Rainfed Cotton Research Articles

Effect of combined use of potassic fertilizer and gliricidia green leaves on soil fertility, nutrient balance and yield of rainfed cotton in Vertisols

A field experiment was conducted at research farm of AICRP for Dryland Agriculture, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola (Maharashtra), to assess the effect of potash management through gliricidia green leaves on soil fertility, nutrient balance and yield of rainfed cotton (Gossypium spp.) in Vertisols during kharif season of 2020. The results revealed that there was significant increase in hydraulic conductivity, organic carbon and available N, P, K of soil and decrease in soil pH, EC and bulk density in the gliricidia incorporated treatments as compared to control. The highest available N (211.1 kg ha-1), P (16.7 kg ha-1) and K (361.5 kg ha-1) was observed with the application of 100 % NP + 10 kg K (inorganic) + 20 kg K through gliricidia which increased by 16, 31.7 and 13.7% respectively over control. Similarly, the nutrient balance after six years of experiment was also higher with the application of 100 % NP + 10 kg K (inorganic) + 20 kg K through gliricidia being 25.4 kg ha-1 for available N, 2.15 kg ha-1 for available P and 39.6 kg ha-1 for available K. There was significant reduction in the bulk density of soil, being lowest (1.40 Mg m-3) in the treatment 100 % NP + 10 kg K (inorganic) + 20 kg K through gliricidia as compared to control. Significant improvement in the seed and stalk yield of cotton was recorded with the application of 100 % NP + 10 kg K (inorganic) + 20 kg K through gliricidia, with increment of 60, 18% and 64, 22% over control and 100% RDF, respectively

Effect of combined use of potassic fertilizer and gliricidia green leaves on soil fertility, nutrient balance and yield of rainfed cotton in Vertisols

A field experiment was conducted at research farm of AICRP for Dryland Agriculture, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola (Maharashtra), to assess the effect of potash management through gliricidia green leaves on soil fertility, nutrient balance and yield of rainfed cotton (Gossypium spp.) in Vertisols during kharif season of 2020. The results revealed that there was significant increase in hydraulic conductivity, organic carbon and available N, P, K of soil and decrease in soil pH, EC and bulk density in the gliricidia incorporated treatments as compared to control. The highest available N (211.1 kg ha-1), P (16.7 kg ha-1) and K (361.5 kg ha-1) was observed with the application of 100 % NP + 10 kg K (inorganic) + 20 kg K through gliricidia which increased by 16, 31.7 and 13.7% respectively over control. Similarly, the nutrient balance after six years of experiment was also higher with the application of 100 % NP + 10 kg K (inorganic) + 20 kg K through gliricidia being 25.4 kg ha-1 for available N, 2.15 kg ha-1 for available P and 39.6 kg ha-1 for available K. There was significant reduction in the bulk density of soil, being lowest (1.40 Mg m-3) in the treatment 100 % NP + 10 kg K (inorganic) + 20 kg K through gliricidia as compared to control. Significant improvement in the seed and stalk yield of cotton was recorded with the application of 100 % NP + 10 kg K (inorganic) + 20 kg K through gliricidia, with increment of 60, 18% and 64, 22% over control and 100% RDF, respectively.

Nutrient Expert for High Yield and Use Efficiency in Rainfed Bt Cotton Hybrids

Low cotton productivity in the rainfed cotton grown in central India is attributed to abiotic (water and nutrients) and biotic (insect pests and diseases) stress. Nutrient stress can be overcome by providing nutrients in right amounts and at the right time when the plant needs the most. Field studies in cereal crops have demonstrated fertilizer recommendations by using the Nutrient Expert® (NE) decision support system to improve crop yields. However, such information in the case of the commercial crop, cotton, is scarce. Therefore, on-farm trials were conducted in three districts of Maharashtra, India during 2018–2020 with the hypothesis that the NE-based fertilizer recommendation would lead to higher cotton productivity and savings in fertilizer. Averaged over two seasons and locations, lint yield was significantly greater in the NE based than the recommended dose of fertilizer (RDF), soil test crop response (STCR), and farmers' practice (FP). Internal utilization efficiency (IE) did not differ among treatments for N (4.8 to 5.9 kg lint kg−1 nutrient uptake) and K (6.7 to 7.2 kg lint kg−1 nutrient uptake). With regard to the fertilizer P applied, the FP treatment had the least IE (17.0 kg lint kg−1 nutrient uptake) and was significantly lower than the other treatments. Partial nutrient balance (PNB) did not vary among treatments for applied fertilizer N. The FP treatment had PNB < 1 in case of fertilizer P and ~20 in the case of fertilizer K. This indicates farmers applied excess of P fertilizers. On the other hand, farmers in the region applied very small amount of K. Although the NE treatment had the highest cost of cultivation, net returns were the greatest followed by the STCR and RDF treatments. Our studies demonstrate that the NE-based fertilizer recommendation is not only productive, but also profitable.

