Keywords

18.1 Advanced Production Technology of Sugar Crops

18.1.1 Introduction

Sugarcane is a perennial plant and a major cash crop and provides raw material to many other industries. Sugarcane is well grown over the tropical and subtropical countries worldwide for the production of sugar and other products. Among the long list of cane-producing countries of the world, the top 10 are Brazil, India, China, Thailand, Pakistan, Mexico, Colombia, Australia, Guatemala and the United States.

The botanical classification of sugarcane is Saccharum officinarum, and it belongs to the family Gramineae. Several species and hybrids of genus Saccharum of family Gramineae are called sugarcane. Those of the widely recognized are Saccharum officinarum and Saccharum barberi.

18.1.2 History and Origin

Sugarcane is the principal sweetener that was first dominant in the subcontinent of India more than 25 centuries ago, while China was the first country where commercial sugar was first produced from sugarcane. The word “sugar” is thought to have been taken from “Sanskrit” and Sanskrit literature from India in between 1500 and 500 B.C. This innovative name was later then changed to “sukkar” in Arabic, “sakharon” in Green and sucre in French and concluded to sugar in English. As far back as chronicled history goes, there are evidences of the use of sugarcane in India and China, and there can be little doubt that primitive man cultivated it long before then. Sugarcane existed in a wide range of types or varieties that differed extensively in colour and form. There can hardly be any doubt that the improvement of sugarcane varieties has a history as long as its cultivation. The history of sugarcane was the introduction of thick curtailed varieties of Saccharum officinarum in 1791 by Captain Bligh.

18.1.3 Economic Importance

Sugarcane is a new substantial for sugar industry. It provides not only income to the cane growers but also service to the field and industry workers. It has many by-products, viz. bagasse, molasses, filter cake and wax. Bagasse is used for the manufacturing of paper and hardboard and also for livestock feed. Molasses can be used in the production of alcohol, livestock feed and fertilizers. Filter cake is a rich source of organic and macro−/micronutrients, whereas sugarcane wax obtained from filter cake is used as a product in the manufacture of shoe polish. The air-dry (AD) “millable” cane stalk, approximately 75% of the entire plant, contains 11–16% fibre, 12–16% soluble sugars, 2–3% non-sugars and 63–73% water.

18.1.4 Choices Before Plantation

18.1.4.1 Selection of Soil

Sugarcane responds better on a fertile, well-drained soil with an abundant moisture supply. It can be grown well on a diversity of soil ranging from sandy loam to heavy clay, but the most suitable soil is deep clay loam as topsoil with high moisture-retaining capacity. Sugarcane crop is tolerant to both acidic and alkaline soils to a certain level (a pH of 6.5 is considered best), but it is also considered as a relatively salt-sensitive crop as salinity induces water stress, which causes restricted growth by premature wilting and scorching of the leaves and, in severe cases, death of the plant. Similarly, waterlogged soil with no drainage is also not suitable for it.

18.1.4.2 Type of Machinery Available

Starting from the land preparation to planting and other operations, different types of machinery are required. Among the various types of primary and secondary tillage instruments, viz. subsoiler or chisel plough, cultivator, ridger, rotavator and disc harrows, we choose one or more instruments depending upon the previous crop. We use machineries for sowing, like pit hole digger and sugarcane ring pit planter, according to our selection of sowing method, whereas other machineries used for plant protection measures, harvesting and miscellaneous purposes include boom sprayer and sugarcane harvester.

18.1.5 Choices at Planting

18.1.5.1 Land Preparation

Ploughing with subsoiler or chisel, twice use of cultivator before making deep trenches with ridger and use of rotavator or disc harrow, if stubbles of previous crop are present, help in good preparation of land before sowing of sugarcane. After normal operations, there is requirement of a holistic approach with respect to each planting method. For pit plantation, 100 mm water is required followed by sequencing water up to the level of field capacity level so that pits can be therefore dug. In case of trench plantation, tractor-mounted ridger is required after pulverizing the soil to fine particles up to the size of clayey loam (0.02 mm). For strip plantation of sugarcane, hand tools can be of very use.

18.1.5.2 Planting Methods

  • Strip planting

  • Pit planting

  • Trench plantation of sugarcane

  • Ring pit plantation

  • Chip bud technology

18.1.5.2.1 Strip Planting

In strip planting, 90/30 cm double row strips are more important. Actually, this method replaced the narrow row methods at 60 cm because it was inefficient in promoting the germination and has about 30–35% yield losses in comparison with the genetic potential yield.

18.1.5.2.2 Pit Planting

Pit plantation was introduced after its successful implementation in growing fruit trees. Pit plantation is being recently introduced for cane cultivation during the last decades. A lot of planting geometries and their effect on the farmer economics are under review. Plant geometry of 45 cm, 60 cm, 75 cm and 90 cm with 30 double-budded setts has been studied. Pits in each case are mined to a level of 90 cm depth which is then filled with farmyard manure (FYM). Moreover, a technique of diagonal pit plantation at different distances has been experimented. There are four observations. Firstly, cane yield in this system depends upon the number of pits in unit area. The more the pits, the more would be the yield. Secondly, cane size remained very thin as cane diameter revolves around 2.2 cm to 2.35 cm. Thirdly, this technique is labour intensive; however, this problem may not be a large issue in ratoon crop. Finally, though yield is more than that of any other system, farmers may not prefer this due to its high cost of production. It is noteworthy that pit plantation is useful in saving 20% water resource and 30% fertilizer resource; thus, close application in rhizosphere can be instrumental in fertilizer use efficiency (FUE) and water use efficiency (WUE).

18.1.5.2.3 Trench Plantation of Sugarcane

Trench plantation is important in the areas of severe drought and water logging situation because planting cane at ridge side can save water and absorb water when it is in excess. Trench plantation is being practised in planting geometries of 90 cm apart and 120 cm apart. With less cost of production, trench planting is practised because of its ability to refurnish farmers with great economic returns. Recently, two modern techniques of cane plantation have been introduced; the first one is ring pit method of cane cultivation and the second one is chip bud technology.

