
120 DAS
|
P. minor
|
Broadleaf weeds
|
P. minor
|
Broadleaf weeds
|
2016-17
|
2017-18
|
2016-17
|
2017-18
|
2016-17
|
2017-18
|
2016-17
|
2017-18
|
PMN, PRE
|
1500
|
8.73
|
8.99
|
8.99
|
9.99
|
39.53
|
47.47
|
64.07
|
80.40
|
MBZ, PRE
|
210
|
10.03
|
12.84
|
6.17
|
7.95
|
50.20
|
127.20
|
34.00
|
61.53
|
CDF, POE
|
60
|
7.47
|
8.82
|
9.67
|
9.91
|
41.27
|
47.73
|
60.00
|
73.13
|
SSN, POE
|
25
|
7.41
|
6.59
|
3.29
|
2.86
|
33.13
|
50.60
|
17.20
|
18.67
|
PDN, POE
|
50
|
1.73
|
5.89
|
7.59
|
7.33
|
10.33
|
53.13
|
31.67
|
38.00
|
MSN + ISN, POE
|
14.4
|
0.98
|
5.03
|
0.0
|
1.27
|
10.13
|
44.20
|
0.00
|
3.60
|
MBZ fb CDF, PRE-POE
|
175 fb 60
|
1.84
|
1.41
|
3.63
|
9.20
|
4.40
|
34.87
|
52.93
|
56.67
|
MBZ fb SSN, PRE-POE
|
175 fb 25
|
2.01
|
1.69
|
0.34
|
0.28
|
5.40
|
19.47
|
2.73
|
0.13
|
MBZ fb PDN, PRE-POE
|
175 fb 50
|
1.41
|
2.79
|
3.78
|
6.91
|
4.47
|
25.20
|
27.80
|
44.87
|
MBZ fb MSN + ISN, PRE-POE
|
175 fb 14.4
|
0.60
|
1.72
|
0.71
|
0.42
|
5.67
|
17.80
|
2.40
|
4.27
|
PMN + MBZ, PRE
|
1500 + 175
|
3.58
|
3.81
|
3.11
|
5.14
|
6.13
|
25.67
|
30.27
|
44.47
|
PMN + MBZ, PRE
|
1000 + 175
|
4.26
|
4.95
|
2.55
|
7.39
|
11.73
|
40.87
|
42.20
|
51.80
|
PSF, PRE
|
105
|
0.00
|
1.64
|
6.71
|
8.01
|
0.00
|
2.93
|
56.00
|
66.40
|
PSF, PRE
|
128
|
0.00
|
0.88
|
5.67
|
7.05
|
0.00
|
2.87
|
38.53
|
56.07
|
PMN fb HW, PRE-POE
|
1500
|
1.18
|
6.29
|
2.87
|
6.49
|
22.27
|
28.60
|
26.20
|
43.07
|
MBZ fb HW, PRE-POE
|
210
|
1.73
|
6.46
|
2.01
|
4.85
|
32.47
|
35.00
|
6.73
|
19.67
|
WF
|
|
0.00
|
0.00
|
0.00
|
0.00
|
0.00
|
0.00
|
0.00
|
0.00
|
WC
|
|
25.44
|
29.21
|
11.08
|
12.99
|
217.53
|
240.40
|
86.27
|
113.07
|
SEm±
|
|
0.46
|
0.58
|
0.57
|
0.75
|
4.16
|
6.44
|
3.83
|
3.29
|
LSD (p = 0.05)
|
|
1.32
|
1.65
|
1.63
|
2.2
|
11.96
|
18.51
|
11.01
|
9.46
|
PMN, pendimethalin; MBZ, metribuzin; CDF, clodinafop; SSN, sulfosulfuron; PDN, pinoxaden; MSN + ISN, mesosulfuron + iodosulfuron (ready mix), PSF- pyroxasulfone, WF-weed free, WC-weedy check, PRE-pre-emergence, POE-post-emergence |
2. Visual crop phytotoxcity (%)
Visual crop phytotoxicity was recorded on 0-100 scale (where 0 = no mortality and 100 = complete mortality). In 2016-17 after first irrigation at 30 DAS, visual phytotoxicity (4.7 to 8.3%) was observed in all treatment which was having metribuzin as a component (Table 5). But it was recovered at later crop stages. Plants show slight phytotoxicity but later on it may be recovered depending upon level of sensitivity of cultivar. Wheat (HD-2329) was completely damaged by metribuzin in pot culture but in field conditions there was no issue (Das, 2011). In second year, no phytotoxicity was observed at 30 DAS. At the time of effective tillers counting, it was observed that some herbicidal treatments suppressed the wheat tillering and it was recorded at same scale considering it as phytotoxcity effect of herbicides which were reducing the tillering. In first year, sequential application of metribuzin (175 g ha− 1) followed by sulfosulfuron (25 g ha− 1) and mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) and pyroxasulfone (105 and 128 g ha− 1) caused 5 to 7.7% reduction in wheat tillers but in second year only pyroxasulfone (128 g ha− 1) caused 6.7% reduction but other treatments did not show any reduction (Table 6). Previous study also reported about injury through pyroxasulfone on wheat crop. Soft red winter wheat injured in the form of stunting ranging 11 to 20% at 120 and 160 g ha− 1 application of pyroxasulfone as PRE (Grey et al. 2017). Hulting et al. (2012) noted 0–8% winter wheat injury and 3% at the end of the season from pyroxasulfone mainly associated with 150 g ha− 1. (Insert Table 5 Here)