Determining Planting Window for Growing Upland Cotton (Gossypium hirsutum L.) during Dry Season in Bandarban, Bangladesh

Farmers in the Chattogram Hill Tracts, Bangladesh have been growing cotton (Gossypium hirsutum L.) in their traditional system of jhum cultivation which is undergoing transformation. Growing rainfed cotton as a monocrop in the uplands is constrained by farmers’ socio-economic conditions and erratic rainfall. Shifting growing season to post-monsoon dry monthscould be an option to sustain cotton production in hilly areas. An exploratory experiment was conducted for two seasons to explore the possibility of growing cotton in valley lands in Bandarban during dry season. Growth and yield potentials of dry season cotton were evaluated in relation to prevailing environmental conditions. Night temperature dropped to 9oC on several occasions in 2018-2019 season; but it remained higher than 11oC throughout the season in 2019-2020. In 2018-2019, day temperatures surged higher past March 15 occasionally exceeding 38oC. Variability in temperatures was more in 2018-19 while average temperatures were higher in 2019-20 season. Rainfall distribution was almost similar in both the growing seasons receiving total rainfall of 757 mm and 579 mm in two seasons, respectively. Higher seed cotton yield (2,047 kg per ha) was recorded for 15 November planted crop compared with 1 December planted crop (1,186 kg per ha). December 1 planted crop was affected more by low temperatures at seedling stage resulting in poor growth and fewer bolls per plant. Late planted crop was more vulnerable to rain damage at boll opening stage. Crops of both the seasons encountered high temperatures (>32oC) during boll development. Changing climate, shorter winter season and rising temperatures may allow cotton production in valley lands shifting growing season from rainy season to post-monsoon dry months. However, the window of dry season cotton growing in Bandarban, Bangladesh seems narrow. Rainfall pattern restricts planting seeds prior to mid-November. Again, high temperatures stress in March and April synchronizing boll development, and rainfall toward late April and May during boll opening may cause yield loss. Development and adoption of short duration, low temperature tolerant upland cotton varieties might be of advantage for adapting to climate change vulnerabilities. Ann. Bangladesh Agric. (2020) 24(2): 1-14

​Defoliants Harvest-aid Chemicals: Cost Effective Technology to Facilitate Synchronized Maturity for Mechanical Harvesting in Cotton: A Review

In the recent years, increasing labour cost and shortage of labour being the major constraints to follow manual harvesting in cotton in staggered manner. Further, it is very expensive and farmers would like to increasingly opt for mechanical harvesting. In this context, it is suggested that research should focus to reduce cost of cultivation substantially by promoting the use of synchronized maturity in cotton and use of defoliants to encourage mechanical harvesting. In agriculture, defoliants are used to eliminate the leaves of a crop plant so that they do not interfere with the harvesting by machinery. Early harvesting with good boll opening can also be achieved by use of defoliants. The use of defoliants also reduces the trash content in picked cotton which will also help in improving the quality of cotton. There is a need to identify suitable defoliant with suitable dose and time of application so as to facilitate mechanical harvesting in rainfed cotton. Some of the successful defoliants for uniform boll bursting and higher yield of cotton such as rthrel, rthepon, mepiquat chloride (MC), sodium salt and DU (Dropp Ultra) are the hormonal defoliants and TDZ thidiazuron butifos, merphos, tribufos and tribufate are the herbicidal defoliants. The best combination of thidiazuron + diuron (DCMU), pyraflufen ethyl, thidiazuron + diuroncellular isozyme, Ethephon + AMADS, ethephon + cyclanilide ethephon + tribufos Mepiquat chloride (MC) + cyclanilide may be recommended to facilitate mechanical harvesting in cotton.

