Introduction

Sugarcane shares 3.2% in value addition in agriculture and 0.5% in gross domestic product (GDP) of Pakistan (GOP 2019). Sugarcane is an imperative crop as it is used for making sugar as well as bioenergy. It provides almost 76% of sugar production for the human-being consumption in world. It is one of the world’s main C₄ sugar producing crops, which are mostly grown in the tropical and subtropical regions (Farooq and Gheewala 2019; Waqas et al. 2019).

Ponda sugarcane (Saccharum officinarum L.) is one of the utmost imperative agronomic crops in the Punjab, Pakistan. Ponda term is used for chewing sugarcane cultivar because it is best for chewing due to high sugar and juice contents (Ullah et al. 2013).

Optimization of management practices like sowing dates, irrigation regimes and nitrogen (N) levels is crucial to improve resource use efficiencies of ponda sugarcane. Radiation use efficiency (RUE) is a valuable parameter to relate canopy photosynthesis to crop production (Silva et al. 2013; López-Pereira et al. 2020; Abbas et al. 2020a). It is an imperative quantifier for cane and sugar yield in relation to photosynthesis process; as it combines both the quantity of solar radiations capturing and its efficiency to produce biomass, presumptuous other factors are not restrictive (Anderson et al. 2015; Schwerz et al. 2018). Measurement of RUE of various management systems involve the collections of biomass, cane and sugar yield, and the accumulations of intercepted photoactive radiations through the canopy over the life cycle of the crop (Olivier et al. 2016; Ahmad et al. 2017). Canopy architecture would be one path toward enhancing crop yield, which might emphasis on more efficiently conversion of available photoactive radiations into dry matter or cane yield and straightway associated to factors contributing to improve RUE (Silva and Costa 2012; Ehsanipour et al. 2019; Abbas et al. 2020b). Optimal planted crop capture more solar radiations by leaves; resultantly more photo assimilates are produced leading to higher RUE for biomass and cane yield. Shukla and Singh (2011) reported higher cane productivity in summer planting dates while Hoy et al. (2006) reported sizable decrease in cane productivity in case of early and late planting. However, Ahmad et al. (1991) concluded more autumn sugarcane productivity in case of August planting than September sown crop.

Water use efficiency (WUE) plays a vital role in improving cane yield over unit water use (Hurst et al. 2004). Water is one of the most important restraining factors of ponda sugarcane productivity; and sugarcane productivity can be enhanced by ensuring necessary irrigations during its whole growing season (Silva et al. 2013). Various research studies report specified that water influence on ponda sugarcane production due to its effect on yield parameters (Singh et al. 2018). In relationship to improvement of WUE, optimum irrigations are necessary to gain maximum cane length, cane diameter, plant height and ultimately more fresh cane yield (Singh et al. 2007; Olivier and Singels 2015). Silva et al. (2007) reported positive correlation amid variables and productivity that increased with irrigation quantity which causes direct rise in cane yield. Bekheet (2006) found that irrigation regimes significantly affected cane length and diameter.

Nitrogen use efficiency (NUE) can be improved by applying optimum amount of N under irrigated arid environment for sugarcane crop (Snyman et al. 2015). Nitrogen plays an imperative role for attaining maximum fresh cane yield and its components (Otto et al. 2016; Hoang et al. 2019). It is involved in several critical processes for example sugarcane growth and development, enlargement of green leaves, and tillers or sucrose contents, particularly in the formation of plant protein, which is vital for the photosynthesis process components like PEPCase or Rubisco enzymes (Suman et al. 2008; Nurhidayati and Basit 2015). The growth and yield of sugarcane cane be enhanced by improving NUE, because excess amount of N can lead to extended vegetative growth period and decreased sugarcane production (Ali et al. 2000; Whan et al. 2010). For instance, increase N uptake and NUE in ponda sugarcane contributed to the increase in fresh cane and sugar yield (Hajari et al. 2017; Thorburn et al. 2017). Sime (2013) reported relationship amid growth along with N application and concluded that higher N level resulted in greater plant height. Rizk et al. (2002) concluded that sugarcane productivity enhanced with increased N levels. Sogheir and Ferweez (2009) noticed that N increase up to 240 t ha^-1 augmented millable canes along with productivity; the cane productivity was increased up to 51% with 138 kg N ha^-1. Mengistu (2013) reported at high N doses (252 and 336 kg ha^-1) positively increased cane-length, millable and stripped-cane-yields and compared to lower rate of 168 kg ha^-1. Greater N application increased cane productivity besides sugar contents (Azzazy and El-Geddawy 2003). The results showed that increasing N dose up to 200 improved cane productivity during two seasons (Shahrzad et al. 2014).

