Film mulching combined with chemical fertilizer increased rice yield by promoting the accumulation of photosynthetic substances in the vegetative growth stage – Nature

Executive Summary

This report details a study on optimizing rice cultivation in Northeast China to enhance food security, a primary objective of Sustainable Development Goal 2 (SDG 2: Zero Hunger). The research investigated the combined effects of plastic film mulching and different fertilization strategies on rice growth, dry matter accumulation, and yield. Four cultivation modes were assessed: bare land with organic fertilizer (NMF0), plastic-mulched land with organic fertilizer (MF0), bare land with chemical fertilizer (NMF1), and plastic-mulched land with chemical fertilizer (MF1). The findings indicate that the combination of plastic film mulching with chemical fertilizer (MF1) demonstrated the most significant yield-increasing effect, with an increase of 2.98% to 30.62% compared to other treatments. This method promotes the accumulation of photosynthetic substances during the vegetative growth stage, providing a viable pathway for achieving green and efficient rice production. These findings offer a theoretical basis for developing agricultural practices that support sustainable food production systems, contributing to SDG 12 (Responsible Consumption and Production) and SDG 13 (Climate Action) by mitigating the impacts of adverse weather conditions.

Introduction: Aligning Rice Cultivation with Sustainable Development Goals

Context: Food Security and Climate Challenges (SDG 2 & SDG 13)

Rice is a cornerstone of global food security, and its stable production is essential for achieving SDG 2 (Zero Hunger). In Northeast China, a critical rice-producing region, cultivation is frequently hampered by low-temperature cold damage, a significant climate-related challenge that threatens yield stability. Addressing this issue through adaptive agricultural practices is crucial for climate action (SDG 13) and ensuring a resilient food supply. This study explores cultivation measures to counteract these environmental stressors and bolster rice production.

Investigated Interventions for Sustainable Production (SDG 12 & SDG 15)

To enhance agricultural sustainability, this research evaluates two key interventions: plastic film mulching and rational fertilization.

• Plastic Film Mulching: This technique increases soil temperature and moisture, mitigating cold damage and promoting crop growth. The use of biodegradable mulching films is noted as a critical advancement for preventing plastic pollution, aligning with SDG 12 (Responsible Consumption and Production) and protecting terrestrial ecosystems (SDG 15: Life on Land).
• Fertilization Strategies: The study compares chemical and organic fertilizers. Chemical fertilizers provide rapid nutrient supply to boost yields (addressing SDG 2), while organic fertilizers improve long-term soil health, enhance fertility, and support soil biodiversity, which are central to SDG 15.

Research Objectives

The primary objective was to investigate the synergistic effects of plastic film mulching and different fertilizer types on rice yield formation. The study hypothesized that:

1. Plastic film mulching would accelerate early-stage rice growth.
2. Organic fertilizer application would sustain photosynthesis during later growth stages.
3. A combination of these practices could coordinate plant growth throughout the cycle, leading to increased yields and contributing to a more sustainable and productive agricultural system.

Methodology for Sustainable Agricultural Assessment

Experimental Design

A field experiment was conducted using two japonica rice varieties, ‘Jinongda 738’ and ‘Jijing 525’. Four distinct cultivation treatments were established to evaluate their impact on sustainable production:

• NMF0: Bare land with organic fertilizer application.
• MF0: Plastic-mulched land with organic fertilizer application.
• NMF1: Bare land with chemical fertilizer application.
• MF1: Plastic-mulched land with chemical fertilizer application.

The experiment utilized a fully biodegradable black agricultural plastic film, promoting responsible production practices (SDG 12).

Site and Materials

The experiment was conducted in Jilin Province, China, on black calcium soil. The site is characterized by an average annual temperature of 4.7 ℃ and annual rainfall of 557 mm. The selection of local rice varieties ensures the relevance of the findings to regional food security efforts.

Fertilization and Cultivation Practices

All plots received equivalent total amounts of Nitrogen (N), Phosphorus (P2O5), and Potassium (K2O). The chemical fertilizer treatment used urea, calcium superphosphate, and potassium sulphate. The organic fertilizer treatment used a high-nitrogen activated organic fertilizer, with nutrient shortfalls supplemented by chemical sources. This design allows for a direct comparison of nutrient delivery mechanisms on crop performance and soil management.

Data Collection and Analysis

To assess the effectiveness of each cultivation mode, the following parameters were measured throughout the growth cycle:

• Agronomic Traits: Tiller number and plant height.
• Physiological Indicators: Leaf age, relative chlorophyll content (SPAD value), and net photosynthetic rate.
• Biomass and Nutrient Translocation: Dry matter weight and translocation rates.
• Productivity Metrics: Final grain yield and harvest index.