Sensitivity of rainfed cotton to the changes in climatic factors and CO2

Sensitivity of rainfed cotton to the changes in climatic factors and CO2

Mapping Vulnerability of Cotton to Climate Change in West Africa: Challenges for Sustainable Development

Climate models project vulnerability to global warming in low-income regions, with important implications for sustainable development. While food crops are the priority, smallholder cash crops support food security, education, and other priorities. Despite its importance as a populous region subject to substantial climate change, West Africa has received relatively slight attention in spatial assessments of climate impacts. In this region, rainfed cotton (Gossypium hirsutum) provides essential smallholder income. We used a spatially explicit species distribution model to project likely changes in the spatial distribution of suitable climates for rainfed cotton in West Africa. We modeled suitable climate conditions from the recent past (1970–2000) and projected the range of those conditions in 2050 (Representative Concentration Pathways (RCP) 4.5 and 8.5). The suitable area declined by 60 percent under RCP4.5 and by 80 percent under RCP8.5. Of 15 countries in the study area, all but two declined to less than ten percent suitable under RCP8.5. The annual precipitation was the most influential factor in explaining baseline cotton distribution, but 2050 temperatures appear to become the limiting factor, rising beyond the range in which rainfed cotton has historically been grown. Adaptation to these changes and progress on sustainable development goals will depend on responses at multiple scales of governance, including global support and cooperation.

Conservation management improves agroecosystem function and resilience of soil nitrogen cycling in response to seasonal changes in climate.

Understanding how conservation agricultural management improves soil nitrogen (N) stability in the face of climate change can help increase agroecosystem productivity and mitigate runoff, leaching and downstream water quality issues. We conducted a 2-year field study in a 36-year-old rain-fed cotton production system to evaluate the impacts of changing climatic factors (temperature and precipitation) on soil N under conservation management, including moderate inorganic N fertilizer application (0 and 67kgNha-1), winter cover crops (fallow; winter wheat, Triticum aestivum L.; hairy vetch, Vicia villosa Roth), and reduced tillage (no-till; disk tillage). Structural equation modeling (SEM) was used to quantify and compare the effects of conservation management and climatic factors on soil N concentrations. Fertilizer and vetch cover crops increased soil total N concentration by 16% and 18%, respectively, and also increased microbial N transformation rate by 41% and 168%. In addition, vetch cover crops also increased soil labile N concentrations by 57%, 21%, and 79%, i.e., extractable organic N, ammonium, and nitrate, respectively. The highest soil δ15N value (6.4±0.3‰) was observed under the 67kgNha-1 fertilizer-wheat-disk tillage treatment, and the lowest value (4.8±0.3‰) under the zero-fertilizer-wheat-no-till treatment, indicating fertilizer and tillage might accelerate microbial N transformation. The SEM showed positive effects of temperature and precipitation on labile N concentrations, suggesting destabilization of soil N and the potential for soil N loss under increased temperature and intensified precipitation. Fertilizer and vetch use might mitigate some of the effects of temperature by accelerating microbial N transformations, with vetch having a larger effect than fertilizer (0.35 vs. 0.15, Table 1). No-till can reduce some of the effects of precipitation on soil labile N by maintaining soil structure. Our study suggests that fertilizer, vetch cover crop, and no-till might help improve function and resilience of agroecosystems in relation to soil N cycling. Soil N stabilization in cropping systems can be enhanced by adjusting agricultural management.

Impact of potash management through gliricidia green leaf manuring on carbon pools and yield of rainfed cotton in vertisols

A field study entitled, “Effect of potash management through gliricidia green leaf manuring on carbon pools and yield of rainfed cotton in Vertisols” was conducted during kharif 2019-20 at Research field of AICRP for Dryland Agriculture, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola, Maharashtra. The soil of the experimental site was Vertisol which was moderately alkaline in reaction, low in available nitrogen, Medium in available phosphorus and high in available potassium. The nine treatments replicated three times in randomized block design comprised of control, 100% RDF (60:30:30 NPK kg ha-1), 100%, 75% and 50% N and 100% P through chemical fertilizers and the combinations of 15, 20 and 30 kg K ha-1 through gliricidia green leaf manure at 30 DAS and remaining recommended dose of potassium as basal dose through inorganic fertilizers. The results indicated that application of 100% NP + 10 kg K (inorganic) + 20 kg K ha-1 through gliricidia green leaf manure at 30 DAS recorded significantly higher cotton yield with improvement in various carbon pools, and it was found to be on par with application of 100% NP + 15 kg K (inorganic) + 15 kg K ha-1 through gliricidia green leaf manure. Among the various carbon pools, the very labile and labile carbon pool was highly correlated with yield of cotton. Hence, it is concluded that conjunctive application of 100% NP + 10 kg K (inorganic) + 20 kg K ha-1 through gliricidia green leaf manuring at 30 DAS resulted in higher organic carbon pools and yield of cotton grown in Vertisols under rainfed conditions.