18.1.5.2.4 Ring Pit Method

In ring pit method, three budded sets are sown in a manually dug pits filled with the fired trash and tops so that potash contents are higher in the system which can save extra potash supplementation and even nitrogen resources.

18.1.5.2.5 Chip Bud Technology

Chip bud technology was first practised in Tamil Nadu, India, and it resembled the process of nursery growing as that of in rice. Only buds at internodes are cut and made to grow either in specialized trays or polythene bags filled with soil. Then these seedlings are transferred to the soil (soil which is between the field capacity and permanent wilting point). Some 6000 seedlings per acre are transferred to the soil. The major advantages of this technology are saving water for the entire germination season and adequate organic matter readily available to the seedlings.

18.1.5.3 Appropriate Time of Planting

There are two planting seasons of sugarcane in Pakistan:

  • Fall: first week of September–mid of October.

  • Spring: mid of February–end of March.

18.1.5.4 Cultivar Selection

Cultivar should be selected according to the recommendation of the government agencies because different cultivars are recommended for the specified areas and time periods. Some early-maturing varieties (Nov–Dec) recommended for the general cultivation in Pakistan include CP 77-400, CP 72-2086, CP 43–33, CPF-237, HSF-240 and HSF-242 (CPF-243 for Southern Punjab only), whereas medium-maturing varieties (Dec–Jan) that are considered the best choice for best yield in Pakistan are SPF-213, SPF-245, SPSG-26 and BL-4 (BF-162 and SPF-234 for Southern Punjab only), and for late-maturing varieties (Feb–Mar), L-118 and CoJ-84 are the best choice for better yield achievement.

18.1.5.5 Seed Rate

There are two bases upon which we can choose the seed rate of sugarcane:

  1. 1.

    Cane weight basis

    • Thick varieties: 90–100 mounds acre−1

    • Medium varieties: 80–90 mounds acre−1

    • Thin varieties: 70–80 mounds acre−1

  2. 2.

    Cane setts basis

    • For normal planting, 24,000 double-budded setts per acre.

    • For late planting, 30,000 double-budded setts per acre.

18.1.6 Management After Planting

18.1.6.1 Irrigation Management

Profitable cultivation of sugarcane requires plenty of water. Twenty mega-litres of water is required on an average by the crop to fulfil its metabolic activities and losses during the course of irrigation and evapotranspirational requirements and thereafter (Shrivastava et al. 2011). For the spring crop, water requirements on an average range from 120 to 160 cm, and for fall crop, it ranges from 200 to 250 cm.

Total irrigation requirement is 16–20 cm. Because of convenience, farmers of subtropical region adopt flood irrigation; however, a lot of water get wasted in this method due to uneven distribution in the field, and therefore, water use efficiency is low. In furrow irrigation method, irrigation water is allowed to soak down in the root zone by running small streams in between cane rows. This method of irrigation is more efficient as the surface area for evaporation is decreased (Singh et al. 2015). The escalating deficit rainfall scenario defines that drought is a recurrent phenomenon associated with tropical sugarcane farming, and the water available for sugarcane cultivation will be decreased in the coming years. However, on the opposite, sufficient soil moisture availability during crop growth period is of paramount importance to get good yield. One kilogramme of sugarcane production requires about 125 L of irrigation water. Cane yield and actual transpiration have a linear relationship (Carr and Knox 2011). Up to 60% productivity losses can be caused by water shortage (Basnayake et al. 2012).

 

Irrigation schedule

 

Months

No. of irrigations

aInterval (days)

March–April

3

20

May–June

5

12

July–August

3

15

Sep–October

3

15

Nov–January

2

40

Total:

16

 
  1. aSubject to the soil and weather conditions. In case of water shortage and during the months of high temperature, apply water by alternate skip irrigation method

18.1.6.2 Earthing Up of Plants

Many aspects are responsible for the low yield of sugarcane. The cane yield is adversely affected by malnutrition and lodging problems (Anwar et al. 2002). The earthing up done to a height of 30 cm can increase millable cane yield by 12% over no earthing up, while lodging can reduce sugarcane yield by 30 percent (Ahmad 1997), and these findings were further supported by recent investigations (Chattha et al. 2006). Aslam et al. observed earthing up improved significant cane yield (Aslam et al. 2005). The ratoon cropping is more efficient and gives better quality juice and sugar recovery than plant cane. Excessive tillering in ratoon crop is a desired inheritance character, but all tillers produced from the ratoon crop may not be millable cane. In decreasing the number of excessive tillers, earthing up plays an important role. Besides, it has added benefits of pruning/cutting of old roots, moisture conservation, addition of organic matter, enhanced availability and uptake of plant nutrients, efficient utilization of solar radiation, suppression of weeds and preventing canes from lodging (Yadav and Shukla 2008). Earthing up crop to a height of 20 cm produced higher soil volume also significantly recorded higher cane length, cane diameter of top middle and bottom cane weight as well as cane yield (Dougall and Halpin 2008). There were other researchers who reported that earthing up by tractor-mounted cane ridger is effective for increase in cane yield (Ali and Afghan 2000).

