Resource Management Domains of Kharif and Rabi Season Fallows in Central Plateau Region of India: A Strategy for Accelerated Agricultural Development

Over last few decades, acreage of total fallow lands (Kharif and Rabi seasons) in India has remained almost unchanged around 25Mha. The acreage of Kharif (summer) and Rabi (winter) Fallows in Madhya Pradesh (MP) are 1.98Mha and 5.51Mha, respectively. In the semi-arid agroclimatic zones of the states, Fallow-Wheat/ Gram/Indian-Mustard cropping systems are practiced. After harvest of Kharif rice, kodo-kutki, maize or sorghum, farmers generally practice post-rainy season Rabi fallows in the sub-humid regions, south of Narmada River. Kharif fallowing is largely the result of the inability of the farmers to make planting dates independent of monsoon forecasts, and make efficient use of rain water. It appears that factors responsible for Kharif and Rabi fallows are distinctly different and a general consequence of distinctly different soil moisture regimes prevailing in the two crop seasons. Kharif and Rabi fallows have two distinct resource management domains. Whereas, Kharif fallows can be tackled with “PMP-dry seeding” agronomy, production constraints of Rabi fallows can be substantively tackled by shifting from tilled to zero-till agriculture with residue management to make efficient use of the conserved rain water. Some irrigation support will prove useful to tackle mid-season droughts in both situations. Conservation agricultural practices can significantly improve and stabilize crop yields in black soils and other associated soils of in the semi-arid tropics region of the Central India. DOI: 10.14302/issn.2639-3166.jar-19-2590 Corresponding author: Raj Gupta, INSA Scientist, CASA, New Delhi, Email: rajbisa2013@gmail.com


Introduction
Since 1960s, India has pursued an agricultural policy aimed largely at enhancing productivity through input based approaches. This strategy resulted in substantial gains in crop production and productivity to overcome recurring food shortages in the country. The strategy however, has ignored the impact of input interventions on the soil health and the associated ecoservices, resulting in declining factor productivity and widespread problems of natural resource degradation [1]. Such gains were generally limited to well-endowed regions where it was possible to alter the production environment through input use. This has raised some serious questions on the suitability of the past approaches considered for achieving the food security goals.
Sustainable agriculture requires land based solutions for management of natural resources, which integrates biophysical and socioeconomic parameters for characterizing the land management units, known as resource management domains. A resource management domain is a homogenous land unit having similar constraints, requiring a similar management approach for specific land use [2][3][4]. The concept of homogenous resource management domains / zones/ has progressed through many stages such as agroclimatic zones and agro-ecological sub-regions which has now found its way into precision farming.
Agro-ecoregional concept [5] adopted by NBSS&LUP however, ignored the fact that introduction of irrigation water alleviates a major production constraint besides providing opportunities for diversification of agriculture.
Hence an approach that integrates productivity concerns with conservation of natural resources is a pre-requisite  In the SAT region, rainfall is generally more than evapotranspiration and soil moisture storage. High intensity rains very often result in runoff, soil erosion and some degradation of black soils. This description would suggest that any effort aimed at improving the productivity of black soils must aim at 'closing the rainy season window' with a crop cover before the actual on-set of monsoons such as to reduce runoff and soil erosion. Thus, it would appear that reversal of degradation processes from bare soils during rainy season is a pre-requisite for addressing concerns of Rabi Fallows and to enhance total system productivity in vertisols and other associated soils.
Tillage effects in red and black soils are short-lived due to structural instability [14][15][16]. Tillage creates a cycle of declines in which tillage increases the need for another tillage operation to maintain infiltration capacity [17][18]. Residue incorporation improved the productivity of crops in red soils [19] and rice-wheat in black soils [16,20]. In Central India where erosion through run off rain water is the major agent of soil degradation and fertility decline, the maximum benefit of residues is likely to be when residues are retained on the soil surface in the tropics [17]. It must also be mentioned here that aquifer formations in plateau region, is by and large restricted to rocky formations wherein natural rate of replenishment of ground water is quite low. Unfortunately, these are also areas (e.g. Malwa Plateau) where ground water development has already reached unsustainable levels [11,21].   Rabi crops are often perceived as more secure than the Kharif crops.

Extent of Kharif and Rabi Fallows and the Prominent Fallow-Cropping Systems
Results of several studies [39] bring out that land kept fallow during rainy season have more stored soil moisture at planting than the continuously cropped systems. Rabi fallowing is generally practiced in areas having (i) shallow soils not able to store sufficient moisture to support a full season winter crop, (ii) agronomic fatigue resulting in significant losses in stored soil moisture due to excessive tillage, and (iii) non-availability of water for supplemental irrigation.
Virmani et al. [33] have indicated that Indian Vertisols can store and supply 41% of the total rainfall to post-rainy season crop. Sahoo et al. [40] reported that It must be mentioned here that many farmers consider dry seeding before the onset of monsoons as a risky proposition in conventionally tilled areas with erratic early-season rainfall [32]. SAT farmers are reluctant practitioners of dry seeding for fear of: • Seed loss through termites and picking by birds, • Loss of seed viability due to extended exposure to high summer temperatures ranging between 38 and 47°C for about a month or so, • Mortality of young seedlings or loss of seed viability in alternate wetting-drying seed cycles during premonsoon period, and  Dry seeding in BBF is practiced on wide-raised beds (90 cm or more). Beds are dismantled every season.
No-till dry seeding with mulching can be practiced in any land configurations that facilitates control traffic.
BBF is practiced on the sloping black soils to provide drainage for the established crops. If farmers are not able to establish the crops before monsoons, tilled bare fields make black soils highly prone to soil erosion during rains.
PMP-DS technology is practiced in no-till fields with residues on the surface. Mulching reduces crusting and soil erosion risks to minimum before the establishment of a crop cover and thereafter.
No natural priming of seed with rain water/ water.
PMP-DS allow seed to experience several natural cycles of hydration-dehydration. In the SAT region, surface cover and tillage methods seem to play a very vital role in establishment of the crops under monsoonal climates. Tillage is known to speed-up loss of soil moisture from surface soils and also shift the receding soil moisture zone into deeper soil layers below 15cm [52] . Surface mulching can slow down the loss of soil water [53] and hence the recession of soil moisture front. This has an important bearing on the depth of seed placement and soil overburden on seed. In central India, Rabi crops must be sown immediately after harvest of Kharif crops, and seeding depth should allow maximum use of moisture from receding soil moisture profiles. Else we need to develop a new design for openers and seeding boots in planters to be able to reduce soil load over the seed for good germination and speedy seedling emergence.

Conclusions
Kharif and Rabi Fallows are found in distinctly