Yield and Quality of Rainfed Cotton (Gossypium hirsutum L.) in Response to Nitrogen Rates under Different Plant Available Water Capacity Sites in Central Dry Zone of Myanmar

The aim of this research was to explore the optimum nitrogen (N) fertilizer rate for yield and quality of rainfed cotton under respective PAWC. A two-year field experiment was conducted in 2019 and 2020 during post-monsoon season at two sites, Pawaingyoe and Kokkokhahla, having different PAWC. Each year at both sites, six levels of N rate (T1 = 0, T2 = 60, T3 = 90, T4 = 120, T5 = 150 and T6 = 180 kg N ha-1) were laid out in randomized complete block design with four replications and cotton variety Ngwechi-6 was tested. Results showed significant response of cotton to N fertilizer application in each year in both sites and it was consistently lower in 2020 compared to 2019. The DUL, CLL and PAWC of Pawaingyoe were higher than Kokkokhahla. Each year, all yield components and yield were superior in Pawaingyoe than Kokkokhahla. At Pawaingyoe in 2019, maximum values of yield components, seed cotton yield and NUE were achieved by T2. In 2020, all the yield components and yield were non-significant in all N applied treatments and the maximum NUE was found in T2. At Kokkokhahla in 2019, maximum values of yield components and seed cotton yield were obtained in T4, but, maximum NUE was observed in T3 and it gave 90.43% of maximum yield. In 2020, maximum values of yield components, seed cotton yield and NUE were achieved from T3. For fiber quality, T2 gave significantly higher fiber strength in Pawaingyoe, while T4 provided maximum fiber length and strength in Kokkokhahla during 2019. This study suggested that T2 (60 kg N ha-1) would be the suitable rate for Pawaingyoe in both high and low rainfall condition (2019 and 2020). For Kokkokhahla, within the range between T3 and T4 (90 to 120 kg N ha-1) would be appropriate in favorable rainfall condition as 2019 and T3 (90 kg N ha-1) might be the most suitable rate in low rainfall such as 2020.

Effect of land configuration and nutrient module on nutrient uptake by cotton

A field study entitled “Effect of land configuration and nutrient module on soil fertility and productivity of rainfed cotton in Vertisols” was conducted during kharif season of 2012-13 at Research field of AICRP for Dryland Agriculture, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola. The experiment comprised of two factors involving land configuration and nutrient module. Land configuration comprised of flat bed, ridges and furrows, opening of furrow after two rows and opening of furrow after each row while nutrient module comprised of five treatments involving RDF 50:25:25 kg NPK ha-1 through chemical fertilizers, FYM @ 10t ha-1 + PSB + Azotobacter, 50% RDF + FYM @ 5t ha-1 + PSB + Azotobacter, vermicompost @2.5t ha-1 + PSB + Azotobacter and glyricidia @ 10t ha-1 + PSB + Azotobacter. Twenty treatment combinations were executed in split plot design with three replications. The results indicated that the opening of furrow in each row at 30-40 DAS and 100% RDF (50:25:25 kg NPK ha-1 through chemical fertilizer) recorded higher nutirent uptake and was found to be on par with ridges and furrows with integrated application of 50% RDF + FYM @ 5t ha-1 + PSB + Azotobactor. Hence, it is concluded that integrated application of 50% RDF (25:12.5:12.5 NPK kg ha-1) + FYM @5t ha-1 + PSB + Azotobactor and opening of furrow after each row at 30-40 DAS resulted in higher nutirent uptake of Vertisols under rainfed conditions.