Table 5
Crop phytotoxicity caused by different weed control treatments
Treatment
|
Dose (g ha− 1)
|
2016-17
|
2017-18
|
30 DAS
|
120 DAS
|
30 DAS
|
120 DAS
|
PNM, PRE
|
1500
|
1.0(0.0)
|
1.0(0.0)
|
0.0(0.0)
|
1.0(0.0)
|
MBZ, PRE
|
210
|
3.0(8.3)
|
1.0(0.0)
|
0.0(0.0)
|
1.0(0.0)
|
CDF, POE
|
60
|
1.0(0.0)
|
1.0(0.0)
|
0.0(0.0)
|
1.0(0.0)
|
SFS, POE
|
25
|
1.0(0.0)
|
1.0(0.0)
|
0.0(0.0)
|
1.0(0.0)
|
PXD, POE
|
50
|
1.0(0.0)
|
1.0(0.0)
|
0.0(0.0)
|
1.0(0.0)
|
MS + IS, POE
|
14.4
|
1.0(0.0)
|
1.0(0.0)
|
0.0(0.0)
|
1.0(0.0)
|
MBZ fb CDF, PRE-POE
|
175 fb 60
|
2.5(6.7)
|
1.0(0.0)
|
0.0(0.0)
|
1.0(0.0)
|
MBZ fb SFS, PRE-POE
|
175 fb 25
|
2.8(7.3)
|
2.6(6.0)
|
0.0(0.0)
|
1.0(0.0)
|
MBZ fb PXD, PRE-POE
|
175 fb 50
|
2.5(5.7)
|
1.0(0.0)
|
0.0(0.0)
|
1.0(0.0)
|
MBZ fb MS + IS, PRE-POE
|
175 fb 14.4
|
3.0(8.3)
|
2.9(6.3)
|
0.0(0.0)
|
1.0(0.0)
|
PNM + MBZ, PRE
|
1500 + 175
|
2.3(4.7)
|
1.0(0.0)
|
0.0(0.0)
|
1.0(0.0)
|
PNM + MBZ, PRE
|
1000 + 175
|
2.4(5.0)
|
1.0(0.0)
|
0.0(0.0)
|
1.0(0.0)
|
PSF, PRE
|
105
|
1.0(0.0)
|
2.4(5.0)
|
0.0(0.0)
|
1.0(0.0)
|
PSF, PRE
|
128
|
1.0(0.0)
|
2.9(7.7)
|
0.0(0.0)
|
2.8(6.7)
|
PNM fb HW, PRE-POE
|
1500
|
1.0(0.0)
|
1.0(0.0)
|
0.0(0.0)
|
1.0(0.0)
|
MBZ fb HW, PRE-POE
|
210
|
2.3(7.0)
|
1.0(0.0)
|
0.0(0.0)
|
1.0(0.0)
|
WF
|
|
1.0(0.0)
|
1.0(0.0)
|
0.0(0.0)
|
1.0(0.0)
|
WC
|
|
1.0(0.0)
|
1.0(0.0)
|
0.0(0.0)
|
1.0(0.0)
|
SEm±
|
|
0.3
|
0.1
|
NA
|
0.04
|
LSD (p = 0.05)
|
|
0.8
|
0.25
|
NA
|
0.11
|
Original value in parenthesis were subjected to square root transformation (√x + 1) before statistical analysis |
PMN, pendimethalin; MBZ, metribuzin; CDF, clodinafop; SSN, sulfosulfuron; PDN, pinoxaden; MSN + ISN, mesosulfuron + iodosulfuron (ready mix), PSF- pyroxasulfone, WF-weed free, WC-weedy check, PRE-pre-emergence, POE-post-emergence |
3. Studies on wheat crop
In all herbicidal treatments, higher grain yield was recorded during first year than in second year (Table 7). Overall in Haryana in 2017-18, anticipated wheat productivity was recorded 4.5% lower than 2016-17 (Anonymous, 2018). Farmers also reported during survey that they faced more problems in 2017-18 than previous years. Sowing time in the experimental field for both the year was almost same (20th November in 2016-17 and 17th November in 2017-18). During crop period weather parameters were almost similar but sowing time weather significantly deferred in second year which has been already described in detail. In 2017-18 throughout growing season, more infestation of weeds (grassy as well as broadleaf) was recorded than in 2016-17 in all treatments. During first year, average number of tillers in all treatments was 441 m− 2 at 75 DAS and 395 m− 2 at harvest. But in second year 371 m− 2 (70 m− 2 down) at 75 DAS and 354 m− 2 (40 m− 2 down) at harvest. Difference in tillers was too high (70 m− 2 at 75 DAS and only 40 m− 2 at harvest). Number of grain per spike was also recorded lower in second year (49) than first in year (53) (Table 6). Other growth parameter