agronomy Article Soil Test Based Fertilizer Application Improves Productivity, Profitability and Nutrient Use Efficiency of Rice (Oryza sativa L.) under Direct Seeded Condition Vijay Kant Singh 1,2 , Poonam Gautam 1, Gangadhar Nanda 3,4 , Salwinder Singh Dhaliwal 2 , Biswajit Pramanick 3,5,*, Shiv Singh Meena 1, Walaa F. Alsanie 6, Ahmed Gaber 7 , Samy Sayed 8 and Akbar Hossain 9,* 1 Department of Soil Science, G.B. Pant University of Agriculture & Technology, Pantnagar 263145, Uttarakhand, India; [email protected] (V.K.S.); [email protected] (P.G.); [email protected] (S.S.M.) 2 Department of Soil Science, Punjab Agricultural University, Ludhiana 141004, Punjab, India; [email protected] 3 Department of Agronomy, G.B. Pant University of Agriculture & Technology, Pantnagar 263145, Uttarakhand, India; [email protected] 4 Animal Production Research Institute, Rajendra Prasad Central Agricultural University, Pusa 848125, Bihar, India 5 Department of Agronomy, Rajendra Prasad Central Agricultural University, Pusa 848125, Bihar, India 6 Department of Clinical Laboratories Sciences, The Faculty of Applied Medical Sciences, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia; [email protected] Citation: Singh, V.K.; Gautam, P.; 7 Department of Biology, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia; Nanda, G.; Dhaliwal, S.S.; Pramanick, [email protected] B.; Meena, S.S.; Alsanie, W.F.; Gaber, 8 Department of Science and Technology, University College-Ranyah, Taif University, P.O. Box 11099, A.; Sayed, S.; Hossain, A. Soil Test Taif 21944, Saudi Arabia; [email protected] Based Fertilizer Application 9 Bangladesh Wheat and Maize Research Institute, Dinajpur 5200, Bangladesh Improves Productivity, Profitability * Correspondence: [email protected] (B.P.); [email protected] (A.H.) and Nutrient Use Efficiency of Rice (Oryza sativa L.) under Direct Seeded Abstract: A field investigation on direct seeded rice (DSR) was carried out in the two consecutive Condition. Agronomy 2021, 11, 1756. rice growing seasons of 2017 and 2018 at Pantnagar, Uttarakhand, India for the development and https://doi.org/10.3390/agronomy validation of soil test crop response (STCR) to fertilizer and for assessing the performance of STCR- 11091756 treatments as compared to the general recommended dose (GRD) in terms of yield, nutrient uptake and use efficiency, and the economics of DSR. For producing 1 Mg of rice-grain, the required nutrients Academic Editors: Umberto Anastasi (N, P, and K) were 2.01 kg, 0.44 kg, and 3.06 kg; the contribution from the soil was 22.05%, 37.34%, and Aurelio Scavo and 41.48%; from applied farmyard manure 23.25%, 28.34%, and 16.80%, from fertilizer 38.08%, Received: 10 August 2021 49.93%, and 252.98%; and from fertilizer with FYM 44.83%, 60.57%, and 278.70%; for N, P, and K, −1 Accepted: 28 August 2021 respectively. The STCR approach, with or without FYM, at both the target yields (4.5 Mg ha and −1 Published: 31 August 2021 5.0 Mg ha ) markedly enhanced the grain yield (20.2% to 32.3%) and production efficiency over the GRD. It also exhibited a higher NPK uptake and use efficiency, along with better profitability, Publisher’s Note: MDPI stays neutral than the GRD. Therefore, the STCR-targeted yield approach could improve the yield, economics, and with regard to jurisdictional claims in efficiency of nutrient use for direct seeded rice. published maps and institutional affil- iations. Keywords: direct seeded rice; soil test crop response; nutrient use efficiency; grain yield; net return Copyright: © 2021 by the authors. 1. Introduction Licensee MDPI, Basel, Switzerland. Rice (Oryza sativa L.) is mostly grown using the transplanting establishment method, This article is an open access article which requires more time, water, and labor for nursery preparation. The profit margins distributed under the terms and of transplanted rice (TPR) have been reduced continuously due to the higher water input conditions of the Creative Commons and labor intensive transplanting, as well as higher labor costs [1]. The water and labor Attribution (CC BY) license (https:// demand may be reduced by growing direct-seeded rice (DSR) instead of TPR [2]. There creativecommons.org/licenses/by/ has been a shift towards DSR in South East Asia during recent times [3]. In India, DSR 4.0/). Agronomy 2021, 11, 1756. https://doi.org/10.3390/agronomy11091756 https://www.mdpi.com/journal/agronomy Agronomy 2021, 11, 1756 2 of 17 produces about 2 to 12 per cent higher GY than TPR [4]. Direct seeding helps in reducing the water consumption by up to 30 per cent, as it does not require seedling raising in a nursery, puddling operations in the main field, transplanting, or maintaining 4 to 5 cm of water in the main field after transplanting. Furthermore, DSR matures about 8 to 10 days earlier than transplanted rice. According to the conventional estimate, food grain demand will be 355 Mt by 2030 in India; while on the other hand, the response ratio (RR) and factor productivity of crops