In view of aforementioned discussion, it is imperative to optimize management practices like sowing dates, irrigation regimes and N levels to improve resource use efficiencies. However, to best of our knowledge, resources use efficiency for ponda sugarcane has not reported in scientific literature. Therefore, this two-years field study was designed to optimize the best sowing date, irrigation regime and N rate to maximize cane yield and resource use efficiencies i.e., RUE, WUE and NUE of ponda sugarcane under irrigated arid environment.

Materials and Methods

Trials were carried out at Vehari (Longitude: 72°34′ E, Latitude: 30°12′ N, Elevation: 134 m, Climate: irrigated arid conditions), Punjab, Pakistan for two years 2017 and 2018. Soil analysis showed soil of clay loam texture, calcareous and alkaline in nature. It had bulk density of 1.2 g cm^-3, pH 8.3, total nitrogen 0.03%, available phosphorus 7.3 mg kg^-1 and available potash 80.5 mg kg^-1. The weather trends for two years of experimental site are presented in Fig. 1.

Experimental treatments and designs are given in Table 1. Seedbed preparation was uniform for each field trial during both years. Pre-soaking irrigation of 10 cm depth was applied before seed bed preparation. At workable moisture level, seedbed was prepared by tractor mounted cultivar by tilling the soil two times to a depth of 10–12 cm followed by planking plus two times sub-soiling and again planking. Ponda variety was planted in all field experiments using seed rate of 74100 double budded setts ha^-1. Planting of sugarcane was done according to sowing dates treatments during both years in experiment 1. Moreover, sugarcane was planted on April 05 during both study years in experiment 2 and 3. Ponda sugarcane was sown in 120 cm spaced double row furrows with plant to plant distance of 22.5 cm. The detailed husbandry practices used to grow ponda sugarcane are given in Table 1. Nitrogen in the form of urea was applied at 228 kg ha^-1, phosphorus and potassium were applied at 120 and 145 kg ha^-1, respectively using di-ammonium phosphate (DAP) and sulphate of potash (SOP) as sources in each experiment. Weeds were controlled using S-Metolachlor, insects’ pests were controlled using Fipronil (Carbofuran) and for disease management Thiophanate methyl was used at recommended rates during both years.

Data recorded

At harvesting, central two ridges from each plot were cut from base to determine total biomass and fresh cane yields. The samples were oven dried at 70°C for two days for determination of dry weight and yield is given as kg ha^-1. Sampling for leaf area and biomass was started at 30 days after planting (DAP) to harvesting of crop with 15-days interval to record leaf area. Leaves were separated, to measure leaf area using leaf area meter (Licor Model-3100). Leaf area index (LAI) was calculated as a ratio of leaf area to ground area. Maximum LAI was recorded at peak tillering stage. Harvested plants, including leaves, were chopped and dried in an oven till constant weight to record dry weight.

Fraction of intercepted PAR

The fraction of PAR (F_i) of sugarcane was valued from leaf area index employing Monteith and Elston (1983) equation.

‘k’ a extinction co-efficient suggested by Monteith (1977). F_iand S_imultiply gave intercepted radiation (Sa).

Radiation use efficiency (RUE)

RUEs for sugarcane for TDM & cane yields by employing equations.