and yield attributing characters like plant height, 1000-grain weight and spike length were not affected by treatments or years and these were non-significant in both years. All treatments recorded significantly higher grain yield in both years than weedy plot, excluding metribuzin (210 g ha− 1) in second year (Table 7). Mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1), alone metribuzin (210 g ha− 1 fb HW) and sequential application of metribuzin (175 g ha− 1) followed by sulfosulfuron (25 g ha− 1), pinoxaden (50 g ha− 1) and mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) recorded equally good grain yield and were statistically at par with weed free treatment in both years. During first year, mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) alone recorded highest grain yield and during second year, it was due to sequential application of metribuzin (175 g ha− 1) followed by mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1). Pre-emergence application of pendimethalin (1500 g ha− 1), metribuzin (210 g ha− 1), pyroxasulfone (128 g ha− 1), pendimethalin + metribuzin (1000 + 175 g ha− 1) and POE application clodinafop (60) or sulfosulfuron (25 g ha− 1) also provided good grain yield but were not at par with weed free. Performance of pinoxaden (50 g ha− 1), pendimethalin (1500 g ha− 1 fb HW) and pendimethalin + metribuzin (1500 + 175 g ha− 1) during first year was good and they were at par with weed free in terms of grain yield but during second year did not give up to mark results and in case of pyroxasulfone (105 g ha− 1), it has reverse trend in second year as it was at par with weed free but not so in first year. Overall, grain yield was ultimately decided by the combined effect of how a particular treatment is able to control P. minor and broadleaf weeds and there phytotoxicity on crop. During first year, sequential application of metribuzin (175 g ha− 1) followed by sulfosulfuron (25 g ha− 1) and mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) and pyroxasulfone (105 and 128 g ha− 1) attained relatively higher weed control efficiency. But it was not reflected in terms of grain yield because these treatments caused crop phytotoxicity and suppressed tillering. During second year, only pyroxasulfone (128 g ha− 1) caused phytotoxicity and did not attain expected yield. Pooled analysis revealed that overall mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) and sequential application of metribuzin (175 g ha− 1) followed by sulfosulfuron (25 g ha− 1) and mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) were adjudged best treatments which were at par with weed free treatments. Higher grain and biological yield by sequential application of PRE and POE herbicides in wheat has been reported earlier also (Yadav et al., 2016; Kaur, 2017; Kumar, 2017; Punia et al., 2018). (Insert Table 6 Here)
Table 6
Effect of different weed control treatments on No. of grain/spike, number of tillers (No. m− 2) at 75 DAS and effective tillers
Treatment
|
Dose (g ha− 1)
|
No. of grain/spike
|
Tillers No. m− 2 at 75 DAS
|
Effective tillers No. m− 2
|
2016-17
|
2017-18
|
2016-17
|
2017-18
|
2016-17
|
2017-18
|
PNM, PRE
|
1500
|
49.3
|
43.3
|
414
|
335
|
367
|
312
|
MBZ, PRE
|
210
|
51.0
|
41.6
|
432
|
314
|
391
|
280
|
CDF, POE
|
60
|
50.4
|
45.3
