1. Introduction
Cropland-suitability assessment plays a vital role in agricultural development and planning. Climate change has emerged as a global challenge that impacts agricultural production and food security across the world [
1]. Due to the increasing population in developing countries such as India, natural resources such as land, water, minerals, and biomass are currently underexploited. Crop production without considering a land suitability analysis would lead to land degradation [
2]. In the present scenario, where land is a limiting aspect, it is unattainable to expand the area being farmed. Therefore, land suitability classes should be identified to increase cereal production with available land. The crops have to be cultivated in their best-suited areas. Hence, land-suitability analysis is required for sustainable crop production [
3,
4].
Many researchers have used GIS and remote-sensing techniques to assess land suitability, to increase crop production and reduce environmental footprints and the cost for the input material [
5,
6,
7,
8]. As a multicriterion decision-analysis (MCDA) technique, AHP is widely adopted and known to be one of the most efficient methods in defining the weights of factors [
9], and to solve different problems based on complex factors at distinct stages. Some researchers have used either the GIS technique [
5,
10,
11] or the AHP method [
12,
13] alone in land-suitability assessment and observed that either managing the weights of each individual parameter is indigent or insufficient in determining a suitability index. Furthermore, the integration of AHP and GIS-based techniques in assessing land suitability has excellent prospects to enhance the efficiency and accuracy of findings [
14,
15,
16,
17,
18]. Using the AHP method of the MCDA technique with GIS is a valuable method for diversifying the crops and cropping systems for obtaining better output from agriculture-food systems [
19]. Hence, GIS permits the build-up of models utilizing a new thematic map (e.g., a land-suitability map) that can be developed from a set of thematic maps (viz., climatic map, soil map, etc.). Identification of suitable crops will further facilitate environmentally friendly sustainable agriculture by developing optimum crop plans. Most of the farmers of Haryana—one of the leading food producer provinces of India—are practicing similar cropping patterns in their land due to a lack of awareness of land-suitability-based crop production.
Table 1 shows the trends pertaining to acreage and per cent share of major crops over the period of the last 50 years in Haryana. More than 50 per cent of the gross cropped area (GCA) is under wheat and rice cultivation in Haryana. The share of both the crops has been increasing over the time. Rice has occupied around 22 per cent of the area of the total cropped area of the state in triennium ending (TE) 2020, which was only 5.7% during TE 1973. Wheat has shown an increase of 15% share during the last 50 years. On the other hand, the share of sorghum, pearl millet and maize decreased considerably in the same period. Favorable government policies and assured prices of rice and wheat have also converted Haryana to a monocrop state, leading to the problem of water scarcity. Therefore, there is need to find the crops that are bio-physically suitable, so as to overcome the problem of water scarcity.
In the present study, the AHP technique coupled with GIS were used to systematically assess the cropland suitability of the target ecology for different cereal crops, such as wheat, rice, maize, sorghum and pearl millet, utilizing soil, climatic and topographical parameters.
Furthermore, the novel research contributions of the presented study are: a) there exists only a handful scientific studies that identify the best-suitable area for cereals production [
20,
21,
22,
23] and these exist mostly for particular districts and not for a whole state, whereas the present work considers the whole state as its study area using the GIS–AHP approach, and b) the study provides an effective approach for the selection of a possible cropping pattern based on agro-ecological suitability, while most of the existing works are based on conventional methods for the same objective [
6,
21,
24,
25,
26].
The remainder of the article is organized as follows:
Section 2 elaborates on the methodology and dataset used in the presented study,
Section 3 describes the results and experiments conducted in the work along with a sensitivity analysis.
Section 4 gives a brief discussion of the obtained results using the proposed methodology, and a compact summary is given in
Section 5 of the article.
4. Discussion
This study integrated climatic, soil, and topography factors to estimate the cropland-suitability classes of cereal crops, namely, wheat, maize, rice, sorghum and pearl millet, which synchronize with several recent study reports. As GIS offers elasticity and accuracy in land-use organization, some researchers [
45,
46,
47,
48,
49] have highlighted the approach of GIS integrated with AHP for incorporating expert opinion in pairwise comparison among criteria at each hierarchy level, which is similar with this study. The precision of the weights utilized is subjective, as it is determined by the experts; however, relative weights results were utilized in the cropland-suitability assessment because the consistency ratios were within the predefined acceptable limits (0.1) [
38]. The consistency ratio for wheat, sorghum, rice, maize and pearl millet was calculated as 0.096, 0.10, 0.096, 0.099 and 0.065, respectively, and is considered acceptable [
40]. Our findings reveal that combining the AHP method with GIS can improve policymakers and planners’ decision-making capability.
Evaluating the extent and classes of cropland suitability in the state for cereal crops is essential to select the right crop for the target region. In performing this evaluation, the crops’ specific necessities were compared with the land features and, based on the extent of matching, the area’s suitability for the crops were determined. The classification was based on the inherent soil properties, external land features and climatic factors that bound the usage of the land for several uses.