Water use efficiency (WUE)

WUE for sugarcane for TDM & cane yields by employing equations.

Nitrogen use efficiency (NUE)

NUE (kg kg^-1) of sugarcane for total biomass and cane yields by employing Nyborg et al. (1995) formula

Here N_x represent to grain yield with N application and N_c is represent grain yield without N application.

Statistical analysis

Data were statistically analyzed using one-way ANOVA for all three experiment using Statistics 8.1 and least significant difference (LSD) test was employed for mean separation at probability level 0.05 (Steel et al. 1997).

Results

Planting dates

Results revealed that planting dates had significant effect on biomass, can yield, RUE_CY and RUE_TDM during both years (Table 2). During both years, crop planted on 25^thMay resulted in significantly higher total biomass and cane while earlier planted crop (April 05) resulted lesser biomass and cane yield. Likewise, late planting (May 25)resulted significantly higher RUE_TDM and RUE_CY while earlier planted crop (April 05) resulted lesser RUE_TDM and RUE_CY, respectively during both years (Table 2).

Irrigation regimes

Results showed that effect of irrigation regimes had significant influence on total dry matter, cane yield, RUE_TDM, RUE_CY, WUE_TDM, WUE_CY (Table 3). During both years, highest number of irrigations applications resulted in significantly higher total biomass and cane yield, while at control, when no irrigation application resulted lesser biomass and cane yield as compared to other irrigation treatments. However, highest irrigations application was statistically at par with irrigation regime of 16 irrigations. Likewise, highest number of irrigations applications resulted significantly higher RUE_TDM and RUE_CY while at control, when no irrigation application resulted lesser RUE_TDM and RUE_CY, respectively during both years Likewise, 20 number of irrigations applications resulted significantly higher WUE_TDM and WUE_CY. However, highest irrigations applications were statistically at par with irrigation regime of 16 irrigations while at control, when no irrigation application resulted lesser WUE_TDM and WUE_CY, respectively during both years. The relationship between RUE and WUE for ponda sugarcane for pooled data has been presented in Fig. 2a. WUE is enhanced with increasing RUE. There was a strong positive correlation between WUE and RUE. More water productivity was gained with more RUE.

Nitrogen levels

The impact of N levels on total dry matter, cane yield, RUE_TDM, RUE_CY, NUE_TDM, NUE_CY was significant (Table 4). During both years, application of 285 kg N ha^-1 resulted significantly higher total biomass and cane yield, however, it was statistically at par with of 228 N kg ha^-1 (Table 4).

Table 1: Experimental details regarding ponda sugarcane at farmer field Vehari

Experimental details	Experiment 1 (Planting dates)	Experiment 2 (Irrigation regimes)	Experiment 3 (Nitrogen levels)
Experimental years	2017 & 2018	2017 & 2018	2017 & 2018
Treatments	PD₁=05^th April; PD₂ = 15^th April; PD₃=25^th April; PD₄=05^th May;PD₅=15^th May;PD₆=25^thMay	I₀ = No Irrigations; I₁ = 4 Irrigations; I₂ = 8 Irrigations; I₃ = 12 Irrigations; I₄ = 16 Irrigations; I₅ = 20 Irrigations	N₀ = 0 kg ha^-1; N₁ = 57 kg ha^-1; N₂ = 114 kg ha^-1. N₃ = 171 kg ha^-1; N₄ = 228 kg ha^-1; N₅ = 285 kg ha^-1
Irrigations	16 Irrigations	As above	16 Irrigations
Planting date	As above	April 05	April 05
Nitrogen	228 kg ha^-1	228 kg ha^-1	As above
Phosphorus	120 kg ha^-1	120 kg ha^-1	120 kg ha^-1
Potassium	145 kg ha^-1	145 kg ha^-1	145 kg ha^-1
Experimental design	RCBD	RCBD	RCBD
Harvest dates	15 November	11 November	12 November

RCBD: Randomized complete block design

Table 2: Effect of different planting dates on total dry matter, cane yield and RUEs for total dry matter and cane yield of sugarcane