18.1.6.3 Integrated Nutrient Management

There is vital need to implement appropriate agronomic practices (like harvesting date, height of harvesting, cutting stubble saving, off-barring) in sugarcane crop for attaining good ratoon yield; one of the most important factor is nutrient management affecting tonnage of ratoon cane (Rana and Singh 2003). There are 16 chemical elements which are known to be necessary for sugarcane according to the standards of plant nutrition. Air and water cover the major portion of carbon (C), hydrogen (H) and oxygen (O). Others like N, P, K, S, Ca, etc. are required in less quantity and require to suppliant in soil is not able to supply them in sufficient amount (ICAR 2006). Being a long duration crop with C4 metabolism, sugarcane produces very heavy biomass and demands massive amounts of moisture, nutrients and sunlight for its optimal production. For every tonne of cane produced, it was expected that the crop releases micronutrients and 0.56–1.20 kg of N, 0.38–0.82 kg of P2O5, 1.00–2.50 kg of K2O, 0.25–0.60 kg of Ca, 0.20–0.35 kg of Mg, 0.02–0.20 kg of Na and 2.0–2.7 kg of SO4 (Zende 1990). Large amounts of nutrients are released from the soil when we cultivate sugarcane continuously. In a virgin soil in Australia, King et al. (1953) found that after 22 years of sugarcane cultivation, N contents decreased from 4.8 g kg−1 to 2.2 g kg−1. The suggested dosages range from 70 to 400 kg N, 0 to 80 kg P2O5 and 0 to 141 kg K2O ha−1 (Singh and Yadav 1996). Dosages of fertilizers recommended are usually higher in tropical states compared to subtropical states. Saini et al. (2006) also said that for sugarcane nutrients application recommendation of up to 400 kg N, 170 kg P and 180–190 kg K ha−1 depends upon its duration and fertility status of the soil. Ambrosano et al. (2011) said that N applied as leguminous green manure recovers the 19–21% N and N applied as ammonium sulphate recovers 46–49% N by the first two consecutive harvests. Cesar et al. (2011) stated that total nitrogen consumed by shoot from urea was 15.9%. The expected seasonal nitrogen use efficiency was 0.841 t of cane kg−1 N (Chattopadhyay et al. 2004). Canes lacking in nitrogen show even yellowing of the leaves, retarded growth, stalks of smaller diameter, senescence of old leaves and premature drying (Humbert and Martin 1955). Cane yield decreases by excessive use of nitrogen and also ultimately affects the cane juice quality (Singh and Yadav 1996). Chiranjivi Rao et al. (1974) stated that upper levels of N application in the variety Co-6304 cause reduction in cane yield and sugar content. More use of nitrogen makes sugarcane juicy and soft, but it becomes prone to pests and disease. Due to heavy top, crop tends to lodge (Verma 2004). Phosphorus is vital to accelerate the development of shoot roots and to increase tillering, but its accessibility depends on the fixation of natural and applied P. Improved yield, final stalk production, weight per cane and tiller production increase by phosphorus application. At optimal level of P application, sugar content and purity of juice are also improved (Elamin et al. 2007). Stunted stalks, reduced tillers, narrow leaves, restricted root development and slow growth result due to deficiency of P. Hunsigi (1993) stated that deficiency of P is shown in poor tillering and rooting, delayed “close-in” and shorter internodes which taper quickly at the growing point. At the time of planting, phosphorus is generally applied at a single dosage. Single super phosphate and diammonium phosphate are sources of P and should preferably be applied in bands near the seed pieces or “setts” to reduce fixation. But insoluble sources should be thoroughly mixed with the soil-like powdered rock phosphate (RP). Potassium plays a significant role in plant growth and metabolism. During moisture stress, potassium plays a role in regulating the uptake of water and leaf stomatal opening, the maintenance of cell turgidity and the formation of proline and is of particular importance in view of the periodic drought conditions that affect the sugar industry. In the accumulation of sucrose synthesis and translocation of proteins and carbohydrates, potassium is also vital. Agronomic value of K rests with improved cane volume, girth and weight per cane, drought and disease resistance and reduced lodging. Mostly when harvest is delayed, K application frequently increases the percentage of sugar in the cane and juice recovery (Hunsigi 2011). Potassium deficiency first appears on older leaves and margins of leaves, and tips become brown with necrotic spots, which coalesce and show typical “marginal firing” (Hunsigi 1993). Potassium increase in plant tissues may delay sugar processing due to scale formation in pans (Hunsigi 2011). Meyer and Wood (2001) also stated that increase in potassium uptake and exhaustibility of final molasses, colour and ash content of raw sugar might be influenced by high potassium level in the juice. Fertigation can be a more effective means of applying crop nutrients, mostly nitrogen and potassium, so that nutrient application rates could be decreased in fertigated crops. Thorburn et al. (2003) studied the different N rates (0–240 kg ha−1 year−1) applied through drip fertigation responses in cane and sugar production in Australia. Through drip irrigation and application of 80 kg ha−1 of N, the cane and sugar yields did not significantly increased, while the recommended dosage for traditional irrigation systems was 160 kg ha−1 year−1. Organic manures like FYM and composts have been conventionally significant inputs in crop production for maintaining soil fertility and yield stability. Long-term studies (Joshi and Zende 1971; Singh and Yadav 1994) have stated the need for basal application of FYM or compost for maintaining optimal soil fertility status. Integrated use of mineral fertilizers with organic manures also helps to capture the decline in cane yield. Several experiments have been conducted in almost all the sugarcane-growing states to study the response of sugarcane to the application of 25 t of FYM per hectare (Kailasam 1999). Crop residues like green foliage of crops, cane trash and rice and wheat straw have been recycled in sugarcane cultivation. As a result, economy in fertilizer N has been affected (Kumarswami et al. 1995; Rana et al. 2003). The nitrogen stability studies using 15 N have provided direct indications for N fixation taking place in sugarcane. Patel et al. (1993) observed that application of 5 kg ha−1 Azotobacter culture by root band method at planting of sugarcane in medium black soil had creased the yield of sugarcane at Padegaon in Maharashtra. The culture with 250 kg N ha−1 gave an economy of 100 kg N ha−1 by producing cane more or less equal to that with 350 kg N ha−1. Farmyard manure, compost and oil cake from groundnut, castor, mustard, mahua, safflower, etc. are very commonly used in sugarcane for increasing cane yield and improving soil fertility (Kumarswami et al. 1995; Rana et al. 2003).