Data were analyzed using SPSS, with the Duncan multiple comparison method used to determine statistical significance (p

Results: Evaluating Cultivation Modes for Enhanced Sustainability and Productivity

Impact on Agronomic Traits and Plant Growth

Plastic film mulching significantly improved the agronomic traits of rice, providing a stronger foundation for achieving SDG 2. Compared to bare land treatments, mulching accelerated the leaf aging process and increased both the tiller number and plant height. Under both mulched and non-mulched conditions, chemical fertilizer (F1) treatments consistently resulted in greater plant height and faster early-stage growth compared to organic fertilizer (F0) treatments.

Influence on Photosynthetic Performance

The photosynthetic capacity, a key driver of biomass and yield, was heavily influenced by the treatments.

• From the tillering to the heading stage, chemical fertilizer application (F1) under mulching conditions increased the SPAD values and net photosynthetic rate, promoting early-stage material accumulation.
• From the grain filling to the maturity stage, organic fertilizer application (F0) was more effective at slowing the decline of photosynthesis, supporting late-stage grain development and contributing to more resilient production systems (SDG 12).

Dry Matter Accumulation and Translocation

The MF1 treatment (mulching with chemical fertilizer) was superior in promoting the accumulation and translocation of dry matter. This combination significantly increased the dry matter of leaves, stem sheaths, and spikes at both the heading and maturity stages. It also enhanced the amount of matter assimilated after heading, which is crucial for grain filling and final yield.

Final Yield and Harvest Index: A Key Metric for SDG 2

The ultimate measure of success in contributing to food security is crop yield. The results demonstrated clear benefits from the combined interventions:

1. Compared to bare land, film mulching increased rice yield by 1.39% to 7.40%.
2. Compared to organic fertilizer, chemical fertilizer increased yield by 21.62% to 26.44%.
3. The MF1 treatment (mulching with chemical fertilizer) delivered the highest yield, outperforming other treatments by 2.98% to 30.62%. This highlights a powerful synergy for maximizing productivity.

Discussion: Implications for Sustainable Food Production Systems

Plastic Film Mulching as a Climate Adaptation Strategy (SDG 13)

The study confirms that plastic film mulching is an effective climate adaptation tool. By increasing soil temperature and conserving moisture, it creates a more favorable microenvironment for rice growth, mitigating the yield-limiting effects of low temperatures. This practice enhances agricultural resilience, a key component of SDG 13, by allowing for more stable production in challenging climates.

Balancing Productivity and Sustainability in Fertilization (SDG 2, SDG 12, SDG 15)

The differing effects of chemical and organic fertilizers present a classic challenge in sustainable agriculture: balancing immediate productivity with long-term environmental health.

• Chemical Fertilizers: Their rapid nutrient release fueled early growth and maximized dry matter accumulation, leading to the highest yields and directly supporting the food security targets of SDG 2.
• Organic Fertilizers: Their slow-release nature sustained photosynthetic activity later in the season and contributed to a higher percentage of effective tillers. This approach supports long-term soil health (SDG 15) and promotes a more circular, responsible production system (SDG 12).

The superior yield of the MF1 treatment suggests that for maximizing short-term food production, chemical fertilizers are highly effective, especially when combined with mulching. However, for holistic sustainability, future research should explore integrated nutrient management that combines both fertilizer types to harness the benefits of each.

Conclusion: Advancing Towards Green and Efficient Rice Production

This research demonstrates that combining plastic film mulching with chemical fertilizer (MF1) is a highly effective strategy for increasing rice yield in the cold climate of Northeast China. This approach directly contributes to SDG 2 (Zero Hunger) by boosting food production. Plastic mulching serves as a valuable climate adaptation technique (SDG 13), while the choice of fertilizer impacts both productivity and long-term sustainability.

The application of chemical fertilizer was most beneficial for photosynthesis and dry matter accumulation in the early growth stages, leading to a yield increase of up to 30.62% in the MF1 treatment. While organic fertilizer showed benefits for late-stage plant health, its overall yield was lower. Therefore, the MF1 cultivation mode is recommended as a superior method for achieving green and efficient rice production under the experimental conditions. To further advance sustainable agriculture, future studies should focus on optimizing the combined use of organic and chemical fertilizers to secure high yields while simultaneously enhancing soil health and ecosystem resilience, fully aligning with the interconnected goals of SDG 12 and SDG 15.

Analysis of Sustainable Development Goals (SDGs) in the Article

1. Which SDGs are addressed or connected to the issues highlighted in the article?

1. SDG 2: Zero Hunger

   The article’s primary focus is on increasing rice yield, which is fundamental to ensuring food security. It directly addresses the challenge of producing more food to support the population. The introduction states, “Rice is one of the primary crops produced and consumed in China, with its yield having a direct impact on the country’s food security and social stability.” The research explores agricultural techniques like plastic film mulching and different fertilization practices specifically to boost crop production, which aligns with the core mission of SDG 2.