Wheat is a vital winter season cereal, which contributes nearly 32% to India’s total foodgrain production. For its growth, fertile, well-drained, loam to clay loam and sandy clay loam soils are considered the best, whereas sandy or poorly drained soils are unsuitable [
50]. As per our study for wheat cultivation in Haryana, temperature was the most important factor, followed by OC, rainfall, pH, ECe, drainage density and texture; while slope was the least important, according to experts’ opinions (
Table 4). The suitability assessment for wheat showed that 71% of the calculated arable land was moderately suitable, and only 6% area was highly suitable (
Figure 5,
Table 10). Most of the districts were found to be moderately suitable due to moderate limitations such as OC (0.4–0.75) and pH (7.5–8.3). Land was found to be highly suitable in the Kaithal district, due to the most favorable temperature, organic carbon (>0.75%) and soil texture. Marginally suitable constitutes only 23% of the arable land, found mainly in Bhiwani, Dadri, Mahendragarh, Rewari, Gurugram and some parts of Sirsa and Mewat (
Figure 6a). The primary constraints for marginal suitable areas are sandy soil (excessively drained) with a low availability of OC and inadequate rainfall to meet the high crop-water demand for wheat [
51]. Based on these findings, it can be suggested that economic levels of food production could be attained by growing the wheat crop in highly (S1) and moderately (S2) suitable regions, and diversification of marginally (S3) suitable regions with other crops and cropping system.
Rice is mainly a tropical and subtropical crop, which can be cultivated in variety of climate–soil–hydrological regimes. The typical temperature needed throughout the life span of the crop ranges from 21 to 35 °C and a total optimum water requirement is 1110–1250 mm. The most suitable soil is heavy soil (clay or clay loam and loam soils) with a broad pH range of soil (4.5 to 8.0) [
43]. For the rice crop, the most critical variable was found to be rainfall, followed by OC, texture, ECe, pH, drainage, and temperature, while slope was the least important, according to the experts’ judgment (
Table 5).
Figure 6b illustrated that a large fraction of the state was observed to be marginally fit for rice cultivation, which covered 72% of the total arable land, found mainly in the southwestern and some parts of the northeastern zone. Rainfall is the dominant limiting factor for rice cultivation, due to its vital importance in the high crop-water demand of rice, which was estimated at more than 1000 mm in Haryana [
51]. Other limiting factors for rice cultivation are low organic carbon availability and pH (7.6 to 8.3). The moderately suitable area was 28% of the arable land, found mainly in Kaithal, Jind, Kurukshetra, Yamunanagar and some parts of Ambala, Panchkula, Jhajjar, Palwal, Sonipat, Panipat and Sirsa, as the rainfall in these regions is more as compared to marginally suitable areas. Thus, rice could be cultivated in the study region with supplementary irrigation only. From the foregoing discussions, it can be stated that the target area holds an extensive coverage of farm land, but the majority of the regions are marginally suitable for rice paddies and come under the S3 suitability class.
In the study area, sorghum is a kharif crop. The optimal temperature and rainfall suitability for its growth and development are 25–30 °C and 500–700 mm, respectively, and organic-matter enriched soils with a heavy texture and having pH 6.0–8.0 are the best fit for its cultivation [
43]. OC was the most critical variable, while temperature was the least important variable for sorghum (
Table 6). For this crop, it was observed that 28% of the arable land area was highly suitable and 71% was found to be moderately suitable (
Figure 5,
Table 10). The highly suitable areas were the Ambala, Kurukshetra, Karnal, Yamunanagar, Panchkula, and the some parts of Sonipat, Panipat, Jhajjar, Jind, Palwal and Mewat, districts (
Figure 6c). These highly suitable areas are characterized by OC (0.5–0.75), rainfall (500–660), drainage density (well drained to moderately well drained) and pH (7.0–8.0).
Maize is a kharif season crop in Haryana that requires well-distributed rainfall of 500–750 mm, and a sandy loam to silt loam texture with good drainage for optimum growth [
43]. Organic carbon was the most important factor for the maize crop, followed by rainfall, temperature, pH, texture, drainage density and ECe and slope (
Table 7).
Figure 5 showed that 85% of the arable land was moderately fit for raising maize, and only 15% of the area of the calculated arable land was observed to be the marginally suitable class (S3). The areas under the marginally suitable class were the Mahendragarh, Rewari and Bhiwani districts, due to the semi-arid and arid climate and slightly undulating topography owing to shifting small sand dunes [
20]. Interestingly, the similar results of the crop of sorghum and maize were noted in an existing study on the nearby state of Uttar Pradesh [
30].
Pearl millet is considered as one of the best drought-tolerant crops, and is primarily grown in semi-arid and arid ecologies where average annual precipitation ranges between 400 and 650 mm. It can be grown in almost all types of soil, but the ideal soil is well-drained sandy loam to loam [
43]. Similar to sorghum, OC was the most critical variable for pearl millet, while the temperature was the least important (
Table 8). The finding indicated that 60 % of the area of the arable land was highly suitable because of prevailing conditions such as rainfall (400–660 mm), neutral pH, and salinity-free sandy loam to loamy soils with good drainage. Meanwhile, 40% of the area was observed under the moderately suitable class, which comprised of mainly the Mahendragarh, Rewari, Bhiwani, Dadri, and some parts of the Gurugram, Fatehabad and Sirsa, districts (
Figure 6e).
Such findings play an important role in crop-suitability-policy designing, as from the above discussion it can be established that pearl millet had the maximum acreage under the highly suitable category, whereas maize, sorghum and wheat had the highest area under the moderately suitable category as farmlands in the class had fewer constraints. Meanwhile, rice constitutes most of the area under the marginally suitable category with major limitations. Introducing more area dedicated to maize, peal millet and sorghum crops into regions could increase the crop choices available during the kharif season. Therefore, the study suggests that rice should be replaced by other more suitable crops, such as maize, sorghum and pearl millet, with less water requirements than rice, which can help in the sustainable crop production of the land.