18.1.6.4 Integrated Pest Management

Weeds, insects, nematodes and pathogen may affect sugarcane (Leslie 2004). Some pests cause serious economic losses by reducing the value of crops to below economic thresholds. For example, eldana (Eldana saccharina Walker) can completely destroy the crop (Leslie 2009), rust (Puccinia melanocephala H&P Sydow) and smut (Ustilago scitaminea H&P Sydow) reduce yields on average by 30% (Rutherford et al. 2003), Cynodon dactylon (L) Pers can cause yield reduction by up to 50% (Campbell et al. 2007a, b), and 60% to 80% yield losses can be caused by high nematode populations (Spaull and Cadet 1990). Knowledge-based integration of all methods that reduce pest levels in crops is the integrated pest management (IPM) (Conlong and Rutherford 2009). As such, IPM covers a wide range of pest control, and growers can use the following methods, chemical, biological, agronomic and regulatory practices, to alleviate the influence of pests on yields and quality. However, emerging farmers do not readily adopt some of these control methods (Eweg 2005). How well the needs of this sector are currently being addressed this should be counted to determine, and to guide future research. Agronomic methods include those that improve soil health, thereby increasing crop resistance to pests such as weeds and nematodes (Berry and Rhodes 2006; Rhodes et al. 2009). Local Pest, Disease and Variety Control Committees (LPD&VCCs) use controlling approaches such as diagnostics (threshold values and surveillance) and regulations governing orders for plough-out and seed cane transport, as well as biosecurity (prevention of the introduction of new pests). For the latter, before permitting external sugarcane consignments from being planted, imported varieties are screened, thus becoming a control method that prevents pests spreading into the local industry (van Antwerpen 2005).

18.1.7 Management at Maturity and Harvesting

18.1.7.1 Right Method of Cutting

The Australian sugar industry has constantly wanted to improve the efficiency of harvesting since the beginning of harvesting machinery in the 1970s. Finding the balance between minimizing sugar losses, maintaining cane quality and optimizing throughput to manage harvesting costs is a major challenge for the industry in the past. The advantages of improved moisture retention and better weed control without the need for continuous cultivation are brought by the adoption of green cane harvesting. However, finding a balance between effective cane cleaning to minimize extraneous matter (EM) levels and excessive cane loss is the challenge created by adopting green cane harvesting. Customers expect to deliver high-quality cane from high-quality sugar drive growers and harvester operators. However, this results in increased sugar losses because it can push harvesting machinery beyond its capabilities. To make simpler harvesting process, mechanical harvesters/cutters were developed to deal with the diminishing supply and increasing cost of labour, stating that physical and all the above-mentioned properties, however, depend on the plant species, variety, stalk diameter, maturity, moisture content, cellular structure, plant height, stalk-cutting direction and bending-plant knockdown.

18.1.7.2 Manual Harvesting

In many countries, even today, various types of hand knives or hand axes are used for manual harvesting. Among the numerous tools, the cutting blade is usually heavier and easier to use and facilitates efficient cutting of cane. Improper harvest of cane leads to loss of cane and sugar yield, poor juice quality and problems in milling due to unnecessary matter. So, manual harvesting requires skilled labourers.

18.1.7.3 Mechanical Harvesting

In view of diversion of labour to other remunerative works in industry, construction, business, etc., harvesting labour is becoming scarce and costly. Because of non-availability of canes, due to shortage of harvesting, labour mill stoppages are common. Many mills are expanding their crushing capacities, and most of the new mills are of higher crushing capacity. Therefore, daily requirement of cane is increasing, hence greater demand for harvesting labour to harvest the sugarcane for mills. Added to this, most of the present-day agricultural labourers are not interested in field operations involving much drudgery. Thus, in the coming years, the labour position deteriorates further. Therefore, adoption of mechanical harvesting of cane in the future is inevitable, so mechanization is unavoidable. In countries where sugarcane cultivation is highly mechanized like Australia, Brazil, the United States, South Africa, Taiwan, Thailand, etc., huge harvesters are employed for cane harvesting. In these countries, large farms owned by either mills or big farmers grow sugarcane on large plantation scale. The working capacity of mechanical cane harvesters varies with the size (2.5 to 4 ha per day of 8 h). The limitation of mechanical harvesting machines is the use of such machineries in small, irregular and fragmented holdings, diversified cropping patterns and limited resource capacity of small and marginal farmers in several countries.

18.1.7.4 Scheduled Harvesting

18.1.7.4.1 Crop Age

Based on maturity (age), group harvesting is done. Farmers who grow a specific variety are usually familiar with the harvesting time. Even based on crop age, most sugar factories give cutting orders to farmers. Since planting time, crop management practices, weather conditions, etc. affect maturity, there is no scientific method. However, there are certain physical and morphological parameters upon which in the field crop maturity can be directed, like calculating brix reading. For example, cane is not fully mature, if the brix reading of lower internode is much higher in comparison to upper internodes. Cane is said to be matured once the said difference is less than or equal to 1.0 unit. Many physicobiochemical indicators for cane maturity have been reviewed by Solomon et al. (2000).

18.1.7.4.2 Cane Plant Parameters

There are some cane parameters that confirm its maturity, like when its foliage turns light green to pale yellow with shedding and drying of lower leaves and when the growth of stalk has completely ceased and the moisture contents of sheath drop from 85 to 72% or even less, while nitrogen content of leaves is 2 to 1.25% or even less.

18.1.7.4.3 Cane Juice Quality Parameters

Similarly, there are many juice quality parameters that are good indicators of cane maturity. Among these, brix, sucrose contents, reducing sugars and NPK contents are very important. Cane maturity has achieved when brix is more than 18, sucrose contents are more than 16, level of reducing sugars falls from 0.4 to 0.2% or even less and purity is higher than 85, whereas optimum NPK concentration at maturity should be around 200, 300 and 1000 ppm (NPK, respectively) in cane juice.