2. SDG 12: Responsible Consumption and Production

   This goal is relevant through the article’s discussion of agricultural inputs and their environmental consequences. The text highlights the “serious problem of plastic pollution in farmland” from traditional plastic mulching films and mentions the shift towards “biodegradable mulching film” as a more sustainable alternative. This reflects a move towards more responsible production patterns that minimize waste and pollution. Furthermore, the comparison between chemical and organic fertilizers touches upon the sustainable management of resources and chemicals in agriculture.

3. SDG 15: Life on Land

   The article connects to SDG 15 by examining practices that affect soil health and quality. It notes that “rational fertilization practices contribute to improved soil quality” and that organic fertilizers can “increase the content of soil organic matter, enhance soil fertility, [and] ameliorate soil physical and chemical properties.” Protecting and restoring terrestrial ecosystems, including agricultural land and soil, is a key component of this goal. The issue of plastic pollution from non-biodegradable films also represents a threat to land quality, which the study implicitly addresses by using a biodegradable alternative.

2. What specific targets under those SDGs can be identified based on the article’s content?

• SDG 2: Zero Hunger

  • Target 2.3: By 2030, double the agricultural productivity and incomes of small-scale food producers. The entire study is designed to find the most effective method for increasing rice yield, a direct measure of agricultural productivity. The conclusion that “MF1 had the best yield-increasing effect, with an increase of 2.98% to 30.62% compared to other treatments” directly supports this target.
  • Target 2.4: By 2030, ensure sustainable food production systems and implement resilient agricultural practices that increase productivity and production, that help maintain ecosystems, that strengthen capacity for adaptation to climate change… and that progressively improve land and soil quality. The research evaluates different cultivation modes, including the use of organic fertilizers and biodegradable films, to find a “green and efficient rice production” method. The mention of improving soil quality and mitigating the effects of “low-temperature cold damage” points towards creating resilient and sustainable agricultural systems.

• SDG 12: Responsible Consumption and Production

  • Target 12.2: By 2030, achieve the sustainable management and efficient use of natural resources. The study’s comparison of organic and chemical fertilizers is an investigation into the efficient use of nutrient resources for crop production while considering long-term effects on soil quality.
  • Target 12.4: By 2020, achieve the environmentally sound management of chemicals and all wastes throughout their life cycle… and significantly reduce their release to air, water and soil in order to minimize their adverse impacts on human health and the environment. The article explicitly addresses this target by acknowledging the “serious problem of plastic pollution in farmland” from traditional PE plastic and testing a “fully biodegradable black agricultural plastic film” as a solution to reduce persistent waste.

• SDG 15: Life on Land

  • Target 15.3: By 2030, combat desertification, restore degraded land and soil… The article discusses how organic fertilizers can “increase the content of soil organic matter, enhance soil fertility, [and] ameliorate soil physical and chemical properties,” which are practices aimed at improving or restoring soil quality and preventing land degradation.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

Yes, the article mentions and implies several indicators that can be used to measure progress:

• Crop Yield (kg/ha)

  This is the most direct indicator mentioned. The article quantifies the increase in rice yield under different treatments, such as: “the film mulching treatment increased the yield by 2.98% to 3.30% and 1.39% to 7.40% respectively.” This directly measures progress towards Target 2.3 (agricultural productivity).

• Soil Quality Parameters

  The article implies the importance of soil quality indicators. In the “Test site” section, it provides baseline measurements for “organic matter content,” “total nitrogen content,” “total phosphorus content,” etc. The discussion highlights that organic fertilizers can “increase the content of soil organic matter,” suggesting that changes in these parameters are key metrics for assessing the sustainability of agricultural practices, relevant to Target 2.4 and Target 15.3.

• Reduction of Plastic Waste

  The article implies an indicator related to waste reduction. By contrasting “traditional PE plastic mulching film” which causes “serious problem[s] of plastic pollution” with the “fully biodegradable black agricultural plastic film” used in the experiment, it points to the adoption of biodegradable materials as a measure of progress in managing waste. This is a qualitative indicator for Target 12.4.

• Photosynthetic Rate and Dry Matter Accumulation

  The study measures the “net photosynthetic rate (Pn)” and “dry matter accumulation.” While not official SDG indicators, these are scientific metrics that serve as proxies for agricultural productivity and efficiency. The article links these measurements directly to yield, stating that improved photosynthesis is “beneficial for the accumulation and transportation of dry matter” and ultimately leads to higher yields, thus providing a scientific basis for tracking progress on Target 2.3.

4. Summary Table of SDGs, Targets, and Indicators

Source: nature.com