Bio-economics of Indian hybrid Bt cotton and farmer suicides

BackgroundThe implementation of hybrid Bt cotton unique to India has been heralded as a grand success by government agencies, seed companies and other proponents, and yet yields have stagnated at low levels and production costs have risen 2.5–3-fold. The low-yield hybrid cotton system of India contributes thousands of farmer suicides to the annual national toll. Conceptual and methodological barriers have hindered bioeconomic analysis of the ecological and social sustainability of such cross-scale agro-ecological problems in time and geographic space, under global technology and climate change. As a paradigm shift, we use conceptually simple, parameter-sparse, theoretically based, mechanistic, weather-driven physiologically based demographic models (PBDMs) to deconstruct the bio-economics of the Indian cotton system.ResultsOur analysis of Indian hybrid cotton system explains some extant ecological and economic problems, and suggests a viable solution. Specifically, the model accurately captured the age-stage mass dynamics of rainfed and irrigated cotton growth/development and the interactions with the key pest pink bollworm across five south-central Indian states, and enabled identification of proximate bioeconomic factors responsible for low yield and their relationship to farmer suicides. The results are reinforced by analysis of Ministry of Agriculture annual state-level data. We explain why short-season, high-density non-GM cotton is a highly viable solution for Indian cotton farmers in rainfed and irrigated cotton areas of the five states, and possibly nationally. The transition from a theoretical bioeconomic construct to a real-world regional bioeconomic analysis proved seamless.ConclusionsThe hybrid long-season Bt technology for rainfed and irrigated cotton is unique to India, and is a value capture mechanism. This technology is suboptimal leading to stagnant yields, high input costs, increased insecticide use, and low farmer incomes that increase economic distress that is a proximate cause of cotton farmer suicides. The current GM Bt technology adds costs in rainfed cotton without commensurate increases in yield. Non-GM pure-line high-density short-season varieties could double rainfed cotton yield, reduce costs, decrease insecticide use, and help ameliorate suicides. The GM hybrid technology is inappropriate for incorporation in short-season high-density varieties.

WAKTU TANAM KAPAS DI SULAWESI SELATAN

<p><strong>Cotton Planting Times in South Sulawesi</strong></p><p>Climatic elements particularly the rainfall strongly influences successful production of rainfed cotton (Gossypium hirsutum). Planting times determined based on more than 20 years daily rainfall data. The rainfall was analyzed using Markov Chain First Order Probability and dryspell probability methods The rainfall data were collected from 46 rainfall stations over Jeneponto, Soppeng, Wajo, Gowa, Bone. Bulukumba. Bantaeng, and Takalar. The planting times varied from the irst week to the fourth week of December for Jeneponto, Takalar, and mostly Gowa. The planting times in Soppeng and Wajo were ranged from the third week of February to the third week of March. Morever, cotton planting times in Bone and Bulukumba were ranged from the third week of March to the third week of April.</p>

Long term effect of nitrogen fertilization on yield and soil fertility status of rainfed cotton under vertisols track of Southern district

A field experiment was conducted in the Agricultural Research Station, Kovilpatti under dryland situation from 2011-‘19 to find out the long term effect of nutrient and combined effect of organic and inorganic nutrients on crop yield and soil fertility status in cotton crop. This experiment was conducted in randomized block design replicated thrice under rainfed situation. The characteristics of the experimental soil was clay in texture and belongs to Kovilpatti Soil Series (Typic Chromusterts). The soil pH was towards alkaline in nature. The available nutrient status of the soil was low in available nitrogen, low to medium in available phosphorus and high in available potassium content. The treatment comprised of nine treatments. T1 - Control, T2 - 100% RDF (40:20:40 NPK kg ha-1), T3- 50% RDF (20:10:20 NPK kg ha-1), T4- 50% N (crop residues), T5 -50% N (FYM), T6 - 50% Inorganic N+ 50% organic N (crop residues) + P (50%) + K (50%), T7 -50% inorganic N+ 50% organic N (FYM) + P (50%) + K (50%), T8 -100% RDF + 25 kg ZnSO4 ha-1 and T9 - FYM @ 12.5 ha-1. The results revealed that among the different treatment schedule over the long term basis, application of 100% RDF + 25 kg ZnSO4 ha-1 registered higher number of sympodial branches/plant (19.3 no’s), number of bolls/plant (15.0 no’s), boll weight (3.4 g) and seed cotton yield (1277 kg ha-1), net income (Rs.24868/ha), B:C (1.76) and RWUE (3.4 kg/ha mm). Soil fertility status also has been increased over the years by the supply of nutrients through integrated plant nutrient system (IPNS) approach.