are continuously declining every year, due to the applied fertilizer in intensive cultivation [5]. The use efficiencies of nitrogen, phosphorus, and potassium are 30–50%, 15–20%, and 60–70%, respectively [5], which is certainly low and increases the cost of cultivation. During the past few decades, the use of fertilizers for enhancing food production has increased many fold, and which, if it exceeds the crop requirements, often causes environmental pollution. The imbalanced use of inorganic fertilizers in India has resulted in a net negative balance of nutrients of about 8 to 10 MT y−1 [6], and by 2025, the extent of this negative balance may rise up to 15 MT y−1. Resource-poor farmers of the nation used to follow an imbalanced fertilization, which disturbs the nutrient availability, leading to a decrease in soil productivity in the long run [7]. Apart from this, increasing fertilizer prices and their availability is one of the main hurdles to balanced fertilization. Excessive chemical fertilizer application has aggravated the deficiencies of secondary and micro-nutrients in different soils. Furthermore, inadequate nutrition of crops worsens the situation, in terms of declined soil fertility. Organic manures (OM) are a valuable source of nutrients, but their sole application is not sufficient to meet the nutrient requirements of high yielding varieties and often results in poor crop yields [8]. Furthermore, using the generally recommended dose (GRD) of fertilizer is not able to maintain yields vis-à-vis the economic returns of crops, due to fatigue in soil health, and this requires refinement for balanced crop nutrition [7]. Therefore, the sole use of neither OM nor chemical fertilizer can enhance the sustainability of an intensive production system [9]. The use of an appropriate combination of OM and chemical fertilizers [10], depending on soil fertility status [11], is a step forward for providing balanced fertilization to crops. Such integrated nutrient management (INM) can increase the income of farmers [12]. The continuous application of the GRD of fertilizer along with FYM enhances rice grain yields and their sustainability [7,13,14]. Harnessing the potential yields of high yielding varieties of crops requires the applica- tion of optimum doses of nutrients [15]. However, an inadequate and imbalanced fertilizer use for crop production, without proper knowledge of the inherent soil capabilities and crop requirements, is also one of the causes that prevent gaining the full yield potential of crops and the deterioration of soil health, as well as economic losses to farmers [8,16], and often resulting in an adverse impact on crops and the soil, in terms of nutrient tox- icity and deficiency [8]. Furthermore, fertilizer use requires knowledge of the expected GY response, which depends upon the crop nutrient requirements, nutrient supply from indigenous sources, and the fate of fertilizers applied to the soil in the short and long term [17]. Therefore, a comprehensive approach, considering soil tests, field research, and profitability, could be employed for fertilizer use. Thus, the soil test crop response (STCR) methodology can be adopted for calculating nitrogen (N), phosphorus (P), and potassium (K) requirements as needed. NPK requirements are linearly correlated with the target yield (TY), depending on the soil test values (STVs). In the STCR approach, the fertilizer doses are prescribed according to the developed fertilizer adjustment equations, after the establishment of a significant relationship between STVs, the added fertilizer nutrients, and the crop response [8] for a particular soil type. Thus, precise fertilizer recommendations can be made using this approach, as it involves data of soil and plant analysis [8]. A higher response ratio is also observed along with a higher benefit–cost ratio as the nutrient applica- tion is based on demand and the correction of soil nutrient imbalances [18]. There is a need to develop a balanced nutrient management strategy, involving the STCR methodology for the sole use of chemical fertilizers and the integrated use of chemical fertilizers and Agronomy 2021, 11, x FOR PEER REVIEW 3 of 18 odology for the sole use of chemical fertilizers and the integrated use of chemical fertiliz- ers and FYM for DSR. Hence, the present study was carried out to (i) develop fertilizer equations for chemical mode and integrated mode using the STCR methodology; (ii) val- idate these equations for achieving target yields; and (iii) assess the performance of STCR treatments with the various prevailing nutrient management strategies, in terms of grain Agronomy 2021, 11, 1756 and straw yield, economics, nutrient uptake, and use efficiency. 3 of 17 2. Material and Methods 2.1.FYM Experimental for DSR. Hence, Site the present study was carried out to (i) develop fertilizer equations for chemicalThe study mode area and falls integrated in the Tarai mode region using, with the STCR a sub methodology;-tropical-humid (ii) climate.