18.1.8 Yield Estimates

Sugarcane is the prominent cash crop of Pakistan, but average yield of this crop is far below than the required estimates to attain self-sufficiency in its production. The yield of sugarcane is quite low, 500–800 mounds acre−1, considerably less than the potential yields. The gap between potential and actual yield is very wide due to poor management practices, higher costs of inputs, low prices of output, delay in payments, postharvest losses and lack of scientific knowledge which were the major problems in sugarcane production (Nazir et al. 2013) including lack in adopting updated production technology by farmers. The traditional methods are usually employed by most of the farmers in the management of sugarcane. Production process is not mechanized and is mostly labour intensive. Majority of the growers do not follow modern practices like proper use of FYM, inter-culturing, fertilizer application, sprays and timely irrigation. The problems of postharvest losses include improper handling, harvesting and inadequate transport facilities (Nazir et al. 2013). In order to fulfil the existing gap between actual and potential yield, the productivity of sugarcane could be enhanced through the substantial government policies like pricing and marketing facilities for the farmers. The industry is not working within research domains of sugarcane improvement; rather, adhocism is being adopted by this sector. Without proper transfer of production technology, adequate credit supplies and utilization of cess funds, it would be impossible for researchers to evolve varieties having better yields and disease resistance. The need of the hour is to adopt improved plant protection and agronomic practices. The need in improvement of better milling and processing practices cannot be overemphasized (Akhtar 2000).

18.1.9 Cane Processing and Utilization

Sugarcane is grown, generally as a perennial crop, in tropical and subtropical areas. The world of sugar production has undergone massive changes in the last decade which have resulted in the emergence of many technological changes as technologists strive to develop more efficient and cheaper processes. Food, feed and energy are the major products of the sugarcane plant; sugarcane fibre and bagasse fuel the cane-processing plants and provide electricity to local grids through cogeneration (Clark and Edye 1996).

According to Clark and Godshall (1988), processing has traditionally taken place in two stages:

  1. 1.

    Extraction of juice from sugarcane and conversion to raw sugar (94–98% sucrose), at factories (mills) in areas where sugarcane is grown.

  2. 2.

    Refinement of raw sugar, shipped from areas of production to areas of consumption, to white and brown refined products (white sugar of 99.9% sucrose).

The sugarcane plant cannot be stored after harvest: sucrose begins to decompose shortly after the stalk is cut. The two-stage production process evolved because of the need to convert cane rapidly into a product that could be stored.

A third major traditional process has been the production of “plantation white” sugar, a white sugar of over 99% sucrose produced directly from sugarcane. The last two decades have seen changes and new trends in these traditional systems, as consumption of sugar in the tropical producer countries increases (and decreases in the United States because of replacement by cheap corn syrups) and as these producer countries, and their growing food processing industries, demand higher-quality sugars. Most notable are the increase in refining done in the tropics and the new processes for production of high-quality white sugar directly from cane juice.

18.1.10 Production and Trade

According to Pakistan Economic Survey 2017–2018, the sugarcane crop production at 81.102 million tonnes showed an increase of 7.4% over the last year’s production of 75.482 tonnes in the country (Table 18.1). Its production accounts 3.6 percent in agriculture’s value addition and 0.7% in overall GDP. Sugarcane crop that was cultivated on an area of 1.31 million hectares compared to last year’s area of 1.22 m ha witnessed an increase of 7.8% (GOP 2018).

Table 18.1 Area, production and yield of sugarcane
Full size table
Fig. 18.1
figure 1

Area and production of sugarcane in most sugar-producing countries

Full size image

The contribution of the Punjab in the total cane production is around 60%, Sindh about 30% and NWFP 10% (Table 18.2). About two-thirds of the total production of sugarcane is used in the production of centrifugal sugar every year, while the remaining harvested crop is used for the preparation of non-centrifugal sugar (Gur) and for seed purpose.

Table 18.2 Area and production of sugarcane by province
Full size table

In Pakistan, the sugar industry has grown from 2 sugar mills in 1947–1950 to the current 77 sugar mills: 39 sugar mills are located in the Punjab, 32 in Sindh and 6 in NWFP. If these mills are to be run at full capacity, it would require about 65 million tonnes of sugarcane, which is still a dream. The sugar production capacity of these mills is above five million tonnes, which has so far not been achieved, due to short production of sugarcane crop. The sugar sector is operating at only 60 to 70% capacity. There is a strong competition among the mills for acquiring more sugarcane. The middleman is very strong in this setup and exploits the situation in his favour. Sometimes the mill has to pay over and above the minimum price announced by the government. The sugar mills in Sindh usually have to face this kind of situation, due to short supply of sugarcane. However, in the Punjab the size of crop is large and the situation is somewhat better. In NWFP, a large part of the sugarcane is used for production of non-centrifugal sugar (Gur), and the situation is even worse because of the low supplier of sugarcane to the sugar mills (Khan and Jamil 2004).

The export of sugar has been increased continuously from 23,980 million tonnes in 2008–2009 to 399,309 million tonnes in 2016–2017. There was 21266.4 million rupees foreign exchange earned through sugar export in 2016–2017. Along with sugar, there were Rs. 1217 million exports of molasses during 2016–2017. The export of molasses has also continuously increased in the last 10 years (Table 18.3).

Table 18.3 Import and export of sugar and molasses
Full size table

In squat, there is need of the hour to establish more research institutes for the development of crop production and increased recovery from the crushed cane in order to attain autarky in sugar and earn more foreign exchange.

18.2 Advanced Production Technology of Sugar Beet

18.2.1 Introduction

Sugar beet (Beta vulgaris) is a sugar-producing, biennial tuber crop, predominantly grown in most of temperate regions of the world. It belongs to Amaranthaceae family, also recognized as the goosefoot family. The plant usually comprises three main parts, namely, crown, neck and roots. The crown produces leaves that, by photosynthesis, formed sugar which is finally stored in the roots. Sugar beet has tap root system that is white in colour, conical in shape, fleshy and having a flat crown in appearance. In composition, roots contain sugars (about 12–20% depending upon the cultivar used and crop husbandry), water contents (75%) and pulp (5%) that is water insoluble. Sugar beet shared 30% (approximately) in world sugar and has higher sugar contents as compared to sugarcane. Among the main sugar beet-producing countries of the world, currently, Russia is the largest producer, followed by France and the United States (FAOSTAT). In Pakistan, during 2016, sugar beet was grown on an area of 2889 hectares with total production of 117,546 tonnes (FAOSTAT). Sugar beets exclusively grow in temperate zones. Foliage has dense green colour and many in number. Plant attains a height of approximately 35 cm in general, while the average weight ranges between 0.5 and 1 kilogramme.