Planting dates	Total dry matter (kg ha^-1)		Cane yield (t ha^-1)		RUE_TD_M (g MJ^-1)		RUE_CY (g MJ^-1)
Planting dates	2017	2018	2017	2018	2017	2018	2017	2018
April 05	31112f	29818f	72.89f	69.86f	2.39f	2.27f	2.03f	1.93f
April 15	36299e	34849e	85.04e	81.64e	2.79e	2.66e	2.37e	2.26e
April 25	40036d	38393d	93.79d	89.94d	3.08d	2.93d	2.62d	2.49d
May 05	43387c	42301c	101.65c	99.10c	3.34c	3.23c	2.84c	2.74 c
May 15	46582b	44781b	109.13b	104.91b	3.59b	3.42b	3.05b	2.90b
May 25	49768a	47732a	116.59a	111.82a	3.83a	3.64a	3.26a	3.10a
LSD value at 5%	1377.0	1489.0	3.22	3.48	0.10	0.11	0.09	0.09

Means sharing different letters in a column differ significantly at P ≤ 0.05

RUE = Radiation use efficiency

Table 3: Effect of different irrigation regimes on total dry matter, cane yield and RUEs for total dry matter and cane yield of sugarcane

Irrigation regimes

Total dry matter (kg ha^-1)

Cane yield (t ha^-1)

RUE_TD_M (g MJ^-1)

RUE_CY (g MJ^-1)

WUE_TD_M (kg ha^-1 mm^-1)

WUE_CY (kg ha^-1 mm^-1)

2017

2018

2017

2018

2017

2018

2017

2018

2017

2018

2017

2018

Control

16177e

15251e

37.90e

35.73e

1.24e

1.16e

1.06e

0.99e

4 Irrigations

26746d

25677d

62.66d

60.15d

2.06d

1.96d

1.75d

1.67d

18.63d

16.19d

16.25d

14.28d

8 Irrigations

33462c

32250c

78.39c

75.55c

2.58c

2.46c

2.19c

2.09c

28.05c

25.35c

24.92c

23.41c

12 Irrigations

39429b

38431b

92.37b

90.03b

3.04b

2.93b

2.58b

2.49b

39.42b

36.08b

35.14b

32.65b

16 Irrigations

46967a

45613a

110.03a

106.86a

3.62a

3.48a

3.07a

2.96a

51.41a

48.21a

46.03a

43.89a

20 Irrigations

48111a

46756a

112.71a

109.54a

3.70a

3.57a

3.15a

3.036a

54.28a

49.54a

48.59a

44.25a

LSD value at 5%

1591.1

1720.9

3.72

4.03

0.12

0.13

0.10

0.11

8.34

8.46

7.29

7.65

Means sharing different letters in a column differ significantly at P ≤ 0.05

RUE = Radiation use efficiency; WUE = Water use efficiency

Table 4: Effect of different nitrogen levels on total dry matter, cane yield, RUE and NUE for total dry matter and cane yield of sugarcane

Nitrogen levels (kg ha^-1)

Total dry matter (kg ha^-1)

Cane yield (t ha^-1)

RUE_TD_M (g MJ^-1)

RUE_CY (g MJ^-1)

NUE_TD_M (kg kg^-1)

NUE_CY (kg kg^-1)

