Leveraging Parrondo's paradox for sustainable agriculture

Rotating crops is a sustainable agricultural technique that has been at the disposal of humanity since time immemorial. Switching between cover crops and cash crops allows the fields avoids overexploitation due to intensive farming. How often the respite is to be provided and what is the optimum cash cover rotation in terms of maximising yield schedule is a long-standing question tackled on multiple fronts by agricultural scientists, economists, biologists and computer scientists, to name a few. Dealing with the uncertainty in the field due to diseases, pests, droughts, floods, and impending effects of climate change, is important to consider when designing the cropping strategy. Analysing this time-tested technique of crop rotations with a new lens of Parrondo's paradox allows us to improve upon the technique and use it in synchronisation with the burning questions of contemporary times. By calculating optimum switching probabilities in a randomised cropping sequence, suggesting the optimum deterministic sequences and judicious use of fertilisers, we propose methods for improving crop yield and the eventual profit margins for farmers. Overall we also extend the domain of applicability of the seemingly unintuitive paradox by Parrondo, where two losing situations can be combined eventually into a winning scenario.

Extrapolation of post-harvest soil test values in barnyard millet-based cropping sequence through multivariate analysis

The soil test value is based on the soil test-based fertilizer prescription/ recommendation equation. Each crop harvesting after the next crop is necessary to analyze the soil. Therefore, it is necessary to develop an alternative technique to predict postharvest soil tests after the harvest of every crop. For that a study was conducted in mixed black calcareous soils at Tamil Nadu agricultural University, Coimbatore to develop the post-harvest prediction equations for available nitrogen, phosphorus and potassium in barnyard millet cropping sequence based on a multiple regression model by considering post-harvest soil test value as the dependent variable and initial available nutrients, fertilizer doses and crop yield or crop nutrient uptake as an independent variables. The developed model was validated by computing R2 value, RMSE (root means square error), RE (relative error), and the ratio of performance to deviation (RPD) and the developed model was found to be valid. Using the validated model, post-harvest soil test values were predicted. A fertilizer recommendation was made for blackgram based on predicted post-harvest soil test values in the barnyard millet-blackgram cropping sequence. The predicted soil test values were compared with actual soil test values and it revealed that the developed model is fairly accurate and best-fitted with more precision. The predicted post-harvest soil test values of barnyard millet could be used in order to prescribe fertilizer for desired yield targets for subsequent crops.

Evaluation of Rock Phosphate Enriched Compost on Soil Nutrient Status after Harvest of Finger Millet-Cowpea Cropping Sequence in High Phosphorus Soils of Cauvery Command Area, Karnataka

A field experiment was conducted at Zonal Agricultural Research Station, VC Farm, Mandya during kharif 2017, summer 2018, kharif 2018 and summer 2019 to study the effect of rock phosphate enriched compost on soil nutrient status after harvest of finger millet-cowpea cropping sequence. Prior to initiation of the field experiment, three different composts viz., urban solid waste compost (USWC), vermicompost and farm yard manure (FYM) were enriched with rock phosphate at 5 per cent. Field experiment consisting of eleven treatment combinations comprising recommended N and K, and P through varied levels of enriched composts. The experiment was laid out in RCBD design with three replications and the test crops were finger millet and cowpea. The initial P2O5 of the experimental site was very high (133.58 kg ha-1). The results revealed that application of recommended N and K + 75 per cent P supplied through enriched USWC (T5) had significantly higher organic carbon (0.56 and 0.58%) in pooled data of both finger millet and cowpea, respectively. Available N (241.94 and 224.86 kg ha-1), P2O5 (138.69 and 120.99 kg ha-1) and K2O (153.92 and 135.31 kg ha-1) were recorded significantly higher in T5 of finger millet and cowpea, respectively. Similarly, in pooled mean, exchangeable Ca [4.15 and 4.04 C mol (P+) kg-1] and Mg [2.16 and 2.05 C mol (P+) kg-1] were recorded significantly higher in treatment which received recommended N and K + 75 per cent P supplied through enriched vermicompost (T8) in both finger millet and cowpea, respectively. The decrease of available P2O5 was 20.98 per cent from initial (133.58 kg ha-1) to final crop (summer 2019) (105.55 kg ha-1).

​Effect of Different Crop Sequences on Soil Nutrient Status, Nutrient Uptake and Crop Yield in Western Himalayas of India

Background: The field experiment was conducted during 2018-19 experimental farm of Department of Agronomy, College of Agriculture, CSK HPKV, Palampur (H.P.), India. The experiment comprised of ten treatments (maize-wheat, maize-wheat + gobhi sarson, dhaincha-cabbage-frenchbean, sunhemp-vegetable pea-frenchbean, maize + soybean chickpea + linseed, rice-wheat + gram, hybrid sorghum + hybrid bajra-oats + sarson (hybrid), hybrid sorghum + hybrid bajra-ryegrass + berseem, babycorn-broccoli-frenchbean and okra-turnip-tomato) which was laid out in randomized block design with three replications. Methods: The present investigation was conducted during October 2018-October 2019 (Kharif and Rabi seasons) at an elevation of 1100 m amsl at a latitude of 32°04’N and longitude of 76°35’ E at Bhadiarkar Experimental Farm, Department of Agronomy, CSK HPKV, Palampur, Kangra district of Himachal Pradesh, India. The soil of the experimental area falls in the order of Alfisols with Paleudalf as the great group as per the Udic Moisture Regime. During kharif and rabi season the crop varieties were applied with the recommended dose of N, P2O5 and K2O (kg ha-1). The source of nitrogen (N), phosphorus (P) and potassium (K) were urea, single super phosphate and muriate of potash. Result: In terms of food for human consumption, highest yield was obtained under the okra-turnip-tomato cropping sequence followed by dhaincha-cabbage-frenchbean and sunhemp-vegetable pea-frenchbean. While in terms of fodder yield, highest was obtained under hybrid sorghum + hybrid bajra-oats + sarson (hybrid) cropping sequence followed by hybrid sorghum + hybrid bajra-ryegrass + berseem. Highest maize grain equivalent yield was obtained with okra-turnip-tomato crop sequence. All other treatments remained superior in comparison to the maize-wheat crop sequence. Maize + soybean-chickpea + linseed emerged to be the best treatment with the highest benefit cost ratio. The treatment comprising okra-turnip-tomato sequence also proved to be the second-best treatment followed by hybrid sorghum + hybrid bajra-oats + sarson (hybrid). Sunhemp-vegetable pea-frenchbean recorded the highest uptake of the available nutrients from soil which was followed by babycorn-broccoli-frenchbean. There was net loss of available nutrients although the loss was less in the sequences with multiple crops during the year. The treatments had no significant effect on the pH and organic carbon content of the soil.