|
419
|
348
|
370
|
325
|
SFS, POE
|
25
|
52.0
|
49.2
|
423
|
379
|
385
|
360
|
PXD, POE
|
50
|
54.0
|
49.1
|
453
|
374
|
407
|
353
|
MS + IS, POE
|
14.4
|
58.3
|
51.3
|
486
|
393
|
443
|
386
|
MBZ fb CDF, PRE-POE
|
175 fb 60
|
54.3
|
49.3
|
453
|
374
|
409
|
355
|
MBZ fb SFS, PRE-POE
|
175 fb 25
|
56.0
|
53.4
|
467
|
413
|
419
|
408
|
MBZ fb PXD, PRE-POE
|
175 fb 50
|
54.3
|
50.4
|
452
|
385
|
407
|
382
|
MBZ fb MS + IS, PRE-POE
|
175 fb 14.4
|
54.4
|
53.8
|
459
|
412
|
410
|
400
|
PNM + MBZ, PRE
|
1500 + 175
|
53.6
|
48.3
|
448
|
362
|
398
|
338
|
PNM + MBZ, PRE
|
1000 + 175
|
53.0
|
48.0
|
431
|
355
|
375
|
335
|
PSF, PRE
|
105
|
54.6
|
53.0
|
448
|
403
|
400
|
390
|
PSF, PRE
|
128
|
50.0
|
49.6
|
412
|
379
|
363
|
362
|
PNM fb HW, PRE-POE
|
1500
|
53.7
|
50.0
|
452
|
364
|
390
|
347
|
MBZ fb HW, PRE-POE
|
210
|
55.7
|
51.6
|
448
|
386
|
403
|
360
|
WF
|
|
58.4
|
53.9
|
488
|
418
|
447
|
411
|
WC
|
|
42.3
|
40.3
|
358
|
291
|
320
|
288
|
SEm±
|
|
1.9
|
1.5
|
18.1
|
16.3
|
12.6
|
10.7
|
LSD (p = 0.05)
|
|
5.6
|
4.4
|
52.0
|
46.9
|
36.3
|
30.8
|
PMN, pendimethalin; MBZ, metribuzin; CDF, clodinafop; SSN, sulfosulfuron; PDN, pinoxaden; MSN + ISN, mesosulfuron + iodosulfuron (ready mix), PSF- pyroxasulfone, WF-weed free, WC-weedy check, PRE-pre-emergence, POE-post-emergence |
4. Economics
All treatments recorded higher gross return, net return and benefit cost ratio than weedy plot. Among different herbicidal treatments in 2016-17, highest gross return (Rs 1,17,275), net return (Rs 31,437 ha− 1) and benefit cost ratio (1.37) were recorded by mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) alone. In 2017-18, sequential application of metribuzin (175 g ha− 1) followed by mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) recorded highest gross return (Rs 1,10,117 ha− 1) but due higher cost of production, it was second best in net return (Rs 18,765 ha− 1). During both years, metribuzin (175 g ha− 1) followed by sulfosulfuron (25 g ha− 1) was the second best treatment in gross return (Rs 111,338 − 109,644 ha− 1) but due low cost of production, it was best treatment in second year in terms of net return with (Rs 19,105 ha− 1). Average gross return (Rs 110,491 ha− 1), net return (Rs 22,328 ha− 1) and B-C ratio (1.25) also indicated that metribuzin (175 g ha− 1) followed by sulfosulfuron (25 g ha− 1) was the best treatment, followed by mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1) alone and metribuzin (175 g ha− 1) followed by mesosulfuron + iodosulfuron (12 + 2.4 g ha− 1). Pyroxasulfone (128 g ha− 1) and sequential application of metribuzin (175 g ha− 1) followed by clodinafop (60 g ha− 1) and pinoxaden (50 g ha− 1) also attained average B-C ratio higher than weed free treatment. But in rest of the treatments, the average B-C ratio recorded lower than weed free treatment and these can’t be recommended to farmers (Table 7). Increase in net return and B-C ratio due to sequential application of PRE and POE herbicides in wheat were also reported earlier (Yadav et al., 2016; Kaur, 2017; Kumar, 2017). (Insert Table 7 Here)
Table 7
Effect of different weed control treatments on grain yield, net return and B-C ratio
Treatment
|
Dose (g ha− 1)
|
Grain yield (q ha− 1)
|
Net Returns (Rs ha-1)
|
B-C ratio
|
2016-17
|
2017-18
|
Pooled
|
2016-17
|
2017-18
|
Avg.