18.2.2 History and Origin

The sugar beet is derived from many years of breeding the domesticated beet (Beta vulgaris L.). It is said to get its name from the Greek letter beta because the swollen, turnip-like root resembles a Greek B. However, the oldest known beet type, chard, was domesticated by at least 2000 B.C. and was grown by both the Greeks and Romans. Chard was originally used medicinally and for its dense foliage growth as a pot herb much like spinach or some of the Chinese leaf vegetables that are used today.

For the first time, sugar beet was cultivated in gardens to use as a vegetable crop about 2000 years ago. However, this practice of sowing sugar beet in gardens has been ended now from years. The selection as vegetable was opted possibly from different Beta species that at that time were growing along the coasts of the Mediterranean. While in the whole Europe started from Middle Ages onwards it was mainly utilized as cooking purposes.

18.2.3 Economic Importance

The largest producer of sugar beet is Europe that accounts for about 75% in the total beet sugar production, whereas the United States and Asia both make up 19% in the total sugar beet production, while Africa and South America account for the rest (Draycott 2006). France is the top producer of sugar beet (33.795 million tonnes) with the highest per hectare yield (84 t ha−1), whereas, currently, in Pakistan, it is only cultivated in Khyber Pakhtunkhwa (KPK) province, and the area under crop is very low (0.117 MT) with low average yield (40 t ha−1) (FAOSTAT) mainly due to lack of modern production technology, rising prices of farm inputs and marketing problems (Iqbal and Saleem 2015). Statistic and economic analysis discovered that sugar beet can give higher net returns (Rs. 9000 ha−1) in comparison to sugarcane.

18.2.4 Choices at Planting

18.2.4.1 Seedbed Preparation

Seed germination is dependent on specific soil moisture condition in which seed imbibition occurs to initiate the germination process. Optimum absorption of moisture to seed requires better seed-soil contact (Bewley et al. 2013; Smýkal et al. 2014). Soil cultivation practices have strong impact on seed germination. Positive soil compaction impact is reported on some crops, but it is important to know what degree of soil compaction is beneficial (Hakansson et al. 2002; Romaneckas et al. 2009b).

Sugar beet usually grows in 45–50 cm apart rows, and plant population should be 80–100,000 plants ha−1 for better crop yield. Sugar beet can’t compensate the area more than 50 cm, so growers must maintain the row spacing to avoid the yield loss (Jaggard 2011). Pelleting technique is frequently used in sugar beet to alter the seed shape suitable for the drill machine. Moreover, seed coating is also being used to facilitate the pesticide application around seed (Hill 1999). Therefore, better understanding of soil-seed contact is needed for successful crop production. Many researchers have defined seed-soil contact on their own way to highlight the importance of seedbed preparation and its role to mature the crop (Brown et al. 1996). Previously, the soil characteristics like bulk density, porosity, compaction, etc. were used to estimate the seed-soil contact. But Brown et al. (1996) reported that due to highly heterogeneous soil structure it’s not easy to estimate the actual seed-soil contact. Due to this, they used the modelling techniques which were further explained by Zhou et al. (2014).

Currently, X-ray computed tomography (X-ray CT) has been used to quantify the soil structure allowing 3D visualization of seedling development (Blunk et al. 2017). X-ray CT has been also used to examine the root architecture and its development (Mooney et al. 2012; Pfeifer et al. 2015). Advantages of this technique have been further expanded to analyse the effect of seed priming within seed (Gagliardi and Marcos-Filho 2011; Devarrewaere et al. 2015). Blunk et al. (2017) used this approach for precise seed-soil contact calculation in sugar beet and found the best strategy to estimate the seedbed preparation.

18.2.4.2 Cultivar Selection

Yield is highly dependent on interaction of genotypes to environmental factors. Better understanding of this interaction and suitability of genotypes leads towards better crop production. Many studies have reported the yield and quality (sugar contents, brix) differences in various sugar beet genotypes (Balakrishnan and Selvakumar 2008). Globally, many sugar beet varieties were studied, and variation was recorded in terms of sugar yield and in some other allied traits. Ahmad et al. (2012) reported the superiority of SD-PAK09/07 among 11 varieties of sugar beet under study. This cultivar showed the highest sugar yield, sugar contents and beet root yield as compared with other cultivars. Refay (2010) added that Samo-2 variety performed better as compared with other varieties in Saudi. Similarly, Radivojevic et al. (2013) studied 17 locally available sugar beet varieties in Serbia and concluded the highest yield in Marcus, while cultivar Esprit gave minimum sugar yield. The best selection of variety as per climate is the basic management strategy for good sugar beet yield.

18.2.4.3 Planting Time

Planting time is very important for successful crop production as it defines the growth period of crop and its response to environmental conditions which varies from one region to another. It has significant impact on seed germination, growth, yield and quality characteristics of sugar beet. Phonological response of plants is dependent on threshold temperature below which growth may cease, and this mechanism differs among plant species (Ash et al. 1999; Bellin et al. 2007). Seedbed moisture and soil temperature affect the sugar beet seed germination as it germinates easily in 20–23% soil moisture, while 15–25 °C soil temperature is considered optimum for sugar beet (Copeland and McDonald 2001; Spaar et al. 2004). Early planting favours better accumulation of sugar in sugar beet roots as compared to late-sown crop in which winter season checks the sugar accumulation (Metcalfe and Elkins 1980). October-sown sugar beet performed better as compared to November-sown crop under climatic condition of Egypt (EL-Kassaby and Leilah 1992). Similarly, Ghonema (1998) added that October-planted sugar beet exhibited improved growth in terms of leaf area index, root characteristics and sugar yield as compared with September-/November-sown crop. Leilah (2005) at Egypt reported that sowing sugar beets on first October resulted in significant increases in length, diameter and fresh weight of roots, foliage fresh weight, root/top ratio as well as root, top and sugar yields ha−1. Meanwhile, the highest TSS, sucrose and purity percentages were found with planting sugar beets on first September.