2017

2018

2017

2018

2017

2018

2017

2018

2017

2018

2017

2018

12649e

12364e

29.63e

28.96e

0.97e

0.94e

0.89e

0.80e

24339d

21985d

57.02d

51.50d

1.88d

1.68d

1.59d

1.42d

180.24d

157.19d

165.35d

144.22d

114

30451c

27609c

71.34c

64.68c

2.35c

2.11c

1.99c

1.79c

225.50c

197.41c

206.85c

181.11c

171

35880b

32893b

84.06b

77.06b

2.76b

2.51b

2.35b

2.13b

265.71b

235.19b

243.77b

215.64b

228

42740a

39055a

100.13a

91.49a

3.29a

2.98a

2.80a

2.53a

316.51a

279.25a

290.36a

256.19a

285

43781a

39958a

102.57a

93.61a

3.37a

3.05a

2.86a

2.59a

324.21a

285.70a

297.44a

262.11a

LSD value at 5%

1513.7

1424.0

3.54

3.33

0.11

0.10

0.09

17.29

20.41

15.85

18.71

Means sharing different letters in a column differ significantly at P ≤ 0.05

RUE = Radiation use efficiency; NUE = Nitrogen use efficiency

Fig. 1: Mean monthly maximum and minimum temperatures, solar radiation and total monthly rainfall at study site during 2017 and 2018

However, lesser biomass and cane yield were observed for control withut N application. Similarly, 285 kg N ha^-1resulted significantly higher RUE_TDM and RUE_CY while control, with no N, resulted lesser RUE_TDM and RUE_CY, respectively during both years of study (Table 4). Likewise, application of N 285 kg ha^-2 resulted significantly higher NUE_TDM and NUE_CY; however, it was statistically at par with 228 kg N ha^-1. Moreover, control, where no N was applied, resulted in lesser NUE_TDM and NUE_CY, respectively during both years of study (Table 4). The relationship between RUE and NUE for ponda sugarcane for pooled data has been presented in Fig. 2b. NUE is enhanced with increasing RUE. There was a strong positive correlation between NUE and RUE. More NUE was attained with more RUE (Fig. 2b).

Fig. 2: Relationships between radiation use efficiency and water use efficiency (a) and nitrogen use efficiency (b) for ponda sugarcane for pooled data

Discussion

The RUE was affected significantly by diverse planting dates and management practices. Maximum RUE was gained at planting date 25 May, application of 16 irrigations and N level of 228 kg N ha^-1 during both years. The main reason behind the higher RUE_CY and RUE_TDM of ponda sugarcane in all experiments was the more accretion of biomass and cane yield recorded at respective treatments in both years (Tables 2–4).

Environmental factors that influence sugar and cane productivity are capturing of more solar radiations that interrelates with uptake of water, nutrients, as well as temperature affecting photosynthesis process; which regulates dry matter accumulation of ponda sugarcane. Ponda sugarcane for best performing treatments during entire life cycle enjoyed favorable temperature for germination and growth, and optimum water and nutrients supply which enabled it to produce more biomass and cane yield leading to higher RUE (Anderson et al. 2015; Schwerz et al. 2018). Factors that influence on photosynthesis process are interception of solar radiations as well as its exploitation with the help of crop canopy configuration, to transformation of light into photo-assimilates and ultimately to translocation of sucrose contents toward sinking organ parts of sugarcane plant (Silva and Costa 2012; Ehsanipour et al. 2019). For the enhancement of resources use efficiency on ponda sugarcane crop, it is vital to upsurge the quantity of intercepted radiations that depend on the cultivar response, optimum planting date, irrigations, and nitrogen amount application (Ahmad et al. 2017). To capture higher amount of intercepted solar radiations, development of a higher LAI during earlier stages of growth and phases is desired. Optimal LAI is the one that permits the highest total biomass productivity, and this can be attained when whole canopy leaves sustain an optimistic steadiness of carbon; when sugarcane plant captivates whole PAR (Anderson et al. 2015; Ehsanipour et al. 2019). Photosynthetically active radiations captured by the ponda sugarcane crop are converted into dry biomass, therefore, the linear relationship among irrigations, N levels and planting dates treatments characterized variations in RUE. Best performing treatments resulted in maximum RUE (Silva et al. 2013; López-Pereira et al. 2020). With increasing irrigation regimes, adequate water and nutrient supply was maintained resulting in better canopy development (as evident with LAI) to capture more solar radiation to prepare more photo-assimilates (Jangpromma et al. 2012) which resulted in better RUE.