|
2016-17
|
2017-18
|
Avg.
|
PNM, PRE
|
1500
|
50.45
|
41.82
|
46.14
|
14,687
|
-852
|
6,917
|
1.17
|
0.99
|
1.08
|
MBZ, PRE
|
210
|
52.47
|
39.35
|
45.91
|
19,513
|
-5738
|
6,887
|
1.23
|
0.94
|
1.08
|
CDF, POE
|
60
|
51.04
|
42.76
|
46.90
|
16,407
|
1,798
|
9,102
|
1.19
|
1.02
|
1.10
|
SFS, POE
|
25
|
51.77
|
47.76
|
49.76
|
18,537
|
9,632
|
14,085
|
1.22
|
1.11
|
1.16
|
PXD, POE
|
50
|
55.26
|
47.37
|
51.31
|
24,229
|
7,856
|
16,043
|
1.28
|
1.09
|
1.18
|
MS + IS, POE
|
14.4
|
60.08
|
49.55
|
54.81
|
31,437
|
12,902
|
22,169
|
1.37
|
1.14
|
1.25
|
MBZ fb CDF, PRE-POE
|
175 fb 60
|
55.61
|
47.62
|
51.61
|
24,527
|
9,087
|
16,807
|
1.29
|
1.10
|
1.19
|
MBZ fb SFS, PRE-POE
|
175 fb 25
|
56.39
|
52.98
|
54.69
|
25,551
|
19,105
|
22,328
|
1.30
|
1.21
|
1.25
|
MBZ fb PXD, PRE-POE
|
175 fb 50
|
55.33
|
49.84
|
52.58
|
23,673
|
11,767
|
17,720
|
1.27
|
1.13
|
1.20
|
MBZ fb MS + IS, PRE-POE
|
175 fb 14.4
|
55.43
|
53.18
|
54.30
|
22,720
|
18,765
|
20,743
|
1.26
|
1.21
|
1.23
|
PNM + MBZ, PRE
|
1500 + 175
|
54.85
|
45.50
|
50.18
|
21,247
|
5,172
|
13,210
|
1.25
|
1.06
|
1.15
|
PNM + MBZ, PRE
|
1000 + 175
|
52.50
|
45.18
|
48.84
|
18,931
|
4,852
|
11,892
|
1.22
|
1.05
|
1.13
|
PSF, PRE
|
105
|
54.42
|
52.22
|
53.32
|
19,804
|
17,589
|
18,696
|
1.23
|
1.19
|
1.21
|
PSF, PRE
|
128
|
50.08
|
48.47
|
49.27
|
13,209
|
9,781
|
11,495
|
1.15
|
1.11
|
1.13
|
PNM fb HW, PRE-POE
|
1500
|
55.93
|
46.38
|
51.16
|
18,745
|
2,882
|
10,813
|
1.21
|
1.03
|
1.12
|
MBZ fb HW, PRE-POE
|
210
|
56.05
|
49.18
|
52.61
|
21,731
|
8,680
|
15,206
|
1.24
|
1.09
|
1.17
|
WF
|
|
60.60
|
53.27
|
56.93
|
23,945
|
11,703
|
17,824
|
1.25
|
1.12
|
1.18
|
WC
|
|
43.43
|
37.08
|
40.26
|
2,535
|
-9,092
|
-3,278
|
1.03
|
0.90
|
0.96
|
SEm±
|
|
2.0
|
1.58
|
1.24
|
|
|
|
|
|
|
LSD (p = 0.05)
|
|
5.8
|
4.55
|
3.50
|
|
|
|
|
|
|
PMN, pendimethalin; MBZ, metribuzin; CDF, clodinafop; SSN, sulfosulfuron; PDN, pinoxaden; MSN + ISN, mesosulfuron + iodosulfuron (ready mix), PSF- pyroxasulfone, WF-weed free, WC-weedy check, PRE-pre-emergence, POE-post-emergence |