18.2.4.4 Planting Methods

Underground part of sugar beet is the main economic component which greatly is influenced by sowing method. Therefore, the soil near the root zone of the sugar beet significantly affects its growth and sugar contents. Studies showed that laser-levelled soil along with deep ploughing enhanced sugar beet root length and its diameter as compared with other treatments (El-Maghraby et al. 2008). Different methods are being used to grow sugar beet like flatbed planting and ridge sowing. In flat bed method, the top soil is ploughed and levelled for seed sowing, while, in case of ridge sowing, the soil is scrapped in defined region to raise seedbed. Both sowing methods affect the soil’s physical, chemical and biological properties, which affects the sugar beet yield. Furthermore, sugar beet is also sensitive to stagnant water which may be avoided to choose the sowing method. Direct sowing of sugar beet is also found better as compared with transplanting of seedlings (Garg and Srivastava 1985). Sugar beet gave the highest yield with more sucrose contents when grown on east-west ridges (Narang and Bains 1987). El-Kassaby and Leilah (1992) added that sugar beet enhanced root diameter and weight when grown on sides of ridges. Contrary to this, study revealed that fault and ridge sowing did not affect the root yield, sucrose contents and sugar yield. Zahoor et al. (2007) found that planting techniques significantly affected the germination, petiole length, number of beets, leaf area, top yield and root yield.

18.2.4.5 Sowing Depth

Seed germination and its emergence are influenced by soil aeration, temperature and physical impedance to move through the seedlings. It is highly needed to sow seed at proper depth to get good plant population in the field for optimum crop yield. Study revealed that sugar beet germination was affected by soil depth and germination of deeply (6 cm) sown seed was less than that of sown in 0–5 cm soil depth (Romaneckas et al. 2009a). Khan (2013) added that seed planted in depth of 1 to 1.25 inches showed maximum germination and seedling emergence.

18.2.5 Management After Planting

18.2.5.1 Integrated Nutrient Management

Plant nutrition is an important factor on which basic success of crop is dependent. Fertile soil favours the growth of plant as compared with unfertile soil due to the nutrient availability. Soil organic matter is the material which binds the moisture and nutrients to reduce its wastage. Intensive cropping with fertilization of inorganic nutrients has greatly influenced the soil organic matter. Many sources of organic matter are available like farmyard manure and compost which should be added along with inorganic nutrient for integrated nutrient application. This strategy not only improves the soil organic matter status but also provides nutrition to crop on sustainable bases. Balakrishnan and Selvakumar (2008) explained that integrated nutrient management treatment enhanced sugar beet yield as compared with sole inorganic application. Another study revealed that application of 120 kg ha−1 inorganic nitrogen along with 20 t FYM meets the nutritional demand of sugar beet crop and enhanced its yield as compared with other fertilization techniques (Bhullar et al. 2010).

18.2.5.2 Irrigation Management

Sugar beet yield can be affected by over- as well as under-irrigation as both may induce stress for plants which leads towards lower crop yield. Water stress in early growing period of sugar beet is the major cause of lower crop yield (Abdollahian-Noghabi 1999). Many researchers highlight the importance of irrigation for sugar beet and reported that irrigation after every 3 weeks enhanced crop yield than irrigation after every 7 weeks (Besheit et al. 1996; Abo-Shady Kh et al. 2010; Hassanli et al. 2010). Isoda et al. (2007) further added that optimum irrigation management in sugar beet not only enhanced the yield but also resulted in improved root sugar contents. Therefore, first irrigation should be given in such a way that water should not flow over the ridges. Depending on the soil type and rainfall, irrigation scheduling is required. Irrigation scheduled at 75 and 50 mm evaporation produced the highest yield of sugar beet. Under this scheduling, 10–12 irrigations are required to grow a luxuriant crop of sugar beet (Shukla and Awasthi 2013). Irrigation requirement of sugar beet is fairly low; not more than 4–5 irrigations amounting to 37.5–60 cm would be required for the purpose (Gupta et al. 2013).

18.2.5.3 Pest Management

Pest management is very much important to be safe from the economic losses in potential sugar beet yield. In this regard, the first step is to establish a best pest management strategy for the identification, and the next step is effective pest scouting and estimation of their damage for the crop. The last option in this regard is to devise control measures to maintain high economic returns. Management options for the control of such pest include:

  • Cultural practices (that include cultivation approaches, alteration in planting geometry, selection of resistant varieties, irrigation management, crop rotation pattern, etc.)

  • Biological control (that include effective use of biological organisms, predators and parasites).

  • Chemical control (exploiting insecticides, weedicides and other chemicals for the control of pathogens and pests).

There is a long list of insects that feed or damage the beet crop including aphids, armyworms, beet leafhopper, cutworms, Empoasca leafhoppers, flea beetles, grasshoppers, leaf miners, salt-marsh caterpillar, seed-corn maggot, spider mites, webworms, whiteflies and wireworms (Becker et al. 2013). Among all these insects of beet crop, the most popular insects are flea beetles (Chaetocnema concinna), thrips (Thrips spp.), capsid bugs (Lygus rugulipennis) and beet leaf miners (Pegomya hyoscyami). For the good crop stand and best yield, the aforementioned management approaches should be exploited. Recommended insecticides after proper insect scouting should be applied for achieving good results. Insect damage is usually associated with the onset of moderate temperatures (15 to 27 °C). Monitoring of the crop field during such weather conditions should be increased, and if required, insecticide should be applied according to the recommendation of the experts.