Energy Balance Studies of Weed Control Practices in Rainfed Cotton

Energy dynamics of the weed control options adopted in rainfed cotton was valuated in a study conducted at College farm, PJTSAU, Hyderabad, Telangana State during kharif, 2017 in red and black soils. Three doses of Diuron (0.5, 0.75 and 1.0 kg ha-1), pendimethalin 38.7% CS at 677 g ha-1 as PE followed by sequential application of pyrithiobac sodium 10% EC 62.5 g ha-1 + quizalofop p ethyl 5% EC 50 g ha-1, intercropping of cotton with green manure crop (Sunhemp), mechanical weeding thrice at 20, 40 and 60 DAS (weed free), polymulch and unweeded control were the treatments included in RBD design which was replicated thrice. The energy balance studies were determined by using direct and indirect energy. The results indicated that the maximum energy input was required for polymulch in both the soils. Highest kapas energy output (EOk) was observed in polymulch and mechanical weeding which was followed by diuron 1.0 kg ha-1PE fb pyrithiobac sodium + quizalofop p ethyl PoEin red soil, whereas in black soils, diuron 0.75 kg ha-1PE fb pyrithiobac sodium + quizalofop p ethyl PoE followed polymulch and mechanical weeding treatments. EUE of both kapas and total output was significantly higher in diuron 1.0 kg ha-1PE fb pyrithiobac sodium + quizalofop p ethyl PoE in red soil. While in black soil, significantly highest EUE of kapas and total output was recorded in diuron 0.75 kg ha-1PE fbpyrithiobac sodium + quizalofop p ethyl PoE.

Late planting has great potential to mitigate the effects of future climate change on Australian rain-fed cotton

The rain-fed cotton industry in Australia is vulnerable to climate change due to its high dependence on seasonal climate and summer rainfall. The rain-fed cotton in eastern Australia is increasingly being incorporated into cereal crop rotations due to government regulation of water resources, restricting opportunities for irrigated cotton. The accurate quantification of future climate impacts on exposed cropping systems such as rain-fed cotton is required to identify effective agronomic practices and inform strategic industry planning for the expansion of Australian cotton industry. Our study utilized 32 General Circulation Model (GCMs) for four cotton-growing regions representing the geographic range of cotton production in eastern Australia. We assessed the climate impacts on rain-fed cotton yield for two future periods (2040s and 2080s) under the RCP4.5 (low) and RCP8.5 (high) emissions scenarios employing the processed-based APSIM-Cotton model. Our results showed that current cotton yields varied with planting date, and the magnitude of yield change was consistent with regional climate variations at four locations representing the current geographic distribution of rain-fed cotton production. Means from multi-GCM ensemble showed growth period temperature increased more under RCP8.5 in the longer-term (2080s). Growth period rainfall changes had significantly positive effects on yield at all planting dates over each site. The projected increases in rainfall were more evident at later planting dates for dry sites than early planting dates at wet sites. In addition, we found planting date had the greatest influence on cotton yield at wet sites, while GCMs accounted for a large portion of variation in cotton yield at dry sites. We conclude that later planting has a great potential to increase rain-fed cotton yields. This provides important insights for regional-specific adaptation strategies for the rain-fed cotton industry in eastern Australia.

Prediction of aphid and jassid in rainfed Bt cotton using regression models based on abiotic factors

Prediction of aphid and jassid in rainfed Bt cotton using regression models based on abiotic factors

Integrated Effect of Potash Management through Gliricidia Green Leaf Manuring and Mineral Fertilizer on Productivity of Rainfed Cotton and Soil Fertility in Vertisols under Semi-arid Agroecosystem

Integrated Effect of Potash Management through Gliricidia Green Leaf Manuring and Mineral Fertilizer on Productivity of Rainfed Cotton and Soil Fertility in Vertisols under Semi-arid Agroecosystem

SENTINEL-1&2 FOR NEAR REAL TIME CROPPING PATTERN MONITORING IN DROUGHT PRONE AREAS. APPLICATION TO IRRIGATION WATER NEEDS IN TELANGANA, SOUTH-INDIA