Maximum NUE was gained under best performing N application. At highest level of N application, NUE was decreased which might be due to losses of N during both years. It is proven fact that an optimum N availability, NUE of ponda sugarcane is improved, through greater height, LAI, intercepted light, along with development of canopy (Hajari et al. 2017; Thorburn et al. 2017). Like inclinations of NUE against N applied in sugarcane crop showed that NUE might be better on total dry matter basis under appropriate N level (Ali et al. 2000; Whan et al. 2010). Ponda sugarcane displayed additional N assimilation at higher N level as compared lower N levels. Optimum N application for ponda sugarcane crop increases productivity in the form of sugar and fresh cane yield, and then likewise enhanced NUE. Optimum N supply enhanced cane length, cane diameter, internodal length and plant height; which leads to higher cane yield and ultimately improved NUE (Suman et al. 2008; Nurhidayati and Basit 2015).

The WUE is a good indicator to determine efficient utilization of scare water resources for any crop under optimal and less than optimal conditions (Farooq et al. 2019). In this study both WUE_CY and WUE_TDM were increased with increasing irrigation regimes and reached to maximum at 16 irrigations (Singh et al. 2007; Olivier and Singels 2015; Table 3). Higher WUE of sugarcane at higher irrigations might be due to its C4 photosynthesis system; as C4 plants efficiently utilize water and nutrients to accumulate more biomass and may result in higher WUE at higher irrigations (Table 3). With increasing irrigation regimes, adequate water and nutrient supply was maintained resulting in better canopy development as evident with LAI to capture more solar radiation to prepare more photo-assimilates (Jangpromma et al. 2012).

Conclusion

Results suggest that productivity and resource use efficiency of ponda sugarcane can be achieved through integrated approaches at farmers’ fields. Higher biomass, cane yield and resource use efficiencies like RUE, WUE and NUE of ponda sugarcane can be achieved by optimizing planting time, irrigation regimes and nitrogen levels under irrigated arid environmental conditions.

Acknowledgements

The authors acknowledge financial support from Bahauddin Zakariya University, Multan.

Author Contributions

The experiment was designed by GA, ZF, and MAK and performed by MNK. Literature was reviewed by PI, AK, and IZ. Data were analyzed by AM. The paper was written by MH and MA. Overall study was supervised by SA. All the authors read paper before submission.

References

Abbas G, S Ahmad, M Hussain, Z Fatima, S Hussain, P Iqbal, M Ahmed, M Farooq (2020a). Sowing date and hybrid choice matters production of maize–maize system. Intl J Plant Prod 93:1–13

Abbas G, Z Fatima, M Hussain, S Hussain, N Sarwar, M Ahmed, S Ahmad (2020b). Nitrogen rate and hybrid selection matters productivity of maize–maize cropping system under irrigated arid environment of Southern Punjab, Pakistan. Intl J Plant Prod 14:309‒320

Ahmad R, M Hussain, MB Gill (1991). Effect of different planting dates on the yield and quality of sugarcane. Pak J Agric Sci 28:388‒391

Ahmad S, M Nadeem, G Abbas, Z Fatima, RJ Khan, M Ahmed, A Ahmad, G Rasul, MA Khan (2017). Quantification of the effects of climate warming and crop management on sugarcane phenology. Clim Res 71:47‒61

Ali FG, MA Iqbal, AA Chattha, A Shahid (2000). Fertilizer-use efficiency and cane yield under different nitrogen levels and weed management practices in spring planted sugarcane. Pak Sugar J 15:22‒26

Anderson RG, R Tirado-Corbalá, D Wang, JE Ayars (2015). Long-rotation sugarcane in Hawaii sustains high carbon accumulation and radiation use efficiency in 2nd year of growth. Agric Ecosyst Environ 199:216‒224

Azzazy NB, IH El-Geddawy (2003). Effect of nitrogen fertilization on yield and quality of some sugar cane varieties under develop surface irrigation system. Egypt J Agric Res 81:1137‒1148

Bekheet MA (2006). Effect of irrigation and potassium fertilization on yield and quality of two sugarcane varieties. Assiut J Agric Sci 37:1‒19