Similarly, there are many diseases, namely, aphid-borne viruses, Cercospora leaf spot, curly top, Erwinia soft rot, Phytophthora and Pythium root rots, powdery mildew, Rhizoctonia root and crown rot, rhizomania, Rhizopus root rot, Sclerotium root rot, seedling diseases and whitefly-borne viruses, which are common in different beet-producing areas of the world (Becker et al. 2013). Among the management measures, definitely prevention is the best choice for the all growers anywhere. In case of controlling disease, soil health plays a vital role, so soil health should be mainly focused. It must be properly nourished and have enough organic matter contents. One important step is the correct diagnosis of plant disease because most diseases have a properly well-established management protocol. In many cases, aphids attain beet yellows virus along with beet mosaic virus mainly from overwintering beets, whereas, beet western yellows virus and beet chlorosis virus have a very extensive host range. For the control measures, remove such overwintering hosts (during beet-free times) along with plants to avoid migrating aphids (vector-free timings, generally during May and June). Once a field has been affected with viral diseases, planting again in that field can cause severe economic loss. So, next time, sowing at least 5 miles away can save such losses.

Weeds are the worst pest of sugar beet that competes with crop for water, space, light and nutrients (Gupta 2004; Qasem and Foy 2001). Furthermore, sugar beet has no good competitive ability, so weed control is necessary. Yield reduction from weeds depends upon on the density, type and competitive ability of the persistent weed species. Early emerging weeds have better chance to grow taller and occupy the area and are considered as the most competitive and can cause even complete yield loss (up to 100%). For such type of weeds, complete weed control program is required. Preventive approaches are often considered the best for such conditions starting from seedbed preparing cultivation till interculture operations (Norris et al. 2003). When all other weed control options fail, chemical control is very much important and often gives the best results. In weed control option, we can exploit pre-emergence or post-emergence selective herbicides available in markets according to type of weeds prevailing in the field. The most common weeds present in sugar beet crop are black bindweed (Fallopia convolvulus), small nettle (Urtica urens), fat-hen (Chenopodium album), common orache (Atriplex patula), cleavers (Galium aparine) and knotgrass (Polygonum aviculare). Sugar beet is a long-season crop that remains in the field for many months. So, long-season weed control is difficult because herbicide applied early in the season may not last till harvesting. Therefore, complete weed control systems include the use of preplant herbicides along with some post-emergence herbicides also. There are several herbicides registered for sugar beet, but no single chemical can give complete weed control. Therefore, combination of two or more herbicides may have yielded good results.

So, summarizing all these pest management options, prevention is the best option that one can adopt. Providing the best sanitation conditions can prevent crop from all types of pests.

18.2.6 Management at Maturity and Harvesting

What is the proper stage of harvesting the roots that is acceptable for its processing? Earlier, there has been a belief that sugar beet experiences a specific ripening point that was known as “sugaring-up” (Ulrich 1955). Later on, it was proved that sugar as a proportion of the root’s dry matter touches a maximum during early August (Milford 1973), and after that, sugar and non-sugar dry matter are added in an equivalent proportion.

Nonetheless, on a fresh-weight basis, it is a natural process for sugar proportion to enhance gradually during summer and early autumn. However, maximum limit of sugars and its time of achievement can widely fluctuate from place to place and season to season, chiefly because of the lowering of soil moisture and rainfall. So, practically, the ideal time for sugar beet harvesting is after passing mid of August when on a fresh-weight basis, sugar concentration reaches its maximum value, that is, about 14%. And this is the least percentage; a processor can think to run his factory. If not harvested at the aforementioned time, beet keeps on growing as long as the environmental conditions allow, but with the passage of time, these conditions become unfavourable for beet growth.

18.2.7 Yield Estimates

The area under sugar beet production in Pakistan was 2813 ha in 2005 which decreased to 800 ha in 2011. There was 45% decrease in cultivated area in 2011 than the previous year. However, after 2011, it is continuously increasing and reached to 3200 ha in 2015. In 2016, there was a slight decrease in cultivated area to 2889 ha, indicating 9.7% decrease than the previous year. The sugar beet yield was 43 tonnes ha−1 in year 2005 and 41 tonnes ha−1 in 2016 (Table 18.4).

Table 18.4 Area, yield and production of sugar beet
Full size table

18.2.8 Production and Trade

Sugar beet is produced annually on the order of 400 million tonnes, in temperate climates. Sugar beet is the second most important sugar crop next to sugarcane that covers 30–40% world sugar (Clark and Edye 1996). The production of sugar beet in Pakistan was 120,902 tonnes in 2005, but due to decrease in cultivation area, it was decreased to 20,900 tonnes in 2011. However, a continuous increase has been observed in sugar beet production after 2011, and production again reached 117,546 tonnes in 2016 (Table 18.4; FAO 2016). Sugar beet has many benefits compared to sugarcane due to short duration with high sucrose contents. The primary product is sugar (sucrose); other products include feeds (molasses and beet pulp) and raffinose, pectin and arabinan. Recently, production of paper from sugar beet pulp has begun (Draycott 2006).

Being sugar beet as a renewable resource, a range of chemicals is available from chemical and microbial reactions on process streams and sugars. Chemical transformations include production of sucrose mono-, di- and polyesters, polyurethanes, carboxylic acid derivatives and thermally stable polymers. Products of microbial processes include polymers to be used as biodegradable plastics and others for food and nonfood use (levan, dextran). Basic chemicals, including citric acid and lactic acid, and amino acids, notably lysine, are produced from sugar sources. The production of ethanol, as fuel or as beverage, is well known (Clark and Edye 1996).

In this regard, sugar beet might be an excellent alternative to sugarcane around the globe by enhancing processing facilities in the existing sugar mills. The policymakers and governments should emphasize the attainment of self-sufficiency in sugar production by increasing sugar beet production.