Abstract. Indian agriculture relies on monsoon rainfall and irrigation from surface and groundwater. The inter-annual variability of monsoon rainfalls is high, which forces South Indian farmers to adapt their irrigated area extents to local water availability. We are developing and testing an automatic methodology for monitoring spatio-temporal variations of irrigated crops in near real time based on Sentinel-1 and -2 data feed over the Telangana State, South India. These freely available radar and optical data are systematically acquired worldwide, over India since 2016, on a weekly basis. Their high spatial resolution (10–20 m) are well adapted to the small size field crops that is common in India. We have focused first on drought prone areas, North of Hyderabad. Crop fraction remains low and varies widely (from 10 to 60%, ISRO-NRSC, Bhuvan). Those upstream areas, mainly irrigated with groundwater, are composed by less than 20% of irrigated areas during the dry season (Rabi, December to March) and up to 60% of the surface is used for crop production during the Kharif (June to November), which includes rainfed cotton and drip irrigated maize crops and inundated rice. A machine learning algorithm, the Random Forest (RF) method, was automatically used over 6 growing seasons (January to March and July to November, from 2016 to 2018) from the Sentinel-1&2 data stacked for each season, to create crop mapping at 10 m resolution over a study area located in the north of Hyderabad (210 by 110 km). Six seasonal land cover field surveys were used to train and validate the classifier, with a specific effort on rice and maize field sampling. The lowest irrigated area extents were found for driest conditions in Rabi 2016 and Kharif 2016, accounting for 3.5 and 5% with moderate classification confusion. This confusion decreases with the increase of irrigated crops areas during Rabi 2017. For this season, 22% of rice and 9% of irrigated crops were detected after heavy rainfall events in September 2017, which have filled surface water tanks (3.4% of the surface area) and groundwater (Central Groundwater Board observations). From this abundance situation, the surface water detected for each season decreased regularly to less than 0.3% together with the rice and irrigated area extents respectively from 22 to 11% and 10 to 3%, despite a good monsoon 2017. Groundwater level show similar trends, with a drop from 20 meters depth in October 2016 and 2017 to more than 30 m in June 2018 (more recent available data). The deficit of the monsoon 2018 will certainly bring this situation to a hydrological drought at the beginning of 2019, probably similar to the Rabi 2016 situation. The estimated Irrigated Water Demand (IWD) varies from 51 to 310 mm/season, depending on water availability. This methodology shows the potential of automatically monitoring, in near real time, with standard computers, irrigated area extents presenting fast high resolution variability. As it is based on standard global satellite acquisitions, it is foreseen to be used for other regions, for any studies on farmer’s adaptation to climate and hydrological variability, as a proxy to estimate irrigation water needs and water resources availability. In Telangana for instance, it provides an inventory of crop production and irrigation practices before the implementation of mega project infrastructures funded by this new state: - the Kâkâtiya tank restoration program to enhance monsoon runoff capture or the Kaleshwaram project to divert Godavari river water toward upstream Telangana region through tunnels and canals in 20 giant reservoirs.

Comparison of Different Land Evaluation Techniques for Evaluating the Soil Suitability for Rainfed Hybrid Cotton

This study compares the performance of three land evaluation methods, viz., FAO Simple Limitation, Storie Index and InfoCrop simulation model, for assessing the suitability of cotton soils (represented by nine different soil series) of Nagpur district, Maharashtra, India. The Simple Limitation method categorised Wardha, Parseoni and Bhugaon soil series as moderately suitable and the remaining are marginally suitable for rainfed cotton. The values of Land Index, determined by the Storie method, ranged from 20.3 for Manori series to 55.3 for Bhugaon series. Rainfed cotton yields, simulated by InfoCrop model ranged from 761 kg ha-1 in Manori series to 2881 kg ha-1 in Katol series. The Relative Yield Index (RYI) ranged from 0.154 for Manori series to 0.585 for Katol series. Kinhala, Katol and Takali soil series, classified as marginally suitable by the Simple Limitation method, were upgraded as moderately suitable by Sys parametric method. The results of InfoCrop model justified this up-gradation with the high values of RYI that ranged from 0.574 to 0.585. Soils of Manori and Hatodi series are not suitable for cultivating rainfed cotton. Soil depth, hydraulic conductivity and plant available water in the soil were critical factors governing cotton yield and ranking of soils for their suitability.