Ehsanipour A, H Abbasdokht, M Gholipour, ARA Mashhadi (2019). Evaluation of radiation use efficiency and weed control in intercropping of sugarcane (Saccharum officinarum L.) and legumes. Iran J Crop Sci 21:67‒79

Farooq M, M Hussain, S Ul-Allah, KHM Siddique (2019). Physiological and agronomic approaches for improving water-use efficiency in crop plants. Agric Water Manage 219:95‒108

Farooq N, SH Gheewala (2019). Water use and deprivation potential for sugarcane cultivation in Pakistan. J Sustain Ener Environ 10:33‒39

GOP (Government of Pakistan) (2019). Economic Survey of Pakistan 2018–2019, Finance Division, Economic Advisory Wing, pp:19‒24. Islamabad, Pakistan

Hajari E, SJ Snyman, MP Watt (2017). The effect of form and level of inorganic N on nitrogen use efficiency of sugarcane grown in pots. J Plant Nutr 40:248‒257

Hoang DT, T Hiroo, K Yoshinobu (2019). Nitrogen use efficiency and drought tolerant ability of various sugarcane varieties under drought stress at early growth stage. Plant Prod Sci 22:250‒261

Hoy JW, AE Arceneaux, CF Savario (2006). Effects of date and rate of billet planting on sugar-cane yield. Amer Soc Sugar Cane Technol 26:116‒124

Hurst CA, PJ Thorburn, D Lockington, KL Bristow (2004). Sugarcane water use from shallow water tables: Implications for improving irrigation water use efficiency. Agric Water Manage 65:1‒19

Jangpromma N, S Thammasirirak, P Jaisil, P Songsri (2012). Effects of drought and recovery from drought stress on above ground and root growth, and water use efficiency in sugarcane (Saccharum officinarum L.). Aust J Crop Sci 6:1298–1304

López-Pereira M, DJ Connor, AJ Hall (2020). Intercepted radiation and radiation-use efficiency in sunflower crops grown at conventional and wide inter-row spacings: Measurements and modeled estimates of intercepted radiation. Field Crops Res 246; Article 107684

Mengistu S (2013). Effect of different nitrogen rates and time of application in improving yield and quality of seed cane of sugarcane (Saccharum spp. L.) variety B41/227. Intl J Sci Res 3:36‒51

Monteith JL (1977). Climate and efficiency of crop production in Britain. Phil Trans Roy Soc Lond B 281:277‒294

Monteith JL, JF Elston (1983). Performance and productivity of foliage in the field. In: The Growth and Functioning of Leaves, pp:499‒518. Dale JE, FL Milthorpe (Eds.). Cambridge University Press, Butterworths, London

Nurhidayati N, A Basit (2015). Improvement of nitrogen use efficiency derived from ammonium sulfate substitute fertilizer in sugarcane cultivation through the addition of organic amendment. Intl J Plant Soil Sci 6:341‒349

Nyborg M, ED Solberg, RC Izaurralde, SS Malhi, M Molina-Ayala (1995). Influence of long-term tillage, straw and N fertilizer on barley yield, Plant-N uptake and Soil-N balance. Soil Till Res 36:165‒174

Olivier FC, A Singels (2015). Increasing water use efficiency of irrigated sugarcane production in South Africa through better agronomic practices. Field Crops Res 176:87‒98

Olivier FC, A Singels, AB Eksteen (2016). Water and radiation use efficiency of sugarcane for bioethanol production in South Africa, benchmarked against other selected crops. S Afr J Plant Soil 33:1‒11

Otto R, SAQ Castro, E Mariano, SGQ Castro, HCJ Franco, PCO Trivelin (2016). Nitrogen use efficiency for sugarcane-biofuel production: What is next? Bioener Res 9:1272‒1289

Rizk NS, EAY Bashbishy, ME Rasian (2002). Effect of macro and micro-nutrients and farmyard manure on sugar cane. Ann Agric Sci Moshtohor 40:2311‒2316

Schwerz F, SL Medeiros, EF Elli, E Eloy, J Sgarbossa, BO Caron (2018). Plant growth, radiation use efficiency and yield of sugarcane cultivated in agroforestry systems: An alternative for threatened ecosystems. Anais Acad Bras Ciênc 90:3265‒3283

Shahrzad MM, N Kamla, AE Hak (2014). Effect of irrigation regime and nitrogen fertilization levels on sugarcane yield and its component. Alexandr Sci Exch J 35:288‒293

Shukla SK, I Singh (2011). Tillering pattern, growth and yield of three promising genotypes of sugarcane under three fertility levels in subtropical India. Ind J Sugar Cane Technol 26:10‒13

Silva ALCD, WAJMD Costa (2012). Growth and radiation use efficiency of sugarcane under irrigated and rain-fed conditions in Sri Lanka. Sugar Technol 14:247‒254

Silva MDA, JL Jifon, CMD Santos, CJ Jadoski, JAGD Silva (2013). Photosynthetic capacity and water use efficiency in sugarcane genotypes subject to water deficit during early growth phase. Braz Arch Biol Technol 56:735‒748

Silva MDA, JL Jifon, JAG Silva, V Sharma (2007). Use of physiological parameters as fast tools to screen for drought tolerance in sugarcane. Braz J Plant Physiol 19:193‒201

Sime M (2013). Effect of different nitrogen rates and time of application in improving yield and quality of seed cane of sugarcane (Saccharum spp. L.) variety B41/227. Intl J Sci Res 3:1‒7

Singh I, RP Verma, TK Srivastava (2018). Growth, yield, irrigation water use efficiency, juice quality and economics of sugarcane in pusa hydrogel application under different irrigation scheduling. Sugar Technol 20:29‒35

Singh PN, SK Shukla, VK Bhatnagar (2007). Optimizing soil moisture regime to increase water use efficiency of sugarcane (Saccharum spp. hybrid complex) in subtropical India. Agric Water Manage 90:95‒100

Snyman SJ, E Hajari, MP Watt, Y Lu, JC Kridl (2015). Improved nitrogen use efficiency in transgenic sugarcane: Phenotypic assessment in a pot trial under low nitrogen conditions. Plant Cell Rep 34:667‒669

Sogheir KSE, H Ferweez (2009). Optimum harvesting age of some promising sugar cane genotypes grown under different nitrogen fertilizer levels. Egypt J Appl Sci 24:195‒214

Steel RG, JH Torrie, DA Dickey (1997). Principles and Procedures of Statistics, A Biometrical Approach, pp:172‒177, 3^rd edn. McGraw Hill Book Co., Inc., New York, USA

Suman A, AK Shrivastava, A Gaur, P Singh, J Singh, RL Yadav (2008). Nitrogen use efficiency of sugarcane in relation to its BNF potential and population of endophytic diazotrophs at different N levels. Plant Growth Regul 54:1‒11

Thorburn PJ, JS Biggs, J Palmer, EA Meier, K Verburg, DM Skocaj (2017). Prioritizing crop management to increase nitrogen use efficiency in Australian sugarcane crops. Front Plant Sci 8; Article 1504

Ullah SMS, M Hossain, S Barman, MH Sohag, SH Prodhan (2013). Genetic diversity analysis of chewing sugarcane (Saccharum officinarum L.) varieties by using RAPD markers. J BioSci Biotechnol 2:34‒45

Waqas MM, SHH Shah, UK Awan, M Arshad, R Ahmad (2019). Impact of climate change on groundwater fluctuation, root zone salinity and water productivity of sugarcane: A case study in Lower Chenab Canal System of Pakistan. Pak J Agric Sci 56:26‒39

Whan A, N Robinson, P Lakshmanan, S Schmidt, K Aitken (2010). A quantitative genetics approach to nitrogen use efficiency in sugarcane. Funct Plant Biol 37:448‒454